Middle atmosphere summer duration as an indicator of long-term circulation changes |
| |
| Institution: | 1. Physics Department, University of Wuppertal, Gauss-Strasse 20, D-42097 Wuppertal, Germany;2. AWI, Potsdam, Germany;3. NCAR, Boulder, USA;4. Free University Berlin, Gemany;5. Met Obs., DWD, Hohenpeissenberg, Germany;1. Center for Environmental Survey, Vidyanagar Society 29/251, Ahmedabad, Gujarat 380015, India;2. Physical Research Laboratory, Navrangpura, Ahmedabad, Gujarat 380009, India |
| |
| Abstract: | Summer duration (SD) is defined here as the time interval between spring and autumn turn around of zonal winds in the stratosphere. SD long-term trends are obtained from analysis of middle stratosphere NCEP and ECMWF data. They are found to be dependent on latitude and altitude. Wind data are available since 1948. The corresponding analysis suggests a breakpoint in the trend at around 1980: SD increases before 1980, and decreases afterwards. Corresponding changes of stratospheric wave activity are analyzed and found to be a major contribution to the SD trends. Long-term computer runs of the Whole Atmosphere Community Climate Model (WACCM 1b) are consistent with these results. Vegetation data on the ground indicate similar trends with a break. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
