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.
The period of the late Miocene Tortonian （11.61~7.25 Ma） was warmer and wetter than today， with atmospheric partial pressure of carbon dioxide （pCO2） near the preindustrial level. Greenhouse climate under low pCO2 was rare throughout the Cenozoic and understanding its mechanisms will help to better forecast the future climate. We summarized two hypotheses to elucidate this mechanism. One is the late Miocene climate-pCO2 "decoupling hypothesis" based on geological records， and the other is "synergistic effects hypothesis" based on climate modeling. Geological records indicate that the late Miocene climate may not have been affected by pCO2， that is， climate and pCO2 were decoupled. Climate modeling results indicate that different vegetation and tectonic conditions in the late Miocene may have contributed to the global temperature increase. However， realistically， it is difficult to fully simulate the amplitude and pattern of the late Miocene warmth. Future work should focus on reconstructing pCO2 records with high accuracy and resolution. Vegetation， clouds， water vapor feedback， and soil properties may be the dominant factors contributing to the late Miocene greenhouse climate， which should also be considered in future simulation work.
Low molecular alkyl amines are the most common and abundant amines in the atmosphere， with high water solubility and strong alkalinity， and are widely dispersed in the atmosphere in both the gas-phase and particle-phase. The gas/particle conversion of atmospheric low molecular alkyl amines contributes significantly to particle nucleation， growth of new particles， and the formation of secondary aerosols. It also affects the particle hygroscopicity， thus contributing to haze formations. The techniques to measure atmospheric low molecular alkyl amines are mainly Ion Chromatography （IC）， Gas Chromatography （GC）， High Performance Liquid Chromatography （HPLC）， Chemical Ionization Mass Spectrometry （CIMS）， and Single Particle Aerosol Mass Spectrometry （SPAMS）. Each measurement method has certain advantages and disadvantages， and limited applications in online mass spectrometry. In recent years， more attention has been paid to atmospheric low molecular alkyl amines. Previous research has measured gas-phase and particle-phase amines in different areas including urban， suburban， and marine. Research has progressed in identifying the concentration， composition， temporal & spatial distribution， source analysis， and atmospheric behaviors of atmospheric low molecular alkyl amines. Research is limited by sampling and measurement methods and our understanding of the mechanisms. We also lack information on time continuity and spatial coverage of different regional types. Improved measurement data is required. Despite our understanding of the sources of atmospheric low molecular alkyl amines and the mechanism of their atmospheric conversion， there remain great deficiencies in source analysis and atmospheric behavior. Further research is needed to address these deficiencies. We aim to introduce the various measurement methods for atmospheric low molecular alkyl amines and evaluate their advantages and disadvantages， the research progress， and existing problems. The atmospheric low molecular alkyl amines in China are discussed based on the aspects of concentration composition， temporal & spatial distribution， source analysis， and atmospheric behaviors. The future research focus on atmospheric low molecular alkyl amines is prospected.
Water stable isotopes （δ） are inherent in the water cycle， changing during water phase changes， and hence widely used to study moisture trajectory and water cycle. Their application to the study of atmospheric circulations over the Tibetan Plateau （TP） has led to a comprehensive understanding in the past decades. This review focuses on field sampling across the extensive TP， and summarizes the spatial and temporal variation patterns in water stable isotopes in precipitation， surface water and ice cores. Complex circulation patterns are found to affect the altitude effect in water stable isotopes， so that monsoon yields a smaller altitudinal lapse rate than westerly， which in extreme cases can result in increasing isotopic composition with increasing altitudes； though the precipitation isotopes have a prevailing dominance over surface water isotopic features. The sensitive response of precipitation stable isotopes to convection is also applied to the judgement of monsoon onset based on abrupt， continuous and significant decrease in δ. Accordingly， the submonsoon system is found to onset earlier over the Bay of Bengal than the South China Sea and varies diversely under global warming. A long-term perspective into atmospheric circulation over the Tibetan Plateau from ice core δ reveals significant impacts of El Nin?o-Southern Oscillation （ENSO） on the TP， with a dampening effect on the temperature significance of ice core isotopes in the southern TP under the monsoon dominance， while a lagged correlation between ENSO and ice core isotopes in the northwestern TP； all pointing to possible teleconnections between TP climates and sea surface temperature. In future studies， the Earth system models will be relied upon to help reveal physical mechanisms behind complex water stable isotope variations， and comprehend unique isotope variation patterns under extreme climates. Based on modern precipitation δ variation features and abrupt changes and triggering mechanisms， variation history of moisture sources is to be reconstructed from paleoproxies. Besides， isotopic parameters including deuterium excesses have high meteorological synoptic capacity， and would be applied to the analysis of changes in sea surface temperature or evaporation， and hence to facilitate the understanding of sea-air interactions， and the interactions of circulation patterns and water cycles on the Tibetan Plateau with global climate changes.
Although satellite precipitation has provided a valuable reference for the precipitation estimation in the sparse region， its uncertainties in the practical application are still challenging. Researchers tried to fuse ground observation and satellite precipitation to evaluate and modify satellite precipitation products for uncertainty reduction. Unfortunately， this paper examined many publications of fusion TRMM precipitation products in mainland China and found a non-negligible directional contradiction between the approaches. The findings will significantly affect the reliability of satellite precipitation in practical applications. It was found that the contradiction has not related to the satellite precipitation products and fusion methods but significantly related to the selection of precipitation observation stations. It was also found that the uncertainty is hard to be reduced only by innovating the fusing methods of TRMM precipitation with ground observation data. Therefore， it is necessary to strengthen the integrity of ground observation and adopt independent practices to verify consistency and reliability.
The frequency of terahertz wave is in the range of 0.1~10 THz （wavelength 3 mm~30 μm）， which is located between the microwave and infrared bands. Its wavelength is similar to the size of typical ice cloud particles， and it has great potential in ice cloud remote sensing. Terahertz region is expected to have a promising prospect concerning measuring cirrus microphysical parameters， which has broad application prospects and application values for Terahertz wave passive remote sensing of ice clouds. Firstly， the basic principle of terahertz remote sensing of ice clouds was summarized. Then， the key technologies were introduced in detail from three aspects， including the measurement instrument， the forward radiative transfer model and the inversion method of the terahertz remote sensing of ice clouds. In particular， the key parameters of the existing terahertz radiometers， the characteristics of terahertz radiative transfer simulators and the advantages and disadvantages of different inversion methods were discussed and analyzed. Finally， the summary and prospect of the terahertz remote sensing of ice clouds were proposed， in order to provide a reference for the future research of terahertz wave passive remote sensing of ice clouds.
Clouds play an import role in weather and climate change， and are one of the most principal sources of uncertainty in climate projection. Long-term accurate observations of clouds are vital to validating and constraining model simulations， and reducing the uncertainty caused by clouds in climate models. The millimeter-wavelength cloud radar is a powerful tool for cloud observation by directly detecting signal backscattered from cloud droplets， and thus can provide cloud three-dimensional features. In this paper， we presented in detail an improved cloud detection algorithm to distinguish real cloud echoes from radar background noise. The bilateral filter idea from image process was adopted into millimeter-wave cloud detection algorithm， which compressed the radar noise while preserving cloud edge， therefore being able to identify more real weak signal ignored by traditional cloud mask methods. We also used the Ka-band Zenith Radar （KAZR） in the Semi-Arid Climate and Environment Observatory of Lanzhou University （SACOL）， and the W-band cloud profiling radar aboard CloudSat， along with the synchronized lidar measurements to demonstrate that the improved algorithm could significantly reduce false negative rate， and increase the cloud detection accuracy. This paper also discussed the advantages of this algorithm for microwave radar in other remote sensing applications， taking track detection as an example. It shows that the algorithm could be generally used for small radar cross section target recognition. We believe this method will enhance the active microwave radar target detection ability especially for the objects with small radar cross section.
The trace of the vertical atmospheric transport has important scientific significance for understanding the transport path of chemical substances in the atmosphere and the process of climate change， and predicting the changing trend of the atmospheric environment. The 7Be and 10Be in the atmosphere are rapidly oxidized after they are formed， and reach the surface with the dry/wet deposition. The concentration of 7Be， 10Be and the ratio of 10Be/7Be can be measured to trace the Stratosphere-Troposphere Exchange （STE）. In order to fully understand the process and research status of 7Be and 10Be trace atmospheric vertical transmission， this work analyzed how the 7Be and 10Be can trace STE from the distribution law and influence the mechanism of their concentration and ratio. At the same time， it summarized and reviewed the results of related research. The reason why 10Be/7Be is used as a sensitive tracer of STE was analyzed. Compared with 7Be， it can avoid tropospheric dry/wet sedimentation and dilution of different air masses. It can also obviously avoid the influence of latitude changes and solar cycle changes on its own yield. Finally， this work pointed out that when tracing STE by 7Be and 10Be， it is necessary to pay attention to the difference between the northern and southern hemispheres， the changes in regional latitude， and the geographic characteristics of the research site. The long-period and high-precision 7Be and 10Be data in various regions play an important role in the deposition flux， the trace STE， and the establishment and verification of global climate models. The influence of resuspended dust on the concentration of 10Be and the ratio of 10Be/7Be cannot be ignored， and the Al element correction method is a more effective correction method to remove the influence of dust.
As an important bridge between the underlying surface and the free atmosphere, the atmospheric boundary layer is not only closely related to the development of various weather processes, but also plays a key role in local and regional weather and climate changes. In view of the complexity of the atmospheric boundary layer, the numerical simulation of the atmospheric boundary layer has always been a hotspot and difficulty in the numerical simulation research of the atmosphere. In this paper, the three numerical model development stages of the atmospheric boundary layer in recent decades were summarized and the important advances in arid and semi-arid areas, Tibet Plateau, urban complex underlying surface, and special typhoon boundary layer were reviewed. At present, there are still five scientific problems to be solved urgently, including cloud and boundary layer interaction, boundary layer parameterization, model resolution, boundary layer data assimilation and boundary layer development mechanism. Moreover, it was pointed out that in this field we need to strengthen the understanding of different types of atmospheric boundary layer processes, boundary layer bottom and top interface exchange, boundary layer development mechanism in special regions, improve boundary layer parameterization scheme and give full play to the advantages of LES in boundary layer simulation.
Convection often produces severe weather which causes a great loss to human lives and properties. Precisely predicting the convection initiation process is crucial but challenging in operational convection nowcasting (0~2 h forecasting). Before the radar-defined CI occurring (e.g., the first occurrence of ≥35 dBZ echoes), observations at high spatial and temporal resolutions from weather radars and geostationary meteorological satellites can reveal precursor information such as the boundary-layer convergence lines and the rapid growth of newborn cumulus clouds. These radar- and satellite-observed precursor information are helpful for evaluating the pre-CI conditions and thus nowcasting the accurate CI timing and location. This paper reviewed the current status of radar- and satellite-based CI research and nowcasting techniques. The milestone works and the following studies in the last four decades were summarized to demonstrate how radar and satellite observations can be related to CI occurrence. The objectives and approaches of the CI research advance as the improvement in the capability of radars and were explained satellites. The research progress aids in the development of various CI nowcasting techniques. This paper introduced three well-established techniques that have been put into operational application, namely, ANC system, SATCAST algorithm, and UWCI algorithm. Some scientific issues with respect to radar- and satellite-based CI research and nowcasting were also presented.
As the important components of the earth’s atmospheric system, cloud and precipitation strongly affect the global hydrology and energy cycles through the interaction of solar and infrared radiation with cloud droplets and the release of latent heat in precipitation development. The microwave observations in cloudy and rainy conditions have a large amount of information closely related to the development of weather systems, especially the severe weather systems like typhoon and rainstorm. Nevertheless, satellite microwave observations are usually only assimilated in clear-sky above the ocean and their cloud and precipitation content is discarded. Over the past two decades, several Numerical Weather Prediction (NWP) centers have gradually developed the “all-sky” approach to make use of the cloud- and precipitation-affected microwave radiances. It’s been proved that the all-sky assimilation can be used to improve the first guessed mass, wind, humidity, cloud and precipitation through the tracer effect. For providing an investigated reference for the future research of all-weather assimilation in domestic numerical weather forecast, this paper reviewed the all-sky assimilation methods using microwave observation data, analyzed the advantages and disadvantages of each method, and discussed the key technical problems and the existing difficulties and challenges in this field. With the development and application of the new generation of NWP model in China, advancing the domestic research of all-weather data assimilation technology will bring more scientific and practical benefits in the future.
Accurate and timely monitoring of atmospheric constituents is the prerequisite for mastering the distribution characteristics of atmospheric constituents, studying the genetic mechanism of the forming of atmospheric pollution, and effectively preventing and controlling air pollution. Among various observation methods of atmospheric constituents, remote sensing monitoring technology can provide the long-distance and real-time observation, have the ability of rapid analysis of diverse atmospheric mixtures, and obtain stereoscopic spatiotemporal distribution of target constituents without sampling. There are various methods and instruments for remote sensing monitoring of atmospheric constituents, and each of them has its unique advantage, covering a multiple gases and aerosol. According to the difference of the height of the remote sensing platform, it can be divided into ground platform, aviation platform and space platform. Remote sensing technology is widely applied in the field of atmospheric constituents monitoring, and meets the observational requirements for a variety of purposes. This paper introduced the remote sensing monitoring methods and platforms of atmospheric constituents and summarized their application examples for different purposes. It also outlined the future development direction of remote sensing methods in atmospheric constituents’ observation.
The changing of atmospheric carbon dioxide concentration is closely related with the changing of global ice sheet，temperature and sea level. Knowledge of the past atmospheric carbon dioxide concentration and its relationship with climate is an important method of predicting the future climate change. Coccolith derived long-chain alkenone carbon isotope is one of the important proxies to reconstruct past carbon dioxide, which is wildly applied in the reconstruction of the Cenozoic atmospheric carbon dioxide. In this paper, we focused on the method of alkenone-based atmospheric carbon dioxide concentration, including the geochemical properties of long-chain alkenone, carbon diffusive model and the carbon isotope fraction. Then, we introduced the development of alkenone-based carbon dioxide proxy and its uncertainty. Coccolith cell geometry and growth rate have great influence on carbon dioxide fraction. Besides, there are some uncertainties about carbon concentration mechanisms in coccolithes, which may have some influence on alkenone-based carbon dioxide method to reconstruct ancient carbon dioxide more accurately. At the end, we summarized the Cenozoic carbon dioxide record with various proxies including alkenone carbon dioxide, boron isotope, palaeosol carbonate nodules and stomatal indices of fossil leaves.
With the development and popularization of smartphones and embedded sensors, a non-professional atmospheric measurement method by using smartphones carried by the public has been proposed recently. Without extra dedicated instrument, this method has many advantages, such as low hardware cost, high spatio-temporal resolution, and wide coverage, and it can supplement the professional atmospheric measurement methods, which has broad applications in the meteorological operation, scientific research, public service, and other fields. At present, the research on the non-professional atmospheric measurement in China is limited. In order to make full use of this method, this paper briefly outlined the states of existing smartphones and embedded sensors, highlighted the measurement of precipitation, air temperature, pressure, aerosols, and radiation by smartphones. To promote the development of smartphones for atmospheric measurement, future research should focus on mechanism study, available sources exploration, data quality control, big data processing, joining and matching with operation, research and service, etc.
Atmospheric bioaerosols have great impact on the global climate, air quality, atmospheric process and human health. The dust events have a role in transporting bioaerosols and affecteing the concentration and property of bioaerosols in the downwind area by facilitating long-distance dispersal events every year. This paper reviewed the study progress on the concentration, characteristics and distribution of bioaerosols in dust weather. The references showed that the ratio of different kind of bioaerosols changed in dust weather with the changing of contribution of bacteria and fungi. The concentration of cultural bacteria, fungi and the total microbes increased on dust days. However, the increase ratio was different for different microbes in different areas. Microbes in bioaerosols mainly distributed in coarse particles; the size distribution of bioaerosols was affected greatly by dust events with different variation for different kinds of bioaerosols. The microbial community and predominant species of microorganism in bioaerosols changed in dust weather. The impact and mechanism of dust on the concentration, size distribution, microbial community and activity of bioaerosols need to be studied further.
Atmospheric circulation anomaly is a direct cause of weather and climate change. In the past, most researches for the relationship between Weather Type (WT) and precipitation have mainly focused on the subjective classification and diagnosis. Compared to the subjective analysis, objective classification uses more consistent index and standard unification, thus, we can get more WTs, and it has been widely used in many areas. By using daily 12UTC Sea Level Pressure (SLP), Precipitable Water (PW), and 700 hPa wind speed (UV700) data from ECMWF’s Interim Reanalysis, the classification of WTs over China was performed with the method of obliquely rotated T-mode principle component analysis. WT and its link to precipitation over China were further analyzed. The results show that the influence of different WTs on precipitation is not uniform over China, and also show distinctly difference in different seasons. A common feature is that WTs great impact on the regions and months with large precipitation, while less impact on regions and months have with less precipitation. In addition, precipitation trends originating from WT intensity changes are much more deterministic, significant, and predictable than trends from WT frequency changes.
In order to study the scale error of low resolution meteorological satellite cloud detection and its impact on the calculation of downlink radiation, cloud detection using high resolution stationary satellite GF-4 data and error analysis were carried out. Firstly, the cloud detection of GF-4 data is carried out by using visible channel threshold method and time series method, and the error of cloud detection results of Himawari-8 and FY-2 (FY-2G, FY-2E) is analyzed based on the results of GF-4 cloud detection.In the study area, FY-2G, FY-2E and Himawari-8 cloud images could distinguish the clouds and clear sky. The main reason for the error was the scale effect produced by different spatial resolution satellites(the differences caused by cloud detection algorithms are not discussed here).Most of the errors occurred in the areas of thin clouds and broken clouds.High resolution data could detect broken clouds, while low resolution data lead to false and missed detection. On this basis, the error of remote sensing calculation of short wave radiation was analyzed,and it was found that the error of the actual cloud amount in the pixel would bring significant error to the estimation of the downward radiation.The relative error of the instantaneous downward radiation in the selected test area was -173.52%, and the maximum relative error of shortwave radiation was -20.20%.The results show that the high resolution stationary satellite data can significantly improve the estimation accuracy of the downlink shortwave radiation in the regions with more broken clouds.
The intensity of lightning thermal effect and its influence scope and duration (temperature, time and space scales), are not only the important characteristic parameters for lightning itself, but also the important factors in lightning disaster, lightning protection, lightning chemistry and other fields of applications. Due to the random feature of lightning occurrence time and place, coupled with a strong return stroke current, it is hard to make direct measurement of the temperature in lightning channel. Therefore, remote sensing technology is the only method at present to be adopted. This article summarized the present status of the methods and techniques based on visible and near-infrared spectra analysis applied for lightning channel thermal effect observations both at home and abroad, and provided a description of using a ground-based, multichannel microwave radiometer for this purpose.
Satellite data assimilation can provide accurate initial field for Numerical Weather Prediction (NWP) models. So far, data variational assimilation is based on the theory where error obeys Gaussian distribution, so as to apply the least square method. During classical variational assimilation, if the data contain outliers, the results of optimal parameter estimation is meaningless. Therefore, quality control is quite necessary for Atmospheric Infrared Sounder (AIRS) data before data assimilation. This paper made a comment of the advances in the quality control using AIRS data, which analyzed and discussed the research status from five aspects: channel selection, outliers elimination, bias correction, cloud detection and data sparseness. Three methods for channel selection were summarized, which are stepwise iterative method based on information entropy, the cumulative effect coefficient of principal component and principal components—Stepwise regression, respectively. Comparatively, stepwise iterative method based on information entropy is more widely used, but the selected channels are weak related; Channel combination with large amount of information can be obtained through the method of principal components—stepwise regression, but the implementation process is time-consuming due to the algorithm. Both the lane of law and the double weight method were used in outliers elimination, and the result shows that the latter one is better. Two kinds of bias correction method including off-line and on-line, were introduced, which contain static, adaptive, regression method, variational, method based on the radiative transfer model, bias correction with Kalman filter and dynamic update of bias correction technique. It is found that the timeliness of static method is better; while variational method could solve the problems of data drift and so on. The result is better when using bias correction based on the model and Kalman methods, but it is more time-consuming and not suitable for business application. Generally, the effect and timeliness of dynamic update one is the best among them. In this paper four kinds of cloud detection method are discussed here, including the sky field-of-view, sky channel, cloud radiation correction and different instrument cloud products matching. The first two methods are more feasible from the perspective of timeliness for numerical prediction, but the data quantity using could detection method of sky field-of-view is less than sky channel, leading to discarding of lots of channel data in climate sensitive area such as upper channel, and thus affecting the quality of analysis field. Further on, the methods of hops jumper, box and principal component applied to AIRS data sparseness were analyzed. From assimilation timeliness and operability, box method is feasible; although there is high complexity with algorithm of principal component analysis, which has a certain application prospect. After reviewing the quality control section, some further research directions in these fields were given respectively.
Nowadays, researchers pay more attention to the atmospheric CO, which are including the chemical characteristics of atmospheric CO and its indirect effects on the climate, environment pollution monitoring, the source and sink, the distribution characteristics and change rules of its concentration and so on. In order to understand the research status well, we carried out a preliminary summary about the research methods of atmospheric CO based on the former research. The purpose of this study is to give some reasonable suggestions to improve the observation of the Polar Regions and the atmospheric chemical models.
The Paris agreement signed in April, 2016 aims to balance global anthropogenic carbon emissions and terrestrial carbon sinks by the middle of the 21st century. To fulfill this goal, it is necessary to calculate carbon fluxes of different regions reliably. The global carbon assimilation system is an effective technique for achieving this goal. The Ministry of Science and Technology of China supports the project entitled as study on the global carbon assimilation system based on multisource remote sensing data through the national key research and development programs for global change and adaptation during the thirteen-five period. This project will develop synergic inversion techniques for retrieving key parameters of biological and atmospheric cycles and for assimilating multisource remote sensing and ground based data. Then, the high resolution global carbon assimilation system coupled with an ecological model will be constructed. This system is able to assimilate jointly multisource observation data and to optimize key model parameters, photosynthesis and respiration carbon fluxes of global terrestrial ecosystems, and anthropogenic carbon emission fluxes of key regions. This system will be used to study quantitatively the spatial and temporal patterns of carbon fluxes of global terrestrial ecosystems and anthropogenic carbon emission fluxes of key regions and to identify the mechanisms driving the global terrestrial carbon sinks and sources. The outputs of this study will be helpful for the fulfillment of the key research and development programs for global change and adaptation and provide valuable data and technical support for the decision-making in China.
India Peninsula and East Asia are high aerosol loading regions as well as major regions influenced by Asian monsoon. The changes of monsoon intensity and precipitation have great influence on economy, especially agricultural production of monsoon regions. There are many researches of impacts of aerosol on Indian monsoon, which have achieved many comprehensive progresses. Earlier researches show that atmospheric brown cloud caused negative radiative forcing and weakened the warming induced by greenhouse gases. Current researches show that absorbing aerosol enhanced the Indian monsoon and increased rainfall in pre-monsoon season, while the scattering effect of aerosol weakened the Indian summer monsoon and the East Asian summer monsoon and rainfall in monsoon season. Due to so many factors affecting the monsoon, researches of aerosol impacts on monsoon become more complex. Thus, these results remain uncertain. This paper reviews previous researches and generalizes the mechanisms of impacts of aerosols on Asian monsoon. By comparing the East Asian summer monsoon with the Indian summer monsoon, we discussed deficiencies of the prior researches, and pointed out the direction for future researches about the impact of aerosol on the Asian summer monsoon, especially on the East Asian summer monsoon.
The establishment of satellite earth observation system is an important means for effective management and application of satellite information resources. From significant demands for earth observation in China as well as cutting-edge scientific issues, we propose some key technologies of developing earth observation satellite data integration system under big data environment, including semantic integration of large heterogeneous earth observation data, fast data processing of satellite remote sensing imagery based on grid, in-depth analysis and knowledge discovery of big satellite data, and collaboration processing of multiple data centers and cloud-platform.It is hoped to provide with new technologies and methods for satellite big data management, analysis and archiving.
By reviewing the advances in chemical processes, transport models and inverse modeling technologies concerning the atmospheric methane, problems in exploiting the sources and sinks of the atmospheric methane were discussed. The inverse modelling with the atmospheric chemical transport models significantly reduced the uncertainty in the estimation of methane emissions from the terrestrial and oceanic methane sources, when the observational data of the atmospheric methane concentration were assimilated in the inverse modeling. But at present, the quantification of the uncertainty in a priori estimations and the measurements of the atmosphere methane concentration were primarily empirically assigned and no scientifically reliable algorithm is available. Remotely sensed observations of the atmospheric methane concentration dynamics of global covering have greatly promoted the availability of the observations and thereafter improved the efficiency of the inverse modeling. With inverse modeling, the methane emission from natural wetland was identified as the major contributor to the inter-annual variation of the atmospheric methane concentration on global scale. And on regional scales, the inversion modeling has been used to revise national methane emission inventories in some countries and will be an option for verifying the national inventory in compliance with the UNFCCC articles.
Carbonaceous aerosols (or particles), which constitute one of most significant contribution of the atmospheric aerosols, are of worldwide concern due to their effects on environment, climate and human health. Two sub-fractions of total carbonaceous content of aerosols, Organic Carbon (OC) and Elemental Carbon (EC), not only differ in their origins but also in their effects on climate and human health. Radiocarbon (14C), as a radioactive isotope of carbon, has been proven to be a powerful tool of qualification and quantification of fossil and non-fossil contributions to OC and EC. This review introduces the principal and recent progress in the development of isolation method of different carbonaceous fraction for 14C measurement and compiles the results from 14C based source apportionment in China. Finally, the review concludes with some comments on current issues and future prospects using 14C as a source apportionment tool of atmospheric aerosols.
Particulate matter system over the ocean (i.e. marine aerosols) is very complex composition and source. Marine aerosols play a significant role in the total number of atmospheric particulate matter and they are an important part in the study of atmospheric science and global change. Compared with traditional offline observational analysis, the online particle mass spectrometric instruments have high sensitivity, high detection efficiency, high spatial and temporal resolution so that online measurements are widely used to characterize the fine particulate matter (fine atmospheric aerosol). The study in this paper focusd on the most widely used Aerosol Mass Spectrometry (AMS) and Aerosol Time of Flight Mass Spectrometry (ATOFMS), which were used to investigate and characterize the aerosol in islands, coastal oceans, open oceans and polar regions, respectively. We suggest the integrated use of the above-mentioned two mass spectrometers to investigate marine aerosol particle size, chemical composition and mixed state to obtain scientific data during China's offshore haze monitoring network and air pollution control.
Haze has become a major environmental problem in Beijing-Tianjin-Hebei in China. How to prevent the environmental degradation without reducing the speed of economic development has attracted the attention of the public and most of scholars. A brief summary about the formation and the control process of atmospheric pollution in some developed countries is reviewed and the particularity of the atmospheric pollution problems in China is pointed out. The importance of regional haze research to the economic and social development, climate and environmental change, human health and the regional harmonious development is reviewed. The frequent haze in Beijing-Tianjin-Hebei is mainly determined by sources and the meteorological elements. Some questions for further research of haze pollution in Beijing-Tianjin-Hebei are proposed. Finally, the atmospheric pollution trends in Beijing-Tianjin-Hebei and East Asia is summarized from the perspective of global climate change.
With the breakthrough of the satellite remote sensing key technology, satellite spectral resolution has reached to the level of distinguish between each spectral line, the researchers begin to research atmosphere profile and various micro constituent inversion using huge number of channels at the same time. This paper make a comment of the advances in Atmospheric humidity profile inversion using AIRS data, Analyzed and discussed the research status of clear sky atmospheric profiles from four aspects: training data, information extraction and dimensionality reduction of channels, inversion algorithm and accuracy improvement of Inversion. CIMSS and brightness temperature simulated used SARTA are usually chose to retrieve water vapor profile using AIRS data. Summarized two kinds of methods to do information extraction and dimensionality reduction, the first is spectral information compression, compared with PCA found that ICA is more practical. The second is channel selection, that is keeping part of channel contained more atmospheric profile information to achieve dimensionality reduction. It is worth mentioning that we need to choose different channel combination under different regional climate types, underlying surface, season, and real-time weather condition. Introduces three kinds of inversion algorithm: eigenvector regression algorithms(ERA), the Newton method(NM), and aritificial neural network algorithms(ANN). Compare the three methods found that ERA is simple, but the precision is not ideal; NW has high precision but it is not suitable for business application due to its long computing time; ANN has high computing speed and its precision can meet the requirements, thus, ANN has excellent foreground. Analyzed several samples classification method and additional factors, and give some suggestions to improve inversion algorithm. Finally, provide a brief introduction of infrared cloudcleared and inversion atmospheric profile under cloud condition.
The atmospheric duct of the troposphere comprises strong vertical refractivity gradient structures. It has great scientific significance and great value for propagations of radio waves and functions of surveillance equipments. According to the atmospheric duct types, the research methods of the atmospheric duct are reviewed. Based on the similarity theory, evaporation duct models are developed or built with dominant emphasis and applied to some local sea. The other duct-type research methods have experienced a process from simple to complex and from qualification analysis to accurate quantification. Numerical simulation with mesoscale meteorological models has become a very important method which has greatly improved the efficiency and accuracy of the atmospheric duct simulation or forecast. Based on the grid data of numerical simulation, atmospheric ducts such as duct occurrence are analyzed statistically and what weather processes or climates that cause them. Finally, using more meteorological methods and technology, research fields are pointed out based on the current condition of the atmospheric duct study. More hydrogeology and meteorological surveys and electromagnetic waves propagation experiments are carried out firstly. Meanwhile mesoscale meteorological and sea-air coupled models are further used with data assimilation and ensemble prediction system in the atmospheric duct study, which improves the accuracy of the atmospheric duct over the sea.
[WT5HZ]Abstract:[WT5BZ] The observation and source apportionment of carbonaceous aerosols is one of the focus of studies in the current scientific community. Radioactive (14C) and stable (13C) carbon isotopes have become useful tools in the source apportionment studies for carbonaceous aerosols. In this paper, we review the recent development of carbon isotope techniques, and explore its potential to be used for source apportionment for carbonaceous aerosols. It was pointed out that 14C has unique advantages in the quantitative distinguishment between fossil fuel and contemporary biomass combustion sources of atmospheric Organic Carbon (OC) and Black Carbon (BC), and that the combined 14C-13C analysis can better constrain the sources of carbonaceous aerosols. Recent progress towards isolating OC and BC from other components of the particles has made it appicable to perform 14C measurements for OC and BC seperately. As for 13C, it was proposed that while it is very important to investigate the isotopic fractionation mechanism of δ13C values of the carbonaceous aerosols, a regional δ13C signature map for the carbonacoues aerosols should be biult up aiming to facilitate explaining the δ13C variations and hence constraining the emisson sources. Future research that uses these carbon isotope techniques, in conjunction with other means such as Chemical Mass Balance (CMB) receptor models, statistical methods, air trajectory analysis and remote sensing, can provide unprecedented new insights into the sources and chemical characteristics of carbonaceous aerosols.
With the network construction of CINRAD weather radar, common radar products gradually have played an important role in weather modification work. For example, analyzing the direction and speed of movement, strength and type of precipitation can provide a reference for operation command. The velocity products can assist in choosing the best operational opportunity and position. The VIL products can identify hail cloud and guide the hail suppression. By integrated application of a variety of radar products on weather modification, command systems and operation parameters can be created and the effective test also can be made. However, there are some gaps and deficiencies in the application of so many products. Finally, some limitations of existing radar observation network are pointed out, but millimeter-wave cloud radar, the dual-polarization radar and the TITAN system can get more potential application. The future development direction of radar observation network is also discussed.
