春夏季转换期东亚地表热通量对温度月际变化的影响

Effects of Surface Heat Flux on Surface Air Temperature Variation Trend in East Asia Region from Spring to Summer

利用1948-2003年的NCEP／NCAR再分析资料，分析了东亚地区春夏季节转换期间地面气温变化趋势以及地面热通量对温度季节变化的影响。结果表明，东亚地区4～7月地面气温月际变化存在明显的与纬度有关的南北向差异、与海陆分布有关的东西向差异以及大陆上中低纬地区以90°E为分界线的东西向差异，大陆上温度月际变化比海洋上显著。通过对月际变温指数的研究发现，中南半岛以及高原东侧在4～5月月际变温明显，印度半岛及高原西侧6～7月月际变温明显，表明月际最大变温有从90°E以东地区向90°E以西地区推进的过程。研究月际变温与地面热通量关系发现，高纬地区大陆上月际温度变化主要与太阳辐射以及潜热变化关系较大，而中低纬地区大陆上月际变温与感热、潜热以及辐射关系都比较密切，且90°E以东的中南半岛及邻近地区的4～5月的月际变温与地面热通量的相关关系最为显著，90°E以西的印度半岛及邻近地区6～7月的月际变温与热通量相关关系最为明显，此时青藏高原西侧辐射以及感热加热作用显著。对于热通量与地面月际变温显著相关区域的进一步分析表明，地面热通量对于温度场的直接影响主要表现在近地层，在高层，两者之间相关关系复杂。

The features of the Surface Air Temperature Variation trend （SATV） and the effect of surface heat flux on SATV in East Asia from spring to summer are analyzed in this paper, using the NCEP/ NCAR reanalysis data from 1948 to 2003. The results indicate that there are notable differences of SATV from south to north because of the latitudinal difference of the solar radiation, and from west to east due to the land sea thermal contrast. The analysis of SATV index shows that from April to May, the intermonthly SATV is evident in the Indo-China Peninsula and the eastern part of the Tibetan Plateau, while from June to July, the SATV in the Indian Peninsula and the western part of the Tibetan Plateau becomes notable. This phenomenon means that the maximal SATV first appears to the east of 90°E, and then emerges in the west. Correlation analysis demonstrates that there exists a close relationship between SATV and surface heat flux variation in the areas where SATV is more visible, such as Indo-China Peninsula, Indian Peninsula. From April to June, the correlation coefficients between SATV and sensible and radiation heat flux variation are obviously positive in the Indo-China Peninsula, and negative between SATV and latent heat flux. From May to July, sensible and latent heat fluxes have significant effects on SATV in the Indian Peninsula, and the radiation flux plays an important role in the western part of the Tibetan Plateau. Over the ocean, the close relationship exists between SATV and sensible heat flux and latent heat flux variation in Kuroshio area. Further research on the correlation between surface heat flux and temperature in different altitudes over two peninsulas and the Tibetan Plateau shows that the surface diabatic heating has an evident effect on the air temperature variation in low levels, and it is different from the relationship between surface heating and air temperature variation in high level.