Analysis of Sea and Land Water Storage Changes in the Western Pacific Under the Influence of ENSO

In this paper, the gravity recovery and climate experiment (GRACE), altimetry, ARGO, TRMM (tropical rainfall measurement mission) data and multivariate ENSO index (MEI) from January 2005 to December 2016 are adopted to analyze the effects of ENSO on the Western Pacific and its coastal areas, from the aspects of sea level, oceanic mass, steric and the terrestrial water storage change. During the GRACE data processing, we remove the effect of tectonic signals, and use an iterative forward modeling method to recover time-varying signal. The result shows, the changes in the Western Pacific mean sea level (WPMSL) in response to ENSO are as follows:The sea level is lower during El Niño and higher during La Niña; in particular, during 2014-2016 El Nino, the WPMSL dropped by nearly 26.2 mm. The steric change is the dominant factor affecting the nonseasonal anomalies of the WPMSL. The nonseasonal anomalies of water storage in Australia and Indochina Peninsula also respond well to the ENSO, and the correlation coefficients with the MEI are -0.61 (lag three months) and -0.65 (lag eight months). The response of the Yangtze River basin to ENSO is mainly in the middle and lower basin, 2014-2016 El Niño caused the water storage in the Yangtze River basin to reach the maximum value in recent years.