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WATER: Dataset of ground truth measurement synchronizing with Envisat ASAR in the arid region hydrological experimental area during the pre-observation period on Sep. 19, 2007

The dataset of ground truth measurement synchronizing with Envisat ASAR was obtained in the arid region hydrological experimental area on Sep. 19, 2007 during the pre-observation period. One scene of Envisat ASAR image was captured on Sep. 19. The data were in AP mode and VV/VH polarization combinations, and the overpass time was approximately at 11:29 BJT. Those provide reliable ground data for remote sensing retrieval and validation of soil moisture from Envisat ASAR image. Observation items included: (1) soil moisture measured by the cutting ring method in Linze reed land, Zhangye farmland, Zhangye gobi, Linze maize land, Linze alfalfa land, Zhangye weather station, and Linze wetland. (2) GPS measured by GARMIN GPS 76 (3) vegetation measurements including the vegetation height, the green weight, the dry weight, the sampling method, and descriptions on the land type, uniformity and dry and wet conditions (4) atmospheric parameters at Daman Water Management office measured 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 and can be opened by ASTPWin. ReadMetext files (.txt) is attached for detail. Processed data (after retrieval of the raw data) archived as Excel files 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. (5) roughness measured by the roughness plate together with the digital camera. 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 text files (.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.

2019-09-13

WATER: Dataset of sun photometer observations in the Binggou watershed foci experimental areas from Mar. 15 to Apr. 2, 2008

The dataset of sun photometer observations was obtained in the Binggou watershed foci experimental areas (N38°04′1.4″/E100°13′15.6″, 3414.41m) from Mar. 15 to Apr. 2, 2008 (to be specific, the daytime of 15-03-2008, 16-03-2008, 17-03-2008, 18-03-2008, 19-03-2008, 21-03-2008, 22-03-2008, 23-03-2008, 24-03-2008, 25-03-2008, 26-03-2008 and 27-03-2008). Those provide reliable data for retrieval of optical depth, Rayleigh scattering, aerosol optical depth, column water vapor (through data in 936 nm) and with various parameters in 550nm, the horizontal visibility can be further developed by MODTRAN or 6S. The optical depth in 1640nm, 1020nm, 936nm, 870nm, 670nm, 550nm, 440nm, 380nm and 340nm were all acquired. Those data include the raw data in .k7 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. Accuracy of CE318 could be influenced by local air pressure, instrument calibration parameters, and convertion factors. (1) Most air pressure was derived from elevation-related empirical method, which was not reliable. For more accurate result, simultaneous data from the weather station are needed. (2) Errors in instrument calibration parameters need correcting. Thus field calibration based on Langly or interior instrument calibration in the standard light is required. (3) Convertion factors for retrieval of aerosol optical depth and the water vapor of the water vapor channel were also from the empirical method, and need further validation. Raw data were archived in .k7 format and can be opened by ASTPWin. ReadMe.txt is attached for detail. Preprocessed 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. Langley was used for the instrument calibration. Two subfolders including raw data and processed data (Geometric Positions and the Total Optical Depth of Each Channel and Rayleigh Scattering and Aerosol Optical Depth of Each Channel), and three data files (Directions on Data Observations, Raw Data and Proprocessed Data) were archived.

2019-05-23

WATER: Dataset of ground truth measurement synchronizing with PROBA CHRIS in the Yingke oasis and Huazhaizi desert steppe foci experimental areas on Jul. 1, 2008

The dataset of ground truth measurement synchronizing with PROBA CHRIS was obtained in the Yingke oasis and Huazhaizi desert steppe foci experimental areas on Jul. 1, 2008. Observation items included: (1) FPAR (Fraction of Photosynthetically Active Radiation) of maize and wheat by SUNSACN and the digital camera in Yingke oasis maize field. FPAR= (canopyPAR-surface transmissionPAR-canopy reflection PAR+surface reflectionPAR) /canopy PAR; APAR=FPAR* canopy PAR. Data were archived in the table format of Word. (2) BRDF of maize by ASD (350~2 500 nm) from Institute of Remote Sensing Applications (CAS) and the self-made multi-angluar observation platform of BNU make in Yingke oasis maize field. The maximum height of the platform was 5m above the ground with the azimuth 0~360° and the zenith angle -60°~60°. An automatic thermometer was attached to the platform for the multiangle radiative temperature. Raw data were binary files direct from ASD (by ViewSpecPro), and pre-processed data on reflectance were in Excel. (3) The radiative temperature of the maize canopy by the automatic thermometer (emissivity: 0.95),at a hight of 50cm from the crown in Yingke oasis maize field. Raw data, blackbody calibrated data and processed data were all archived in Excel format. (4) Atmospheric parameters at the resort 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 details. 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. (5) The multiangle radiative temperature by the automatic thermometer (emissivity: 1.0) attached on the observation platform, at an interval of 0.05s. The data were archived in .txt files (.dat format). The first seven lines were the header file, including acquisition date, time, and intervals; besides, Time (starting time), TObj (target temperature), Tint (the interior temperature of the probe), TBox (the temperature of the box) and Tact (the actual temperature calculated from the given emissivity) were also listed.

2019-05-23