Dr R. Chawn Harlow

Chawn manages the Atmospheric Radiation Research Group which uses data from the FAAM BAe146 aircraft for various radiative transfer and remote sensing applications.

Areas of expertise

  • Airborne retrievals of millimetre wave surface emissivities and effective temperature.
  • Microwave emission modelling particularly of snow packs.
  • Lambertian and specular surface interaction.
  • Clear air microwave radiative transfer.

Publications by Chawn

Current activities

While managing the Atmospheric Radiation Group, Chawn leads airborne campaigns related to remote sensing of the atmosphere and surface. A recent campaign of note was SALSTICE in which the goals were to diagnose the sources of errors in the Unified Model (UM) representation of Land Surface Temperature (LST) and evaluation of the IASI-B instrument on MetOp-B.  Chawn and his group are currently analysing data from this campaign with the view of improving the UM simulations of LST and evaluating satellite retrievals of LST.
 
Future campaigns that Chawn is engaged in planning for are the Cold-air Outbreak and Sub-Millimetre Ice Cloud Study (COSMICS) and the Year of Polar Prediction (YOPP). COSMICS is a campaign using the ISMAR instrument to demonstrate the capability to retrieve ice cloud properties using sub-millimetre radiometer in preparation for the Ice Cloud Imager (ICI) to be launched on MetOp-SG in 2022. YOPP will contribute to a WMO project to improve NWP and seasonal forecasts for the polar regions. A FAAM campaign for YOPP is being proposed to (1) improve satellite data assimilation over the polar regions in line with Chawn's previous work on microwave emissivity and (2) improve treatment of cloud cover and the surface albedo over sea ice which impacts seasonal and climate predictions.

Career background

Chawn graduated from high school in Lakeview, Oregon, in June 1987. He received the B.Sc. degree in physics and astronomy; the M.Sc. degree in physics; and the Ph.D. degree in hydrology, with a minor in atmospheric science, from the University of Arizona, Tucson, in 1992, 1994, and 2003, respectively, where his dissertation was titled "Remote and in situ measurement of soil moisture and vegetation water content."
 
From 2005 to 2010, he served as Radiation Research Scientist with the Observational Based Research at the Met Office based in Exeter. His work focused on snow and sea-ice emissivities in the Advanced Microwave Sounding Unit wavelengths in order to improve satellite retrievals of atmospheric profiles of temperature and humidity. He also served as a Mission Scientist and MARSS Operator on the FAAM BAe-146.
 
Chawn now serves as Manager of the Atmospheric Radiation Group and Chairman of the FAAM Radiation and Lidar Instrument Working Group.

External recognition

In February 2010, Chawn received the L. G. Groves Memorial Prize for Meteorological Observations for his contribution to the planning and implementation of the CLPX-II campaign.

Last updated: 24 February 2015