Sciences and Exploration Directorate

Tamas Varnai



Org Code: 613

Mail Code: 613
Greenbelt, MD 20771



Research Associate Professor

University of Maryland Baltimore County: Joint Center for Earth Systems Technology and the Department of Physics - Baltimore, MD

2008 - Present


Research Assistant Professor

University of Maryland Baltimore County: Joint Center for Earth Systems Technology and the Department of Physics - Baltimore, MD

2001 - 2008


Assistant Research Scientist

University of Maryland Baltimore County: Joint Center for Earth Systems Technology - Baltimore, MD

1999 - 2001


Postdoctoral Research Associate

University of Arizona - Tucson, AZ

1997 - 1999


Postdoctoral Research Associate

McGill University - Montreal, Canada

1996 - 1997


Research Meteorologist

Hungarian Meteorological Service - Budapest, Hungary

1989 - 1991



1996 - Ph.D. in Atmospheric and Oceanic Sciences, McGill University, Montreal, Canada, Dissertation: "Reflection of solar radiation by inhomogeneous clouds"
1989 - M.Sc. equivalent degree in Meteorology, Eotvos Lorand University, Budapest, Hungary, Thesis: "The adaptation of a spectral global circulation model"

Professional Service

2019 - present: Member of the editorial board for the journal Remote Sensing



Várnai, T., and A. Marshak. 2021. Analysis of Near-Cloud Changes in Atmospheric Aerosols Using Satellite Observations and Global Model Simulations Remote Sensing 13 (6): 1151 [10.3390/rs13061151]

Gatebe, C. K., H. Jethva, R. Gautam, R. Poudyal, and T. Várnai. 2021. A new measurement approach for validating satellite-based above-cloud aerosol optical depth Atmospheric Measurement Techniques 14 (2): 1405-1423 [10.5194/amt-14-1405-2021]

Kostinski, A., A. Marshak, and T. Várnai. 2021. Deep Space Observations of Terrestrial Glitter Earth and Space Science 8 (2): 2020EA001521 [10.1029/2020ea001521]

Varnai, T., A. Marshak, and A. B. Kostinski. 2020. Deep Space Observations of Cloud Glints: Spectral and Seasonal Dependence IEEE Geoscience and Remote Sensing Letters 1-5 [10.1109/lgrs.2020.3040144]

Varnai, T., A. B. Kostinski, and A. Marshak. 2019. Deep Space Observations of Sun Glints from Marine Ice Clouds IEEE Geoscience and Remote Sensing Letters 17 1-5 [10.1109/lgrs.2019.2930866]

Várnai, T., C. Gatebe, R. Gautam, R. Poudyal, and W. Su. 2019. Developing an Aircraft-Based Angular Distribution Model of Solar Reflection from Wildfire Smoke to Aid Satellite-Based Radiative Flux Estimation Remote Sensing 11 (13): 1509 [10.3390/rs11131509]

Wu, D., T. Wang, T. Várnai, et al. J. Limbacher, R. Kahn, G. Taha, J. Lee, J. Gong, and T. Yuan. 2018. MISR Radiance Anomalies Induced by Stratospheric Volcanic Aerosols Remote Sensing 10 (12): 1875 [10.3390/rs10121875]

Várnai, T., and A. Marshak. 2018. Satellite Observations of Cloud-Related Variations in Aerosol Properties Atmosphere 9 (11): 430 [10.3390/atmos9110430]

Fauchez, T., S. Platnick, T. Várnai, et al. K. Meyer, C. Cornet, and F. Szczap. 2018. Scale dependence of cirrus heterogeneity effects. Part II: MODIS NIR and SWIR channels Atmospheric Chemistry and Physics 18 (16): 12105-12121 [10.5194/acp-18-12105-2018]

Yang, W., A. Marshak, T. Várnai, and Y. Knyazikhin. 2018. EPIC Spectral Observations of Variability in Earth’s Global Reflectance Remote Sensing 10 (2): 254 [10.3390/rs10020254]

Várnai, T., A. Marshak, and T. F. Eck. 2017. Observation-Based Study on Aerosol Optical Depth and Particle Size in Partly Cloudy Regions Journal of Geophysical Research: Atmospheres 122 (18): 10,013-10,024 [10.1002/2017jd027028]

Fauchez, T., S. Platnick, K. Meyer, et al. C. Cornet, F. Szczap, and T. Várnai. 2017. Scale dependence of cirrus horizontal heterogeneity effects on TOA measurements – Part I: MODIS brightness temperatures in the thermal infrared Atmospheric Chemistry and Physics 17 (13): 8489-8508 [10.5194/acp-17-8489-2017]

Marshak, A., T. Várnai, and A. Kostinski. 2017. Terrestrial glint seen from deep space: Oriented ice crystals detected from the Lagrangian point Geophysical Research Letters Online [10.1002/2017gl073248]

Wen, G., A. Marshak, T. Varnai, and R. C. Levy. 2016. Testing the Two-Layer Model for Correcting Near Cloud Reflectance Enhancement Using LES/SHDOM Simulated Radiances J. Geophys. Res., Atmos. (121): 9661–9674 [10.1002/2016JD025021]

Gautam, R., C. K. Gatebe, M. K. Singh, T. Várnai, and R. Poudyal. 2016. Radiative characteristics of Clouds Embedded in Smoke derived from airborne multi-angular measurements J. Geophys. Res. Atmos. 121 (15): 9140–9152 [10.1002/2016jd025309]

Varnai, T., and A. Marshak. 2015. Effect of cloud fraction on near-cloud aerosol behavior in the MODIS atmospheric correction ocean color product Rem. Sens 7 5283-5299 [10.3390/rs70505283]

Yang, W., A. Marshak, T. Varnai, and R. Wood. 2014. CALIPSO observations of near-cloud aerosol properties as a function of cloud fraction Geophys. Res. Lett 41 9150-9157 [10.1002/2014GL061896]

Varnai, T., and A. Marshak. 2014. Near-cloud aerosol properties from the 1 km resolution MODIS ocean product J. Geophys. Res. Atmos. 119 (3): 1546-1554 [10.1002/2013JD020633]

Marshak, A., K. F. Evans, T. Varnai, and G. Wen. 2014. Extending 3D near-cloud corrections from shorter to longer wavelengths Journal of Quantitative Spectroscopy and Radiative Transfer 147 79-85 [10.1016/j.jqsrt.2014.05.022]

Yang, Y., A. Marshak, A. B. Kostinski, and T. Varnai. 2013. Shape-induced gravitational sorting of Saharan dust during transatlantic voyage: Evidence from CALIOP lidar depolarization measurements Geophys. Res. Lett 40 (12): 3281-3286 [10.1002/grl.50603]

Wen, G., A. Marshak, R. C. Levy, et al. L. A. Remer, N. Loeb, T. Varnai, and R. F. Cahalan. 2013. Improvement of MODIS aerosol retrievals near clouds J. Geophys. Res. Atmos. 118 (16): 9168-9181 [10.1002/jgrd.50617]

Varnai, T., A. Marshak, and W. Yang. 2013. Multi-satellite aerosol observations in the vicinity of clouds Atmos. Chem. Phys. 13 (8): 3899-3908 [10.5194/acp-13-3899-2013]

Yang, W., A. Marshak, T. Varnai, O. V. Kalashnikova, and A. B. Kostinski. 2012. CALIPSO observations of transatlantic dust: vertical stratification and effect of clouds Atmos. Chem. Phys. 12 (23): 11339-11354 [10.5194/acp-12-11339-2012]

Yang, W., A. Marshak, T. Varnai, and Z. Liu. 2012. Effect of CALIPSO cloud–aerosol discrimination (CAD) confidence levels on observations of aerosol properties near clouds Atmospheric Research 116 134-141 [10.1016/j.atmosres.2012.03.013]

Gatebe, C. K., T. Varnai, R. Poudyal, C. M. Ichoku, and M. D. King. 2012. Taking the pulse of pyrocumulus clouds Atmospheric Environment 52 121-130 [10.1016/j.atmosenv.2012.01.045]

Chiu, J., A. Marshak, C. Huang, et al. T. Varnai, R. Hogan, D. Giles, B. Holben, E. OConnor, Y. Knyazikhin, and W. Wiscombe. 2012. Cloud droplet size and liquid water path retrievals from zenith radiance measurements: examples from the Atmospheric Radiation Measurement Program and the Aerosol Robotic Network Atmos. Chem. Phys. 12 (21): 10313-10329 [10.5194/acp-12-10313-2012]

Varnai, T., and A. Marshak. 2012. Analysis of co-located MODIS and CALIPSO observations near clouds Atmos Meas Tech 5 (2): 389-396 [10.5194/amt-5-389-2012]

Pounder, N., R. Hogan, T. Varnai, A. Battaglia, and R. F. Cahalan. 2012. A Variational Method to Retrieve the Extinction Profile in Liquid Clouds Using Multiple-Field-of-View Lidar J Appl Meteor Climatol 51 (2): 350-365 [10.1175/JAMC-D-10-05007.1]

Yang, Y., A. Marshak, S. P. Palm, T. Varnai, and W. J. Wiscombe. 2011. Cloud Impact on Surface Altimetry From a Spaceborne 532-nm Micropulse Photon-Counting Lidar: System Modeling for Cloudy and Clear Atmospheres IEEE Trans. Geosci. Remote Sensing 49 (12): 4910-4919 [10.1109/TGRS.2011.2153860]

Oreopoulos, L., M. Wilson, and T. Varnai. 2011. Implementation on Landsat Data of a Simple Cloud-Mask Algorithm Developed for MODIS Land Bands IEEE Geosci. Remote Sensing Lett. 8 (4): 597-601 [10.1109/LGRS.2010.2095409]

Varnai, T., and A. Marshak. 2011. Global CALIPSO Observations of Aerosol Changes Near Clouds IEEE Geosci. Remote Sensing Lett. 8 (1): 19-23 [10.1109/LGRS.2010.2049982]

Varnai, T. 2010. Multiyear Statistics of 2D Shortwave Radiative Effects at Three ARM Sites J Atmos Sci 67 (11): 3757-3762 [10.1175/2010JAS3506.1]

Yang, Y., A. Marshak, T. Varnai, W. J. Wiscombe, and P. Yang. 2010. Uncertainties in Ice-Sheet Altimetry From a Spaceborne 1064-nm Single-Channel Lidar Due to Undetected Thin Clouds IEEE Trans. Geosci. Remote Sensing 48 (1): 250-259 [10.1109/TGRS.2009.2028335]

Varnai, T., and A. Marshak. 2009. MODIS observations of enhanced clear sky reflectance near clouds Geophys. Res. Lett. 36 (6): L06807 [10.1029/2008GL037089]

Evans, K., A. Marshak, and T. Varnai. 2008. The Potential for Improved Boundary Layer Cloud Optical Depth Retrievals from the Multiple Directions of MISR Journal of the Atmospheric Sciences 65 (10): 3179-3196 [10.1175/2008JAS2627.1]

Varnai, T., and R. F. Cahalan. 2007. Potential for airborne offbeam lidar measurements of snow and sea ice thickness J. Geophys. Res. 112 (C12): C12S90 [10.1029/2007JC004091]

Varnai, T., and A. Marshak. 2007. View angle dependence of cloud optical thicknesses retrieved by Moderate Resolution Imaging Spectroradiometer (MODIS) J. Geophys. Res. 112 (D6): D06203 [10.1029/2005JD006912]

Marshak, A., S. E. Platnick, T. Varnai, G. Wen, and R. F. Cahalan. 2006. Impact of three-dimensional radiative effects on satellite retrievals of cloud droplet sizes J. Geophys. Res. 111 (D9): D09207 [10.1029/2005JD006686]

Oreopoulos, L., A. Marshak, R. F. Cahalan, et al. T. Varnai, A. B. Davis, and A. Macke. 2006. New directions in the radiative transfer of cloudy atmospheres Eos Trans. AGU 87 (5): 52 [10.1029/2006EO050006]

Cahalan, R., L. Oreopoulos, A. Marshak, et al. K. Evans, A. Davis, R. Pincus, K. Yetzer, B. Mayer, R. Davies, T. Ackerman, H. Barker, E. Clothiaux, R. Ellingson, M. Garay, E. Kassianov, S. Kinne, O. Macke, O. Macke, O. Macke, P. Partain, S. Prigarin, A. Rublev, G. Stephens, F. Szczap, E. Takara, T. Varnai, G. Wen, and T. Zhuravleva. 2005. The International Intercomparison of 3D Radiation Codes (I3RC): Bringing together the most advanced radiative transfer tools for cloudy atmospheres Bull Amer Meteor Soc 86 (9): 1275-1293 [10.1175/BAMS-86-9-1275]

Cahalan, R. F., M. J. Mcgill, J. Kolasinski, T. Varnai, and K. Yetzer. 2005. THOR—Cloud Thickness from Offbeam Lidar Returns Journal of Atmospheric and Oceanic Technology 22 (6): 605-627 [10.1175/JTECH1740.1]

Varnai, T. 2003. A method for analyzing how various parts of clouds influence each other's brightness J. Geophys. Res. 108 (D22): 4706 [10.1029/2003JD003561]

Varnai, T., and A. Marshak. 2002. Observations of three-dimensional radiative effects that influence satellite retrievals of cloud properties Quart Jour of Hungarian Meteor Service (Idojaras) 106 265-278

Varnai, T., and A. Marshak. 2002. Observations of three-dimensional radiative effects that influence MODIS cloud optical thickness retrievals J Atmos Sci 59 1607-1618

Varnai, T., and A. Marshak. 2001. Statistical analysis of the uncertainties in cloud optical depth retrievals caused by three-dimensional radiative effects J Atmos Sci 58 1540-1548