SURFACE WIND MINIMUM ALONG THE SST FRONTS AND ITS CAUSE
ZHOU Yan
LIU Xuan-fei
LI Zhi
Abstract：By using QuickSCAT and AVHRR high resolution satellite data and CFSR reanalysis data during 2000--2008,the atmospheric response to the SST fronts in the Gulf Stream (GS),the East China Sea Kuroshio (ESK),the Brazil-Malvinas Confluence (BMC) and the Agulhas Return Current (ARC) is investigated.The minimum surface wind is found to be universal along the above fronts,which occurs in JJA for the GS,June for ESK,year-round both for the BMC and ARC.The pre-condition for generating the minimum surface wind is that the large-scale sea level pressure (SLP) gradient (SLPG) is basically in the same direction with the local sea surface temperature gradient near the fronts.This can be explained as follows according to the SLP adjustment mechanism:the warmer (colder) side of the fronts will produce lower (higher) SLP,and such a local SLPG will counteract with the large-scale SLPG,thus leading to the minimum resultant SLPG as well as the minimum surface wind along the fronts.Furthermore,the surface wind will turn to the lower SLP side due to the friction.The difference between components of surface wind along (across) the fronts will produce cyclonic shear vorticity (convergence in wind speed) over the warmer side of the fronts,thereby forming ascending motion and enhanced precipitation there.The atmospheric response is opposite to that over the colder side of the fronts.
Keywords：oceanic frontpressure adjustment mechanismsea surface vector windminimum
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：10( 167-176 )