Acta Geodaetica et Cartographica Sinica ›› 2019, Vol. 48 ›› Issue (5): 547-554.doi: 10.11947/j.AGCS.2019.20180308

• Geodesy and Navigation • Previous Articles     Next Articles

Detecting droughts in Southwest China from GPS vertical position displacements

YAO Chaolong1, LUO Zhicai2, HU Yueming1,3,4,5, WANG Changwei1, ZHANG Rui1, LI Jinming1   

  1. 1. College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China;
    2. MOE Key Laboratory of Fundamental Physical Quantities Measurement, Institute of Geophysics, School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China;
    3. Key Laboratory of the Ministry of Land and Resources for Construction Land Transformation, South China Agricultural University, Guangzhou 510642, China;
    4. Guangdong Provincial Key Laboratory of Land Use and Consolidation, South China Agricultural University, Guangzhou 510642, China;
    5. Guangdong Province Land Information Engineering Technology Research Center, South China Agricultural University, Guangzhou 510642, China
  • Received:2018-06-27 Revised:2019-02-21 Online:2019-05-20 Published:2019-06-05
  • Supported by:
    The National Natural Science Foundation of China (No. 41604017);The Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, Wuhan University (No. 17-01-08);The Dean's Fund of College of Natural Resources and Environment, South China Agricultural University (No. ZHXY2018A01)

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Abstract: The solid Earth responds elastically to terrestrial water storage (TWS) changes. Here global positioning system(GPS)vertical position data at 31 stations from crustal movement observation network of China (CMONOC)from August 2010 to December 2016 are used to detect droughts in Southwest China. Monthly GPS vertical position displacements respond negatively to precipitation changes and TWS changes observed by gravity recovery and climate experiment(GRACE) as well as river water level variations. GPS vertical position anomalies (the nonseasonal term) are well correlated negatively (correlations of about -0.70) with the commonly used meteorological composite index (CI) in China and the GRACE drought severity index (GRACE-DSI), but less correlated with the standardized precipitation evapotranspiration index (SPEI). Compared to CI, GPS vertical position anomalies have the advantage in detecting droughts caused by abrupt precipitation deficits in a short time period. GRACE-DSI is less accurate in drought monitoring for some periods due to the missing data, while the severity of abrupt precipitation absent in some cases can be overestimated from SPEI with big variability. This study shows the reliability and advantages of GPS data in drought monitoring.

Key words: GPS vertical displacement, terrestrial water storage, GRACE, drought

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