Current Browsing: 2008-04-01


WATER: Dataset of airborne microwave radiometers (L&K bands) mission in the A'rou flight zone in the morning of Apr. 1, 2008

This data set was acquired by the L & K band airborne microwave radiometer on the morning of April 1, 2008, in the A'rou flight zone. The frequency of L-band is 1.4GHz, and the backsight is 35 degrees to obtain dual polarization (H and V) information; the frequency of K-band is 18.7ghz, and there is no polarization information. The plane took off from Zhangye airport at 8:06 (Beijing time, the same below) and landed at 11:17. 8: 50-10:13 fly from north to south, observe and reserve 10 routes, flight height is about 4100m, flight speed is about 260km / hr. 10: At 20-10:35, Jiafei 6-8 and 6-9 lines completed the observation. The original data is divided into two parts: microwave radiometer data and GPS data. The L and K bands of microwave radiometer are non imaging observations. The digital values obtained from the instantaneous observation are recorded in the text file, and the longitude and latitude as well as the aircraft attitude parameters are recorded in the GPS data. When using microwave radiometer to observe data, it is necessary to convert the digital value recorded into the bright temperature value according to the calibration coefficient (the calibration coefficient file is filed with the original observation data). At the same time, through the clock records of microwave radiometer and GPS, we can connect the microwave observation with GPS record and match the geographic coordinate information for the microwave observation. Due to the coarse observation resolution of microwave radiometer, the effects of aircraft yaw, roll and pitch are generally ignored in data processing. According to the target and flight relative altitude (H), after calibration and coordinate matching, the observation information can also be gridded. The resolution (x) of L band and K band is consistent with that of observation footprint. The reference resolution is: L band, x = 0.3H; K band, x = 0.24h. After the above steps, we can get the products that users can use directly.

2020-03-10

WATER: Dataset of mobile meteorological station observations

The dataset of mobile meteorological station observations was obtained in the foci experiment area from March to April, 2008. To synergize the very high resolution airborne remote sensing and ground-based measurements, 11 mobile observations, including meteorological stations (for meteorological data) and GPS (for observation sites), were carried out in Binggou, A'rou and Biandukou. The items included the wind speed and direction at 3.03m (the truck height 1.84m plus the vane height 1.19m), the air temperature and humidity at 3.04m (the truck height 1.84m plus the vane height 1.2m), the surface temperature (the truck height 1.84m plus 1.06m) and the total radiation (the truck height 1.84m plus 1.39m). The observation sites and time were as follows: Dadongshu mountain pass-A'rou 15-3-2008 Biandukou-Qilian 18-3-2008 A'rou-Biandukou 19-3-2008 Qilian-Minle 20-3-2008 Mingle-Zhangye 21-3-2008 Binggou-Dadongshu mountain pass 22-3-2008 Binggou-Dadongshu mountain pass 24-3-2008 Binggou-Dadongshu mountain pass 29-3-2008 Binggou-Dadongshu mountain pass 30-3-2008 Qilian-A'rou 31-3-2008 A'rou 01-4-2008 The data were named after WATER_Mobile_ AWS_yyyymmdd (yyyymmdd for observation time).

2019-05-23

WATER: Dataset of snow depth measured by the graduated snow sticks in the Binggou watershed foci experimental area

The dataset of snow depth measured by the elevation-graduated snow sticks was obtained in the Binggou watershed foci experimental area from Nov. 11 to 16, 2007, during the pre-observation period. 51 snow-stakes (2m long) were arranged according to different topographic landscapes, such as the flat, ubac, tailo and partial shade, and the length above the ground was recorded. From Mar. 2 to Apr. 6, 2008, the intensive observation period, ten measurements (Mar. 2, Mar. 4, Mar. 9, Mar. 16, Mar. 19, Mar. 21, Mar. 23, Mar. 29, Apr. 1 and Apr. 6) were carried out both manually and additionally by the telescope for the snow depth around the snow-stakes. Two files including raw data and preprocessed snow depth data were archived. Those provide reliable data for snow spatial heterogeneity study and snow accumulation and melt monitoring in the Binggou watershed.

2019-05-23

WATER: Dataset of setting of the sampling plots and stripes in the A'rou foci experimental area

The dataset of position of the sampling plots and stripes was obtained in A1, A2, A3, L1, L2, L3, L4, L5 and L6 of the A'rou foci experimental area. The quadrates were changed from 4×4 into 3×3 subsites during the foci experimental period, with each one spanning a 30×30 m2 plot. The centers and corners of each subsite were collected. As for the sampling lines, samples were collected every 100 m along them from south to north. The points were named in the form of L1-1, indication No. 1 point in No. 1 line. The coordinates and elevation of each sampling point were included in the dataset in Excel format.

2019-05-23

WATER: Dataset of GPS radiosonde observations

The dataset of GPS radiosonde observations was obtained at an interval of 2 seconds in the cold region hydrology experimental area in March, 2008 and the arid region hydrology experimental area from May to July, 2008. The items were the air temperature, relative humidity, air pressure, the dew temperature, the water vapor mixing ratio, latitudinal and longitudinal wind speeds, the wind speed and direction. Simultaneous with the satellite/airplane overpass, GPS radiosonde observations were carried out: Binggou watershed on Mar. 14, A'rou on Mar. 15, Binggou watershed on Mar. 15, Biandukou on Mar. 17, Binggou watershed on Mar. 22, Binggou watershed on Mar. 29, and A'rou on Apr. 1 for the upper stream experiments; Linze grassland station on May 30, Yingke oasis on Jun.1, Huazhaizi desert station on Jun. 4, Linze grassland station on Jun. 5, Linze grassland station on Jun. 6, Huazhaizi desert station on Jun. 16, Yingke oasis on Jun. 29, Binggou watershed on Jul. 5, Yingke oasis on Jul. 7, Linze grassland station on Jul. 11, and Yingke oasis at 0, 4:10, 8:09, and 12:09 on Jul. 14 for middle stream experiments.

2019-05-23

WATER: Dataset of sun photometer observations in the Zhangye city foci experimental areas from Mar. 30 to Apr. 2, 2008

The dataset of sun photometer observations was obtained in the Zhangye city foci experimental areas (38°56′8.9″N, 100°27′8.3″E, 1400m) from Mar. 30 to Apr. 2, 2008. Measurements were carried out by CE318 for 1640nm, 1020nm, 936nm, 870nm, 670nm, 550nm, 440nm, 380nm and 340nm, and column water vapor by 936 nm data on Mar. 30 and 31, Apr. 1 and 2, 2008. 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 empiricism, which was not reliable. For more accurate result, simultaneous data from the weather station are needed. (2) Errors from instrument calibration parameters need correcting. Thus field calibration based on Langly or interior instrument calibrationcin 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 empiricism, and need further checking. 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 parts are included in CE318 result data (see “Geometric Positions and the Total Optical Depth of Each Channel” and “Rayleigh Scattering and Aerosol Optical Depth of Each Channel”).

2019-05-23

WATER: Dataset of ground truth measurements synchronizing with the airborne microwave radiometers (L&K bands) and thermal imager mission in the A'rou foci experimental area on Apr. 1, 2008

The dataset of ground truth measurements synchronizing with the airborne microwave radiometers (L&K bands, between 8:06~11:17BJT) and thermal imager mission (between 12:48~16:35BJT) was obtained in L2, L3, L4, L5 and L6 of the A'rou foci experimental area on Apr. 1, 2008. The samples were collected every 100m along the strip from south to north in the the morning and from north to south in the afternoon. In L2, L4 and L6, the soil temperature, soil volumetric moisture, the loss tangent, soil conductivity, and the real part and the imaginary part of soil complex permittivity were acquired by the POGO soil sensor, the mean soil temperature from 0-5cm by the probe thermometer, the surface radiative temperature measured three times by the hand-held infrared thermometer, and soil gravimetric moisture, volumetric moisture, and soil bulk density after drying by the cutting ring (100cm^3). In L3, soil volumetric moisture was acquired by ML2X, the mean soil temperature from 0-5cm by the probe thermometer, the surface radiative temperature measured three times by the hand-held infrared thermometer, and soil gravimetric moisture, volumetric moisture, and soil bulk density after drying by the cutting ring (100cm^3). In L5, soil volumetric moisture, soil conductivity, the soil temperature, and the real part of soil complex permittivity were acquired by WET, the mean soil temperature from 0-5cm by the probe thermometer, the surface radiative temperature measured three times by the hand-held infrared thermometer, soil gravimetric moisture, volumetric moisture, and soil bulk density after drying by the cutting ring (100cm^3). Besides, the handheld thermal imager observations were carried out in L4. Those provide reliable ground data for retrieval and validation of soil moisture and freeze/thaw status from active remote sensing approaches. Seven files were included, two ground-based microwave radiometers (L&K-band and L-band) observations, L2 data, L3 data, L4 data, L5 data and L6 data.

2019-05-23

WATER: Dataset of airborne L-band microwave radiometer and thermal imager mission in the Binggou-A'rou flight zone in the afternoon of Apr. 1, 2008

The dataset of airborne L-band microwave radiometer and thermal imager mission was obtained in the Binggou-A'rou flight zone in the afternoon of Apr. 1, 2008. The frequency of L bands was 1.4 GHz with back sight of 35 degree and dual polarization (H&V) was acquired. The plane took off at Zhangye airport at 12:48 (BJT) and landed at 16:35 along the scheduled lines at the altitude about 5000m and speed about 260km/hr.. The raw data include microwave radiometer (L) data, thermal imager data (7.5-13 um; FOV: 24×18º) and GPS data; the first were instantaneous non-imaging observation recorded in text, which could be converted into brightness temperatures according to the caliberation coefficients (filed with raw data together), and the third are aircraft longitude, latitude and attitude. Moreover, based on the respective real-time clock log, observations by the microwave radiometer and GPS can be integrated to offer coordinates matching for the former. Yaw, flip, and pitch motions of aircraft were ignored due to the low resolution of microwave radiometer observations. Observation information can also be rasterized, as required, after calibration and coordinates matching. L band resolution (x) and footprint can be approximately estimated as x=0.3H (H is relative flight height). The thermal imager was 320*240 pixels and with FOV of 24×18º. The thermal imager data were stored in binary format with a text header file. The recorded value was brightness temperature at sensor with scale and gain parameter recorded in the header file. And the thermal images were not geometrically corrected because there were gaps between sequential images.

2019-05-23

WATER: Dataset of setting of the sampling plots and stripes in the Linze station foci experimental area

The dataset of setting of the sampling plots and stripes in the Linze station foci experimental area was as follows: (1) Wulidun farmland quadrates (90m×90m), which was divided into nine subplots (30m×30m). Numbering of Cold and Arid Regions Environmental and Engineering Research Institute was different from that of BNU, in which the former was 1-9 from south to north, and the latter was A-I from north to south. (2) the west-east desert strip, which was composed of 20 neighbouring pairs of subplots (30×30m). They were numbered S0-S20 from the south corner on and N0-N20 from the north corner on; the common corner points in the middle were numbered M0-M20. Corner points were measured during the satellite or airplane overpass. (3) the north-south desert strip, which was composed of nine non-conterminous subplots (40m×40m, numbered from A1-A9) at intervals of 60m. Corner points and center points were measured during the satellite or airplane overpass. (4) three quadrates (30m×30m) of the transit zone, LY06,LY07,LY08 strips. Samples were selected following the zigzag line from the northwest corner and numbered 1-9. (5) the poplar forest (90×90m), which was divided into 9 subplots (30m×30m). (6) 6 desert strips with 17 sample points each. (7) maize plots (3m×3m) inside Linze station. Data including coordinates of each sample point were archived as Excel files.

2019-05-23