印尼—澳大利亚北部低频夏季风活动及其与南北半球环流的联系

本文根据ECMWF/WMO资料和NOAA极轨卫星提供的向外长波辐射(OLR)资料,应用扩展经验正交函数(EEOF)展开的方法,研究了1981年11月—1982年3月印尼—澳大利亚北部30—60天低频夏季风活动及其与南北半球环流的联系。 结果表明,在850hPa上,来自东亚沿岸的30—60天低频东北(西南)风向南传播越过赤道后,可以转为印尼—澳大利亚北部地区的低频夏季西北(东南)风,当其与澳大利亚西部加强了的低频西南(东北)风辐合(散)时,夏季风区对流(干旱)加强并向东扩展。850hPa低频位势高度场的变化特征与其相协调。这些结果与未经滤波的实际资料研究结果相类似,从而说明低频变化分量表现了热带环流变化过程的主要特征。 

LOW FREQUENCY SUMMER MONSOON MOTION IN INDONESIA-NORTHERN AUSTRALIA AND ITS RELATIONSHIP TO GENERAL CIRCULATIONS IN SOUTHERN AND NORTHERN HEMISPHERES

The 30-60-day low frequency summer monsoon motion in Indonesia-Northern Australia during the period of November of 1981 to March of 1982 and its relationship to the general circulations in both Southern and Northern Hemispheres, based on the data from ECMWF/WMO and the data of outgoing longwave radiation (OLR) provided by the polar orbit satellite NOAA, have been studied by employing a method of extended empirical orthogonal function (EEOF).The result shows that the 30-60-day low frequency northeast (southwest) wind flowed from the coastal area of East Asia at 850 hPa could be turned to a low frequency summer monsoon northwest (southeast) wind in Indonesia-Northern Australia as it moves southwards across the equator. The convection (drought) over the area prevailing summer monsoon air is enhanced and then stretches eastwards when a convergence occurs since the low frequency summer monsoon northwest (southeast) wind meets the strengthened low frequency southwest (northeast) wind in Western Australia. addition, the pattern of the low frequency geopotantial hight fields at 850hPa is well coordinated.These outcomes of investigation are similar to that one based on the practical data of radius filtering, thereby illustrating that the component of the low frequency variation tropical general circulation variation.