Kai-Wei Chang

PhD Candidate
PhD Topic: 
Clouds and water vapor near the tropical tropopause
MS Topic: 
Temperature and humidity retrievals from AIRS and COSMIC
BS Major: 
Atmospheric science
Department of Atmospheric and Oceanic Sciences
University of Wisconsin-Madison
Room 1345
1225 West Dayton Street
Madison, WI 53706
Student Bio: 

Some of the coldest temperatures in the atmosphere are actually found in the tropical tropopause layer, where the temperature controls the amount of moisture entering the lower stratosphere. When air encounters these cold regions, it is thought that cirrus clouds form to dehydrate the air. What processes are responsible for producing these extremely cold temperatures, especially over the Western Pacific?  Can we use observations to find connections between cirrus and water vapor near the tropical tropopause? These are the questions I have become interested in during my PhD track here in Madison. I am using observations from satellite instruments such as the Aura MLS, COSMIC, and CloudSat/CALIPSO to study the connection between water vapor, temperature, and cirrus clouds.   I am also involved in satellite retrievals of ice cloud properties. We seek to utilize the suite of active radar/lidar and passive radiometer observations along the A-Train constellation to characterize ice clouds in as much detail as possible. We are testing which cloud paramters can possibly be retrieved through analyzing the Shannon information content of these observations. Following the analysis, our goal is to develop a joint retrieval algorithm using AIRS, MODIS, CloudSat CPR, and CALIPSO. 


Chang K.- W., T. L'Ecuyer, V. Natraj, and B.H. Kahn, 2017: Information Content of Visible and Mid-Infrared Radiances for Retrieving Tropical Ice Cloud Properties. J. Geophys. Res., 122, doi:10.1002/2016JD026357 [Download]

Research Highlights