【作者】 简茂球；

【导师】 罗会邦；

【作者基本信息】 中山大学 ， 气象学， 2004， 博士

【摘要】 本工作利用1958-2000年共43年NCEP/NCAR再分析资料计算了全球逐日的大气显热源,并处理成月平均资料,及利用我国160站1951-2000年的逐月降水资料和1958-1998年月平均海温资料,应用统计分析方法,研究了大气热源的季节突变性,其年际、年代际变化与我国降水的关系和海气相互作用过程中海温异常与下垫面热通量的变化特征,揭示出一些新的观测事实,得到以下一些结果。亚洲季风区的大气热源的季节演变具有明显的突变性。东亚季风区和印度季风区大气热源的冬夏型间转换的过度季节都较短,即冬夏型之间的转换具有明显的突变性。两地大气热源的季节突变时间与环流的季节突变时间颇为一致。大气热源的年较差以亚洲季风区最显著,澳大利亚北部次之。在全球范围,总体而言是热源的年际尺度分量占的方差比重大,但也有部分区域是年代以上尺度占优。大气热源的年际尺度和年代际尺度的方差分布有明显的差别。在热带地区,年际变化的方差极大值区呈南北双带分布,并随季节有南北移动;夏季西太平洋暖池区是热源年际、年代际方差的极大值中心区。而年代际方差极值区在热带呈纬向相间分布。在年际尺度上,我国夏季(5-8月)各月降水的主要异常型都与西太暖池附近的热源异常有密切关系,特别地,7、8月青藏高原东部热源异常对同期长江及附近区域的降水异常有更重要的影响。7月华南地区的降水异常与同年发生的ENSO事件造成的大范围的热源异常有关,即暖事件(冷事件)发生当年7月华南降水偏涝(偏旱)。另外,与ENSO事件有关的冬季赤道太平洋的热源异常与我国南方冬季的降水异常也有显著的相关关系。特别是在年代际尺度上,我国5-8月各月的主要降水异常区降水的年代际变化有明显差异。我国南方5月降水的年代际变化与热带印度洋东西偶极子型的热源年代际演变有关;而6-8月各月主要雨带降水的年代际变化与热带西太平洋的热源的年代际变化有密切关系。7月长江流域的降水异常与8月长江和黄河之间地区的的降水异常有很好的同号性;8月沿江西-湖南-广西一带的降水偏多(少),则9月在华南中、东部的降水也偏多(少)。由于我国的洪涝灾害主要出现在7、8月份,故7、8月长更多还原

【Abstract】 The global heat sources are calculated using the NCEP/NCAR dailyreanalysis data from 1958 to 2000. The seasonal, interannual andinterdecadal variations of the heat sources have been analyzed, and theirrelationship with the rainfall over China have been also investigated.Some new observed evidences have been found. The main results aresummarized as follows: The seasonal transition of the heat sources over the East Asianmonsoon area and the Indian monsoon area are of abruptness, which havea good consistence with the variations in the general circulations. Theannual range in the Asian monsoon area is most prominent in the world,and the second one is in the north to Australia. The variance of theinterannual scale heat sources is usually more remarkable than theinterdecadal one except in some area.The interannual variance of heat source has a co-belt spatial pattern,while the interdecadal variance has a zonally fluctuating distribution inthe tropics. On the interannual scale, the dominant anomaly patterns ofrainfall in summertime over China have very close relation with the heatsource anomalies over the warm pool area in the western Pacific and theeastern Tibetan Plateau especially. The floods/ droughts in the SouthernChina in July are remarkably related to the developing El Ni?o/La Ni?aevents. On interdecadal timescale, the rainfall over the southern area ofChina in May has a close linkage with the dipole pattern of heat sourceanomalies over the tropical Indian Ocean, while in June to August therainfalls over the Yangtze River basin and its vicinities are also relatedclosely with the heat sources variations in the tropical western Pacific.The rainfall anomalies in the Yangtze River basin and its vicinities inJuly and August have a good consistent variation. This rainfall anomalypersistency in July and August usually leads to the flood or droughtdisasters in the area mentioned above. These disaster events have linkagewith the heat source anomalies over the Pacific on ocean-wide scale. Theheat source anomalies over the central and eastern tropical Pacific andover the Tibetan Plateau area in the previous months, such as in May andJune, may provide an favor background to the flood or drought disastersin the Yangtze River basin and its vicinities.In the Indian-Pacific oceans, the dominant abnormal mode of seasurface temperature in boreal winter closely relates with the dominantabnormal mode in the followed spring and the abnormal modes inAsian-Australian monsoon area in summer and fall. The latent heat fluxand the sensible heat flux anomalies are very remarkable in the air-seainteraction processes in boreal winter and spring, and have importanteffects on the sea surface temperature and the low-level wind. However,the heat flux anomalies are weak generally in boreal summer. Theabnormal mode of the sea surface temperature in Asian-Australianmonsoon area in boreal summer may result to the rainfall anomalies overthe middle reaches of Yangtze River basin.更多还原