对流圈加热场特征及其同我国江淮流域旱涝联系的初步研究

FEATURES OF THE TROPOSPHERIC HEATING FIELDS AND THE RELATION TO DROUGHT OR FLOOD IN THE REACHES OF YANGTZE RIVER AND HUAIHE RIVER

本文采用热流量方程计算了对流圈下半部(1000—500hPa)与对流圈上半部(500—200hPa)1980—1983年各年全球月平均加热场,讨论了冬夏季全球加热场分布及年际变化特点,指出中国东部降水异常与加热场异常之间有较一致的关系,凝结潜热在加热场中起主要作用,加热场特点同我国长江中下游区域旱涝存在一定关系,旱涝前期某些区域的加热率有明显差异。ENSO事件期间,发现亦道太平洋区域存在这样的关系(ΔQ/ΔT)>(ΔQ/ΔT)海温区,上升气流最强支移到赤道太平洋中部,同亦道西太平洋之间构成一个反Walker环流,赤道太平洋中部纬向风速是辐散的,经向风速则是辐合的,赤道西太平洋加热性质对ENSO出现有先兆现象。

In this paper, we have computed the global monthly mean heating rates of lower troposphere (1000-500hPa) and upper troposphere (500-200hPa) for four years (1980-1983) by using the thermodynamic equation, and analyzed the features of the heating fields in the winter and summer season and their interannual changes. It is found that the distribution of the monthly mean precipitation anomalies in eastern China is rather similar to that of the monthly mean heating anomalies. The condensation heating plays an important role in the heating fields. There exists some relationship between the drought (flood) in the middle and lower reaches of the Yangtze River and the features of heating fields. In certain region, the heating rates during January through October of the drought year are quite different from that of the flood year. During ENSO event, we find in the tropic area (△Q/△T)high SST region >(△Q/△T) low SST region, The location of the strongest ascending air shifts from the equatorial western Pacific to equatoral central Pacific. Between equatorial western and central Pacific there exists a inverse Walker circulation. In the equatoral central Pacific the zonal winds are divergent, but the meridional winds convergent. The heating rates in the equatoral western Paicfic in the preceding winter of an ENSO event is different from those of normal years.