不同ENSO空间型对福建省前汛期降水异常的影响OA

Based on precipitation data from 66 meteorological stations in Fujian Province from 1961 to 2024,alongside NOAA sea surface temperature(SST)and outgoing long wavelength radiation(OLR)datasets,and NCEP/NCAR reanalysis data,this study investigates the physical mechanisms linking diverse El Niño-Southern Oscillation(ENSO)spatial patterns to precipitation anomalies during the pre-flood season(April-June). The results indicate that pre-flood season precipitation accounts for 41.1%of the annual total and exhibits prominent interannual and decadal variations,showing a spatial gradient that increases from the southeastern coast to the northwestern inland.During the decaying pre-flood season following an Eastern-Pacific(EP)El Niño,precipitation across the province is generally above normal,with significant enhancement in the northwestern region(Nanping and Sanming).This is primarily driven by an anomalous western North Pacific anticyclone(WNPAC),resembling a negative phase of the Western Pacific(anti-WP)pattern,which substantially intensifies southwesterly moisture flux into Fujian in cooperation with enhanced localized convection(negative OLR anomalies).Conversely,following an EP La Niña,precipitation is profoundly suppressed statewide as the large-scale circulation exhibits a typical positive WP pattern that severely obstructs moisture supply.Following a Central-Pacific(CP)El Niño,precipitation displays a distinct"north-rich and south-poor"spatial pattern;the Western Pacific subtropical high(WPSH)shifts westward and southward while the India-Burma trough weakens,confining significant moisture convergence to northern inland areas.Following a CP La Niña,precipitation increases primarily along the central and southern coasts-a trend closely linked to a higher frequency of early-season typhoons-although the seasonal mean intensity is constrained by widespread background moisture divergence.Mechanistically,EP El Niño events trigger a prominent"west-high and east-low"teleconnection wave train across mid-high latitude Eurasia at 500 hPa,which accelerates cold air outbreaks to confront the warm-moist airflow along the northern periphery of the WPSH.In contrast,CP events modify moisture transport pathways primarily through localized shifts of the WPSH and asymmetric tropical convective responses.This study highlights how ENSO spatial patterns modulate regional climate anomalies by reshaping large-scale circulations and moisture flux pathways,thereby providing crucial scientific insights for seasonal climate prediction and disaster mitigation over Southeast China.