长江流域陆地水储量异常的卫星重力监测与干旱指数对比分析北大核心CSCD

利用GRACE/GRACE-FO数据对长江流域2003~2021年期间发生的干旱事件进行定量分析,以探究卫星重力监测区域性干旱的可行性。采用3个机构发布的5种GRACE/GRACE-FO数据产品(CSR_SH、JPL_SH、GFZ_SH、CSR_M、JPL_M)反演长江流域陆地水储量异常(TWSA),计算陆地水储量亏损(WSD)和水储量亏损指数(WSDI),结合气象干旱数据(SPI、SPEI、scPDSI)对5种数据产品的结果进行比较,并对2003~2021年长江流域干旱事件进行分析。结果表明,不同机构发布的GRACE/GRACE-FO数据产品对长江流域干旱事件严重等级的划分具有一定差异;WSDI与6个月时间尺度的SPEI相关性最高,相关系数为0.66,与scPDSI相关系数最低为0.54,降水是影响长江流域陆地水储量变化的重要因素;长江流域最严重的干旱事件发生在2019年夏秋季,干旱强度为2.31,持续10个月,水储量累计亏损达到415 Gt,此次干旱事件的WSDI空间分布图显示2019-09干旱最为严重,出现极端干旱区域。WSDI可反映长江流域干旱分布的时空变化,可在监测全球和大尺度区域干旱方面发挥重要作用。

Comparison of Satellite Gravimetry of Terrestrial Water Storage Anomaly and Drought Indices in the Yangtze River Basin

We quantitatively analyze the drought events in the Yangtze river basin from 2003 to 2021 by using GRACE data to explore the feasibility of satellite gravimetry in monitoring regional drought. Firstly, we use five GRACE data products(CSR_SH, JPL_SH, GFZ_SH, CSR_M and JPL_M) released by three centers to retrieve the terrestrial water storage anomaly(TWSA) in the Yangtze river basin, and calculate the terrestrial water storage deficit(WSD) and water storage deficit index(WSDI). We then compare the results of five data products in combination with meteorological drought data(SPI, SPEI and scPDSI). Lastly, we analyze the drought events in the Yangtze river basin from 2003 to 2021. The results show that GRACE data products released by different centers have a certain impact on quantifying drought severity in the Yangtze river basin. WSDI has the significant correlation with SPEI on 6-month time scale, with the highest correlation coefficient of 0.66 and the lowest correlation coefficient with scPDSI of 0.54. Precipitation is a dominated factor affecting the change of terrestrial water storage in the Yangtze river basin. The most serious drought event in the Yangtze river basin occurred in the summer and autumn of 2019. The drought intensity was 2.31 and lasted for 10 months. The cumulative loss of water storage reached 415 Gt. The spatial distribution of WSDI of this drought event shows it was most serious in September 2019, with extreme drought areas. WSDI can reflect the temporal and spatial variation of drought distribution in the Yangtze river basin and play an important role in monitoring global and large-scale regional drought.