Research Associate Professor
Ph.D. Atmospheric and Oceanic Sciences – McGill University, 1996
M.Sc. Meteorology – Eötvös Loránd University, 1989
Dr. Várnai joined UMBC in 1999, after working as research associate at McGill University and at the University of Arizona. His work focused on cloud measurements by the Terra satellite’s MISR instrument. He is a member of UMBC's Joint Center for Earth Systems Technology, and is affiliated to the Physics Department.
My work focuses on three-dimensional (3-D) radiative processes that occur in clouds. While most current studies and satellite products rely on one-dimensional (1-D) radiative theory and assume horizontal homogeneity, my interest lies in cloud fields that display significant horizontal variations and therefore create 3-D radiative effects such as shadowing. My research goals have included better understanding the mechanisms of 3-D radiative interactions, estimating their influence on satellite-derived cloud properties (especially on MODIS cloud products), and incorporating them into computer simulations of cloud development. I am also interested in taking advantage of 3-D radiative effects for measuring cloud properties that have so far eluded 1-D remote sensing techniques. In particular, I have participated in the THOR project with the goal of using multiview lidars to determine the thickness and internal structure of thick clouds, snow, and sea ice.
"Potential for airborne offbeam lidar measurements of snow and sea ice thickness”, T. Várnai, and R. F. Cahalan, J. Geophys. Res. 112, doi:10.1029/2007JC004091 (2007).
"View angle dependence of cloud optical thicknesses retrieved by MODIS", T. Várnai, and A. Marshak, J. Geophys. Res, 112, doi:10.1029/2005JD006912 (2007).
"Impact of 3D radiative effects on satellite retrievals of cloud droplet sizes", A. Marshak, S. Platnick, T. Várnai, G. Wen, and R. F. Cahalan, J. Geophys. Res., 111, doi:10.1029/2005JD006686 (2006).
"New directions in 3D atmospheric radiative transfer", L. Oreopoulos, A. Marshak, R. F. Cahalan, T. Várnai, A. B. Davis, and A. Macke, EOS 87, 52 (2006).
"THOR—Cloud thickness from offbeam lidar returns", R. F. Cahalan, M. McGill, J. Kolasinski, T. Várnai, and K. Yetzer, J. Atmos. Ocean. Tech. 22, 605-627 (2005).
"A method for analyzing how various parts of clouds influence each other’s brightness", T. Várnai, and A. Marshak, J. Geophys. Res. 108, doi: 10.1029/2003JD003561 (2003).
"Observations of three-dimensional radiative effects that influence MODIS cloud optical thickness retrievals", T. Várnai, and A. Marshak, J. Atmos. Sci. 59, 1607-1618 (2002).
"Influence of three-dimensional radiative effects on the spatial distribution of shortwave cloud reflection", T. Várnai, J. Atmos. Sci. 57, 216-229 (2000).
"Effects of cloud heterogeneities on shortwave radiation: Comparison of cloud top variability and internal heterogeneity", T. Várnai, and R. Davies, J. Atmos. Sci. 56, 4206-4223 (1999).