The Climatic Characteristics And Interdecadal Changes Of The Global Heat Source

Making use of the daily and monthly NCEP/NCAR reanalysis data, the climatic distribution of every season of the heat source are computed. The laws of seasonal and interdecadal variation of the global heat source are analysed during 1948-2002. The variations in summer and winter are studied emphatically, with the results as follows:(1) The atmospheric heat sources are not symmetrical in both southern and northern hemisphere, and the heating in northern is stronger than southern. The positions locate in the north of equator in summer, but is opposite in winter. There are four primary atmospheric heat source centers and their positions change with season. In summer, they are located respectively in mid-Africa, the Bey of Bengal, the Philippines in the tropical western Pacific and the southwest of Caribbean, In winter, they move to the South Africa, around the ocean-continent to the Indian Ocean, the northwest Australia to the southern Pacific and north of South America.(2) The key areas of the seasonal variation of the heat sources are mostly in active monsoon regions and its surrounding areas. The coverage and intensity of the atmospheric heat sources are the largest and strongest in summer and then turn smaller and weaker in autumn and winter, then in turn begin to become larger and stronger in spring again. The position of the moisture sources (sinks) are in accordance with the heat sinks (sources) which is clear in land in summer and obvious in ocean in winter.(3) The result of EOF technique is that the dominant regions of interdecadal changes of the global heat source locate in Asian, Africa and South America. The abnormity of the heat source has obviously region different, which is stronger near the equator and weaker in the two poles. In most years, the abnormity presents obviously positive-negative interval array in meridional aspect, and in longitudinal aspect, it shows some abnormal heating or lose-heating centers.(4) In summer, the variety of the heat source in mid-Africa, the Philippines in tropical western Pacific and the southwest of Caribbean takes on obviously interdecadal changes. The heat source in mid-Africa presents weaken mutation in 70 's, but that in the Philippines in the tropical western Pacific and the southwest of Caribbean present enhancive mutation. The heat source in the Bey of Bengal present weaken trend.(5) In winter, the heat source in the north of South America takes on obviously interdecadal changes. It presents enhancive mutation in middle 70's. The heat sources in South Africa and around ocean-continent to the Indian Ocean present enhancive trend, but it presents weaken trend in the northwest of Australia to the southern Pacific.