Dunhuang
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The Dunhuang site is located in the Gobi Desert in northwest China, situated on a stabilized alluvial fan. Atmospheric aerosols over the site are typical of a rural continental location, although some larger particles have been observed, possibly due to influx from the sand dunes to the northwest. Sandstorms affect the site about eight days per year, and atmospheric dust is a significant factor about 60 days per annum. Sources of meteorological data for the site include the Dunhuang-PAM automated weather station, which is part of the Asian Automatic Weather Station Network. According to a 2002 study [1], the test site has very good spatial homogeneity with a coefficient of variation of the reflectance in any spectral band lower than 3 percent. Based on the atmospheric measurements, at 0.55 μm wavelength, the total atmospheric optical depth (about 0.34) and the aerosol optical depth (about 0.26) are relatively low. The effect of atmospheric water vapor content is also relatively small. These characteristics make this site useful to the satellite sensor calibration community.
Dunhuang has low temporal spectral variabilities, which make it useful for vicarious calibration of space-borne sensors to monitor radiometric drift over time. The site also enables inter-comparisons and cross-calibration of different sensors [21]. According to the spectral characterization of Dunhuang using hyperspectral measurements [3], this site is useful for satellite calibration and validation. Aerosol properties obtained from sun photometer and lidar have been analyzed over this site as well [4]. Moreover, the BRDF properties of this site has been analyzed in recent years for better sensor calibration characterization [5].
| Location (City, State, Country): |
Dunhuang, Gobi Desert, Gansu Province, China, Asia
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| Landsat WRS - 2 Path / Row: |
137/32
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| Center Latitude (degrees): |
N 40.13
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| Center Longitude (degrees): |
E 94.34
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| CEOS Region of Interest |
N 40.13, E 94.34 Search this area in EarthExplorer (Landsat 8-9 Collection 2 Level-1) - date range, datasets, cloud cover and other criteria can be modified once initial results are returned |
| Size of Usable Area (km): |
25 x 25
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| Altitude above sea level (meters): |
1,220
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| Purpose: |
Radiometry
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| Co-located Instrumented Networks: |
AERONET
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| Status: |
Active
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- Min, Xiangjun, Zhimin Wang, Qiaoyan Fu, and Yingqi Gu. "Ground simultaneous measurements and analysis of radiometric characterization of Dunhuang test site for calibrating CBERS-1 sensors." Geo-information Science 9 (2002): 43-50.
- Bacour, C.; Briottet, X.; Bréon, F.-M.; Viallefont-Robinet, F.; Bouvet, M. Revisiting Pseudo Invariant Calibration Sites (PICS) Over Sand Deserts for Vicarious Calibration of Optical Imagers at 20 km and 100 km Scales. Remote Sens. 2019, 11, 1166.
- Cao, Changyong, Lingling Ma, Sirish Uprety, Chuanrong Li, and Lingli Tang. "Spectral characterization of the Dunhuang calibration/validation site using hyperspectral measurements." In Earth Observing Missions and Sensors: Development, Implementation, and Characterization, vol. 7862, p. 78620J. International Society for Optics and Photonics, 2010.
- Chen, Lin, Yingying Jing, Peng Zhang, and Xiuqing Hu. "Analysis of aerosol properties derived from sun photometer and lidar over Dunhuang radiometric calibration site." In Remote Sensing of the Atmosphere, Clouds, and Precipitation VI, vol. 9876, p. 98763G. International Society for Optics and Photonics, 2016.
- Tan-qi, Y. U., W. E. I. Wei, Z. H. A. N. G. Yan-na, Z. H. A. N. G. Yun-jie, L. I. Xin, Z. H. E. N. Xiao-bing, and S. U. N. Ling. "Analysis of the BRDF characteristics of Dunhuang radiometric calibration site in the spring." Acta Photonica Sinica 47, no. 6 (2018): 612004.
Note: This information has been compiled by the USGS ECCOE Team, using the best sources currently known. Updates will be made as more information becomes available. Please contact eccoe@usgs.gov with any updates you would like to contribute.