The representation of the TTL in a tropical channel version of the WRF model

Results of the simulations show that the model reproduces the mean temperature and its variability above 50 hPa as well as the tropical tropopause height. However, the model cold point tropopause temperature is colder than the reanalyses by ~1.2 K. The model captures the location of TTL water vapor minimum in the Western Pacific but is drier than the MLS observations in the TTL. To assess possible reasons for the tropopause temperature discrepancy, an additional WRF experiment was conducted using analysis nudging for water vapor.

This experiment produces more tropical cirrus clouds in the upper troposphere and a warming of ~1.5 K of the cold point tropopause. This suggests that the radiative effects of cirrus clouds and water vapor must be considered for accurate temperature simulations in the TTL.