Dr. Lazaros Oreopoulos

Dr. Lazaros Oreopoulos

  • SUPV RSCH AST, CLIMATE&RADIATION STD
  • 301.614.6128
  • NASA/GSFC
  • Mail Code: 613
  • Greenbelt , MD 20771
  • Employer: NASA
  • Brief Bio

    Dr. Lazaros Oreopoulos (a.k.a Lazaros Oraiopoulos) is the Chief of the Climate and Radiation Lab. He has over two decades of experience conducting research on the modeling and remote sensing of clouds, their impact on the Earth’s Radiation Budget, aerosol-cloud interactions, and many aspects of atmospheric radiative transfer for climatic applications. He is the Deputy Project Scientist for the Aqua satellite mission, and a current member of the Precipitation Measurement Mission and CloudSat-CALIPSO Science Teams. He has previously been a member of the MODIS, AIRS, and Landsat Science Teams, and has served in the International Radiation Commission, the AMS Atmospheric Radiation Committee, and the GEWEX Radiation Panel. He received the NASA Exceptional Scientific Achievement Medal (ESAM) in 2018.

    Dr. Oreopoulos holds a B. Sc. in Physics from Aristotle's University of Thessaloniki, Greece, and M. Sc. and Ph. D. degrees in Atmospheric Sciences from McGill University, Montreal. Web of Science publications and citation metrics can be found here; see also Google Scholar.

    Research Interests

    Atmospheric Radiation

    Especially interactions with clouds and aerosols. Atmospheric radiation problems are studied both for the purpose of remotely sensing properties atmospheric constituents, but also for climate applications, for example radiation and energy budgets.

    Cloud Modeling

    Mainly for Large Scale Modeling applications, for example cloud parameterizations for Global Climate Models that reproduce as faithfully as possible water and energy budgets.

    Current Projects

    Continual Intercomparison of Radiation Codes (CIRC)

    http://circ.gsfc.nasa.gov Purpose is to assess how various classes of radiative transfer codes perfom relative to benchmark line-by-line calculations.

    Cloud Microphysics in Large Scale Models

    This is funded by NASA's Modeling Analysis and Prediction (MAP) program and aims at more realistic prediction of cloud particle and number concentrations given meteorological conditions and aerosol loadings.

    Cloud regimes from A-Train

    This project funded by the NASA Science of Terra and Aqua program aims to decompose water and energy budget by cloud regimes as identified by various methods and criteria that rely on passive and active satellite observations.

    Positions/Employment

    2/2013 - Present

    Supervisory Research Physical Scientist (Lab Chief)

    NASA, GSFC, Climate and Radiation Lab  
    12/2008 - 2/2013

    Research Physical Scientist

    NASA, GSFC, Climate and Radiation Laboratory, Code 613  
    1/2006 - 12/2008

    Research Associate Professor

    JCET/UMBC, NASA GSFC, Climate and Radiation Branch, Code 613.2  
    4/1999 - 12/2005

    Research Assistant Professor

    JCET/UMBC, NASA GSFC, Climate and Radiation Branch, Code 613.2  
    10/1997 - 3/1999

    Assistant Research Scientist

    JCET/UMBC, NASA GSFC, Climate and Radiation Branch, Code 613.2  
    8/1996 - 10/1997

    Research Scientist

    Meteorological Service of Canada, Cloud Physics Research Division, Downsview, Ontario, Canada  

    Education

     – B. Sc. in Physics 1989, Aristotle's University of Thessaloniki, Greece

    – M. Sc. in Meteorology 1992, McGill University, Montreal, Canada

    – Ph. D. in Atmospheric and Oceanic Sciences, 1996, McGill University, Montreal, Canada

     

    Professional Societies

    American Meteorological Society, 1991 - Present
    American Geophysical Union, 1991 - Present

    Professional Service

    – Member of the International Radiation Commission
    – Former member of the GEWEX (Global Water and Energy Exchanges project) Radiation Panel
    – Member of the Science Steering Commitee of GEWEX's GASS (Global Atmospheric System Studies) panel
    – Former member of the AMS (American Meteorological Society) Radiation Committee

    Grants

    06/01/2019 - 05/31/2022 CloudSat and CALIPSO Science Team Recompete, NASA, NASA NRA #: NNH18ZDA001N

    Using CloudSat and CALIPSO observations to assess and inform Global Climate Model hydrometeor generators about the horizontal and vertical subgrid variability of clouds and precipitation

    ; Principal Investigator
    02/01/2019 - 01/31/2022 Precipitation Measurement Missions (PMM) Science Team, NASA, NASA NRA #: NNH18ZDA001N

    Combined Analysis Of GPM And MODIS Datasets to Unveil The Climatological Relationships Between Clouds and Precipitation

    ; Principal Investigator
    04/11/2014 Science of Terra and Aqua, NASA
    Understanding the links between clouds and their environment by employing MODIS cloud regimes in compositing studies ; Principal Investigator
    05/22/2013 NASA MAP: Modeling Analysis and Prediction, NASA
     Further enhancement of the cloud prediction capabilities of the GEOS-5 AGCM for radiative and aerosol indirect effect studies ; Principal Investigator
    05/26/2010 NASA CloudSat/CALIPSO Science Team Recompete, NASA
     Extracting the essence of cloud horizontal and vertical variability from CloudSat for the benefit of Large Scale Models ; Principal Investigator
    12/07/2006 Atmospheric Radiation Measurements Program, Department of Energy
     Evaluation of GCM Column Radiation Models under cloudy conditions with the ARM BBHRP Value Added Product ; Principal Investigator
    12/12/2005 Science Team for the Landsat Data Continuity Mission, United States Geological Survey
     Cloud detection and avoidance for the Landsat Data Continuity Mission
    02/15/2002 Global Water and Energy Cycle, NASA
     Use of new RT schemes and satellite data for more realistic cloud radiative forcing and hydrologic cycle in climate models ; Principal Investigator

    Selected Publications

    Refereed

    Yuan, T., C. Wang, H. Song, et al. S. Platnick, K. Meyer, and L. Oreopoulos. 2019. "Automatically Finding Ship-tracks to Enable Large-scale Analysis of Aerosol-Cloud Interactions." Geophysical Research Letters, [10.1029/2019gl083441]

    Tan, I., L. Oreopoulos, and N. Cho. 2019. "The Role of Thermodynamic Phase Shifts in Cloud Optical Depth Variations With Temperature." Geophysical Research Letters, 46 (8): 4502-4511 [10.1029/2018gl081590]

    Tan, J., and L. Oreopoulos. 2019. "Subgrid Precipitation Properties of Mesoscale Atmospheric Systems Represented by MODIS Cloud Regimes." Journal of Climate, 32 (6): 1797-1812 [10.1175/jcli-d-18-0570.1]

    Zhang, W., J. Wang, D. Jin, L. Oreopoulos, and Z. Zhang. 2018. "A Deterministic Self-Organizing Map Approach and its Application on Satellite Data based Cloud Type Classification." 2018 IEEE International Conference on Big Data (Big Data), [10.1109/bigdata.2018.8622558]

    Tan, J., L. Oreopoulos, C. Jakob, and D. Jin. 2018. "Evaluating rainfall errors in global climate models through cloud regimes." Climate Dynamics, 50: 3301–3314 [10.1007/s00382-017-3806-7]

    Yuan, T., L. Oreopoulos, S. E. Platnick, and K. Meyer. 2018. "Observations of Local Positive Low Cloud Feedback Patterns and Their Role in Internal Variability and Climate Sensitivity." Geophysical Research Letters, 45 (9): 4438-4445 [10.1029/2018gl077904]

    Jin, D., L. Oreopoulos, D. Lee, N. Cho, and J. Tan. 2018. "Contrasting the Co-variability of Daytime Cloud and Precipitation over Tropical Land and Ocean." Atmospheric Chemistry and Physics, 1-31 [https://doi.org/10.5194/acp-18-3065-2018]

    Oreopoulos, L., N. Cho, and D. Lee. 2017. "New insights about cloud vertical structure from CloudSat and CALIPSO observations." Journal of Geophysical Research: Atmospheres, 122 (17): 9280-9300 [10.1002/2017jd026629]

    Malavelle, F. F., J. M. Haywood, A. Jones, et al. A. Gettelman, L. Clarisse, S. Bauduin, R. P. Allan, I. H. Karset, J. E. Kristjánsson, L. Oreopoulos, N. Cho, D. Lee, N. Bellouin, O. Boucher, D. P. Grosvenor, K. S. Carslaw, S. Dhomse, G. W. Mann, A. Schmidt, H. Coe, M. E. Hartley, M. Dalvi, A. A. Hill, B. T. Johnson, C. E. Johnson, J. R. Knight, F. M. O’Connor, D. G. Partridge, P. Stier, G. Myhre, S. Platnick, G. L. Stephens, H. Takahashi, and T. Thordarson. 2017. "Strong constraints on aerosol–cloud interactions from volcanic eruptions." Nature, 546 (7659): 485-491 [10.1038/nature22974]

    Oreopoulos, L., N. Cho, and D. Lee. 2017. "Using MODIS cloud regimes to sort diagnostic signals of aerosol-cloud-precipitation interactions." Journal of Geophysical Research: Atmospheres, 122 (10): 5416-5440 [10.1002/2016jd026120]

    Jin, D., L. Oreopoulos, and D. Lee. 2017. "Regime-based evaluation of cloudiness in CMIP5 models." Climate Dynamics, 48: 89-112 [10.1007/s00382-016-3064-0]

    Leinonen, J., M. D. Lebsock, L. Oreopoulos, and N. Cho. 2016. "Interregional differences in MODIS-derived cloud regimes." Journal of Geophysical Research: Atmospheres, 121: [10.1002/2016jd025193]

    Mlawer, E. J., M. J. Iacono, R. Pincus, et al. H. W. Barker, L. Oreopoulos, and D. L. Mitchell. 2016. "Contributions of the ARM Program to Radiative Transfer Modeling for Climate and Weather Applications." Meteorological Monographs, 57: 15.1-15.19 [10.1175/amsmonographs-d-15-0041.1]

    Jin, D., L. Oreopoulos, and D. Lee. 2016. "Simplified ISCCP Cloud Regimes for Evaluating Cloudiness in CMIP5 Models." Climate Dynamics, 48: 113-130 [10.1007/s00382-016-3107-6]

    Oreopoulos, L., N. Cho, D. Lee, and S. Kato. 2016. "Radiative effects of global MODIS cloud regimes." J. Geophys. Res. Atmos., 121 (5): 2299–2317 [10.1002/2015jd024502]

    Zhang, Z., K. Meyer, H. Yu, et al. S. Platnick, P. Colarco, Z. Liu, and L. Oreopoulos. 2016. "Shortwave direct radiative effects of above-cloud aerosols over global oceans derived from 8 years of CALIOP and MODIS observations." Atmos. Chem. Phys., 16 (5): 2877-2900 [10.5194/acp-16-2877-2016]

    Yuan, T. L., L. Oreopoulos, M. Zelinka, et al. H. Yu, J. Norris, M. Chin, S. E. Platnick, and K. G. Meyer. 2016. "Positive low cloud and dust feedbacks amplify tropical North Atlantic multidecadal oscillation." Geophysical Research Letters, 43 (3): 1349–1356 [10.1002/2016gl067679]

    Pincus, R., E. J. Mlawer, L. Oreopoulos, et al. A. S. Ackerman, S. Baek, M. Brath, S. A. Buelhler, K. E. Cady-Pereira, J. N. Cole, J.-L. Dufresne, M. Kelley, J. Li, J. Manners, D. J. Paynter, R. Roehrig, M. Sekiguchi, and M. D. Schwarzkopf. 2015. "Radiative flux and forcing parameterization error in aerosol-free clear skies." Geophys. Res. Lett, 42 (13): 5485-5492 [10.1002/2015GL064291]

    Huang, X., X. Chen, G. L. Potter, et al. L. Oreopoulos, J. Cole, D. Lee, and N. G. Loeb. 2014. "A Global Climatology of Outgoing Longwave Spectral Cloud Radiative Effect and Associated Effective Cloud Properties." Journal of Climate, 27 (19): 7475-7492 [10.1175/JCLI-D-13-00663.1]

    Oreopoulos, L., N. Cho, D. Lee, S. Kato, and G. J. Huffman. 2014. "An examination of the nature of global MODIS cloud regimes." Journal of Geophysical Research: Atmospheres, 119 (13): 8362-8383 [10.1002/2013JD021409]

    Lee, D., Y. C. Sud, L. Oreopoulos, et al. K. M. Kim, W. K. Lau, and I. S. Kang. 2014. "Modeling the influences of aerosols on pre-monsoon circulation and rainfall over Southeast Asia." Atmos. Chem. Phys., 14 (13): 6853-6866 [10.5194/acp-14-6853-2014]

    Zhang, Z., K. Meyer, S. Platnick, et al. L. Oreopoulos, D. Lee, and H. Yu. 2014. "A novel method for estimating shortwave direct radiative effect of above-cloud aerosols using CALIOP and MODIS data." Atmos. Meas. Tech., 7 (6): 1777-1789 [10.5194/amt-7-1777-2014]

    Huang, X., J. N. Cole, F. He, et al. G. L. Potter, L. Oreopoulos, D. Lee, M. J. Suarez, and N. G. Loeb. 2013. "Longwave Band-By-Band Cloud Radiative Effect and Its Application in GCM Evaluation." J. Climate, 26 (2): 450-467 [10.1175/JCLI-D-12-00112.1]

    Yi, B., P. Yang, B. A. Baum, et al. T. LEcuyer, L. Oreopoulos, E. J. Mlawer, A. J. Heymsfield, and K. N. Liou. 2013. "Influence of Ice Particle Surface Roughening on the Global Cloud Radiative Effect." Journal of the Atmospheric Sciences, 70 (9): 2794-2807 [10.1175/JAS-D-13-020.1]

    Meyer, K. G., S. E. Platnick, L. Oreopoulos, and D. Lee. 2013. "Estimating the direct radiative effect of absorbing aerosols overlying marine boundary layer clouds in the southeast Atlantic using MODIS and CALIOP." J. Geophys. Res. Atmos., 118 (10): 4801-4815 [10.1002/jgrd.50449]

    Wen, G., R. F. Cahalan, J. D. Haigh, et al. P. Pilewskie, L. Oreopoulos, and J. W. Harder. 2013. "Reconciliation of modeled climate responses to spectral solar forcing." J. Geophys. Res. Atmos., 118 (12): 6281–6289 [10.1002/jgrd.50506]

    Yuan, T. L., and L. Oreopoulos. 2013. "On the global character of overlap between low and high clouds." Geophys. Res. Lett., 40 (19): 5320-5326 [10.1002/grl.50871]

    Lee, D., L. Oreopoulos, G. J. Huffman, W. B. Rossow, and I.-S. Kang. 2013. "The Precipitation Characteristics of ISCCP Tropical Weather States." J. Climate, 26 (3): 772-788 [10.1175/JCLI-D-11-00718.1]

    Randles, C. A., S. Kinne, G. Myhre, et al. M. Schulz, J. Fischer, L. Doppler, E. Highwood, C. Ryder, B. Harris, J. Huttunen, Y. Ma, R. T. Pinker, B. Mayer, D. Neubauer, R. Hitzenberger, L. Oreopoulos, D. Lee, G. Pitari, G. DiGenova, J. Quaas, F. G. Rose, S. Kato, S. T. Rumbold, I. Vardavas, N. Hatzianastassiou, C. Matsoukas, H. Yu, F. Zhang, H. Zhang, and P. Lu. 2013. "Intercomparison of shortwave radiative transfer schemes in global aerosol modeling: results from the AeroCom Radiative Transfer Experiment." Atmos. Chem. Phys., 13 (5): 2347-2379 [10.5194/acp-13-2347-2013]

    Sud, Y. C., D. Lee, L. Oraiopoulos, et al. D. Barahona, A. Nenes, and M. Suarez. 2013. "Performance of McRAS-AC in the GEOS-5 AGCM: aerosol-cloud-microphysics, precipitation, cloud radiative effects, and circulation." Geosci. Model Dev., 6 (1): 57-79 [10.5194/gmd-6-57-2013]

    Wilson, M. J., and L. Oreopoulos. 2012. "Enhancing a Simple MODIS Cloud Mask Algorithm for the Landsat Data Continuity Mission." IEEE Transactions on Geoscience and Remote Sensing, 51 (2): 723-731 [Full Text (Link)] [10.1109/TGRS.2012.2203823]

    Morales Betancourt, R., D.-M. Lee, L. Oraiopoulos, et al. Y. Sud, D. Barahona, and A. Nenes. 2012. "Sensitivity of cirrus and mixed-phase clouds to the ice nuclei spectra in McRAS-AC: single column model simulations." Atmos. Chem. Phys., 12 (22): 10,679-10,692 [10.5194/acp-12-10679-2012]

    Yuan, T. L., L. A. Remer, H. Bian, et al. J. R. Ziemke, R. Albrecht, K. E. Pickering, L. Oreopoulos, S. Goodman, H. Yu, and D. J. Allen. 2012. "Aerosol indirect effect on tropospheric ozone via lightning." J. Geophys. Res., 117 (D18): D18213 [10.1029/2012JD017723]

    Oreopoulos, L., D. Lee, Y. Sud, and M. Suarez. 2012. "Radiative impacts of cloud heterogeneity and overlap in an atmospheric General Circulation Model." Atmos. Chem. Phys., 12 (19): 9097-9111 [10.5194/acp-12-9097-2012]

    Oreopoulos, L., E. J. Mlawer, J. S. Delamere, et al. T. Shippert, J. Cole, B. Fomin, M. J. Iacono, Z. Jin, J. Li, J. Manners, P. Räisänen, F. G. Rose, Y. Zhang, M. J. Wilson, and W. B. Rossow. 2012. "The Continual Intercomparison of Radiation Codes: Results from Phase I." J Geophys Res, 117 (D6): D06117 [10.1029/2011JD016821]

    Oreopoulos, L., and W. B. Rossow. 2011. "The cloud radiative effects of International Satellite Cloud Climatology Project weather states." J. Geophys. Res., 116 (D12): D12202 [10.1029/2010JD015472]

    Oreopoulos, L., and P. Norris. 2011. "An analysis of cloud overlap at a midlatitude atmospheric observation facility." Atmos. Chem. Phys., 11 (12): 5557-5567 [10.5194/acp-11-5557-2011]

    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]

    Oreopoulos, L., and E. Mlawer. 2010. "MODELING: The Continual Intercomparison of Radiation Codes (CIRC)." Bull Am Met Soc, 91 (3): 305-310 [10.1175/2009BAMS2732.1]

    Oreopoulos, L., S. E. Platnick, G. Hong, P. Yang, and R. F. Cahalan. 2009. "The Shortwave Radiative Forcing Bias of Homogeneous Liquid and Ice Clouds Observed by MODIS." [PowerPoint slides] Retrieved from Current Problems in Atmospheric Radiation (IRS 2008 Proceedings), [10.1063/1.3117049]

    Oreopoulos, L., E. Mlawer, J. Delamere, and T. Shippert. 2009. "The Continual Intercomparison of Radiation Codes (CIRC): A New Standard for Evaluating GCM Radiation Codes." [PowerPoint slides] Retrieved from Current Problems in Atmospheric Radiation (IRS 2008 Proceedings),

    Oreopoulos, L., S. Platnick, G. Hong, P. Yang, and R. Cahalan. 2009. "The shortwave radiative forcing bias of liquid and ice clouds from MODIS observations." Atmos. Chem. Phys., 9 (16): 5865-5875 [10.5194/acp-9-5865-2009]

    Joiner, J., M. Schoeberl, A. Vasilkov, et al. L. Oreopoulos, S. Platnick, N. Livesey, and P. Levelt. 2009. "Accurate satellite-derived estimates of the tropospheric ozone impact on the global radiation budget." Atmos. Chem. Phys., 9 (13): 4447-4465 [10.5194/acp-9-4447-2009]

    Vasilkov, A. P., J. Joiner, L. Oreopoulos, et al. J. F. Gleason, P. Veefkind, E. Bucsela, E. A. Celarier, R. J. Spurr, and S. E. Platnick. 2009. "Impact of tropospheric nitrogen dioxide on the regional radiation budget." Atmos Chem Phys, 9: 6389-6400 [10.5194/acp-9-6389-2009]

    Oreopoulos, L., and S. Platnick. 2008. "Radiative susceptibility of cloudy atmospheres to droplet number perturbations: 2. Global analysis from MODIS ." J. Geophys. Res., 113 (D14S21): 10.1029/2007JD009655.

    Platnick, S., and L. Oreopoulos. 2008. "Radiative susceptibility of cloudy atmospheres to droplet number perturbations: 1. Theoretical analysis and examples from MODIS." J. Geophys. Res., 113 (D14S20): 10.1029/2007JD009654.

    Norris, P. M., L. Oreopoulos, A. Y. Hou, W. K. Tao, and X. Zeng. 2008. "Representation of 3D heterogeneous cloud fields using copulas: Theory for water clouds." Q. J. R. Meteorol. Soc., 1843-1864: 10.1002/qj.321.

    Koren, I., L. Oreopoulos, G. Feingold, L. Remer, and O. Altaratz. 2008. "How small is a small cloud?" Atmos Chem Phys, 8 (2): 6379-6407 [10.5194/acpd-8-6379-2008]

    Oreopoulos, L., R. Cahalan, and S. Platnick. 2007. "The Plane-Parallel Albedo Bias of Liquid Clouds from MODIS Observations." J. Climate, 20 (20): 5114-5125 [10.1175/JCLI4305.1]

    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]

    Oreopoulos, L. 2005. "The impact of subsampling on MODIS level-3 statistics of cloud optical thickness and effective radius." IEEE Trans. Geosci. Remote Sensing, 43 (2): 366-373 [10.1109/TGRS.2004.841247]

    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]

    Oreopoulos, L., and R. Cahalan. 2005. "Cloud Inhomogeneity from MODIS." J. Climate, 18 (23): 5110-5124 [10.1175/JCLI3591.1]

    Oreopoulos, L., M. Chou, M. Khairoutdinov, H. Barker, and R. Cahalan. 2004. "Performance of Goddard Earth Observing System GCM column radiation models under heterogeneous cloud conditions." Atmospheric Research, 72: 365-382 [10.1016/j.atmosres.2004.03.025]

    Oreopoulos, L., A. Marshak, and R. Cahalan. 2003. "Consistency of ARESE II cloud absorption estimates and sampling issues." J. Geophys. Res., 108 (D1): 4029 [10.1029/2002JD002243]

    Oreopoulos, L., and M. Khairoutdinov. 2003. "Overlap properties of clouds generated by a cloud-resolving model." J. Geophys. Res., 108 (D15): 4479 [10.1029/2002JD003329]

    Cahalan, R. F., L. Oreopoulos, G. Wen, et al. A. Marshak, S.-C. Tsay, and T. DeFelice. 2001. "Cloud characterization and clear sky correction from Landsat 7." Remote Sens Environ, 78 (1-2): 83-98 [10.1016/S0034-4257(01)00251-6]

    Wen, G., R. Cahalan, S.-C. Tsay, and L. Oreopoulos. 2001. "Impact of cumulus cloud spacing on Landsat atmospheric correction and aerosol retrieval." J. Geophys. Res., 106 (D11): 12129-12138 [10.1029/2001JD900159]

    Oreopoulos, L., R. F. Cahalan, A. Marshak, and G. Wen. 2000. "A new normalized difference cloud retrieval technique applied to Landsat radiances over the Oklahoma ARM Site." J Appl Meteor, 39 (12): 2305-2320 [10.1175/1520-0450(2000)039<2305:ANNDCR>2.0.CO;2]

    Oreopoulos, L., A. Marshak, R. F. Cahalan, and G. Wen. 2000. "Cloud three-dimensional effects evidenced in Landsat spatial power spectra and autocorrelation functions." J Geophys Res, 105 (D11): 14777-14788 [10.1029/2000JD900153]

    Wen, G., S.-C. Tsay, R. F. Cahalan, and L. Oreopoulos. 1999. "Path radiance technique for retrieving aerosol optical thickness over land." J. Geophys. Res., 104 (D24): 31321-31332 [10.1029/1999JD900964]

    Oreopoulos, L., and H. W. Barker. 1999. "Accounting for subgrid-scale cloud variability in a multi-layer 1d solar radiative transfer algorithm." Q.J Royal Met. Soc., 125 (553): 301-330 [10.1002/qj.49712555316]

    Marshak, A., W. Wiscombe, A. Davis, L. Oreopoulos, and R. Cahalan. 1999. "On the Removal of the Effect of Horizontal Fluxes In Two-Aircraft Measurements of Cloud Absorption." Q.J Royal Met. Soc., 125 (558): 2153-2170 [10.1002/qj.49712555811]

    Marshak, A., L. Oreopoulos, A. Davis, W. Wiscombe, and R. Cahalan. 1999. "Horizontal radiative fluxes in clouds and accuracy of the independent pixel approximation at absorbing wavelengths." Geophys. Res. Lett., 26 (11): 1585-1588 [10.1029/1999GL900306]

    Oreopoulos, L., and R. Davies. 1998. "Plane Parallel Albedo Biases from Satellite Observations. Part II: Parameterizations for Bias Removal." J. Climate, 11 (5): 933-944.

    Oreopoulos, L., and R. Davies. 1998. "Plane Parallel Albedo Biases from Satellite Observations. Part I: Dependence on Resolution and Other Factors." J. Climate, 11 (5): 919-932.

    Oreopoulos, L., and R. Davies. 1993. "Statistical Dependence of Albedo and Cloud Cover on Sea Surface Temperature for Two Tropical Marine Stratocumulus Regions." J. Climate, 6 (12): 2434-2447.

    Non-Refereed

    Oreopoulos, L., and E. Mlawer. 2009. "CIRC to Provide Key Intercomparisons of GCM Radiative Transfer Codes Prior to Next IPCC Assessment." GEWEX 8.

    Brief Bio

    Dr. Lazaros Oreopoulos (a.k.a Lazaros Oraiopoulos) is the Chief of the Climate and Radiation Lab. He has over two decades of experience conducting research on the modeling and remote sensing of clouds, their impact on the Earth’s Radiation Budget, aerosol-cloud interactions, and many aspects of atmospheric radiative transfer for climatic applications. He is the Deputy Project Scientist for the Aqua satellite mission, and a current member of the Precipitation Measurement Mission and CloudSat-CALIPSO Science Teams. He has previously been a member of the MODIS, AIRS, and Landsat Science Teams, and has served in the International Radiation Commission, the AMS Atmospheric Radiation Committee, and the GEWEX Radiation Panel. He received the NASA Exceptional Scientific Achievement Medal (ESAM) in 2018.

    Dr. Oreopoulos holds a B. Sc. in Physics from Aristotle's University of Thessaloniki, Greece, and M. Sc. and Ph. D. degrees in Atmospheric Sciences from McGill University, Montreal. Web of Science publications and citation metrics can be found here; see also Google Scholar.

    Selected Publications

    Refereed

    Yuan, T., C. Wang, H. Song, et al. S. Platnick, K. Meyer, and L. Oreopoulos. 2019. "Automatically Finding Ship-tracks to Enable Large-scale Analysis of Aerosol-Cloud Interactions." Geophysical Research Letters [10.1029/2019gl083441]

    Tan, I., L. Oreopoulos, and N. Cho. 2019. "The Role of Thermodynamic Phase Shifts in Cloud Optical Depth Variations With Temperature." Geophysical Research Letters 46 (8): 4502-4511 [10.1029/2018gl081590]

    Tan, J., and L. Oreopoulos. 2019. "Subgrid Precipitation Properties of Mesoscale Atmospheric Systems Represented by MODIS Cloud Regimes." Journal of Climate 32 (6): 1797-1812 [10.1175/jcli-d-18-0570.1]

    Zhang, W., J. Wang, D. Jin, L. Oreopoulos, and Z. Zhang. 2018. "A Deterministic Self-Organizing Map Approach and its Application on Satellite Data based Cloud Type Classification." 2018 IEEE International Conference on Big Data (Big Data) [10.1109/bigdata.2018.8622558]

    Tan, J., L. Oreopoulos, C. Jakob, and D. Jin. 2018. "Evaluating rainfall errors in global climate models through cloud regimes." Climate Dynamics 50 3301–3314 [10.1007/s00382-017-3806-7]

    Yuan, T., L. Oreopoulos, S. E. Platnick, and K. Meyer. 2018. "Observations of Local Positive Low Cloud Feedback Patterns and Their Role in Internal Variability and Climate Sensitivity." Geophysical Research Letters 45 (9): 4438-4445 [10.1029/2018gl077904]

    Jin, D., L. Oreopoulos, D. Lee, N. Cho, and J. Tan. 2018. "Contrasting the Co-variability of Daytime Cloud and Precipitation over Tropical Land and Ocean." Atmospheric Chemistry and Physics 1-31 [https://doi.org/10.5194/acp-18-3065-2018]

    Oreopoulos, L., N. Cho, and D. Lee. 2017. "New insights about cloud vertical structure from CloudSat and CALIPSO observations." Journal of Geophysical Research: Atmospheres 122 (17): 9280-9300 [10.1002/2017jd026629]

    Malavelle, F. F., J. M. Haywood, A. Jones, et al. A. Gettelman, L. Clarisse, S. Bauduin, R. P. Allan, I. H. Karset, J. E. Kristjánsson, L. Oreopoulos, N. Cho, D. Lee, N. Bellouin, O. Boucher, D. P. Grosvenor, K. S. Carslaw, S. Dhomse, G. W. Mann, A. Schmidt, H. Coe, M. E. Hartley, M. Dalvi, A. A. Hill, B. T. Johnson, C. E. Johnson, J. R. Knight, F. M. O’Connor, D. G. Partridge, P. Stier, G. Myhre, S. Platnick, G. L. Stephens, H. Takahashi, and T. Thordarson. 2017. "Strong constraints on aerosol–cloud interactions from volcanic eruptions." Nature 546 (7659): 485-491 [10.1038/nature22974]

    Oreopoulos, L., N. Cho, and D. Lee. 2017. "Using MODIS cloud regimes to sort diagnostic signals of aerosol-cloud-precipitation interactions." Journal of Geophysical Research: Atmospheres 122 (10): 5416-5440 [10.1002/2016jd026120]

    Jin, D., L. Oreopoulos, and D. Lee. 2017. "Regime-based evaluation of cloudiness in CMIP5 models." Climate Dynamics 48 89-112 [10.1007/s00382-016-3064-0]

    Leinonen, J., M. D. Lebsock, L. Oreopoulos, and N. Cho. 2016. "Interregional differences in MODIS-derived cloud regimes." Journal of Geophysical Research: Atmospheres 121 [10.1002/2016jd025193]

    Mlawer, E. J., M. J. Iacono, R. Pincus, et al. H. W. Barker, L. Oreopoulos, and D. L. Mitchell. 2016. "Contributions of the ARM Program to Radiative Transfer Modeling for Climate and Weather Applications." Meteorological Monographs 57 15.1-15.19 [10.1175/amsmonographs-d-15-0041.1]

    Jin, D., L. Oreopoulos, and D. Lee. 2016. "Simplified ISCCP Cloud Regimes for Evaluating Cloudiness in CMIP5 Models." Climate Dynamics 48 113-130 [10.1007/s00382-016-3107-6]

    Oreopoulos, L., N. Cho, D. Lee, and S. Kato. 2016. "Radiative effects of global MODIS cloud regimes." J. Geophys. Res. Atmos. 121 (5): 2299–2317 [10.1002/2015jd024502]

    Zhang, Z., K. Meyer, H. Yu, et al. S. Platnick, P. Colarco, Z. Liu, and L. Oreopoulos. 2016. "Shortwave direct radiative effects of above-cloud aerosols over global oceans derived from 8 years of CALIOP and MODIS observations." Atmos. Chem. Phys. 16 (5): 2877-2900 [10.5194/acp-16-2877-2016]

    Yuan, T. L., L. Oreopoulos, M. Zelinka, et al. H. Yu, J. Norris, M. Chin, S. E. Platnick, and K. G. Meyer. 2016. "Positive low cloud and dust feedbacks amplify tropical North Atlantic multidecadal oscillation." Geophysical Research Letters 43 (3): 1349–1356 [10.1002/2016gl067679]

    Pincus, R., E. J. Mlawer, L. Oreopoulos, et al. A. S. Ackerman, S. Baek, M. Brath, S. A. Buelhler, K. E. Cady-Pereira, J. N. Cole, J.-L. Dufresne, M. Kelley, J. Li, J. Manners, D. J. Paynter, R. Roehrig, M. Sekiguchi, and M. D. Schwarzkopf. 2015. "Radiative flux and forcing parameterization error in aerosol-free clear skies." Geophys. Res. Lett 42 (13): 5485-5492 [10.1002/2015GL064291]

    Huang, X., X. Chen, G. L. Potter, et al. L. Oreopoulos, J. Cole, D. Lee, and N. G. Loeb. 2014. "A Global Climatology of Outgoing Longwave Spectral Cloud Radiative Effect and Associated Effective Cloud Properties." Journal of Climate 27 (19): 7475-7492 [10.1175/JCLI-D-13-00663.1]

    Oreopoulos, L., N. Cho, D. Lee, S. Kato, and G. J. Huffman. 2014. "An examination of the nature of global MODIS cloud regimes." Journal of Geophysical Research: Atmospheres 119 (13): 8362-8383 [10.1002/2013JD021409]

    Lee, D., Y. C. Sud, L. Oreopoulos, et al. K. M. Kim, W. K. Lau, and I. S. Kang. 2014. "Modeling the influences of aerosols on pre-monsoon circulation and rainfall over Southeast Asia." Atmos. Chem. Phys. 14 (13): 6853-6866 [10.5194/acp-14-6853-2014]

    Zhang, Z., K. Meyer, S. Platnick, et al. L. Oreopoulos, D. Lee, and H. Yu. 2014. "A novel method for estimating shortwave direct radiative effect of above-cloud aerosols using CALIOP and MODIS data." Atmos. Meas. Tech. 7 (6): 1777-1789 [10.5194/amt-7-1777-2014]

    Huang, X., J. N. Cole, F. He, et al. G. L. Potter, L. Oreopoulos, D. Lee, M. J. Suarez, and N. G. Loeb. 2013. "Longwave Band-By-Band Cloud Radiative Effect and Its Application in GCM Evaluation." J. Climate 26 (2): 450-467 [10.1175/JCLI-D-12-00112.1]

    Yi, B., P. Yang, B. A. Baum, et al. T. LEcuyer, L. Oreopoulos, E. J. Mlawer, A. J. Heymsfield, and K. N. Liou. 2013. "Influence of Ice Particle Surface Roughening on the Global Cloud Radiative Effect." Journal of the Atmospheric Sciences 70 (9): 2794-2807 [10.1175/JAS-D-13-020.1]

    Meyer, K. G., S. E. Platnick, L. Oreopoulos, and D. Lee. 2013. "Estimating the direct radiative effect of absorbing aerosols overlying marine boundary layer clouds in the southeast Atlantic using MODIS and CALIOP." J. Geophys. Res. Atmos. 118 (10): 4801-4815 [10.1002/jgrd.50449]

    Wen, G., R. F. Cahalan, J. D. Haigh, et al. P. Pilewskie, L. Oreopoulos, and J. W. Harder. 2013. "Reconciliation of modeled climate responses to spectral solar forcing." J. Geophys. Res. Atmos. 118 (12): 6281–6289 [10.1002/jgrd.50506]

    Yuan, T. L., and L. Oreopoulos. 2013. "On the global character of overlap between low and high clouds." Geophys. Res. Lett. 40 (19): 5320-5326 [10.1002/grl.50871]

    Lee, D., L. Oreopoulos, G. J. Huffman, W. B. Rossow, and I.-S. Kang. 2013. "The Precipitation Characteristics of ISCCP Tropical Weather States." J. Climate 26 (3): 772-788 [10.1175/JCLI-D-11-00718.1]

    Randles, C. A., S. Kinne, G. Myhre, et al. M. Schulz, J. Fischer, L. Doppler, E. Highwood, C. Ryder, B. Harris, J. Huttunen, Y. Ma, R. T. Pinker, B. Mayer, D. Neubauer, R. Hitzenberger, L. Oreopoulos, D. Lee, G. Pitari, G. DiGenova, J. Quaas, F. G. Rose, S. Kato, S. T. Rumbold, I. Vardavas, N. Hatzianastassiou, C. Matsoukas, H. Yu, F. Zhang, H. Zhang, and P. Lu. 2013. "Intercomparison of shortwave radiative transfer schemes in global aerosol modeling: results from the AeroCom Radiative Transfer Experiment." Atmos. Chem. Phys. 13 (5): 2347-2379 [10.5194/acp-13-2347-2013]

    Sud, Y. C., D. Lee, L. Oraiopoulos, et al. D. Barahona, A. Nenes, and M. Suarez. 2013. "Performance of McRAS-AC in the GEOS-5 AGCM: aerosol-cloud-microphysics, precipitation, cloud radiative effects, and circulation." Geosci. Model Dev. 6 (1): 57-79 [10.5194/gmd-6-57-2013]

    Wilson, M. J., and L. Oreopoulos. 2012. "Enhancing a Simple MODIS Cloud Mask Algorithm for the Landsat Data Continuity Mission." IEEE Transactions on Geoscience and Remote Sensing 51 (2): 723-731 [Full Text (Link)] [10.1109/TGRS.2012.2203823]

    Morales Betancourt, R., D.-M. Lee, L. Oraiopoulos, et al. Y. Sud, D. Barahona, and A. Nenes. 2012. "Sensitivity of cirrus and mixed-phase clouds to the ice nuclei spectra in McRAS-AC: single column model simulations." Atmos. Chem. Phys. 12 (22): 10,679-10,692 [10.5194/acp-12-10679-2012]

    Yuan, T. L., L. A. Remer, H. Bian, et al. J. R. Ziemke, R. Albrecht, K. E. Pickering, L. Oreopoulos, S. Goodman, H. Yu, and D. J. Allen. 2012. "Aerosol indirect effect on tropospheric ozone via lightning." J. Geophys. Res. 117 (D18): D18213 [10.1029/2012JD017723]

    Oreopoulos, L., D. Lee, Y. Sud, and M. Suarez. 2012. "Radiative impacts of cloud heterogeneity and overlap in an atmospheric General Circulation Model." Atmos. Chem. Phys. 12 (19): 9097-9111 [10.5194/acp-12-9097-2012]

    Oreopoulos, L., E. J. Mlawer, J. S. Delamere, et al. T. Shippert, J. Cole, B. Fomin, M. J. Iacono, Z. Jin, J. Li, J. Manners, P. Räisänen, F. G. Rose, Y. Zhang, M. J. Wilson, and W. B. Rossow. 2012. "The Continual Intercomparison of Radiation Codes: Results from Phase I." J Geophys Res 117 (D6): D06117 [10.1029/2011JD016821]

    Oreopoulos, L., and W. B. Rossow. 2011. "The cloud radiative effects of International Satellite Cloud Climatology Project weather states." J. Geophys. Res. 116 (D12): D12202 [10.1029/2010JD015472]

    Oreopoulos, L., and P. Norris. 2011. "An analysis of cloud overlap at a midlatitude atmospheric observation facility." Atmos. Chem. Phys. 11 (12): 5557-5567 [10.5194/acp-11-5557-2011]

    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]

    Oreopoulos, L., and E. Mlawer. 2010. "MODELING: The Continual Intercomparison of Radiation Codes (CIRC)." Bull Am Met Soc 91 (3): 305-310 [10.1175/2009BAMS2732.1]

    Oreopoulos, L., S. E. Platnick, G. Hong, P. Yang, and R. F. Cahalan. 2009. "The Shortwave Radiative Forcing Bias of Homogeneous Liquid and Ice Clouds Observed by MODIS." [PowerPoint slides] Retrieved from Current Problems in Atmospheric Radiation (IRS 2008 Proceedings) [10.1063/1.3117049]

    Oreopoulos, L., E. Mlawer, J. Delamere, and T. Shippert. 2009. "The Continual Intercomparison of Radiation Codes (CIRC): A New Standard for Evaluating GCM Radiation Codes." [PowerPoint slides] Retrieved from Current Problems in Atmospheric Radiation (IRS 2008 Proceedings)

    Oreopoulos, L., S. Platnick, G. Hong, P. Yang, and R. Cahalan. 2009. "The shortwave radiative forcing bias of liquid and ice clouds from MODIS observations." Atmos. Chem. Phys. 9 (16): 5865-5875 [10.5194/acp-9-5865-2009]

    Joiner, J., M. Schoeberl, A. Vasilkov, et al. L. Oreopoulos, S. Platnick, N. Livesey, and P. Levelt. 2009. "Accurate satellite-derived estimates of the tropospheric ozone impact on the global radiation budget." Atmos. Chem. Phys. 9 (13): 4447-4465 [10.5194/acp-9-4447-2009]

    Vasilkov, A. P., J. Joiner, L. Oreopoulos, et al. J. F. Gleason, P. Veefkind, E. Bucsela, E. A. Celarier, R. J. Spurr, and S. E. Platnick. 2009. "Impact of tropospheric nitrogen dioxide on the regional radiation budget." Atmos Chem Phys 9 6389-6400 [10.5194/acp-9-6389-2009]

    Oreopoulos, L., and S. Platnick. 2008. "Radiative susceptibility of cloudy atmospheres to droplet number perturbations: 2. Global analysis from MODIS ." J. Geophys. Res. 113 (D14S21): 10.1029/2007JD009655

    Platnick, S., and L. Oreopoulos. 2008. "Radiative susceptibility of cloudy atmospheres to droplet number perturbations: 1. Theoretical analysis and examples from MODIS." J. Geophys. Res. 113 (D14S20): 10.1029/2007JD009654

    Norris, P. M., L. Oreopoulos, A. Y. Hou, W. K. Tao, and X. Zeng. 2008. "Representation of 3D heterogeneous cloud fields using copulas: Theory for water clouds." Q. J. R. Meteorol. Soc. 1843-1864 10.1002/qj.321

    Koren, I., L. Oreopoulos, G. Feingold, L. Remer, and O. Altaratz. 2008. "How small is a small cloud?" Atmos Chem Phys 8 (2): 6379-6407 [10.5194/acpd-8-6379-2008]

    Oreopoulos, L., R. Cahalan, and S. Platnick. 2007. "The Plane-Parallel Albedo Bias of Liquid Clouds from MODIS Observations." J. Climate 20 (20): 5114-5125 [10.1175/JCLI4305.1]

    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]

    Oreopoulos, L. 2005. "The impact of subsampling on MODIS level-3 statistics of cloud optical thickness and effective radius." IEEE Trans. Geosci. Remote Sensing 43 (2): 366-373 [10.1109/TGRS.2004.841247]

    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]

    Oreopoulos, L., and R. Cahalan. 2005. "Cloud Inhomogeneity from MODIS." J. Climate 18 (23): 5110-5124 [10.1175/JCLI3591.1]

    Oreopoulos, L., M. Chou, M. Khairoutdinov, H. Barker, and R. Cahalan. 2004. "Performance of Goddard Earth Observing System GCM column radiation models under heterogeneous cloud conditions." Atmospheric Research 72 365-382 [10.1016/j.atmosres.2004.03.025]

    Oreopoulos, L., A. Marshak, and R. Cahalan. 2003. "Consistency of ARESE II cloud absorption estimates and sampling issues." J. Geophys. Res. 108 (D1): 4029 [10.1029/2002JD002243]

    Oreopoulos, L., and M. Khairoutdinov. 2003. "Overlap properties of clouds generated by a cloud-resolving model." J. Geophys. Res. 108 (D15): 4479 [10.1029/2002JD003329]

    Cahalan, R. F., L. Oreopoulos, G. Wen, et al. A. Marshak, S.-C. Tsay, and T. DeFelice. 2001. "Cloud characterization and clear sky correction from Landsat 7." Remote Sens Environ 78 (1-2): 83-98 [10.1016/S0034-4257(01)00251-6]

    Wen, G., R. Cahalan, S.-C. Tsay, and L. Oreopoulos. 2001. "Impact of cumulus cloud spacing on Landsat atmospheric correction and aerosol retrieval." J. Geophys. Res. 106 (D11): 12129-12138 [10.1029/2001JD900159]

    Oreopoulos, L., R. F. Cahalan, A. Marshak, and G. Wen. 2000. "A new normalized difference cloud retrieval technique applied to Landsat radiances over the Oklahoma ARM Site." J Appl Meteor 39 (12): 2305-2320 [10.1175/1520-0450(2000)039<2305:ANNDCR>2.0.CO;2]

    Oreopoulos, L., A. Marshak, R. F. Cahalan, and G. Wen. 2000. "Cloud three-dimensional effects evidenced in Landsat spatial power spectra and autocorrelation functions." J Geophys Res 105 (D11): 14777-14788 [10.1029/2000JD900153]

    Wen, G., S.-C. Tsay, R. F. Cahalan, and L. Oreopoulos. 1999. "Path radiance technique for retrieving aerosol optical thickness over land." J. Geophys. Res. 104 (D24): 31321-31332 [10.1029/1999JD900964]

    Oreopoulos, L., and H. W. Barker. 1999. "Accounting for subgrid-scale cloud variability in a multi-layer 1d solar radiative transfer algorithm." Q.J Royal Met. Soc. 125 (553): 301-330 [10.1002/qj.49712555316]

    Marshak, A., W. Wiscombe, A. Davis, L. Oreopoulos, and R. Cahalan. 1999. "On the Removal of the Effect of Horizontal Fluxes In Two-Aircraft Measurements of Cloud Absorption." Q.J Royal Met. Soc. 125 (558): 2153-2170 [10.1002/qj.49712555811]

    Marshak, A., L. Oreopoulos, A. Davis, W. Wiscombe, and R. Cahalan. 1999. "Horizontal radiative fluxes in clouds and accuracy of the independent pixel approximation at absorbing wavelengths." Geophys. Res. Lett. 26 (11): 1585-1588 [10.1029/1999GL900306]

    Oreopoulos, L., and R. Davies. 1998. "Plane Parallel Albedo Biases from Satellite Observations. Part II: Parameterizations for Bias Removal." J. Climate 11 (5): 933-944

    Oreopoulos, L., and R. Davies. 1998. "Plane Parallel Albedo Biases from Satellite Observations. Part I: Dependence on Resolution and Other Factors." J. Climate 11 (5): 919-932

    Oreopoulos, L., and R. Davies. 1993. "Statistical Dependence of Albedo and Cloud Cover on Sea Surface Temperature for Two Tropical Marine Stratocumulus Regions." J. Climate 6 (12): 2434-2447

    Non-Refereed

    Oreopoulos, L., and E. Mlawer. 2009. "CIRC to Provide Key Intercomparisons of GCM Radiative Transfer Codes Prior to Next IPCC Assessment." GEWEX 8

                                                                                                                                                                                            
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