热带气象学报
熱帶氣象學報
열대기상학보
2009年
6期
740-746
,共7页
大气环流%SVD%黑潮%北太平洋%热通量%耦合关系
大氣環流%SVD%黑潮%北太平洋%熱通量%耦閤關繫
대기배류%SVD%흑조%북태평양%열통량%우합관계
atmospheric circulation%SVD%Kuroshio%the North Pacific%heat flux%coupled mode
利用NCEP/NCAR和OAFlux月平均资料,采用SVD方法分析冬季黑潮海域的热通量和北太平洋500 hPa位势高度场之间的关系.第1对奇异向量占总方差的86.24%,表现为黑潮北部海域异常多的放热和北太平洋中西部的500 hPa位势高度场异常低.将正负异常年的各气象要素的距平场进行合成分析后表明:当阿留申低压增强(减弱)时,黑潮海域上空的西北风增强(减弱),导致近地面层大气温度降低(升高),使得热通量异常释放增加(减少),从而降低(升高)了海表面温度.在黑潮海域及其下游,温度场在纬向垂直方向是斜压结构,位势高度场是相当正压结构,反映的是冷低压(暖脊)结构.通过分析风场无旋分量和垂直速度的距平发现,在中纬度地区存在距平的纬向环流圈:大气在北太平洋中部的低层上升(下沉),在对流层高层(低层)分别向西、向东运动,在黑潮海域和北美西部下沉(上升),增强(减弱)了中纬度纬向环流圈(MZC).
利用NCEP/NCAR和OAFlux月平均資料,採用SVD方法分析鼕季黑潮海域的熱通量和北太平洋500 hPa位勢高度場之間的關繫.第1對奇異嚮量佔總方差的86.24%,錶現為黑潮北部海域異常多的放熱和北太平洋中西部的500 hPa位勢高度場異常低.將正負異常年的各氣象要素的距平場進行閤成分析後錶明:噹阿留申低壓增彊(減弱)時,黑潮海域上空的西北風增彊(減弱),導緻近地麵層大氣溫度降低(升高),使得熱通量異常釋放增加(減少),從而降低(升高)瞭海錶麵溫度.在黑潮海域及其下遊,溫度場在緯嚮垂直方嚮是斜壓結構,位勢高度場是相噹正壓結構,反映的是冷低壓(暖脊)結構.通過分析風場無鏇分量和垂直速度的距平髮現,在中緯度地區存在距平的緯嚮環流圈:大氣在北太平洋中部的低層上升(下沉),在對流層高層(低層)分彆嚮西、嚮東運動,在黑潮海域和北美西部下沉(上升),增彊(減弱)瞭中緯度緯嚮環流圈(MZC).
이용NCEP/NCAR화OAFlux월평균자료,채용SVD방법분석동계흑조해역적열통량화북태평양500 hPa위세고도장지간적관계.제1대기이향량점총방차적86.24%,표현위흑조북부해역이상다적방열화북태평양중서부적500 hPa위세고도장이상저.장정부이상년적각기상요소적거평장진행합성분석후표명:당아류신저압증강(감약)시,흑조해역상공적서북풍증강(감약),도치근지면층대기온도강저(승고),사득열통량이상석방증가(감소),종이강저(승고)료해표면온도.재흑조해역급기하유,온도장재위향수직방향시사압결구,위세고도장시상당정압결구,반영적시랭저압(난척)결구.통과분석풍장무선분량화수직속도적거평발현,재중위도지구존재거평적위향배류권:대기재북태평양중부적저층상승(하침),재대류층고층(저층)분별향서、향동운동,재흑조해역화북미서부하침(상승),증강(감약)료중위도위향배류권(MZC).
The Singular Vector Decomposition(SVD) analysis of monthly data of the NCEP-NCAR reanalysis and OAFlux reanalysis data for wintertime is used to study the relationship between the Kuroshio anomalous heating and the North Pacific geopotential height at 500 hPa. The first SVD mode shows that the anomalous heating in northern Kuroshio is associated with anomalously low geopotential height in the central and western parts of the North Pacific at 500 hPa. Composite analysis of meteorological variables for both positively and negatively anomalous years reveals that while the Aleutian low strengthens(weakens), the north-westerly wind overlying the Kuroshio strengthens(weakens) and induces the cooling(warming) of the air near the sea surface, and further increases(decreases) the upward anomalous heat flux and cools(warms) the sea surface temperature. Over the Kuroshio and its downstream region, the vertical structure of air temperature along the latitude is baroclinic while the geopotential height is equivalently barotropic. This reflects a cool-low(warm-ridge) spatial structure. Analysis of divergent wind and vertical velocity shows the existence of an anomalously zonal circulation cell. It is characterized by air rising (falling) in the central North Pacific, flowing westward and eastward in the upper troposphere, and falling (rising) in the Kuroshio region and the west of the North America, which strengthens(weakens) the mid-latitude zonal cell(MZC).
