地理学报

Acta Geographica Sinica ›› 2018, Vol. 73 ›› Issue (9): 1778-1791.doi: 10.11821/dlxb201809013

• Climate Change and Ecological Environment • Previous Articles     Next Articles

Evaluation of remote sensing and reanalysis soil moisture products on the Tibetan Plateau

FAN Keke1,2,3(),ZHANG Qiang1,2,3(),SHI Peijun1,2,3,SUN Peng4,YU Huiqian1,2,3   

  1. 1. Key Laboratory of Environmental Change and Natural Disaster, Ministry of Education, Beijing Normal University, Beijing 100875, China
    2. Academy of Disaster Reduction and Emergency Management, Beijing Normal University, Beijing 100875, China
    3. Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
    4. College of Territorial Resources and Tourism, Anhui Normal University, Wuhu 241002, Anhui, China
  • Received:2017-08-31 Online:2018-09-25 Published:2018-09-19
  • Supported by:
    Creative Research Groups of National Natural Science Foundation of China, No.41621061;National Science Foundation for Distinguished Young Scholars of China, No.51425903

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Abstract:

Soil water is the key link between land surface and atmosphere in water-heat exchange and it is the key element of water cycle. It is also the key control factor affecting the process of surface runoff. The Himalayan-Tibetan Plateau (HTP), also known as the "Asian Water Tower", is the source region of many Asian rivers. Meanwhile, HTP has direct impacts on its surrounding climate via hydro-meteorological processes, and on establishment and maintenance of Asian monsoon. This study collected observed soil moisture data from 100 in-situ soil moisture observatory stations and evaluated applicability of the available remote sensing and reanalysis soil moisture datasets such as ECV, ERA-Interim, MERRA, and Noah at different spatial resolutions (0.25°×0.25°, 0.5°×0.5°, 1°×1°) during different time intervals such as non-freezing and freezing periods. Statistical indicators such as R, RMSE and Bias were used to evaluate the performances of these remote sensing and reanalysis soil moisture datasets. The results indicated that: (1) All remote sensing and reanalysis soil moisture datasets except ERA can well estimate soil moisture changes of the Tibetan Plateau and the soil moisture changes are in generally good line with precipitation changes. In the Naqu region, however, the remote sensing and reanalysis soil moisture datasets substantially underestimate observed soil moisture. In space, MERRA and Noah are mostly consistent with the change of vegetation index, and can well estimate spatial distribution of soil moisture changes. (2) Soil moisture changes across most parts of the Tibetan Plateau are greatly influenced by precipitation changes. In addition, soil moisture changes in the western flank of the Tibetan Plateau and Himalayas are the combined results of melting snow/glaciers and precipitation. (3) Except in the Ngari region, soil moisture during non-freezing period is usually higher than that during freezing period. In the Naqu region, all remote sensing and reanalysis soil moisture datasets overestimate soil moisture amount during freezing periods, while they underestimate it during non-freezing periods. Besides, from a spatial scale viewpoint, at medium and large scales, remote sensing and reanalysis soil moisture datasets can better evaluate soil moisture availability compared with at small scale. This study provides a theoretical basis for selection of the right remote sensing and reanalysis soil moisture datasets for evaluation and analysis of soil moisture of the Tibetan Plateau.

Key words: remote sensing dataset, reanalysis dataset, soil moisture, Tibetan Plateau