Dunhuang
This site was operational radiometric calibration and validation for Chinese satellite sensors in 2001, and located on the east edge of the Kumutage Penniform Desert in Gansu province, South-West China. It is a Gobi desert, and about 35 km west
the city of Dunhuang . The whole target area for vicarious calibration is situated on a stabilised alluvial fan, 30 km x 30 km size. The area used for high spatial sensors (such as CBERS, TM etal) vicarious calibration measurements is approximately 400 m x 400 m in the centre of the fan and the surface comprises cemented gravels, and 15km×15km for low spatial sensors (Such as NOAA/AVHRR, FY-1/FY-3 optical imagers and EOS/MODIS etal ) vicarious calibration with no vegetation.
Sources of meteorological data for the site include the Dunhuang-PAM automated weather station, which is part of the Asian Automatic Weather Station Network. Atmospheric aerosols over the site are typical of a rural continental location, although some larger particles were observed, possibly influx from the sand dunes to the north-west. Sandstorms affect the site on around 8 days per annum and atmospheric dust is a significant factor on around 60 days per annum. [1]
It is one of the CEOS LANDNET Sites. The site is managed by NSMC/CMA; for more detailed information regarding the site, the point of contact is Xiuqing Hu (huxq@cma.gov.cn)
Instruments on the Test Site
ASD field spectroradimeter (350-2500nm)
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Climatological Data for Dunhuang
| Parameter | Mean | Std Dev | Min | Max | Max-Min | (Max-Min)/Mean | CV |
|---|---|---|---|---|---|---|---|
| Cloud Fraction (%) | 0.4080 | 0.1247 | 0.1830 | 0.5964 | 0.4134 | 1.0132 | 0.3055 |
| Water Vapour Content (g/cm2) | 0.8692 | 0.6696 | 0.2490 | 2.1530 | 1.9040 | 2.1906 | 0.7704 |
| Precipitation (mm/day) | 0.1836 | 0.1988 | 0.0075 | 0.6511 | 0.6436 | 3.5059 | 1.0827 |
| Ozone Content (Dobson) | 316.7750 | 24.2629 | 289.0000 | 349.1000 | 60.1000 | 0.1897 | 0.0766 |
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| Temporal Variability of Cloud Fraction: on the X axis scale is one year (Jan-Dec); on the Y axis scale is the fraction 0-1 |
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| Temporal Variability of Water Vapour Content: X axis scale is one year (Jan-Dec); Y axis scale is 0-6 g/cm2 |
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| Temporal Variability of Precipitation. X axis scale is one year (Jan-Dec); Y axis scale is 0-10 mm/day |
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| Temporal Variability of Ozone Content. X axis is one year (Jan-Dec); Y axis is 0-500 Dobson |
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| Spectral Temporal Variability | ||
Literature
Links
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View LANDNET SITES in a larger map
References
[2] WP230 - Site Characterization from Climatological Dataset
[3] QA4EO Document - QA4EO-WGCV-IVO-CSP-002 - PDF