Experimental Investigations of Tropospheric and Stratospheric Phenomena
(2012) For many years I have been involved in using NASA aircraft to address various issues in stratospheric and tropospheric science. In the past these studies have dealt with volcanic clouds, stratospheric ozone loss, stratospheric transport processes, searching for evidence of heterogeneous chemistry in the troposphere, as well as investigating the formation and radiative properties of cirrus clouds and the sensitivity of cirrus clouds to emissions from aircraft. I was the Co-project scientist for CRYSTAL/FACE in 2002. This project was aimed at understanding the role of deep convection in forming high altitude cirrus, and their role in influencing the energy budget of Earth. Six research aircraft made numerous flights from Key West, Fla. I was the Co-Mission Scientist for NASA’s Tropical Composition, Clouds and Climate Coupling Experiment which took place in Costa Rica in July and Aug. 2007 to help validate Aura and the A-Train satellites, and to learn more about tropical clouds and stratosphere-troposphere exchange. Currently I am Co-Project Scientist for the ATTREX field missions using the NASA Global Hawk to investigate water vapor in the upper troposphere and how it enters the stratosphere. I am also the Campaign Leader for SEAC4RS to investigate how air pollution over Southeast Asia may be lofted by deep convective clouds and then enter the stratosphere over Nepal.
Planetary Atmospheres and Exobiology
(2012) The focus of this work is to understand the clouds and climates of the terrestrial planets. Presently Victoria Hartwick, a graduate student, is developing a climate model for Mars based on the NCAR terrestrial climate models. She hopes to better understand how dust and clouds altered the ancient climate of Mars. Erik Larson, a graduate student, is running a climate model for Titan, to simulate the organic haze on that planet and compare with satellite data. Eric Wolf , a graduate student, is running a climate model for ancient Earth to better understand the faint young sun problem.
Aerosols and Clouds Above the Tropopause
(2012) This work has two facets – investigations of stratospheric aerosols and studies of polar stratospheric and mesospheric clouds. We have constructed a numerical model of stratospheric volcanic aerosols over the past two decades. The model was initially one-dimensional, approximating Earth as a vertical column of air. As computational tools have improved we expanded to a two dimensional framework, and now have developed a fully three-dimensional global model by combining our microphysical model with the NCAR WACCM/CAM dynamical models so that detailed predictions can be made. These calculations aid in the analysis of remote sensing information, as well as being useful to studies of stratospheric ozone loss and to studies of climate change. Student Yunqian Zhu is working on a model for polar stratospheric clouds, to improve our ability to simulate stratospheric ozone.
Tropospheric Clouds, Aerosols, and Radiative Transfer
(2012) Numerical simulations of the interactions between tropospheric aerosols and clouds are being conducted. One goal is to determine if the indirect effects of aerosols on clouds is a significant feature of Earth’s climate system. Another goal is to simulate the life cycle of tropospheric aerosols and clouds in detail. The eventual goal is to be able to model tropospheric aerosols, marine boundary layer clouds and cirrus clouds including three-dimensional dynamics, atmospheric chemistry, and detailed microphysics. Student Pengfei Yu is investigating smoke clouds from biomass burning and anthropogenic burning and other organic aerosols. Student Megan Bela is investigating how aerosols interact with deep convective clouds. Student Chris Maloney is working on cirrus clouds.