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  • Yihui DING, Yanju LIU, Ying XU, Ping WU, Tong XUE, Jing WANG, Ying SHI, Yingxian ZHANG, Yafang SONG, Pengling WANG
    Advances in Earth Science. 2023, 38(6): 551-562.

    The Northwest region of China is a major battlefield and an important ecological and environmental security barrier to China’s western development. Flourishing the Belt and Road Initiative, climate change in this region has a direct impact on water resources, ecology, and environmental security. In the context of global climate change, Northwest China has shown an obvious and rapidly developing warming-wetting trend, which has resulted in increasingly prominent environmental and public security risks that are seriously affecting the sustainable development of the regional economy and society. This poses new challenges for climate change responses, water resource management, and disaster prevention and mitigation in this region. Research on the evolution characteristics, causes, and physical mechanisms of warming-wetting as well as its future trends and possible risks were reviewed. It further summarizes the current scientific consensus and existing problems, and finally looks forward to the key directions of future scientific research. A systematic review of the trend, causes, and future projection of climate warming-wetting in Northwest China will have important scientific implications for further research on this issue.

  • Jun SHI, Linli CUI, Yudan GU, Ping TANG
    Advances in Earth Science. 2023, 38(8): 771-779.

    Climate extremes threaten human health, economic stability, and the safety of both natural and built environments. Compound extreme events are combinations of multiple climate drivers and/or hazards that contribute to societal or environmental risks, and their impacts on human society and natural ecosystems are often more serious and destructive than those of a single extreme event. Understanding the changes in compound extreme events is important for adaptation, mitigation strategies, and disaster risk management. Here, the definitions and connotations of compound extreme events are briefly discussed, including preconditioned, multivariate, temporal, and spatial compounding events. Subsequently, the progress in compound extreme event research is discussed in terms of temporal and spatial evolution characteristics, influencing factors, and future scenario projections. Given the problems in current research, we suggest that future studies should focus on studying compound extreme events regarding variable/index selection and threshold determination, dependence and interaction analysis among drivers and/or hazards, simulation performance evaluation and future projections, and their dynamic processes and disaster-causing mechanisms. Compound extreme events are expected to increase in frequency and intensity in a warming world, and many regions are projected to experience an increase in the probability of compound events with greater global warming. Therefore, we must improve our understanding of the causes and drivers of compound and cascade events.

  • Xiang ZHANG, Shuzhe HUANG, Yuhang GUAN
    Advances in Earth Science. 2023, 38(6): 563-579.

    Droughts spread through interrelated land-atmosphere systems and hydrological processes, and evolve into different types of droughts, such as hydrological, agricultural, ecological, and socioeconomic droughts, in different geographical and temporal contexts. Against the backdrop of global climate change and intensified human activities, the propagation and evolution of different types of drought present more uncertainties. Over the past decade, our understanding of the spatiotemporal characteristics, research methods, evolutionary processes, and driving factors of drought propagation has gradually deepened, but clear scientific views have not been realized. Beginning from the definition of drought propagation, this study systematically analyzed the scientific connotation of the problem and clarified the developmental stages of drought propagation research. Six quantitative research methods for current drought propagation were comprehensively summarized: threshold method and run theory, correlation analysis, causal analysis, cross-wavelet analysis, probability models, and meteorological-hydrological models. Furthermore, from the perspective of meteorological-hydrological and meteorological-agricultural drought propagation scenarios and drought propagation driving forces, the main acquired scientific knowledge was analyzed and summarized. The findings reveal the propagation order, stage threshold, spatiotemporal heterogeneity, and human-driven processes of drought propagation research worldwide. Finally, a series of challenges that future drought propagation research will face were analyzed. These include further exploration of spatiotemporal heterogeneity in the propagation process, bridging the gap between mathematical and physical knowledge to establish trustworthy models, and integrating cross-disciplinary knowledge to achieve a full-process analysis of propagation. The systematical analysis of the progress and challenges of domestic and international drought propagation research will provide key theoretical and methodological support for the next steps in drought disaster analysis and scientific management.

  • Yansong HAN, Wei JIANG, Yuwen XIAO, Yangyang YONG, Kefu YU
    Advances in Earth Science. 2023, 38(5): 515-532.

    Tropical Cyclones (TCs) are meteorological phenomena that affect middle and low latitudes worldwide. This paper systematically summarizes and reviews the research progress on the main characteristics, potential influencing factors, and influencing mechanisms of TCs at home and abroad, and summarizes and analyzes their changing trends under the climate background of GW. With the significant increase in global temperature, the sources and tracks of global TCs have shifted poleward, with a slight increase in translation speed, decrease in frequency, and increase in intensity; however, there are significant differences in each ocean. This paper focuses on reviewing the effects of volcanic activity, El Ni?o-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), solar radiation, Intertropical Convergence Zone (ITCZ), and aerosols on TC activity. Volcanic eruptions release a large amount of aerosols in the stratosphere, thereby reducing sea surface temperature and negatively affecting TCs. However, there are regional variations in this mechanism. ENSO and PDO modulate the global TC activity through teleconnections, while changes in solar activity and ITCZ are also associated with TC activity. Aerosols have opposite influence mechanisms on TCs at different development stages. Due to the lack of time length and the coarse resolution of most surrogate indicators of instrumental TC data, research on the impact of potential influencing factors on TCs under long-term climate fluctuations is severely restricted. In the future, we should be able to quantify the history of storm activities by finding high-resolution record carriers, thereby further analyzing the relationships between TCs and potential influencing factors, and improving our understanding of the change mechanism in TC activity under the influence of climate fluctuations.

  • Li WANG, Xiaoyue LIU, Jianping HUANG
    Advances in Earth Science. 2023, 38(7): 715-728.

    Human activities have changed the air oxygen content in urban areas and threatened the regional atmospheric oxygen balance. However, studies on urban atmospheric oxygen (O2) remain limited, and a systematic assessment of the mechanisms that drive urban O2 variability is not yet possible. Therefore, the long-term observation of atmospheric O2 in urban areas is of utmost importance. This study provides an in-depth overview of the Lanzhou online atmospheric oxygen observation platform, which is the first in situ, high-precision, continuous atmospheric O2 observation platform in China. The platform uses a gas chromatography-thermal conductivity detector (GC-TCD) method to measure the atmospheric O2 content and establishes an XGBoost-based correction model for atmospheric O2 observation data. After correction, the observation system error of atmospheric O2 has significantly reduced to -0.68 μmol/mol. The observation results showed that atmospheric O2 has clear seasonal and daily variation characteristics and good correspondence with urban human activity indicators (NOx). Based on the capabilities of the atmospheric oxygen observation platform demonstrated in this study, the platform can detect microvariations in atmospheric O2 against a high background, providing crucial data to support research into urban atmospheric O2 levels. Due to the close relationship between carbon and oxygen cycles, the long-term observation of atmospheric O2 can be a scientific basis for establishing regionally appropriate “double carbon” practical paths.

  • Ziqi NONG, Pengyu HUANG, Hanlie XU, Xiuqing HU, Min MIN
    Advances in Earth Science. 2023, 38(5): 533-550.

    With the development of spaceborne low-light imagers, extremely low-magnitude nocturnal visible radiance can accurately be detected. After accurate radiometric calibration, quantitative applications of satellite-based low-light imager observation data attract particularly increased scientific interest. This investigation systematically summarizes the advances in applications and research of satellite-based low-light imager data in the atmospheric, marine, and environmental sciences at night. First, the development history of satellite-based low-light imager payload is briefly introduced. Subsequently, the typical applications of low-light imager data in the atmospheric, marine, and environmental fields and the corresponding new scientific discoveries are summarized. Finally, considering new scientific objectives, advanced design concepts and application prospects for future satellite-based low-light imagers are proposed and discussed.

  • Jiangfeng WEI, Yuanyuan SONG, Boyan LU
    Advances in Earth Science. 2023, 38(9): 881-889.

    The Diurnal Cycle of Precipitation (DCP) is the result of various dynamic and thermodynamic processes in the climate system and is closely related to the water cycle and land-atmosphere interactions. In North China, the DCP is influenced by factors such as valley wind circulation, boundary layer inertial oscillations, and sea-land breeze circulation, exhibiting two peaks during the early morning and afternoon. In addition, the DCP in North China is influenced by anthropogenic aerosol emissions. This study introduces the fundamental characteristics and factors influencing the DCP in North China and summarizes recent research on the connection between the DCP and land-atmosphere coupling in North China, the modeling of the DCP, and the influence of aerosols on the DCP. The existing scientific knowledge is synthesized, and its shortcomings and challenges are outlined. Overall, investigating the DCP and its influencing factors can help us better understand the mechanisms of precipitation formation and evolution. This provides scientific support for enhancing the accuracy of fine-scale precipitation forecasting.

  • Xiaokang SHI, Yanbing HU, Panfeng WANG, Wenjun ZHANG, Bo LIU
    Advances in Earth Science. 2023, 38(9): 916-930.

    At around 20 km height in the atmosphere, a natural phenomenon occurs, in which the lower westerly (easterly) zonal wind changes into the upper easterly (westerly) zonal wind during a specific season, while the meridional wind is very small. This transition layer of the zonal wind is called stratospheric Quasi-Zero Wind Layer (QZWL). The low speed and direction transition of the wind in the QZWL are beneficial for stratospheric airships, high-altitude balloons, and other weakly powered or unpowered near-space vehicles, allowing them to stay there for longer periods. The characteristics of the QZWL with time in the northern hemisphere, the entire China, and key regions in China were summarized based on the QZWL results. The influence mechanisms and characteristics of the thermal wind, stratospheric Quasi-Biennial Oscillation (QBO), Stratospheric Sudden Warming (SSW), eddy flux transport of planetary wave, South Asia high and subtropical westerly jet on the QZWL formation were systematically analyzed. The advantages and disadvantages of MST radar, laser radar, sounding rocket and upper-air balloon in QZWL detection and some relevant facts were compared and analyzed. The advantages and disadvantages of middle atmosphere modeling and numerical weather modeling regarding QZWL forecasting were summarized. Numerical weather modeling is currently the main method for QZWL forecasting and meteorological support, and diagnostic schemes, such as the bottom height and thickness of the QZWL, are the basis for the quantitative study of the refined structure and evolution of the QZWL. The working principle of stratospheric vehicles using the QZWL is summarized. Finally, prospects regarding the key directions of future scientific research are presented. This review of the research progress on the QZWL will provide the basis for the future in-depth study of the QZWL and the deployment and meteorological support of stratospheric vehicles.

  • Nan YAO, Yaoming MA
    Advances in Earth Science. 2023, 38(6): 580-593.

    The Tibetan Plateau (TP), Iranian Plateau (IP), and Mongolian Plateau (MP) belong to Asian high-altitude regions. Thermal forcing over the three plateaus is important in contemporaneous and subsequent weather and climate in China. Examination of the spatial and temporal variation characteristics of surface sensible heat over the three plateaus revealed remarkable interannual and interdecadal changes attributable to global warming that occurred from the end of the 20th century to the beginning of the 21st century. Their relationships and possible mechanisms are discussed. A summary of the research progress on the impact of surface thermal conditions over the three plateaus on the weather and climate of China during spring and summer revealed three findings. First, over the TP, sensible heating has a significant impact on the formation, development, and eastward movement of the TP vortex, which induces rainstorms in the eastern part of China with an appropriate circulation background. Second, the Tibetan-Iranian Plateau (TIP) “sensible heat driven air-pump” favors the development of upward flow over the Asian monsoon region. The combined contribution of TIP thermal condition is greater than their linear superposition to the summer precipitation in southern China. Third, the warmer and drier conditions in northern China are closely related to the compensatory downdraft induced by thermal forcing over the TP, IP, and MP. In addition, the abnormal surface heating of the three plateaus triggers abnormalities in local circulation and regulates the weather and climate over northern China through teleconnection patterns. The paper concludes with a discussion of future research considerations and challenges regarding the synergism of the TP, IP, and MP.

  • Na YUAN, Lingling Deng, Xia YIN, Shanhai SONG, Suihua LIU
    Advances in Earth Science. 2023, 38(11): 1145-1157.

    Guizhou Province, characterized by unique topography and complex climatic conditions, offers an excellent opportunity to study spectral surface albedo (short-wave, near-infrared, and visible light). Analyzing this refines surface parameters and understands the characteristics of solar spectral radiation but also provides scientific references to explore the physical processes of the relevant spectral radiation, variables in the process of energy conversion of the earth-air system in mountainous areas at low latitudes. Therefore, based on MCD43A3 albedo data, MCD15A2H Leaf Area Index (LAI), temperature, precipitation, land use, and soil moisture data, using anomalous variance analysis, Theil-Sen (T-S) and Mann-Kendall (M-K) trend analyses, and geophones, we analyzed the spatial and temporal trends and driving factors of spectral surface albedo in Guizhou Province. The results show that interannual changes in spectral surface albedo were in the order of size: near-infrared>short-wave>visible. In addition to visible surface albedo being on the rise (the three bands of surface albedo high-value area were basically the same), there was a line from the northeast to the southwest, and the western distribution of the characteristics of the County of Weining; considering seasonal changes, the size order of short-wave and near-infrared surface albedo was the same, as follows: summer>autumn>spring>winter and that of visible surface albedo was spring>winter. The sizes of short-wave and short-wave albedo were the same, as follows: summer> autumn>spring>winter, and that of visible surface albedo was: spring>winter>autumn>summer; the driving factors of spectral surface albedo were LAI, followed by land use. The results of this study reveal spatial and temporal variations and driving mechanisms of the spectral surface albedo in Guizhou, which can provide a reference for the ecological protection of mountainous areas in Guizhou.

  • Yujiu XIONG, Xu WANG, Chenbin WU
    Advances in Earth Science. 2023, 38(11): 1097-1106.

    Evapotranspiration (ET) encompasses water loss through transpiration and evaporation from soil and water surfaces. Accurate observation of ET is essential for comprehending the ET process, and mechanism, as well as water-energy nexus and land-atmosphere feedback. ET serves as a pivotal link between the hydrological cycle and energy processes. In-situ measurements provide fundamental datasets for validating remotely sensed ET products. The surface renewal theory differs from the commonly used eddy covariance method in describing the physical ET process. Unlike the expensive sonic anemometers in the eddy covariance system, the surface renewal method is cost-effective because it uses a fine- diameter thermocouple to record high-frequency air temperature and estimate the sensible heat flux through coherent structures. The surface renewal method for measuring ET, with an accuracy comparable to that of the eddy covariance system, and it has been widely applied for ET measurements in America and Europe. Recognizing the substantial potential of this method, this paper reviews the theory of surface renewal and research advancements in the method made over the past 30 years. Additionally, preliminary studies related to ET measurements in China using the surface renewal method are also presented. By summarizing this progress and exploring the challenges in the application of the surface renewal method, we can enhance our understanding and promote a variety of domestic ET observation methods.

  • Weidong YANG, Lianbo ZENG, Xiang LI
    Advances in Earth Science. 2023, 38(2): 151-167.

    Carbon neutrality has become a topic of global consensus. To achieve carbon neutrality, it is also important to enhance carbon sequestration and sink capabilities, apart from the development of new energy to minimize carbon emissions. Carbon sinks can be divided into marine and terrestrial types. The marine carbon sink is mainly composed of three parts: the coastal ecological carbon sink mainly formed by the carbon sequestration effect of coastal vegetation and coastal sediment load, and the marine ecological carbon sink mainly formed by dissolution and microbial pumps in the ocean. Both are directly related to monsoon oceanic current conditions, terrestrial organic inputs, coastal geographical conditions, and human activity. The feasibility of an artificial oceanic carbon sink depends on its impact on marine ecology. In terrestrial carbon sinks, vegetation carbon sinks are formed by organic carbon generated by the photosynthesis of terrestrial plants, including forest, grassland, and wetland vegetation. The influencing factors include temperature and precipitation, atmospheric composition, land use and its changes, and natural disturbance effects. Natural geological carbon sinks mostly consist of soil and karst carbon sinks. Soil carbon sinks are affected by regional vegetation, climatic conditions, soil utilization, and other factors. Karst carbon sinks are mainly produced by weathering between carbonate and silicate rocks absorbing atmospheric CO2, which is affected by temperature, precipitation, rock type, hydrological conditions, and human activity. An artificial geological carbon sink was formed because the captured CO2 was injected into the designated area underground for storage. The storage capacity depends on the evaluation of geological characteristics, reservoir conditions, oil distribution, and production. For the future, it is necessary to act decisively in climatic, natural resources, the social economy, and other aspects to fix carbon, enhance carbon sequestration, and achieve carbon neutrality.

  • Weibin GAO, Yang CHEN, Haoxian WANG
    Advances in Earth Science. 2023, 38(2): 137-150.

    Since the industrial revolution, human activities have emitted large amounts of CO2 into the atmosphere, causing a rapid increase in global surface temperatures. To cope with global warming, it is necessary to apply negative-emission technologies on a large scale. Enhanced silicate Rock Weathering (ERW) is a form of negative-emission technology based on geochemical principles that accelerates the chemical weathering process of silicate rock by adding silicate rock powder to farmland or forests to stabilize atmospheric CO2 over a short time period. China has abundant and widely-distributed basalt reserves and a large amount of unused mine tailings and alkaline silicate wastes. Therefore, there is great potential for the removal of atmospheric CO2 through ERW. The calculation results show that China can remove 0.13~0.80 Gt CO2 through ERW annually, which is conducive to the realization of the “carbon neutrality” goal. However, ERW still faces many problems. Combining the progress of domestic and international research, the main application effects and influencing factors of ERW are summarized, the potential of ERW application in China is analyzed, and the main issues facing ERW application in China are discussed from five aspects: technology, economy, safety, society, and policy. In view of the focus and shortcomings of the current research, the calculation of ERW carbon sequestration, potential hazards of application, and other key concerns and challenges are presented.

  • Chunlin HUANG, Jinliang HOU, Weide LI, Juan GU, Ying ZHANG, Weixiao HAN, Weizhen WANG, Xiaohu WEN, Gaofeng ZHU
    Advances in Earth Science. 2023, 38(5): 441-452.

    Data-driven methods with deep learning as their core have been gradually applied in Earth science; however, challenges remain regarding the interpretability of models and physical consistency. With the background of remote sensing big data, combining deep learning and data assimilation methods to develop new techniques for the simulation and prediction of terrestrial water cycle processes has become an important research direction in Earth science. Τhe progress in deep learning in recent years combines improving the quality of observation data of terrestrial water cycle components and reducing the uncertainty of physical models. Furthermore, the key scientific issues regarding data assimilation in terrestrial hydrology based on deep learning fusing remote sensing big data are classified according to the observations, physical models, and system integration: How can the temporal and spatial representativeness of samples be enhanced when deep learning inverts remote sensing products? How can a new physics-guided deep learning method be developed within the framework of data assimilation? How can the predictability of the terrestrial water cycle be improved through the “data-model” dual drive? Relevant research and exploration should help promote the in-depth application of the “data-model” hybrid modeling method in the field of hydrology and improve the simulation and prediction capacity of the terrestrial water cycle process.

  • Liyang ZHANG
    Advances in Earth Science. 2023, 38(5): 453-469.

    Cherts are widely distributed in Precambrian to Cenozoic orogenic belts and sedimentary basins.The origin and depositional environment of cherts are of great importance in understanding the regional paleogeographic, paleotectonic, paleo-ocean, and paleoclimate evolutions. After summarizing the existing geochemical methods for identifying the origin and depositional environment of cherts, it is concluded that the identification of the origin of cherts should focus on authigenic siliceous minerals and use exotic interfusion materials as references. Effective proxies include Al, Ti, Fe, Th, Ge/Si, Si isotopes, Rare Earth Elements (REE), etc. The essence of the discrimination of the depositional environment of cherts is to distinguish the relative contribution of terrigenous and hydrothermal materials; although previous discrimination diagrams provide practicability, they still involve errors and need to be used carefully. As an important type, cherts outcropped in orogenic belts are closely related to the Ocean Plate Stratigraphy (OPS). Here, a correlation scheme between them has been established. According to this correlation scheme, cherts outcropped in orogenic belts can be divided into the ridge subtype, pelagic abyssal plain subtype Ⅰ, pelagic abyssal plain subtype Ⅱ, ocean island-seamount subtype, intra-oceanic arc subtype, and forearc trench subtype. The cherts-OPS correlation scheme not only provides a basis for reconstructing the original sequence of the accretionary complex in an orogenic belt using cherts, but also considers cherts as important evidence for distinguishing the main oceanic basins from the back-arc and inter-arc oceanic basins. Taking the Eocene cherty ooze obtained by oceanic drilling in the Pacific as an example, it is suggested that the main oceanic basin is characterized by deep-sea plain cherty rocks that are almost unaffected by terrigenous and hydrothermal materials. These cherty rocks have geochemical characteristics such as Fe/Ti values close to 20, Eu/Eu* values close to 1.1 and negative Ce/Ce* values. These results provide new perspectives and references for subsequent research on cherts in orogenic belts.

  • Minggui ZHENG, Ming YU, Qiurong FAN, Yuhua LIN
    Advances in Earth Science. 2023, 38(4): 377-387.

    The inconsistency between the supply and demand of lithium carbonate is becoming increasingly serious. Scientific prediction of the future lithium carbonate demand is of great significance for China’s lithium resource production, import and export arrangements, and national energy policy formulation. Based on a combined model of grey correlation analysis and the ARIMA-GM-BP neural network, data on the driving variables of China’s per capita GDP, industrial structure, urbanization level, grease production, ceramic production, glass production, air conditioning production, lithium-ion battery production, and new energy vehicle production in 2002-2021 were selected to predict China’s lithium carbonate resource demand between 2025 and 2035. The results show that the selected driving variables are highly correlated with China's lithium carbonate resource demand, and the combined model is more accurate than a single model. The predicted average quantity demand for lithium carbonate in 2025, 2030, and 2035 is 0.42 million tons, 0.69 million tons, and 1.03 million tons, respectively. Accordingly, some policy suggestions have been proposed.

  • Qingxiang ZHONG, Yu ZHANG, Zhen TAO, Yicong HE, Di WU, Peisong LIN
    Advances in Earth Science. 2023, 38(1): 44-56.

    Selenium (Se) is an essential micronutrient for many organisms (including soil microorganisms, plants, animals, and humans), and has dual biological effects on plants, animals, and humans. The migration, transformation, and enrichment of Se in soil-plant systems have attracted considerable attention for more than half a century. There are five forms of soil Se: soluble Se (SOL-Se), exchangeable carbonate-bound Se (EXC-Se), iron-manganese oxide-bound Se (FMO-Se), organic matter-bound Se (OM-Se), and residual Se (RES-Se), of which SOL-Se and EXC-Se are characterized by bioavailability. OM-Se can be converted into soluble Se by the decomposition of organic matter and is a potentially effective selenium source in soil. The Se content of different plants depends on the soil-available Se content and the Se absorption and enrichment levels of different plants. Therefore, the bioavailability of soil Se plays a critical role in determining the Se content in the food chain, and soil-available Se can improve plant stress resistance by regulating the rhizosphere environment and metabolic processes. Soil-plant system Se migration is a complex biogeochemical process that is dominated by coupled crustal movement, parent rock properties, climate, geomorphology, soil environment (physico-chemical properties and microbial activity) conditions, soil Se content and chemical properties, plant species and biological habits, and field management processes. For the rational utilization of soil Se resources, research needs to focus on Se migration, transformation, and enrichment in plants, especially the main food crops, vegetables, fruit trees, and Authentic Chinese herbs. This study provides basic data for Se biofortification in Se-deficient areas, and crop selection, food selection, and risk assessment in Se-rich areas.

  • Min ZHENG, Min LUO, Binbin PAN, Duofu CHEN
    Advances in Earth Science. 2023, 38(3): 236-255.

    Benthic O2 uptake is a robust proxy for organic matter mineralization in marine sediments. Therefore, studying sediment oxygen consumption is conducive to understanding the global marine carbon cycle. Three approaches are commonly used to measure oxygen consumption at the SWI: oxygen microprofiling, benthic incubation, and the eddy covariance technique. The emerging eddy covariance technique is a non-invasive approach that can measure benthic O2 flux on a relatively large scale, and thus has wide application. Globally, benthic oxygen consumption is controlled by water depth and primary productivity in surface water. In addition, benthic diffusive oxygen uptake and total oxygen uptake decreased significantly and their ratios approached 1 with increasing water depth. This was mainly caused by the substantial decrease in benthic biomass and resulting benthic oxygen consumption with increasing water depth. Despite more than half a century of observations of benthic oxygen consumption, in-situ data remain scarce, especially in deep-sea and extreme marine environments. A large amount of measured data are still single-point observations within a short time period. Against the background of global warming and the increasing impact of human activities on marine environments and ecosystems, it is necessary to conduct high-precision and long-term in situ observations of benthic oxygen consumption globally.

  • Senwei TONG, Jinyu YANG, Xianhui WAN, Qingqing NIU, Shuh-Ji KAO
    Advances in Earth Science. 2023, 38(7): 688-702.

    Hydroxylamine (NH2OH) is one of the most active trace forms of nitrogen in oceans, and it is the key intermediate product of many nitrogen cycle processes, such as ammonia oxidation, dissimilatory nitrate reduction to ammonium and anaerobic ammonia oxidation. Therefore, it is an important component of the marine nitrogen cycle network framework. Concurrently, NH2OH is an important precursor of the greenhouse gas nitrous oxide (N2O), closely related to the production and release of marine N2O. Accordingly, a systematic understanding of the source and sink, spatiotemporal variations, and regulatory mechanisms of NH2OH in the ocean is essential to understand the oceanic nitrogen cycle and climate effects. However, the nanomolar concentration of NH2OH in the ocean and its complex and active migration and transformation processes render the oceanographic community’s understanding of NH2OH unclear. Current research on marine NH2OH is systematically reviewed, focusing on the potential source and sink processes of NH2OH, the determination methods of NH2OH, the possible contribution of NH2OH to marine N2O, and the distribution characteristics and potential impact factors of NH2OH in the ocean. Finally, the problems and difficulties in determining NH2OH and the possible mechanisms affecting its distribution are summarized, and suggestions and prospects for future research on marine NH2OH are discussed.

  • Xueyun LU, Jianqing JI, Lining WANG, Dalai ZHONG
    Advances in Earth Science. 2023, 38(3): 270-285.

    Climate-tectonic-erosion interactions have recently become a research hotspot in Earth science as a significant aspect of geosphere interactions near the Earth’s surface. Here, studies related to climate-tectonic-erosion interactions over the past 30 years are reviewed mainly from three fields: analytical treatment, numerical modelling, and field verification, and it is suggested that advancement of near-surface geosphere interaction research has been limited by the thought pattern of cause and effect. Orogenic belts are best viewed as evolving open systems driven by energy from endogenous and exogenous forces. An orogenic system with a tendency towards equilibrium will respond to perturbations in endogenous and exogenous forces and also exert impacts on relatively independent endogenous and exogenous factors. Beyond cause and effect, the system-oriented view of orogenic evolution can resolve controversial issues in the study of climate-tectonic-erosion interactions.

  • Qingwei ZENG, Lei LIU, Shuai HU, Xichuan LIU, Taichang GAO
    Advances in Earth Science. 2023, 38(7): 661-674.

    The accurate acquisition of in situ particle detection information in clouds is important in revealing the physical mechanism of cloud precipitation formation, improving the parameterization scheme of numerical weather prediction models, and evaluating the seeding effect of weather modification. Digital holographic measurement technology can obtain three-dimensional positioning information of particles and has advantages, including a wide measurement range (μm to mm), high spatial resolution (mm magnitude), and accurate determination of instrument sampling space. Therefore, it has wide application prospects in cloud microphysics observations. This study summarizes the current situation of holographic cloud particle imagers worldwide. Several key technical issues involved in the development of instruments were analyzed, such as the holographic optical path design, mechanical protection design, and hologram processing. Applications of holographic observations to reveal the freezing mechanism of ice crystals in mixed-phase clouds and microphysical mechanisms in clouds with turbulent mixing were introduced. Finally, certain thoughts and prospects were discussed from the perspective of technology application, which can provide a reference for the development of related instruments and research on cloud microphysics observations.

  • Leiming MA, Hong LIN, Hai CHU, Chunguang YIN, Junping ZHANG, Lei CHEN, Haibin WANG, Kang XU, Xuliang FAN
    Advances in Earth Science. 2023, 38(2): 111-124.

    Severe convective weather systems often cause rainstorms, lightning, gales, hail, and other disasters owing to their small spatial scale and rapid and violent development. Accurate forecasting has always been a difficult and bottleneck problem in the international meteorological field, and it is the focus of disaster prevention and mitigation in Shanghai. This research introduces key technologies developed by the Shanghai Meteorological Department in recent years, such as self-adaptive networking observation of strong convection targets, intelligent identification and prediction of strong convection abrupt structural features, machine learning correction of numerical prediction errors, and system integration. Based on this, an intelligent monitoring and early warning system that can simulate the three-dimensional structure and evolution of a strong convective system is established and applied, which has significantly improved the early warning capability fo severe convection in Shanghai. Relevant technical achievements have provided support for major services such as the China International Import Expo (CIIE) and have been promoted for application in urban disaster prevention and mitigation.

  • Yafei XIA, Yuhui LIU, Ting GAO, Chengshuai LIU
    Advances in Earth Science. 2023, 38(4): 331-348.

    Heavy metal migration and enrichment in areas affected by mining and smelting cause severe soil contamination. A thorough understanding of the sources and migration of heavy metals in the soil is the scientific basis for the efficient treatment of soil pollution. In recent years, metal stable isotopes have shown great advantages in identifying sources of soil heavy metal contamination and analyzing heavy metal migration processes, thus acting as powerful tools to trace the environmental behavior of heavy metals. In this paper, we reviewed the analysis technology, tracing principles, and tracing models of metal stable isotopes, determined the isotope fractionations caused by mineral mining and smelting processes (high-temperature smelting, electrochemical processes, and tailing weathering), and discussed the representative applications of metal stable isotopes in the traceability of soil pollution in mining- and smelting-affected areas. The V isotope system is in the initial stages of investigation, and its applications in heavy metal soil source analysis are relatively lacking. Zn, Cd, and Hg isotopes are advantageous for identifying heavy metal contamination sources associated with high-temperature smelting processes. Cu, Tl, and Ni isotopes can directly indicate the ore content of the soil. However, some problems remain, such as the difficulty in analyzing certain systems of metallic stable isotopes, limitations in the application of tracer models, and source uncertainties due to isotope fractionation. Therefore, in the future, it will be necessary to further explore and optimize metal isotope analysis methods, establish more metal stable isotope fingerprints, develop traceability models with stronger applicability and more accurate results, comprehend the characteristics and mechanisms of isotope fractionation in complex interfacial processes and reactions, and strengthen the practical application of metal stable isotopes to trace the history of soil heavy metal pollution.

  • Qiting ZUO
    Advances in Earth Science. 2023, 38(1): 1-8.

    Water resources are indispensable for human survival and economic and social development. Ensuring sustainable utilization of water resources is important for sustainable economic and social development; therefore, studying the sustainable utilization of water resources and their contribution to water control in China is essential. Based on previous research, this study expounds the background of the sustainable utilization of water resources and the history of foreign and domestic research. Here, the research on sustainable utilization of water resources in China was first divided into three stages: early stage (before 2000), 2000-2010, and after 2010. We then introduced the representative results and research status based on the summary of China's thoughts on water control since 2000, and the contribution of the research on sustainable utilization of water resources to modern water control in China is expounded. Finally, the developmental needs of water control and the research prospects of the sustainable utilization of water resources under the new situation were analyzed. These findings can provide a reference for further research on the sustainable utilization of water resources and the formulation of water control strategies in China.

  • Donghai LIU, Jing HUANG, Juan LIU, Yang ZHOU, Kun QIN
    Advances in Earth Science. 2023, 38(4): 349-362.

    Mesoscale weather phenomena have a significant impact on human production and life. Mesoscale numerical prediction models are one of the main tools used for numerical weather prediction. Owing to the limitations of model resolution and insufficient understanding of the physical mechanisms of weather phenomena, many complex weather processes can only be implicitly expressed by parameterization schemes, the research of which is helpful in promoting the continuous optimization of the simulation and prediction effects of mesoscale numerical prediction models. Based on the characteristics of typical mesoscale numerical prediction models at home and abroad, the research status of cumulus convective, cloud microphysical, planetary boundary layer, land surface process, and radiation transfer process parameterization schemes, which are important according to the main forms of atmospheric motion, have been summarized. The theoretical basis and application scenarios of representative parameterization schemes are also compared in the present study. The main research paradigms in this field are comparative experiments that include the comparison of different scheme effects in simulating the same weather phenomenon, comparison of the same scheme effects in different weather scenarios, and optimization experiments on independent or combined schemes. In the future, the physical mechanisms of various weather phenomena and their influencing factors will be explored in depth, and parameterization schemes will be coupled at the levels of multiple elements, scales, and schemes. Subsequently, the simulation of the gray area will receive more attention, and the application options of parameterization schemes will be more diversified. Owing to the arrival of the big data era and the high demand for data analysis, parameterization schemes and machine learning will be developed to form a new mechanism driven by methods and data.

  • Yongqi GONG, Haipeng YU, Jie ZHOU, Yu REN, Yun WEI, Shanling CHENG, Yaoxian YANG, Hongyu LUO
    Advances in Earth Science. 2023, 38(2): 168-182.

    In the context of global warming and climate change, significant changes in precipitation have occurred in the drylands of East Asia, where water vapor transport has a significant impact on precipitation anomalies. Recent studies on water vapor sources in the drylands of East Asia have been reviewed and analyzed, focusing on external water vapor transport sources, seasonal differences, and internal evapotranspiration variations. Future research directions are discussed and predicted. Existing studies show that water vapor from the Bay of Bengal–Indian Ocean, the South China Sea, the western Pacific Ocean, and the Eurasian continent are transported to the semi-arid regions of East Asia by the South Asian, South China Sea, and subtropical monsoons, and the mid-latitude westerly wind belt; the water vapor from the South China Sea and the western Pacific Ocean dominates during summer and depends on the water vapor content carried by the westerly winds during winter. Since 1979, the annual precipitation recirculation rate in semi-arid regions of East Asia has been increasing, and the recirculation rate in summer is higher than that in winter on a seasonal scale. The sources and paths that dominate water vapor transport in the drylands of East Asia, particularly summer water vapor transport, need to be further verified. Quantifying the relative contributions of the external water vapor input and internal water vapor evaporation may become a future research topic. Furthermore, the relationship between global changes and changes in precipitation water vapor sources must be analyzed in depth.

  • Xiaoyi PAN, Linlin LI, Dawei WANG, Huabin SHI
    Advances in Earth Science. 2023, 38(2): 192-211.

    High-resolution geophysical data indicate that there are numerous submarine landslides in the China Sea region at various scales, particularly on continental slopes. Potentially devastating tsunami hazards generated by submarine landslides pose a great threat to the populous coastal region, fisheries, and oil and gas exploitation in the deep sea. Thus, hazard assessment is necessary. This study investigates the potential tsunami hazards generated by four representative submarine landslides in the South China Sea (SCS). The geological background and triggers of these submarine landslides are summarized. The key parameters of each landslide were constrained by currently available geological and geophysical data. A combined modeling approach, NHWAVE and FUNWAVE-TVD, was used to model the dynamic process of landslide movement and the generation and propagation of landslide tsunamis. The simulation results show that the tsunamigenic capacities of the Baiyun and Zengmu Ansha Slides differ significantly, although they have comparable volumes. This large difference was attributed to the discrepancy in the initial water depth and slope gradient. Tsunami waves generated by the Baiyun Slide rose up to approximately 12 m in the source area and mainly affected the northern region of the SCS, particularly the southern mainland Chinese coast. The Zengmu Ansha Slide generated 38 m tsunami waves that assailed the majority of the coastline of the southern SCS. The Zhongjiannan Slide generated highly localized tsunami waves about 10 m near the source region on the west SCS coast. The North Xisha trough slide produced a minor tsunami impact with tsunami waves that were approximately 0.9 m high in the source region. The distribution of the maximum surface elevation and the propagation characteristics of tsunami waves suggest that the tsunamigenic potential of submarine landslides is controlled by geometric and kinematic parameters. Meanwhile, complex bathymetry and coastlines change the energy distribution of tsunami waves, increasing the difficulty of tsunami hazard assessment. Conducting landslide-tsunami simulations for typical landslides in the SCS and establishing a landslide-tsunami database is of great research significance and will assist in improving the prediction of marine geo-hazards in China.

  • Shaopeng CHEN, Yuefang DUAN
    Advances in Earth Science. 2023, 38(1): 86-98.

    Examining the research status, focus, and developing trend of the agricultural carbon effect in China can provide references to researchers and improve the breadth and depth of research on the agricultural carbon effect. In this study, 708 high-quality papers published from 2009 to 2021 in the Chinese Academic Journal Network Publishing Database were retrieved as basic data. CiteSpace software was used for a visualized analysis of information, including authors, institutions, and keywords. The results suggested that, in terms of research status, the number of papers experienced a high-speed growth period and a stable growth period; With their authors being mostly scattered and only some being concentrated. Most institutions conduct their research independently. In terms of research focus, the core words found throughout the existing research were agricultural carbon emissions, carbon emissions, low-carbon agriculture, greenhouse gas, farmland ecosystem, and carbon sink. Six clusters were identified, namely agricultural carbon emissions, soil carbon sequestration, carbon footprint, low-carbon agriculture, agricultural carbon emissions efficiency, and carbon emissions reduction. Additionally, 12 burst terms were observed, namely soil carbon sequestration, soil organic carbon, low-carbon agriculture, greenhouse gas emissions reduction, low carbon economy, carbon sequestration and emissions reduction, greenhouse gas, countermeasures, carbon sink, lmdi model, carbon sequestration rate, and agricultural carbon emissions efficiency. Five categories of research focus were summarized, namely agricultural carbon source/sink, agricultural carbon sequestration, agricultural carbon emissions reduction, agricultural carbon footprint, and low-carbon agriculture. In terms of research trends, the keywords were concentrated in papers published from 2009 to 2014. Research on the agricultural carbon effect shows trends of increasing research popularity, decreasing research topics, and increasing research methods. Finally, the prospect of the agricultural carbon effect in China was based on five aspects: mid-small areas, comprehensive perspective, the entire industry chain, farmer behavior, and grain security.

  • Yao LU, Liangbo HUANG, Junjie JIA, Yang GAO
    Advances in Earth Science. 2023, 38(1): 57-69.

    Inland water is an important component of the global carbon (C) cycle and plays a key role in regulating climate change. The Primary Productivity (PP) of inland water is defined as the amount of organic matter produced by primary producers in inland water bodies through photosynthesis per unit time and unit area, which reflects the quantitative relationship between the organic and inorganic C pools. The assessment of inland water PP can help analyze the C cycle mechanism of photosynthesis and quantify the C absorption of aquatic ecosystems to examine the differences in the ecological environment in different regions and evaluate the importance of inland water bodies in the global ecosystem C cycle. There are many methods for estimating PP in inland water, including the light-dark bottle incubation method, the vertically generalized production model method, and the 13C method. Each of these have application scopes and limitations. The unreasonable use of PP restricts the understanding of its variability and driving mechanism in inland water bodies. The mechanism, advantages, disadvantages, and applicability of each method are compared by summarizing domestic and international research on PP estimation methods in recent years. Two new methods based on dissolved oxygen concentration or oxygen isotopes, namely, diel O2 technology and 18/16O technology, are introduced. This study serves as a reference for research on inland water metabolism, productivity, and nutrient cycles.

  • Chunxiao WANG, Yaoming MA, Cunbo HAN
    Advances in Earth Science. 2023, 38(4): 414-428.

    Studying the atmospheric boundary layer over the Tibetan Plateau is of great significance for understanding the heat and water budget, weather, and climate change of the plateau and its surrounding areas. However, the research on the weather and climate of the Tibetan Plateau is restricted by the lack of observational data. The atmospheric science experiments on the atmospheric boundary layer over the Tibetan Plateau were reviewed in the present study. Furthermore, the research progress on the height, wind field structure, temperature, and humidity field structure of the atmospheric boundary layer over the Tibetan Plateau was summarized, and the development mechanism of the atmospheric boundary layer was introduced from the perspectives of thermal and atmospheric dynamics. Accordingly, the shortcomings of the current research in this field were discussed, and it was highlighted that the research on the atmospheric boundary layer of the Tibetan Plateau is still in the exploration stage and that the research on the development mechanism is not thorough enough. Few studies have simultaneously examined the linkages between different regions on the plateau at the same time. Finally, considering the aforementioned shortcomings, future developments have been proposed.

  • Tianye WANG, Ping WANG, Zening WU, Jun YIN, Jingjie YU, Huiliang WANG, Zhilei YU, Hongshi XU, Lihe YIN, Denghua YAN
    Advances in Earth Science. 2023, 38(8): 790-801.

    Ecological resilience, the ability of an ecosystem to absorb and adapt to environmental change to maintain its sustainability, was first systematically introduced by the Canadian ecologist C.S. Holling in 1973 and has since rapidly attracted attention and been used across multiple disciplines. In the context of global change, the response of terrestrial ecosystems to increasingly intensifying arid environments, specifically the spatial patterns and evolutionary mechanisms of vegetation ecological resilience under drought stress, has become a core focus of current ecological and ecohydrological research. In recent years, numerous studies have been conducted on the relationship between vegetation change and water stress, enhancing our understanding of this mechanism. However, the interpretation of the ecological resilience of vegetation varies widely and remains controversial, and one of the main reasons for this is that the understanding of the connotations of ecological resilience is not yet unified. To address this issue, we synthesized the views of researchers worldwide and suggested that the analysis of ecological resilience should not only consider the system resistance and recovery capacity under drought events but also the system response and adaptation behavior under changing environments from the perspective of system evolution. These include resistance, recovery, and adaptation, which should be the three most important dimensions for determining ecological resilience. Focusing on these three main dimensions, we reviewed the results of recent research conducted globally and summarized the current understanding of ecological resilience and the key issues to be addressed in terms of spatial patterns, impact mechanisms, and adaptation strategies for ecological resilience. Through an analysis of the concept of ecological resilience and the current state of research, we hope to promote academic discussions on the definition of ecological resilience and its quantitative methods to facilitate an understanding of the evolution of resilience and its underlying mechanisms.

  • Mengwei DUAN, Ruren LI, Dong LIU, Xintong JIANG, Zhiqiang QIU, Keyu LI
    Advances in Earth Science. 2023, 38(7): 675-687.

    Dynamic monitoring of suspended sediment in rivers has important application values for channel changes, safe operation of water conservancy projects, ecology, and environmental protection. Real-time remote sensing technology can monitor suspended sediment in sizeable regional river water bodies. Compared to large bodies of water such as oceans and lakes, remote sensing of suspended sediment in rivers has received less attention. Existing research has primarily focused on estuarine areas where rivers enter the sea. This study systematically summarizes published data sources and models of satellite remote sensing of suspended sediment in rivers worldwide to fully utilize the advantages of multi-source satellite remote sensing data with different temporal, spatial, and spectral resolutions and to realize remote sensing monitoring of suspended sediment transport in a broader area and at different river levels. The difficulties and challenges of satellite remote sensing of suspended sediments in rivers are discussed. On this basis, the future development of remote sensing monitoring of suspended sediment in rivers has been viewed from three perspectives: removing atmospheric correction of the proximity effect, concentration on remote sensing considering suspended sediment particle size distribution, and three-dimensional remote sensing of suspended sediment transport flux.

  • Yu LI, Junjie DUAN, Haiye LI, Mingjun GAO, Yuxin ZHANG, Yaxin XUE
    Advances in Earth Science. 2023, 38(4): 388-400.

    Lakes play an essential role in the evolution of regional water cycles and ecosystems. In previous studies on lake evolution, most lake sediment proxy indicators have been used to reconstruct lake and climate change processes. However, there is a lack of quantitative research on the lake water cycle characteristics. Based on the water balance model for watersheds and lakes in distinct periods and the lake energy balance model based on the simulation of the transient climate, water balance calculations and lake evolution simulations for six typical lakes in the Qinghai-Tibet Plateau and its surrounding areas were carried out in this study. The results showed that the precipitation and evaporation variabilities in Xiao Qaidam Lake and Lop Nur were relatively small during the Holocene. The precipitation and evaporation variabilities in Selinco and Namco were relatively large during the early-middle Holocene, mainly controlled by temperature and net radiation changes. The precipitation and evaporation variabilities in Qinghai Lake and Zhuyeze were close during the early and mid-late Holocene. This study systematically analyzed and calculated the evolution of lake water cycle elements in different climatic regions of the Qinghai-Tibet Plateau during the Holocene, which will help to understand the paleoclimatic mechanism of lake evolution in this region.

  • Yang GAO, Juhua XIONG, Zhonghao ZHANG, Shun CAI, Li ZHANG, Yu AN, Kaixu BAI, Ruzi LI, Yanli YANG, Zhen YANG
    Advances in Earth Science. 2023, 38(10): 1015-1024.

    The National Natural Science Foundation of China (NSFC) has received widespread attention as the primary funding institution for basic scientific research in China. Here, we analyze the results of the proposals received by the Division of Geography, Department of Earth Sciences, National Natural Science Foundation of China, in 2023. An analysis of the proposal review and funding processes was undertaken for three sub-disciplines (Physical Geography, Human Geography and Geographic Informatics); three types of projects (general program, Young Scientists Funding Program, and Regional Funding Project); and four scientific themes or focus areas, as formulated by the NSFC. In addition, issues to be noted in the proposal submission and peer review are discussed. For projects completed by the end of 2022, we first analyzed the publication status of SCI/SSCI/EI/CSCD/CSSCI indexed articles in various project categories and then focused on the representative achievements.

  • Wuhui LIN, Fan ZHANG, Kefu YU, Hao MA, Jinqiu DU, Zhenni MO, Yinghua LI, Xianwen HE, Minting MO
    Advances in Earth Science. 2023, 38(3): 286-295.

    Coral reef ecosystems are characterized by high primary production and biodiversity, providing rich biological resources and valuable ecosystem goods and services for humans. Reef-building corals survive in coastal areas near several nuclear power plants in China. Additionally, coral islands can potentially support future applications of floating nuclear power plants in remote marine environments for energy supply. Although artificial radionuclides derived from nuclear power plants are released into coral reef ecosystems, there is limited information on the biogeochemical behavior of artificial radionuclides and their radiological impacts on coral reef ecosystems. In this study, key artificial radionuclides, including 14C, 239+240Pu90Sr, 236U, 129I, and 137Cs, were carefully selected and comprehensively investigated from the perspectives of activity concentration, coral skeleton-seawater distribution coefficient (Kd value indicating the ability of enrichment), and radiation dose rates derived from the ERICA model. Based on our previous studies on 14C, 90Sr, and 137Cs in coral reef ecosystems, we reviewed and analyzed the research progress on key artificial radionuclides, which were classified into low-level (Kd ≤1 L/kg), medium-level (1 L/kg<Kd <1 000 L/kg), and high-level (Kd ≥1 000 L/kg) enrichment groups according to the Kd value. The Kd values were ranked in descending order as 14C>239+240Pu>90Sr and 236U>129I>137Cs. The radiation dose rates of the above-mentioned artificial radionuclides and naturally occurring radionuclides of 210Po in coral polyps were simultaneously calculated using the ERICA tool and ranked in the order 14C>90Sr>137Cs> 239+240Pu>236U>129I. The total radiation dose rate of artificial radionuclides was estimated to be 4.73×10-4 μGy/h, which was much lower than the radiation dose rate of 210Po (6.60 μGy/h) and the screening benchmark level of no effect (10 μGy/h). Therefore, artificial radionuclides in the surface seawater of the South China Sea should not pose significant radiological risks to coral polyp populations. Overall, our results provide technical support for the assessment of nuclear safety in coral reef ecosystems in the context of the potential application of floating nuclear power plants in coral islands in the South China Sea.

  • Qian XU, Cunde XIAO, Yaru FENG, Zhiheng DU, Lei WANG, Zhiqiang WEI
    Advances in Earth Science. 2023, 38(5): 470-482.

    As a result of global warming, the melting of ice-rich permafrost causes the ground to collapse, thereby creating thermokarst lakes, while the greenhouse effect caused by the concurrent release of greenhouse gases results in a positive feedback with climate warming. Microorganisms play important roles in various aspects of the carbon cycle. Understanding the mechanisms of microbial regulation of the carbon cycle in thermally melting lakes is of great significance for coping with future climate change. Therefore, by combining previous studies, this paper first elucidates the formation process of thermokarst lakes and the microorganisms inhabiting these special habitats; subsequently, the main microorganisms involved in organic carbon decomposition, methane production, and methane oxidation, and the regulation mechanisms and influencing factors are analyzed in detail. Based on this analysis, we conclude the following: The organic matter in thermokarst lakes originates from the land, while some nutrients, such as phosphates, plant biopolymers, and leucine residues, are also transported from the land to the water. With improvements in temperature and aeration conditions, the availability of most nutrients increases the genetic diversity of microorganisms and promotes their roles in organic carbon decomposition. Changes in temperature, substrate, dissolved oxygen, and microbial community affect the processes of methane production, methane oxidation, and carbon sequestration, thereby affecting the carbon cycle. Some deficiencies in previous studies are summarized, and a new research perspective is proposed to deepen our understanding of microbial involvement in the carbon cycle in thermokarst lakes. With the help of metagenomic technology and incubation, the regulatory mechanisms of microbes for the carbon cycle can be revealed more clearly, and field observations of carbon emissions from thermokarst lakes under different environmental conditions can be strengthened. Exploring the use of microbes for mitigating the negative effects of climate change should be based on the above fundamental research.

  • Zhi HE, Jun TIAN
    Advances in Earth Science. 2023, 38(1): 17-31.

    The Middle Miocene Climate Transition (MMCT, 14.2~13.9 Ma) was a global climate change event characterized by significant changes in ice sheets, ocean currents, and carbon cycles. Clarifying the driving mechanism is important for understanding the global cooling during the Cenozoic. Two hypotheses have been proposed to explain the mechanism of MMCT, one emphasizing the reorganization of ocean circulation and the other highlighting the importance of the carbon cycle. However, neither hypothesis can explain the various phenomena of the MMCT. The ice sheets, ocean circulation, and carbon cycle are crucial in the mechanism of the MMCT, and form a coupled system that causes climate change on Earth. With the help of these three elements and combined with geological records, these two mechanisms lead to an increase in deep ocean carbon storage and a decrease in atmospheric pCO2, which further promotes climate cooling and ice sheet growth. In comparison with that on carbon cycle processes and ice sheet changes, existing research regarding ocean circulation, particularly in the deep Southern Ocean and Pacific Ocean, during the MMCT period is insufficient. Consequently, future research should focus on the changes in ocean circulation in these key regions to improve our understanding of the forcing mechanism of MMCT.

  • Liming BO, Wei WEI, Lang ZHAO, Li YIN, Junnan XIA
    Advances in Earth Science. 2023, 38(4): 401-413.

    A scientific understanding of the spatio-temporal evolution process and driving factors of water ecological space in the Tibetan Plateau is an urgent requirement to build the “Asian water tower” and establish the coordinated and sustainable development of human-water resources-ecology in the region. In this study, a spatial transformation matrix, spatial correlation analysis, and geographical detector were used to determine the evolutionary characteristics and driving mechanisms of the aquatic ecological space in the Tibetan Plateau from 2000–2020. The following results were obtained: During the past 20 years, the aquatic ecological space in the Tibetan Plateau has increased by 21.53%. The northwest side of the Hengduan Mountains, the intersection of Tibet and the Qinghai, Sichuan, and Yunnan provinces, “Dari County, Guoluo Prefecture, Qinghai Province-Chayu County, Linzhi City, Tibet Autonomous Region,” had the most significant increase. The transformation from other ecological space to water ecological space is the dominant change type, and climate warming and human influence have caused glaciers and snowmelt to flow into rivers and lakes. Therefore, water resources in the Tibetan Plateau have melted and water ecological space have been extended eastward. The evolution of water ecological space in the Tibetan Plateau is jointly driven by many factors, such as policy engineering, natural geography, traffic location, and social economy. Each type of factor had a nonlinearly enhanced interactive driving effect as a whole; this caused the average value of the action intensity q of natural geography and traffic location to be far greater than that of other factors, which is the dominant driving factor for the evolution of the water ecological space in the Tibetan Plateau.

  • Yaohui LI, Jinglei YU, Juan GU, Wenjun SANG, Xiaolin JIN, Yu HUANG
    Advances in Earth Science. 2023, 38(1): 9-16.

    Carbon emissions are major a focus of the international community, and carbon reduction and neutralization have become common global goals. CO2 is the most abundant gas emitted during aviation flight. Although it accounts for a small proportion of the total carbon emissions from human activities, its impact will increase considerably. The joint action of the global response to climate change has caused the aviation industry to pay attention to its CO2 emissions. With the rapid development of China’s civil aviation industry, the carbon emissions generated by aviation fuel consumption are also growing, which will increase the pressure on China to achieve its carbon emission reduction goal. Therefore, the effect of carbon emissions from civil aviation on climate change is an important topic for scientific research. Many studies have been conducted on this subject, especially internationally, with significant achievements. Here, we review the current mainstream research progress and work trends of aviation carbon emissions and their effects on climate change from the perspective of carbon emission measurement and the impact of carbon emissions on climate change, and propose future exploration. This review summarizes the impact of aviation emissions from a different perspective, which will help to gain a more comprehensive understanding of climate change in the future and provide a reference for scholars and scientists from relevant departments to conduct scientific and comprehensive research on emission reduction measures in China to more effectively cope with climate change.

  • Yuxin ZHANG, Xinxin ZUO
    Advances in Earth Science. 2023, 38(2): 212-220.

    A small amount of organic carbon, referred to as phytolith-occluded carbon (PhytOC), is occluded during phytolith formation. This carbon fraction has been demonstrated to be an important form of carbon sequestration. Thus, it has drawn particular attention from many researchers in the study of the terrestrial carbon cycle because it is of great significance for increasing terrestrial ecosystem carbon sinks and delaying global warming caused by the greenhouse gas effect. First, we briefly reviewed the research history and current status of PhytOC. Then, focusing on the long-term changes in PhytOC, we discussed the questions and challenges of PhytOC and terrestrial ecosystem carbon sinks as well as the recent argument that carbon sequestration by PhytOC in terrestrial ecosystems was highly overestimated. However, to more accurately estimate the phytolith carbon sink, some factors should be considered regarding long-term changes in PhytOC, such as different carbon-occluded abilities, carbon source, and stability of phytolith, decay rate of PhytOC in soil, and the impact of different phytolith extraction methods on PhytOC. As a result, the status and importance of PhytOC in studying terrestrial carbon sinks would be enhanced.