近50 a北半球和青藏高原地面及其高空温度变化的初步分析

通过分析北半球和青藏高原地面平均气温与它们上空500hPa平均温度、200一500hPa平均厚度在不同时期和不同纬度带的趋势变化特征,了解其地面气温和其对流层中上层温度的年代际变化趋势以及相互关系。可以看到近50a地面气温和500hPa温度年代际变化大致相同,20世纪70年代中期之前都为降温,70年代中期以后为不同程度的升温。200—500hPa厚度代表的对流层上层温度与对流层下层温度变化趋势相反,70年代前明显升温,70年代后明显降温。分析还表明,对流层各层温度在不同纬度和不同季节的变化也不同。

A Preliminary Analysis of Surface and Middle-Upper Level Temperature over the Northern Hemisphere and the Tibetan Plateau in Recent 50 Years

Monthly mean temperature at surface and 500hPa,and the thickness between 200hPa and 500hPa over the Northern Hemisphere and Tibetan Plateau are analysed to investigate their interdecadal variation tendency in different seasons and latitudes,and their relations as well.It's revealed that the interdecadal tendency in temperature at surface is similar to that at 500hPa in the recent 50 years,with a cooling(warming) tendency before(after) the middle of 1970s.While the interdecadal tendency of temperature in the upper troposphere is opposite to that in the lower troposphere,with a warming(cooling) tendency before(after) 1970s.Analysis also shows difference among the changes of the temperature at different levels of troposphere in different latitudes and seasons.