We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Tropical convection regimes in climate models: evaluation with satellite observations.
- Authors
Steiner, Andrea K.; Lackner, Bettina C.; Ringer, Mark A.
- Abstract
High quality observations are powerful tools for the evaluation of climate models towards improvement and reduction of uncertainty. Particularly at low latitudes, the most uncertain aspect lies in the representation of moist convection and interaction with dynamics, where rising motion is tied to deep convection and sinking motion to dry regimes. Since humidity is closely coupled with temperature feedbacks in the tropical troposphere a proper representation of this region is essential. Here we demonstrate the evaluation of atmospheric climate models with satellite-based observations from Global Positioning System (GPS) radio occultation (RO), which feature high vertical resolution and accuracy in the troposphere to lower stratosphere. We focus on the representation of the vertical atmospheric structure in tropical convection regimes, defined by high updraft velocity over warm surfaces, and investigate atmospheric temperature and humidity profiles. Results reveal that some models do not fully capture convection regions, particularly over land, and only partly represent high updraft or downdraft velocities. Models show large biases in tropical mean temperature of more than 4 K in the tropopause region and the lower stratosphere. Reasonable agreement with observations is given in mean specific humidity in the lower to mid-troposphere. In moist convection regions, models tend to underestimate moisture by 10 % to 30 % over oceans whereas in dry downdraft regions they overestimate moisture by 100 %. Our findings provide evidence that RO observations are a unique source of information, with a range of further atmospheric variables to be exploited, for the evaluation and advancement of next generation climate models.
- Subjects
ATMOSPHERIC models; GLOBAL Positioning System; TROPOSPHERE
- Publication
Atmospheric Chemistry & Physics Discussions, 2017, p1
- ISSN
1680-7367
- Publication type
Abstract
- DOI
10.5194/acp-2017-669