Studv of unusual waether regimes in the summers of 1993 and 1994

1993年和1994年夏季异常天气状况的研究

基本信息

批准号：
07304069
负责人：
YASUNARI Tetsuzo
金额：
$ 3.71万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07304069/
关键词：
Climate Change Unusual Weather Cool Summer Hot Summer Atmosphere-Ocean System Sea surface Temperature General Circulation Model Tropical Zone ENSO

项目摘要

The cause of the unusual and wet summer of 1993 and the unusual hot and dry summer of 1994 are clarified based on the detailed data analysis and the theoretical consideration by using the general circulation model. It is documented that the unusual weather in both summers are considerably affected by the tropical atmosphere-ocean system. In addition, it is confirmed that air temperature shows remarkable decrease due to the appearance of sub-polar jet stream in the lower troposphere over Siberia and the developing of the Blocking High over the Sea of Okhotsk in 1993. It is also found that summer precipitation increase as the result that the Baiu Front. is intensified by the large north-south temperature gradient around Japan. In 1994, it is clear that the increase of surface temperature is amplified due to the eastward migration of Tibetan High and the local surface dryness. These analytical results in both summers are almost supported by the climatological simulation by using general circulation model. Especially, it is shown that spatial distribution of sea surface temperature in the western tropical Pacific in the two years are slightly different, From the examination by using longer climatic data, it is found that the range of temperature change is large in 1950s-60s and after 1980s. We also obtain the result that the global atmosphere-ocean system affecting summer temperature in Japan is different between before 1970s and after 1980s.

利用大气环流模型，在详细的资料分析和理论思考的基础上，阐明了1993年夏季异常多雨和1994年夏季异常炎热干燥的原因。据记载，这两个夏季的异常天气很大程度上受到热带大气-海洋系统的影响。此外，还证实1993年西伯利亚对流层低层出现副极地急流以及鄂霍次克海阻塞高压的发展导致气温显着下降。同时还发现夏季降水量增加。增加的结果是Baiu Front。日本周围巨大的南北温度梯度加剧了这种情况。 1994年，由于青藏高压东移和局部地表干燥，地表温度升高明显放大。这两个夏季的分析结果几乎得到了利用大气环流模型进行的气候模拟的支持。特别是，两年间热带西太平洋海表温度的空间分布略有不同，利用较长的气候资料检验发现，1950-60年代温度变化幅度较大， 20世纪80年代后。我们还得到了影响日本夏季气温的全球大气-海洋系统在1970年代之前和1980年代之后是不同的结果。