简介:Recentstudiesindicatedthatexceptfortheland-seathermalcontrast,therealsoexistedtheland-landthermalcontrast.Thecompositeanalysisandt-testmethodareusedtofurtherstudythelocalthermalcontrastvariationovertheAsiancontinent,andtodiscusstheassociationofseasonalvariationoflandthermalstatewithcirculationoverEastAsia,theearlysummerandsummermonsoonactivity,andtheprecipitationanomalyinChinainthedecadalscale.Resultsshowthatthepositivemeridionaltemperatureanomalytransportsdownwardfromuppertroposphericlayersinmiddle-highlatitudesnorthof25°Ninthepositiveyears.Inthezonaldirection,theTibetanPlateauheatinginthesuccessivespringactsasaforcetoinfluencetheatmosphere,leadingtotherapidtemperaturewarmingovereasternChinesecontinent,whichcouldincreasetheland-seathermalcontrastwiththenegativeSSTA.Accordingly,themonsoonactivityinearlysummeroverEastAsianestablishesearlierandthesummermonsoonintensitybecomesstronger.Theearlysummerprecipitationismore-than-normalovertheYangtzeRiver,andthesummerprecipitationismore-than-normaloverthenorthChinaandthesouthwestChina.Thesituationiscontraryinthenegativeyears.