The maximum freezing depth is an important indicator for the thermal state of seasonally frozen ground， and its changes have an important impact on the regional water cycle， ecological processes and engineering stability. This paper released a soil maximum freezing depth grid dataset for 10-year period from 1961 to 2020 in Northwest China and Tibet， with a spatial resolution of 1 km. The dataset was produced by integrating downscaled and bias corrected weather data， elevation and soil properties using a support vector machine model with 200 ensemble simulations. The 10-fold cross-validation shows that the accuracy of the support vector machine model is acceptable ［R² = 0.70 ± 0.29， RMSE = （23.63 ± 10.30） cm， bias = （-0.77 ± 6.01） cm］. Validation using in-situ data shows that the R² for the four periods 1980s， 1990s， 2000s and 2010s are 0.77， 0.83， 0.73 and 0.71 respectively， and the RMSE are 27.14 cm， 22.42 cm， 21.63 cm and 23.58 cm respectively. The uncertainty of the simulation results is stable throughout the simulation period. Based on this dataset， we found that the soil maximum freezing depth in the Northwest China and Tibet decreased significantly between 1960s and 2020s， with an average rate of 3.02 cm per decade. The dataset can be downloaded via the National Tibetan Plateau/Third Pole Environment Data Center （DOI： 10.11888/Geocry.tpdc.271774）.

Since the 1960s， 297 expeditions carried out by Scientific Ocean Drilling have recovered more than 4×10⁵ meters of cores and collected a large amount of data. However， the data based on core sample testing and direct observation are scattered in different documents and databases in a heterogeneous format， which hinders the extensive sharing and effective use of them. Through systematic investigation of the official reports， databases， and academic papers of the four stages of Scientific Ocean Drilling， we show the present status of these scientific data including their sources， storage media， and specific types. The data of Scientific Ocean Drilling mainly consist of shipboard and post-expedition results. Nearly 200 data types classified into 15 categories including coring summary， lithostratigraphy， sedimentology and mineralogy， paleontology， stratigraphy， geochemistry， structural geology， geophysics， etc. are recorded in tables， figures， and texts. We find that these scientific data are hierarchically organized and have specific spatial-temporal properties； their sources are both straightforward and complex with different storage formats； and data types of different sites are not only consistent but also diverse. The data of Scientific Ocean Drilling are typical scientific big data in the field of earth sciences. Meanwhile， it is believed that the compilation of the Scientific Ocean Drilling Data would be of significance for fast data acquisition and future studies. This step not only has the potential to solve major scientific problems in the field of Earth science such as long-term biological evolution， global material circulation， paleoclimate and paleoceanography， and deep-sea mineral resource evaluation， but may contribute to the transformation of scientific research paradigm as well. Meanwhile， a proposal for data format unification and data compilation is also presented here.

Model test is widely accepted and used in the field of civil engineering， mining engineering and earth sciences， etc. At present， the static terrain data are measured before and after each experiment by terrestrial laser scanning， however it is necessary to explore new technology to obtain dynamic terrain data in the course of the experiment. By taking the specified experimental tests of debris avalanche as an example， the method of 4D reconstruction based on dynamic photogrammetry was described in detail. The dynamic terrain data of the model test were obtained after the data had been processed， and then the propagation and deposit features of debris avalanche were analyzed in detail. The results show that the dynamic terrain data of the model test can be obtained accurately with the method， and the interpretation of the propagation and deposit should be relatively easy by analyzing the data of model test in detail. This is not only the new technology applied in the document of the dynamic terrain of the model test， but also causes a great change for the experimental analysis， and it deserves to be applied widely.

Scientific data are strategic resources, and the aggregation of scientific data is an important method to seize the upstream and competitive highlands of scientific data. Notably, it is challenging to grasp the international situation and the scientific laws concerning the mode of scientific data aggregation; exploring the modes and methods of scientific data aggregation that are suitable for China's national conditions is also difficult. This paper investigated and analyzed the modes of scientific data aggregation both at home and abroad from the viewpoints of international organizations, international scientific programs, government agencies, and professional data centers. Five modes of scientific data aggregation were summarized, including scientific research projects converging to designated data centers/repositories, scientific research projects dispersing to data centers/repositories, individual scientists submitting datasets to data centers/repositories with published papers, scientific research projects/individual scientists sharing directories/networks, big data computing/processing platform, and citizen science models of open and public convergence. This paper analyzed each mode and the corresponding cases. On this basis, the paper put forward six suggestions for the reasonable aggregation of scientific data in China, including the implementation of the “Measurement of Scientific Data Management”, certification of data aggregation centers, scientific data collection and publishing in journals, construction of data aggregation networks, aggregation of international resources, and construction of the whole data aggregation chain.

The U-Pb chronology of detritus zircon is an important method to explore sediment provenance, which is widely used in sedimentology, geotectonics, geomorphology and other fields. This paper reviewed the recent progress of the U-Pb chronology of detrital zircon from three aspects: data acquisition, analysis and comparison. In terms of data acquisition, the sample preparation method, isotope age data selection and test quantity were expounded from the basic principle; In terms of data analysis, the data visualization methods of Probability Density Plot (PDP), Kernel Density Estimate (KDE) and Cumulative Age Distribution (CAD) were compared; In terms of data comparison, the basic algorithm and application advantages of quantitative comparison were analyzed with examples, including (dis)similarity measures based on non-parametric hypothesis tests (K-S test), (dis)similarity measures based on age spectrum comparison (Cross-correlation coefficients) and (dis)similarity measures based on Multi-Dimensional Scali (MDS). Finally, three commonly used software tools were introduced. Suggestions were given in terms of data acquisition, analysis and comparison for future research.

In order to evaluate the quality of the offshore magnetic data in the Earth Magnetic Anomaly Grid (2-arc-minute resolution)(EMAG2), the authors chose the aeromagnetic data at 1∶500 000 and 1∶1 000 000 scales of the southern section of the Kolbeinsey Ridge with a total area of 193 500 km² to compare and analyze. Based on the EMAG2 data, the authors obtained the EMAG2 (downward continuation 4 km) and the aeromagnetic anomaly (upward continuation 4 km) using the analytical continuation method. Then, the correlation coefficients between the aeromagnetic anomaly (upward continuation 4 km) and the EMAG2, and the aeromagnetic anomaly and the EMAG2 (downward continuation 4 km) were calculated by the correlation analysis method. Finally, through comprehensive analysis of the features of these correlation coefficients and differences, the quality of the magnetic data of the southern section of the Kolbeinsey Ridge was evaluated in the database EMAG2. The results showed that the EMAG2 integrated a large number of the airborne or offshore magnetic data. The quality of the offshore magnetic data is relatively high in the offshore areas with dense lines. However, the quality of the offshore magnetic data is relatively low if the EMAG2 data at 4 km altitude is converted to the anomaly data at sea level.

Scientific data is an important scientific and technological basis and national strategic resource. With the coming of the era of big data, countries all over the world have added scientific data management into their national development strategies. In order to improve the scientific data management in our country and make full use of the development opportunity from big data, the General Office of the State Council officially issued “The Measures for the Administration of Scientific Data” in March, 2018. In the new international and domestic policy on data management, this study analyzed and summarized 11 aspects of international situation of scientific data management, and dissected the development models of developed countries’ scientific data centers deeply. And also, the study put forward new ideas for the policy-making of scientific data, the construction of scientific data centers, the life cycle management of scientific data, the capacity building of data organizations, the authentication of scientific data, the publication of data, the return mechanism of the data and the comprehensive integration, and the safety management of the data in the scientific data management of Earth sciences in China.

With the successful launch of the sixteen MEO satellites of the Beidou-3 global satellite navigation system and the broadcast of new signals, Beidou has officially entered the global construction stage while the international GNSS Monitoring and Assessment System (iGMAS) is also performing systematic testing and evaluation on various aspects of operational performance from satellite end to ground receiving end of Beidou-3 system. This paper analyzed and evaluated the observation quality of new signals B1C and B2a broadcasted by the twelve new Beidou-3 MEO satellites on the observation data integrity rate, multipath error, pseudorange noise and Carrier-to-Noise Ratio (CNR) compared with GPS and GALILEO. The results show that the observation data integrity rate of B1C signal is better than that of B2a signal in the Beidou-3 system. In the aspects of multipath error, pseudorange noise and CNR, B2a signal is better than that of B1C. The performances of the twelve MEO satellites of Beidou-3 are equivalent, that is, for Beidou-3, the consistency of satellites can be guaranteed. In terms of pseudo-range noise, Beidou-3 is slightly worse than GPS and GALILEO While the observation data integrity rate, multipath error and CNR of Beidou-3 are equivalent to those of GPS and GALILEO.

The mechanism of earthquake inoculation and the process of earthquake occurrence are very complicated. Additionally, earthquakes do not happen very often, and we lack enough cognition to the earth’s interior structure, activity regularity and other key elements. As a result, research progress about the theory of earthquake precursors has been greatly restricted. Ground gravity observation has become one of the main ways to study earthquake precursor information in many countries and regions. This paper briefly summarized the surface gravity observation technology and observation network in China: the surface gravity measurement instrument developed from Huygens physical pendulum in seventeenth Century to today’s high-precision absolute gravimeter, and its accuracy reached to ±1×10^-8 m/s². China has successively established the National Gravity Network, Digital Earthquake Observation Network of China,the Crustal Movement Observation Network of China Ⅰ and the Crustal Movement Observation Network of China, to provide a public platform for monitoring non tidal gravity change, seismic gravity and tectonic movement. The use of specific examples illustrated the role of gravity observation data in earthquake prediction. The gravity observation data of ground gravity can be used to capture the information of gravity change in the process of strong earthquake inoculation, and to provide an important basis for the long-term prediction of strong earthquakes. The temporal and spatial variation characteristics of the regional gravity field and its relation to strong earthquakes were analyzed: Before the earthquake whose magnitude is higher than M_S 5, generally there will be a large amplitude and range of gravity anomaly zones. Strong earthquakes occur mainly in areas where the gravity field changes violently. The dynamic change images of gravity field can clearly reflect the precursory information of large earthquakes during the inoculation and occurrence. Finally, the existing problems of surface gravity technology in earthquake precursor observation were put forward and the use of gravity measurement data in earthquake prediction research was prospected.