NASA - National Aeronautics and Space Administration

Dr. Timothy Liu’s recent work on hurricane research involves the improvement of seeing horizontal or vector winds from spacebased scatterometer instruments, under the severe conditions of tropical cyclones. A scatterometer is a microwave radar designed specifically to measure ocean near-surface wind speed and direction from an aircraft or a satellite.

He has studied how tropical cyclones change when they move out of the tropics and become severe marine storms that endanger shipping in the busy shipping lanes. He studied the interplay between wind and rain in tropical cyclones, the two factors that cause destruction when tropical cyclones move on land. He also found that tropical cyclones increase the biological productivity of the ocean that may enhance fisheries and reduce the carbon dioxide ­ a greenhouse gas, in the atmosphere.

Dr. Liu received a B.S degree in Physics from Ohio University in 1971, a Masters in Science and a Ph.D. in Atmospheric Sciences from the University of Washington, in 1974 and 1978 respectively. Liu is also a Fellow of the American Meteorological Society.

Currently, he is a Principal Scientist at NASA's Jet Propulsion Laboratory (JPL), California Institute of Technology in Pasadena, Calif. He became a Senior Research Scientist at JPL, which is equivalent to a full professor in major U.S. universities, in 1993. He was the Leader of the Air-sea Interaction and Climate Team at JPL between 1989 and 2005. He has been the Project Scientist of a series of NASA space missions - NSCAT, QuikSCAT, and SeaWinds, all of which have a scatterometer onboard to study winds.

He was selected as a principal investigator or a science team member of many Earth observing space missions, including NSCAT, Topex, European Remote Sensing Satellite (ERS-1), the Tropical Rainfall Measuring Mission (TRMM), Aqua satellite, and the Advanced Microwave Scanning Radiometer (AMSR) instrument. He has chaired and participated in many science working groups and expert panels of NASA and the World Climate Research Program. Up to the end of 2004, he had a total of 121 peer-reviewed publications.

Dr. Liu’s interests are in ocean-atmosphere interaction and satellite oceanography. In the 1979, he proposed a revolutionary method to compute ocean surface evaporation from routine reports. Its impact is still felt 25 years later.

In the 1980s, he developed the first credible method of using satellite data to estimate evaporation and changes in latent heat.

Since joining NASA/JPL, Liu's interest has been in the understanding and application of spaceborne sensors, with publications on scatterometer data, synthetic aperture radar, microwave radiometer, and altimeter data. His present interest includes relating the fluxes to storage and transport through the depths of the ocean and atmosphere. He is leading research effort to combine a variety of satellite data synergistically to study global climate and environmental changes.

Related Web Sites:

http://airsea.jpl.nasa.gov

NASA Winds page

NASA Air-Sea Interaction and Climate Page

Satellite Sees Double Zones Of Converging Tropical Winds Around The World

Rob Gutro
Goddard Space Flight Center