849 Can Shifting Cloud Radiative Effects Influence Tropical Stratification Changes?

Tuesday, 14 January 2020
Hall B (Boston Convention and Exhibition Center)
Timothy M. Merlis, McGill Univ., Montreal, Canada; and Y. Li and A. A. Wing

Tropical stratification changes from global warming or other climate changes are often described as resulting from the temperature-sensitivity of moist adiabats. Here, we examine an alternative, radiative pathway for stratification changes. Global warming leads to upward shifts in the tropopause and high clouds. These cloud shifts will, in turn, alter radiative heating rates at a given pressure level and will have warming temperature tendencies near the climatological tropopause. To assess the quantitative importance of shifting clouds, we compare the stratification changes in global climate model and cloud-system resolving model simulations where cloud radiative effects are deactivated to conventional simulations where they are active. Eliminating cloud radiative effects does modestly (~5-10%) reduce the upper tropospheric warming, confirming a secondary role for radiative changes compared to the conventional perspective that convective processes dominate tropical stratification changes.
- Indicates paper has been withdrawn from meeting
- Indicates an Award Winner