Mapping long-term spatial impact of ENSO on hydroclimatic variables in China

Understanding the impact of El Ninio-Southern Oscillation (ENSO) on hydroclimatic variables is critical to early warning of ENSO-induced disasters. However, most studies employed the sea surface temperature anomaly (SSTa) index of the Ninio 3.4 region (hereinafter called Ninio 3.4 SSTa) to assess its impact on those variables, while ignoring that of other Ninio regions. This study aims to assess the long-term spatial impact of Ninio 1 + 2 SSTa index on hydroclimatic variables in China. After removing seasonality, we found that the correlation between standardized surface pressure (SP)/ temperature (T)/ evapotranspiration (ET)/ terrestrial water storage (TWS) and Ninio 1 + 2 SSTa was significantly better than that without removing seasonality. Ninio 1 + 2 SSTa was also demonstrated to have a substantial impact on standardized precipitation index (SPI) in China, particularly during drought period. Notably, precipitation is a key driver of ET in response to Ninio 1 + 2 SSTa in the time span. In addition, compared to that of Ninio 3.4 SSTa, the hydroclimatic variables in response to Ninio 1 + 2 SSTa are able to capture the basic geographical characteristics of China. In particular, the spatial configuration of China's terrain (TWS trend) is largely depicted by the spatial pattern of correlation coefficient between Ninio 1 + 2 SSTa and SP (TWS), respectively. The above findings indicate that the spatial pattern of the long-term variations of hydroclimatic variables in China can potentially be monitored by SSTa in the Ninio 1 + 2 region.& COPY; 2023 COSPAR. Published by Elsevier B.V. All rights reserved.