Upper Troposphere/Lower Stratosphere Water Vapor in the National Center for Atmospheric Research Whole-Atmosphere Climate/Chemistry Model

University Of Maryland, College Park, College Park MD

Investigators

Abstract

The abundance of water vapor in the upper troposphere and lower stratosphere is an important determinant of the chemical and climatic state of the earth's atmosphere. The ability to predict water vapor at these high altitudes remains one of the most important challenges in general circulation models. The PI will investigate this using the National Center for Atmosphere Research (NCAR) Whole Atmosphere Community Climate Model (WACCM). He will introduce two stable isotopes of water, HDO and H218O, and the associated physics, into the model. In addition, medium-lived tracers, such as ozone and carbon monoxide, that do not condense will be analyzed. The research will be focused in the "tropical tropopause layer", a transition region between the troposphere and the stratosphere. Model integrations for several years will be compared with measurements using traces such as ozone, carbon monoxide, and the isotopes of water. The results should provide new understanding of the pathways by which air reaches the stratosphere and of the mechanisms that control the stratospheric water vapor concentration. The research work will be done in collaborating with the WACCM team at NCAR. The isotopic modules developed will be made available to the general community and, possibly, be included in the standard version of the WACCM. The research will also provide good opportunities for graduate studies.