The Characteristics of Huaxi Autumn Rain and its Relationship with Sea Surface Temperatures over the Equatorial Pacific

Features of Huaxi Autumn Rain (HAR) quasi-four-year period and their relationship to Sea Surface Temperature (SSTs) over the equatorial Pacific Ocean are examined using data from meteorological stations in Huaxi, NCEP/NCAR reanalysis data, NOAA SST data and the Multi-Taper Method-Singular Value Decomposition (MTM-SVD) method. Results show that central equatorial Pacific SSTs cause a notable quasi-four-year period in the HAR, with yearly characteristics that are stronger, a bit strong, weaker, and a bit weak, during each year within the period, and SST joint features that are lower, a bit low, higher, and a bit high during each year. The signal is present from early summer until late fall. Circulation analysis indicates that the HAR is strong (weak) when the summer central equatorial Pacific SST anomaly is low (high), the 500-hPa height field anomaly is positive (negative), the west Pacific subtropical winds are westerly (easterly), and moisture transport from the south China Sea and Bay of Bengal is more (less). The HAR also responds to the El Niño-Southern Oscillation (ENSO), and is mainly evident during strong ENSO events.