Current Browsing: China


Long-term serial GIMMS vegetation index dataset in China (1981-2006)

GIMMS (glaobal inventory modelling and mapping studies) NDVI data is the latest global vegetation index change data released by NASA C-J-Tucker and others in November 2003. The dataset includes the global vegetation index changes from 1981 to 2006, the format is ENVI standard format, the projection is ALBERS, and its time resolution is 15 days and its spatial resolution is 8km. GIMMS NDVI data recorded the changes of vegetation in 22a area in the format of satellite data. 1. File format: The GIMMS-NDVI dataset contains all rar compressed files with a 15-day interval from July 1981 to 2006. After decompression, it includes an XML file, an .HDR header file, an .IMG file, and a .JPG image file. 2. File naming: The naming rules for compressed files in the NOAA / AVHRR-NDVI data set are: YYMMM15a (b) .n **-VIg_data_envi.rar, where YY-year, MMM-abbreviated English month letters, 15a-synthesized in the first half of the month, 15b-synthesized in the second half of the month, **-Satellite. After decompression, there are 4 files with the same file name, and the attributes are: XML document, header file (suffix: .HDF), remote sensing image file (suffix: .IMG), and JPEG image file. In this data set, the user uses the remote sensing image file with the suffix .IMG to analyze the vegetation index. Remote sensing image files with suffix of .IMG and .HDF used by users to analyze vegetation indices can be opened in ENVI and ERDAS software. 3. The data header file information is as follows: Coordinate System is:     PROJECTION ["Albers_Conic_Equal_Area"],     PARAMETER ["standard_parallel_1", 25],     PARAMETER ["standard_parallel_2", 47],     PARAMETER ["latitude_of_center", 0],     PARAMETER ["longitude_of_center", 105],     PARAMETER ["false_easting", 0],     PARAMETER ["false_northing", 0],     UNIT ["Meter", 1]] Pixel Size = (8000.000000000000000, -8000.000000000000000) Corner Coordinates: Upper Left (-3922260.739, 6100362.950) (51d20'23.06 "E, 46d21'21.43" N) Lower Left (-3922260.739, 1540362.950) (71d16'1.22 "E, 8d41'42.21" N) Upper Right (3277739.261, 6100362.950) (151d 8'57.22 "E, 49d 9'35.37" N) Lower Right (3277739.261, 1540362.950) (133d30'58.46 "E, 10d37'13.35" N) Center (-322260.739, 3820362.950) (101d22'21.08 "E, 35d42'18.02" N) Band 1 Block = 900x1 Type = Int16, ColorInterp = Undefined     Computed Min / Max = -16066.000,11231.000 4. Conversion relationship between DN value and NDVI  NDVI = DN / 1000, divided by 10000 after 2003   The NDVI value should be between [-1,1]. Data outside this interval represent other features, such as water bodies.

2020-06-08

A China Dataset of soil hydraulic parameters pedotransfer functions for land surface modeling (1980)

This data uses soil conversion functions to take sand, silt, clay, organic matter, and bulk density as inputs to estimate soil hydrological parameters, including parameters of the Clapp and Hornberger function and van Genuchten and Mualem function, field water holding capacity, and withering coefficient. Median and coefficient of variation (CV) provide estimates. The data set is in a raster format with a resolution of 30 arc seconds, and the soil is layered vertically into 7 layers with a maximum thickness of 1.38 meters (ie 0-0.045, 0.045--0.091, 0.091--0.166, 0.166--0.289, 0.289-- 0.493, 0.493--0.829, 0.829--1.383 meters). The data is stored in NetCDF format. The data file name and its description are as follows: 1. THSCH.nc: Saturated water content of FCH 2. PSI_S.nc: Saturated capillary potential of FCH 3. LAMBDA.nc: Pore size distribution index of FCH 4. K_SCH.nc: Saturate hydraulic conductivity of FCH 5. THR.nc: Residual moisture content of FGM 6. THSGM.nc: Saturated water content of FGM 7. ALPHA.nc: The inverse of the air-entry value of FGM 8. N.nc: The shape parameter of FGM 9. L.nc: The pore-connectivity parameter of FGM 10. K_SVG.nc: Saturated hydraulic conductivity of FGM 11. TH33.nc: Water content at -33 kPa of suction pressure, or field capacity 12. TH1500.nc: Water content at -1500 kPa of suction pressure, or permanent wilting point

2020-06-08

A China dataset of soil properties for land surface modeling

The source data of this data set are 1:1 million Chinese soil maps and 8,595 soil profiles from the second soil census.The data include section depth, soil thickness, sand, silt, clay, gravel, bulk density, porosity, soil structure, soil color, pH value, organic matter, nitrogen, phosphorus, potassium, exchangeable cation amount, exchangeable hydrogen, aluminum, calcium, magnesium, potassium, sodium ion and root amount.The dataset also provides data quality control information. The data is in raster format with a spatial resolution of 30 arc seconds.To facilitate the use of CLM model, soil data is divided into 8 layers, with the maximum depth of 2.3 meters (i.e. 0- 0.045, 0.045- 0.091, 0.091- 0.166, 0.166- 0.289, 0.289- 0.493, 0.493- 0.829, 0.829- 1.383 and 1.383- 2.296 m) Data file description: 1 Soil profile depth PDEP.nc 2 Soil layer depth "LDEP.nc LNUM.nc" 3 pH Value (H2O) PH.nc 4 Soil Organic Matter SOM.nc 5 Total N TN.nc 6 Total P TP.nc 7 Total K TK.nc 8 Alkali-hydrolysable N AN.nc 9 Available P AP.nc 10 Available K AK.nc 11 Cation Exchange Capacity (CEC) CEC.nc 12 Exchangeable H+ H.nc 13 Exchangeable Al3+ AL.nc 14 Exchangeable Ca2+ CA.nc 15 Exchangeable Mg2+ MG.nc 16 Exchangeable K+ K.nc 17 Exchangeable Na+ NA.nc 18 Particle-Size Distribution Sand SA.nc Silt SI.nc Clay CL.nc 19 Rock fragment GRAV.nc 20 Bulk Density BD.nc 21 Porosity POR.nc 22 Color (water condition unclear) Hue Unh.nc Value Chroma Unc.nc 23 Dry Color Hue Dh.nc Value Chroma Dc.nc 24 Wet Color Hue Wh.nc Value Chroma Wc.nc 25 Dominant and Second Structure S1.nc SW1.nc RS.nc 26 Dominant and Second Consistency C1.nc CW1.nc RC.nc 27 Root Abundance Description R.nc

2020-06-08

Geomorphological of China 1:4,000,000

The integration of geomorphological information in western China was completed by a team led by Dr. Xie Chuanjie, Institute of Geography, Resources and Environment, Chinese Academy of Sciences. These include the national geomorphological database of 1: 4 million and the western geomorphological database of 1: 1 million. The geomorphological data of 1: 4 million are tracked, collected and collated by the Geography Department of the National Planning Commission of the Chinese Academy of Sciences, "China Geomorphological Map (1: 4 million)" edited by Li Bingyuan and "Geomorphological Map of China and Its Adjacent Areas (1: 4 million)" edited by Chen Zhiming. Scan and register the data, vectorize all registered maps by ArcMap software, and establish their own classification and code systems. Geomorphological types are divided into basic geomorphological types and morphological structure types (point, line and surface representation) according to map spots (common staining) and symbols. Data are divided into structural geomorphology and morphological geomorphology. Projection information: Projection: Albers False_Easting: 0.000000 False_Northing: 0.000000 Central_Meridian: 105.000000 Standard_Parallel_1: 25.000000 Standard_Parallel_2: 47.000000 Latitude_Of_Origin: 0.000000 Linear Unit: Meter (1.000000) Geographic Coordinate System: datumg Angular Unit: Degree (0.017453292519943299) Prime Meridian: <custom> (0.000000000000000000) Datum: D_Krasovsky_1940 Spheroid: Krasovsky_1940 Semimajor Axis: 6378245.000000000000000000 Semiminor Axis: 6356863.018773047300000000 Inverse Flattening: 298.300000000000010000

2020-06-08

China 1km resolution digital elevation model dataset

DEM is the English abbreviation of Digital Elevation Model, which is an important source of data for river basin terrain and feature recognition. The principle of DEM is to divide the watershed into m rows and n columns of quadrilaterals (CELLs), calculate the average elevation of each quadrilateral, and then store the elevations in a two-dimensional matrix. Because DEM data can reflect local terrain features with a certain resolution, a large amount of surface morphological information can be extracted through DEM. These information include the slope, aspect, and relationship between cells in a watershed grid cell. At the same time, a certain algorithm can be used to determine the surface water flow path, the river network and the boundary of the watershed. Therefore, to extract watershed characteristics from DEM, a good watershed structure model is the premise and key of designing algorithms. The data includes: 1. 1: 1KM basic DEM Data based on China's 1: 250,000 contours and elevation points, including DEM, mountain shadows, slopes, and aspect maps 2. SRTM 1km DEM Cut from SRTM data of 1KM worldwide, including DEM, mountain shadow, slope, aspect map 3. ASTER GDEM According to the 30-meter ASTER GDEM, stitching, cutting, and resampling into 1KM The file formats are: geotiff Data set projection: Projection = Albers Conical Equal Area ", GEOGCS ["Krasovsky", DATUM ["Krasovsky", SPHEROID ["Krasovsky", 6378245,298.3000003760163]], PRIMEM ["Greenwich", 0], UNIT ["degree", 0.0174532925199433]], PROJECTION ["Albers_Conic_Equal_Area"], PARAMETER ["standard_parallel_1", 25], PARAMETER ["standard_parallel_2", 47], PARAMETER ["latitude_of_center", 0], PARAMETER ["longitude_of_center", 105], PARAMETER ["false_easting", 0], PARAMETER ["false_northing", 0], UNIT ["metre", 1,] Data range: Corner Coordinates: Upper Left (-3656885.097, 6579746.944) (51d 4'21.50 "E, 51d19'19.71" N) Lower Left (-3656885.097, 1560746.944) (73d20'22.18 "E, 9d42'56.35" N) Upper Right (3405114.903, 6579746.944) (155d50'50.17 "E, 52d29'29.44" N) Lower Right (3405114.903, 1560746.944) (134d36'43.08 "E, 10d27'15.15" N) Center (-125885.097, 4070246.944) (103d32'28.11 "E, 37d57'32.64" N)

2020-06-07

AVHRR_Path Finder vegetation index dataset of long time series in China (1981-2001)

The data used in this research was provided by the Pathfinder database of the EROS (Earth Resource Observation System) data center. The vegetation index NDVI was prepared by using the NOAA-AVHRR data source after radiation correction and geometric rough correction. Every day, each track image is processed with geometric fine correction, removal of bad lines, and removal of clouds, etc., and then NDVI calculation and synthesis. The daily NDVI calculation formula is: 1000 × (b2-b1) / (b2 + b1), where b1 and b2 are the first and second channels of AVHRR.          Parameter table of Pathfinder AVHRR Parameter / Variable Definition Unit Range NDVI Normalized Vegetation Index None (-1,1) CLAVR identification Cloudiness index from CLAVR algorithm None (0,30) QC identification Data quality identification None (0,16) Scanning angle Sensor angle Radian (-1.05, 1.05) Solar zenith angle Solar zenith angle per pixel Radian (0, 1.04) Relative zenith angle Relative zenith angle of the sensor Radian (-1.05, 1.05) Ch1 reflectance Reflectance of the first channel (0.58-0.68um) Percent (0,100) Ch2 reflectance Reflectivity of the second channel (0.72--1.10um) Percentage (0, 100) Ch3 brightness temperature Bright temperature value of the third channel (3.55-3.95um) Kelvin temperature scale (160, 340) Ch4 brightness temperature Brightness value of the fourth channel (10.3-11.3um) Kelvin temperature scale (160, 340) Ch5 brightness temperature Bright temperature value of the fifth channel (11.5-12.5um) Kelvin temperature scale (160, 340)     The data set includes data on NDVI in China's sub-regions from 1981 to June-September 2001, and data on tens of months in each of the years 1982, 1986, 1991, and 1996 (a total of 343 in 84 months, of which 1981 in June 1981). Data are missing in January and July 1st, and September 3rd 1994) Dataset attributes and format: This data set is stored in a year folder, which contains .HDR header files, .IMG files, and .JPG image files under the same file name. The data in the IMG is stored as integers. The naming rules are as follows: avhrrpf. *. Intfgl.yymmdd_geo where * represents ch1 or ch2 or ch4 or ch5 or ndvi, please refer to Table 1 for its specific meaning and range; yy represents the last two digits of the year; mm represents the month; dd represents the specific date. Data projection: Size is 963, 688 Coordinate System is: GEOGCS ["WGS 84",     DATUM ["WGS_1984",         SPHEROID ["WGS 84", 6378137,298.257223563,             AUTHORITY ["EPSG", "7030"]],         TOWGS84 [0,0,0,0,0,0,0],         AUTHORITY ["EPSG", "6326"]],     PRIMEM ["Greenwich", 0,         AUTHORITY ["EPSG", "8901"]],     UNIT ["degree", 0.0174532925199433,         AUTHORITY ["EPSG", "9108"]],     AUTHORITY ["EPSG", "4326"]] Origin = (70.035426000000001, 54.945585999999999) Pixel Size = (0.072727000000000, -0.072727000000000) Corner Coordinates: Upper Left (70.0354260, 54.9455860) (70d 2'7.53 "E, 54d56'44.11" N) Lower Left (70.0354260, 4.9094100) (70d 2'7.53 "E, 4d54'33.88" N) Upper Right (140.0715270, 54.9455860) (140d 4'17.50 "E, 54d56'44.11" N) Lower Right (140.0715270, 4.9094100) (140d 4'17.50 "E, 4d54'33.88" N) Center (105.0534765, 29.9274980) (105d 3'12.52 "E, 29d55'38.99" N) Band 1 Block = 963x1 Type = UInt16, ColorInterp = Undefined     Computed Min / Max = 1.000,55480.000

2020-06-04

Dataset of gridded daily precipitation in China (Version 2.0) (1961-2013)

The National Meteorological Information Center Meteorological Data Room has detected, controlled and corrected the quality of 2474 national-level ground stations' basic meteorological data and formed a set of high-quality, national and provincial ground-based basic data files. On the basis of the basic ground data of the precipitation data files, the thin-plate spline method is used, introducing the digital elevation data to eliminate the influence of the elevation on the precipitation precision under the unique terrain conditions in China. A dataset of 0.5°×0.5° grid values for the surface precipitation in China since 1961 is established. It provides a data basis for accurately describing the trends and magnitudes of precipitation changes in China. One of two data sources for the development of “Dataset of Gridded Daily Precipitation in China (Version 2.0)” was 1) the monthly and daily precipitation data of 2474 national-level stations in the country archived by the Meteorological Data Room for nearly 50 years. The information comes from the monthly information of the “Monthly Report of the Surface Meteorological Record” reported by the climate data processing departments of all the provinces, municipalities and autonomous regions. That information is collected, organized and strictly checked and reviewed by the National Meteorological Information Center. Since the establishment of the station, many stations in the country have undergone historical changes such as business reform and station migration. In 1961, the total number of stations had stabilized above 2,000, and the number of backstage stations in the late 1970s reached 2,400. 2) The second data source was a Chinese range of 0.5°×0.5° digital elevation model data DEMs generated by GTOP030 data (resolution 30′′×30′′) resampling. For the quantitative analysis and evaluation of the data, please see the Dataset of Gridded Daily Precipitation in China - Data Specification.

2020-06-03

National annual average surface temperature and freezing index by remote sensing (2008)

The 2008 national remote sensing annual average surface temperature and freezing index is a 5 km instantaneous surface temperature data product based on MODIS Aqua/Terra four times a day by Ran Youhua et al. (2015). A new method for estimating the annual average surface temperature and freezing index has been developed. The method uses the average daily mean surface temperature observed by LST in morning and afternoon to obtain the daily mean surface temperature. The core of the method is how to recover the missing data of LST products. The method has two characteristics: (1) Spatial interpolation is carried out on the daily surface temperature variation observed by remote sensing, and the spatial continuous daily surface temperature variation obtained by interpolation is utilized, so that satellite observation data which is only once a day is applied; (2) A new time series filtering method for missing data is used, that is, the penalty least squares regression method based on discrete cosine transform. Verification shows that the accuracy of annual mean surface temperature and freezing index is only related to the accuracy of original MODIS LST, i.e. the accuracy of MODIS LST products is maintained. It can be used for frozen soil mapping and related resources and environment applications.

2020-06-03

Frozen soil map of China (2000)

Overviewing the various frozen soil maps in China, there are great differences in the classification systems, data sources, and mapping methods. These maps represent the stage of understanding of the permafrost distribution of China in the past half century. To reflect the distribution and area of frozen soil in our country more reasonably, we have made a new frozen soil distribution map based on the analysis of the existing frozen soil maps. The map combines several existing maps of permafrost and the simulation results of a permafrost distribution model on the Tibetan Plateau. It unifies the acquisition time of data from various parts of the country and reflects the distribution of permafrost in our country around 2000. In the new frozen soil map, the distributions of various types of frozen soil are determined according to the following principles. 1. The base map uses the Geocryological Regionalization and Classification Map of the Frozen Soil in China (1:10 000 000) (Guoqing Qiu et al., 2000). The distribution of permafrost and instantaneous frozen soil in the high mountains outside the Tibetan Plateau follows the original map; the boundaries of seasonal frozen soil and instantaneous frozen soil, instantaneous frozen soil and nonfrozen soil remain unchanged, too. The distribution of permafrost on the Tibetan Plateau and in the high latitudes of the Northeast is updated with the following results. 2. The distribution of high-altitude permafrost and alpine permafrost in the Tibetan Plateau region is updated using the simulation results of Zhuotong Nan et al. (2002). This model uses the measured average annual ground temperature data of 76 boreholes along the Qinghai-Tibet Highway to perform regression statistical analysis and obtains the relationship between annual mean geothermal data with latitude and elevation. Based on this relationship, combined with the GTOPO30 elevation data (global 1-km digital elevation model data developed under the leadership of the US Geological Survey's Earth Resources Observation and Technology Center), the average annual ground temperature distribution over the entire Tibetan Plateau is simulated, the average annual ground temperature is 0.5 C, and it is used as the boundary between permafrost and seasonal frozen soil. 3. The distribution of permafrost at high latitudes in the Northeast is based on the latest results from Jin et al. (2007). Jin et al. (2007) analyze the average annual precipitation and soil moisture in Northeast China over the past few decades and conclude that the relationship between the southern boundary of permafrost in Northeast China and the annual average temperature has not changed substantially in the past few decades. 4. Alpine permafrost distribution in other regions is updated with the Map of the Glaciers, Frozen Ground and Deserts in China (1:4 million) (Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, 2006). In terms of classification systems, the current existing frozen soil maps use continuous standards for the division of permafrost, but the specific definition of continuity is very different. Many studies have shown that the continuity criterion is a concept closely related to scale, it is not suitable for the classification of permafrost at high altitude (Guodong Cheng, 1984; Cheng et al., 1992), and it cannot be applied to the permafrost distribution model that uses grid as the basic simulation unit. In this paper, we abandon the continuity criteria and take the existence of frozen soil in the mapping unit (grid or region). The new frozen soil map divides China's frozen soil into several categories: (1) High latitude permafrost; (2) High altitude permafrost; (3) Plateau permafrost; (4) Alpine permafrost; (5) Medium-season seasonal frozen soil: the maximum seasonal freezing depth that can be reached is >1 m; (6) Shallow seasonal frozen soil: the maximum seasonal freezing depth that can be achieved is <1 m; (7) Instant frozen soil: less than one month of storage time; and (8) Nonfrozen soil. For a specific description of the data, please refer to the explanatory documents and citations.

2020-06-03

Anhui 1:1 million wetland data (2000)

The data was compiled from "China's 1:100,000 wetland data". "China 1:100,000 wetland data" mainly reflects the information of marshes and wetlands throughout the country in the 2000s, and is represented by geographical coordinates in decimal scale. The main contents include: types of marshes and wetlands, types of water supply, types of soil, types of main vegetation, and geographical regions.The information classification and coding standard of China sustainable development information sharing system was implemented.Data source of this database: 1:20 swamp map (internal version), 1:500 000 swamp map (internal version) of qinghai-tibet plateau, 1:100 000 swamp survey data and 1:400 000 swamp map of China;The processing steps are as follows: data source selection, preprocessing, marshland element digitization and coding, data editing and processing, establishment of topological relationship, edge-to-edge processing, projection transformation, connection with attribute database such as geographical name and acquisition of attribute data.

2020-05-28