The dataset of surface roughness measurements was obtained in No. 1 and 2 quadrates of the Biandukou foci experimental area during the pre-observation period. Both the quadrates were divided into 3×3 subsites, with each one spanning a 30×30 m2 plot. The original photos of each sampling point, surface height standard deviation (cm) and correlation length (cm) were included. With the roughness grid board 110cm long and the measuring intervals of 1cm, the samples were collected along the soil surface from south to north and from east to west, respectively. The coordinates of sample points would be got with the help of ArcView; and after geometric correction, surface height standard deviation (cm) and correlation length (cm) could be acquired based on the formula listed on pages 234-236, Microwave Remote Sensing, Vol. II. The roughness data files were initialized by the sample name, which was followed by the serial number, the name of the file, standard deviation and correlation length. Each .txt file is matched with one sample photo and standard deviation and correlation length represent the roughness. In addition, the length of 101 needles is also included for further checking. Those provide reliable ground data for improving and verifying the microwave remote sensing algorithms.

The dataset of ground truth measurement synchronizing with MODIS was obtained in C1, G1 and B2 of the Biandukou foci experimental area on Mar. 12, 2008. Observation items included: (1) the surface temperature by the handheld infrared thermometer in C1, G1 and B2 from 11:30 to 12:15. The underlying surface was the deep plowed land, the rape stubble and the grassland. (2) the gravimetric soil moisture (soil samples from 0-1cm, 1-3cm, 3-5cm, 5-10cm and 10-20cm) by the microwave drying method. (3) the frost depth by the chopstick and the ruler. The soil was considered frozen when it was hard and with ice crystal. The land cover type photos were archived. Four data files were archived, MODIS data, C1 (the land cover type, the surface temperature and the vegetation parameters), G1 ( the surface temperature, the frost depth and the soil moisture) and B2 (the surface temperature, the frost depth and the soil moisture) data.

The dataset of ground truth measurements synchronizing with ASTER was obtained in the saline plot B, the alfalfa plot D and the barley plot E of the Linze grassland foci experimental area on May 28, 2008. 49 points at intervals of 60m in each plot (360m×360m) were selected and observation items included: (1) the land surface radiative temperature by the hand-held infrared thermometer from east to west in the saline plot B, the alfalfa plot D and the alfalfa plot E. Each point was numbered, such as D22-23, indicating from No. 22 to 23 in the alfalfa plot D. In the salineplot B, 5 measurements were carried out each 5m; in the alfalfa plot D and the barley plot E, measurements were at random. Calibration information was archived in the hand-held infrared thermometer calibration.xls. (2) soil gravimetric moisture, volumetric moisture, and soil bulk density after drying measured by the cutting ring and the mean soil temperature from 0-5cm measured by the probe thermometer in plot B; the soil temperature, soil moisture, the loss tangent, soil conductivity, the real part and the imaginary part of soil complex permittivity measured by the POGO soil sensor, and the mean soil temperature from 0-5cm measured by the probe thermometer in plot D; soil moisture, soil conductivity, the soil temperature, and the real part of soil complex permittivity were measured by WET, and the mean soil temperature from 0-5cm by the probe thermometer in plot E. Six Excel files on soil moisture and the land surface radiative temperature in plot B, D and E were archived. See WATER: Dataset of setting of the sampling plots and stripes in the foci experimental area of Linze station for more information.

The dataset of ground truth measurement synchronizing with Landsat TM was obtained in the Yingke oasis and Huazhaizi desert steppe foci experimental areas on May 20, 2008. Observation items included: (1) LAI in Yingke oasis maize field. The maximum leaf length and width of each alfalfa and barley were measured. Data were archived in Excel format. (2) Reflectance spectra in Yingke oasis maize field by ASD FieldSpec (350-2500nm, the vertical canopy observation and the transect observation) from Institute of Remote Sensing Applications (CAS), and in Huazhaizi desert No. 2 plot by ASD FieldSpec (350-1603nm, the vertical observation and the transect observation for reaumuria soongorica and the bare land) from Beijing Academy of Agriculture and Forestry Sciences. The grey board and the black and white cloth were also used for calibration spectrum. Raw data were binary files direct from ASD (by ViewSpecPro), and pre-processed data on reflectance were in Excel format. (3) the radiative temperature by 3 handheld radiometers in Yingke oasis maize field (Institute of Remote Sensing Applications, BNU and Institute of Geographic Sciences and Natural Resources respectively, the vertical canopy observation and the transect observation), and by 3 handheld infrared thermometers in Huazhaizi desert No. 2 plot (the vertical vegetation and bare land observation). The data included raw data (in Word format), recorded data and the blackbody calibrated data (in Excel format). (4) the radiative temperature of maize, wheat and the bare land of Yingke oasis maize field by ThermaCAM SC2000 (1.2m above the ground, FOV = 24°×18°). The data included raw data (read by ThermaCAM Researcher 2001), recorded data and the blackbody calibrated data (archived in Excel format). (5) Photosynthesis of maize, wheat and the bare land of Yingke oasis maize field by LI6400, carried out according to WATER specifications. Raw data were archived in the user-defined format (by notepat.exe) and processed data were in Excel format. (6) Maize albedo by the shortwave radiometer in Yingke oasis maize field. R =10H (R for FOV radius; H for the probe height). Data were archived in Excel format. (7) Atmospheric parameters in Huazhaizi desert No. 2 plot by CE318 (produced by CIMEL in France). The total optical depth, aerosol optical depth, Rayleigh scattering coefficient, column water vapor in 936 nm, particle size spectrum and phase function were then retrieved from these observations. The optical depth in 1020nm, 936nm, 870nm, 670nm and 440nm were all acquired by CE318. Those data include the raw data in k7 format and can be opened by ASTPWin. ReadMe.txt is attached for detail. Processed data (after retrieval of the raw data) in Excel format are on optical depth, rayleigh scattering, aerosol optical depth, the horizontal visibility, the near surface air temperature, the solar azimuth, zenith, solar distance correlation factors, and air column mass number. (8) Coverage fraction of Reaumuria soongorica by the self-made coverage instrument and the camera (2.5m-3.5m above the ground) in Huazhaizi desert No. 2 plot. Based on the length of the measuring tape and the bamboo pole, the size of the photo can be decided. GPS data was used for the location and the technology LAB was used to retieve the coverage fractionof the green vegetation. Besides, such related information as the surrounding environment was also recorded. Data included the vegetation iamge and coverage (by .exe). (9) The radiative temperature of Reaumuria soongorica canopy and the bare land by 2 fixed automatic thermometers (FOV: 10°; emissivity: 0.95) in Huazhaizi desert No. 2 plot, observing straight downwards at intervals of 1s. Raw data, blackbody calibrated data and processed data were all archived in Excel format.

The dataset of airborne imaging spectrometer (OMIS-II) mission was obtained in the Dayekou watershed flight zone on Jun. 4, 2008. Data after radiometric correction and calibration and geometric approximate correction were released. The flying time of each route was as follows: {| ! id ! flight ! file ! starttime ! lat ! long ! alt ! image linage ! endtime ! lat ! long ! alt |- | 1 || 4-13 || 2008-06-04_13-19-02_DATA.BSQ || 13:23:45 || 38.542 || 100.382 || 4624.5 || 3125 || 13:27:13 || 38.493 || 100.230 || 4617.5 |- | 2 || 4-12 || 2008-06-04_13-30-55_DATA.BSQ || 13:31:21 || 38.494 || 100.214 || 4644.9 || 2912 || 13:34:35 || 38.543 || 100.370 || 4626.3 |- | 3 || 4-11 || 2008-06-04_13-38-17_DATA.BSQ || 13:39:14 || 38.551|| 100.381 || 4616.2 || 3051 || 13:42:38 || 38.500 || 100.221 || 4656.5 |- | 4 || 4-10 || 2008-06-04_13-46-20_DATA.BSQ || 13:47:09 || 38.502 || 100.212 || 4640.3 || 2866 || 13:50:20 || 38.550 || 100.365 || 4633.4 |- | 5 || 4-9 || 2008-06-04_13-54-02_DATA.BSQ || 13:55:01 || 38.558 || 100.374 || 4644.3 || 2897 || 13:58:14 || 38.511 || 100.223 || 4628.4 |- | 6 || 4-8 || 2008-06-04_14-01-56_DATA.BSQ || 14:01:51 || 38.511 || 100.209 || 4644.6 || 2751 || 14:04:54 || 38.558 || 100.359 || 4655.7 |- | 7 || 4-7 || 2008-06-04_14-08-36_DATA.BSQ || 14:09:28 || 38.568 || 100.373 || 4630.5 || 2995 || 14:12:48 || 38.519 || 100.218 || 4642.8 |- | 8 || 4-6 || 2008-06-04_14-16-30_DATA.BSQ || 14:16:38 || 38.521 || 100.209 || 4650.1 || 2705 || 14:19:38 || 38.568 || 100.357 || 4652.9 |- | 9 || 4-5 || 2008-06-04_14-23-20_DATA.BSQ || 14:24:25 || 38.576 || 100.367 || 4649.0 || 2958 || 14:27:42 || 38.526 || 100.210 || 4673.5 |- | 10 || 4-4 || 2008-06-04_14-31-24_DATA.BSQ || 14:31:09 || 38.527 || 100.199 || 4631.3 || 2817 || 14:34:17 || 38.576 || 100.353 || 4641.7 |- | 11 || 4-3 || 2008-06-04_14-37-59_DATA.BSQ || 14:39:55 || 38.579 || 100.346 || 4599.6 || 2555 || 14:42:46 || 38.536 || 100.210 || 4612.0 |- | 12 || 4-2 || 2008-06-04_14-46-28_DATA.BSQ || 14:46:20 || 38.535 || 100.194 || 4620.5 || 2869 || 14:49:31 || 38.583 || 100.345 || 4639.2 |- | 13 || 4-1 || 2008-06-04_14-53-13_DATA.BSQ || 14:55:36 || 38.594 || 100.364 || 4621.2 || 3018 || 14:58:58 || 38.544 || 100.206 || 4606.9 |}

The dataset of ground truth measurements synchronizing with ASTER was obtained in the Linze station foci experimental area on May 28, 2008. Observation items included: (1) soil moisture (0-5cm) measured once by the cutting ring method at the corner points of the 40 subplots of the west-east desert transit zone strip once by cutting ring method in the corner points of nine subplots of the north-south desert transit zone, once by the cutting ring method and once by ML2X Soil Moisture Tachometer in the center points of nine subplots of the farmland. The preprocessed soil volumetric moisture data were archived as Excel files. (2) surface radiative temperature measured by the handheld infrared thermometer (5# and 6# from Cold and Arid Regions Environmental and Engineering Research Institute which were both calibrated) in 40 subplots of the west-east desert transit zone strip (repeated 14-30 times), and nine subplots of the north-south desert transit zone strip (repeated 12-30 times). Data were archived as Excel files. (3) BRDF of maize and desert scrub measured by ASD Spectroradiometer (350～2 500 nm) from BNU, the 40% reference board , two observation platforms of BNU make and one of Institute of Remote Sensing Applications make in Wulidun farmland quadrates and the desert transit zone strips. Raw spectral data were archived as binary files, which were recorded daily in detail, and pre-processed data on reflectance and transmittivity were archived as text files (.txt). (4) LAI measured by two methods in the the Wulidun farmland quadrates and Linze station quadrates. One is manual method. The LAI, plant height and the spacing of selected samples were measured by the ruler and the number of the sapmles in the quadrate were counted. Then the LAI can be calculated. The other method is LI-3100. Data were archived as Excel files.

The dataset of fresh snow properties observations was obtained at the temporary sampling plot in the Qilian county on Mar. 20, 2008. Those provide reliable data for retrieval of snow parameters from remote sensing approaches. Observation items included: (1) Snow parameters such as snow depth, snow grain size by the handheld microscope, and snow density by the snow shovel (2) Fresh snow albedo by the total radiometer (3) Fresh snow spectrum by ASD Two files including raw data and preprocessed data were archived.

On 19 August 2012, a RCD30 camera of Leica Company boarded on the Y-12 aircraft was used to obtain the CCD image. RCD30 camera has a focal length of 80 mm and four bands including red, green, blue and near-infrared bands. The absolute flight altitude is 2900 m and ground sample distance is 10 cm. The data includes TIF images and exterior orientation elements.

The dataset of ground truth measurement synchronizing with the airborne microwave radiometers (L&K bands) mission in the Linze station foci experimental area on Jul. 4, 2008. Observation items included: (1) soil moisture (0-5cm) measured by the cutting ring method (50cm^3) from sample points of the P1 to P6 strips (17 sample points each),. Photos were also taken. The preprocessed soil volumetric moisture data were archived as Excel files. (2) surface radiative temperature measured by the three handheld infrared thermometer (5# and 6# from Cold and Arid Regions Environmental and Engineering Research Institute, and one from Institute of Geographic Sciences and Natural Resources, which were all calibrated) from P1 to P6 strips quadrates. There are 34 sample points in total and each was repeated three times synchronizing with the airplane. Photos were taken. Data were archived as Excel files. See the metadata record “WATER: Dataset of setting of the sampling plots and stripes in the Linze station foci experimental area” for more information of the quadrate locations.

The dataset of ground truth measurements synchronizing with the airborne microwave radiometers (L&K bands) mission was obtained along the sample lines 1, 2, 3, 4, 5 and 6 of the Linze grassland foci experimental area on May 25, 2008. Complementary measurements were carried out along Line 7 on Jun. 2. 25 points at intervals of 100m were selected at each line. Simultaneous with the satellite overpass, numerous ground data were collected, the soil temperature, soil moisture, the loss tangent, soil conductivity, the real part and the imaginary part of soil complex permittivity measured by the POGO soil sensor, the mean soil temperature from 0-5cm measured by the probe thermometer, and the surface radiative temperature measured three times by the hand-held infrared thermometer in L1, L2, L3 and L4; soil volumetric moisture, soil conductivity, the soil temperature, and the real part of soil complex permittivity were measured by WET, the mean soil temperature from 0-5cm measured by the probe thermometer, and the surface radiative temperature measured three times by the hand-held infrared thermometer in L5 and L6; the soil temperature, soil moisture, the loss tangent, soil conductivity, the real part and the imaginary part of soil complex permittivity by the POGO soil sensor, the mean soil temperature from 0-5cm measured by the probe thermometer, and the surface radiative temperature measured by the hand-held infrared thermometer, and soil gravimetric moisture, volumetric moisture, and soil bulk density measured by the cutting ring in L7. See WATER: Dataset of setting of the sampling plots and stripes in the foci experimental area of Linze station for more information.

The dataset of surface roughness measurements was obtained in A1, A2, A3, L1, L2, L3, L4, L5 and L6 of the A'rou foci experimental area. The quadrates were changed into 3×3 subsites during the foci experimental period, with each one spanning a 30×30 m2 plot. With the roughness plate 110cm long and the measuring points distance 1cm, the samples were collected along the strip from south to north and from east to west, respectively. As for the sampling lines, the samples were collected every 100 m along them from south to north. Photos were named in the form of A3-1EW, indicating No. 1 point in A3 measured from east to west. The coordinates of the sample would be got with the help of ArcView; and after geometric correction, surface height standard deviation (cm) and correlation length (cm) could be acquired based on the formula listed on pages 234-236, Microwave Remote Sensing, Vol. II. The roughness data were initialized by the sample name, which was followed by the serial number, the name of the file, standard deviation and correlation length. Each .txt file is matched with one sample photo and standard deviation and correlation length represent the roughness. In addition, the length of 101 radius is also included for further checking. Those provide reliable ground data for improving and verifying the remote sensing algorithms. Nine files were included, ARou_SampleArea1, ARou_SampleArea2, ARou_SampleArea3, ARou_SampleLine1, ARou_SampleLine2, ARou_SampleLine3, ARou_SampleLine4, ARou_SampleLine5 and ARou_SampleLine6.

The dataset of the truck-mounted dual polarized doppler radar observations (time-continuous 10-minute on the 250m×250m horizontal grid) was obtained in the arid region hydrology experiment area from May 20 to Jul. 5, 2008. The observation site (38.73°N, 100.45°E, 1668m) was typical of complex underlying surface and transit zone landscapes. The aim was to explore and retrieve precipitation type and intensity by radar in cold regions, with the precipitation particle drop size analyzer and ground intensive measurements occurring simultaneously, thus making it possible to produce a high resolution precipitation dataset. The 714XDP X-band dual-linear polarization Doppler weather radar was with a horizontal resolution of 150 m, an azimuth resolution of 1, VCP from 10-22 layers and the scanning cycle 10 minutes. ZH, ZDR and KDP could be acquired together. For more details, please refer to Readme file.