Recent Research:

1. Aerosol Optical Depth:
   One of my tasks, after joining the Space and Remote Sensing Group at the LANL, was to develop science applications using the Multispectral Thermal Imager (MTI). The aerosol optical depth (AOD) characterizes the amount and optical activities of natural and anthropogenic atmospheric aerosols. AOD is an important parameter needed for assessment of mankind induced global change (aerosols counteract the heating effects of greenhouse gases) and for atmospheric correction of satellite imagery. By combination of theoretical work and the MTI image analysis we were able to develop a method of satellite based AOD retrieval that reduces the error of retrieval by about a factor of three compared to the error of current NASA and NOAA satellite instruments. We were able to show that by adapting our method for a suitable sub-set of NASA MODIS (Moderate Resolution Imaging Spectroradiometer) images, the error of the AOD retrieval was reduced from 0.12 to 0.04. Our work on AOD satellite retrieval helped to establish LANL as a recognized center of atmospheric remote sensing. In recognition of my work I have received the Los Alamos National Laboratory Award for Scientific and Technical Leadership in 2004. The major publications include:
   • P. Chylek, B. Henderson and M. Mishchenko, Aerosol Radiative Forcing and the Accuracy of the Satellite Aerosol Optical Depth Retrieval, J. Geophys. Res.. 108 (D24), 4764, doi: 10.1029/2003JD004044, 2003
   • P. Chylek, B. Henderson, and Glen Lesins, Aerosol Optical Depth retrieval Over the NASA Stennis Space Center: MTI, MODIS and AERONET. IEEE Transactions on Geosciences and Remote Sensing, 2005, in print;
   • B. Henderson and P. Chylek, The Effect of Resolution on Satellite Aerosols Optical Depth Retrieval, IEEE Trans. Geosci. Remote Sens., 2005, in print.
2. Water, Ice and Mixed Phase Clouds:
   Based on our earlier laboratory measurements we have developed a satellite based method for remote sensing of the thermodynamic phase (water, ice or mixture of water and ice) of clouds. To be able to determine the cloud phase is essential for assessing the climate change, for atmospheric corrections in remote sensing and for flying through the clouds (aircraft icing occurs usually only in mixed phase clouds). Using the MTI high spatial resolution imagery we have shown that the Arctic stratus clouds often contain pockets of pure water and pockets of pure ice in addition to mixed phase region. The published paper
   • P. Chylek, and C. Borel, Mixed Phase Clouds Water/Ice Structure From High Spatial Resolution Satellite Data, Geophys. Res. Lett., 31, doi:10.1029/2004GL020428, 2004.

   has been recognized by the Board of AGU Editors as Journal Highlight in August 2004. The IGPP funded project, developed in collaboration with Prof. Q. Fu from the Department of Atmospheric Sciences, University of Washington, supports a graduate student who will continue the research and its remote sensing and climate change applications.

3. Special MTI Related Section of the IEEE Transactions on Geosciences and Remote Sensing:
   To recognize the success of an open science applications of the LANL MTI project I have organized a special MTI related section of the IEEE Transactions on Geosciences and Remote Sensing. The goal is to enhance the LANL reputation as a world-class center of remote sensing. A total of seven manuscripts have been submitted for publication by members of the former MTI team. By now six of the submitted papers have been accepted; one manuscript is still in the reviewing process. The special section is expected to be published in late 2005 or early 2006.
4. Aerosols-Climate and Hydrological Cycle:
   I have helped to develop the LDRD-DR funded project "Resolving the Aerosol-Climate-Water Puzzle (20050014DR - M. Dubey -PI)", where I am now leader of the observational part of the proposed research. Within the past few months, we have made a major discovery concerning the effect of aerosols on the size distribution of ice crystals of cirrus clouds. It is reasonably well documented that the man made pollution modifies the size distribution of water droplets in clouds toward smaller sizes which leads to higher cloud reflectivity and cooling of the climate (a partial compensation of the warming produced by greenhouse gases). Till now it has been assumed that man made pollution will have a similar effect on ice clouds. Our satellite based observations suggest, however, that aerosols may have an opposite effect on ice clouds. The paper describing our results is currently in preparation in collaboration with the foremost climate experts (V. Ramanathan - Scripps; U. Lohmann - ETH Zurich; Y. Kaufman -NASA GSFC).

Complete CV:

Petr's complete CV is a available here