CAJ | 학술논문

用NCEP/NCAR月平均再分析资料对南亚高压和对流层上层西风急流的季节变化及盛夏两类型态进行对比.结果表明,南亚高压和西风急流中心都有从冬到夏的西移北进和从夏到冬的东退南撤,急流中心位于南亚高压中心北侧.东亚夏季风盛行期间南亚高压中心的北移提前于西风急流中心的北移,二者的强度呈反相的季节变化.一般情况下,伊朗高压对应西部急流型,青藏高压对应东部急流型.典型东、西部急流年份中高纬气温及高度场的差异表明气压梯度力强弱对比是急流东西型变化的主要原因,南亚高压的位置基本上决定了急流中心的型态,但由于南亚高压具有"趋热性",而急流的移动符合热成风的规律,因而二者的热力影响机制有所不同.
용NCEP/NCAR월평균재분석자료대남아고압화대류층상층서풍급류적계절변화급성하량류형태진행대비.결과표명,남아고압화서풍급류중심도유종동도하적서이북진화종하도동적동퇴남철,급류중심위우남아고압중심북측.동아하계풍성행기간남아고압중심적북이제전우서풍급류중심적북이,이자적강도정반상적계절변화.일반정황하,이랑고압대응서부급류형,청장고압대응동부급류형.전형동、서부급류년빈중고위기온급고도장적차이표명기압제도력강약대비시급류동서형변화적주요원인,남아고압적위치기본상결정료급류중심적형태,단유우남아고압구유"추열성",이급류적이동부합열성풍적규률,인이이자적열력영향궤제유소불동.
The relationship between the east Asia subtropical westerly jet (EASWJ) in the upper troposphere and the south Asian high and the thermal mechanism are examined by using the monthly mean NCEP/NCAR reanalysis data. The results show that the EASWJ in the upper troposphere and the south Asian high both experience seasonal variation, which migrate northward and westward from winter to summer and southward and eastward from summer to winter, but the change in the intensity is reverse. The EASWJ center is located in the northern side of the south Asian high, and the westerly wind to the northern side of the anticyclone, corresponding in the south Asian high, is composed of the major part of the westerly jet. During the monsoon season, the south Asian high center migrates northward prior to EASWJ center. In general, the Iranian high corresponds to the western jet pattern, and the Tibetan high to the eastern jet pattern. The pressure gradient contrast between the western jet pattern and eastern jet pattern is responsible for the westerly jet pattern difference. The westerly jet pattern is determined by the location of the south Asian high. Moreover, there exists apparent difference in the thermal mechanism, due to the south Asian high following the high temperature center.