Science update: Recent variability of the tropical tropopause inversion layer

In a new GRL article, W. Wang and co-authors investigate recent variability of the tropopause temperature and the tropopause inversion layer (TIL) using GPS-RO observations and the WACCM chemistry-climate model. They find that the tropopause temperature increased by 0.8K from 2001-2011, while the TIL decreased in strength by 0.4K over the same period. This indicates that the vertical temperature gradient in the tropopause region has declined, and therefore the stability above the tropopause weakened. Model simulations show that the increased tropopause temperature and weaker TIL are related to weakened tropical upwelling. Such changes in the thermal structure of the UTLS may have important consequences, including, for example, a possible increase in water vapour entering the lower stratosphere. The full abstract can be found here.