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.