近40年中国高空温度变化的初步分析

为了了解高空气温的长期变化趋势,利用中国28个高空探空站1961—2000年间地面至高空10hPa的温度资料进行了统计分析,结果表明:从地面到高空200hPa最冷在1月,最热在7月;但是在最冷的100hPa层以上,其气温年变化位相相反,即1月最热,8月最冷;50hPa层以上温度的年变化不大。近40余年来,年平均气温变化趋势自地面至700hPa,绝大部分地区温度上升,尤其是地面增温最为显著,而西南地区有降温趋势;对流层上层至50hPa的平流层的温度在降低,尤其是50hPa降温最为显著。北半球的较强火山喷发对中国32°N以南的低纬与32°N以北的中高纬地区高空温度的影响不同。火山喷发后,低纬地区平流层第1~26个月温度均有不同程度增温,其中在第7~8个月增温最明显;在对流层以下,第6~11个月、第16~27个月出现2次明显降温时段,第1次降温最明显。中高纬地区平流层在第1~16个月、第20~29个月出现2段增温,第1段增温时间跨度长、强度大,第17~19个月出现了降温。在对流层以下第2~5个月、第14~18个月、第21~30个月出现3次明显降温时段,第3次降温持续时间长,整体降温强度较大。

Primary Analyses of Upper-Air Temperature Changes in China in past 40 years

Based on the temperature data from the surface to the 10 hPa levels in China at 28 radiosonde stations in 1961-2000,the seasonal variation and long-term trend are studied.The main results are as follows: The seasonal evolution features between surface and 200 hPa and 100 hPa levels are different,e.g.,from surface to 200 hPa the hottest month is July,the coldest month is January,but above 100 hPa levels the result is the oppositive.In late 40 years,the temperature in the lower troposphere significantly increases over almost the country except for south-west China,but it decreases in both upper troposphere and lower stratosphere(especially on 50 hPa levels).The influences of major volcanic eruptions on upper temperature of low latitude and mid-high latitude regions of China are different.In 26 months after volcanic eruption stratosphere temperature is positive abnormaly in lower latitude region,especially from seventh to eighth months the warming is remarkable.Troposphere temperature is cooling in 6~7th months and 16~27th months,the intensity of first cooling period is larger.In middle-high latitude regions,the stratosphere temperature has two obvious warming periods in 1~16th months and 20~29th months,but it is cooling in 17~19th months.The troposphere temperature is cooling in 2~5th months,14~18th months and 21~30th months. The intensity of third cooling period is larger.