Sciences and Exploration Directorate

Lazaros Oreopoulos

(SUPV RSCH AST, CLIMATE&RADIATION STD)

 lazaros.oraiopoulos-1@nasa.gov

 301.614.6128

Org Code: 613

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 currently serves as the Project Scientist for the Aqua satellite mission. He has been a member of the Precipitation Measurement Mission, CloudSat-CALIPSO, 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, the GSFC Robert H. Goddard award for Science in 2019, and the NASA Outstanding Leadership Medal in 2022.

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

Earth Science: Clouds

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.

Current Projects

Precipitation behavior of the world's cloud regimes

Precipitation

The goal of the project is to diagnose relationships between clouds and precipitation at an
unprecedented scope and level of detail. Such a study is now possible at nearly global scales
because of continual improvements in the coverage and quality of cloud and precipitation
retrievals from satellites. The effort relies on gridded data and is the first major attempt to make extensive combined use of distinct cloud and precipitation products at near-global scales.

Informing cloud subcolumn generators from active observations

Clouds

This research effort has three main thrusts: (a) Develop a framework to systematically evaluate previous efforts of generation of cloud subgrid variability using CloudSat and CALIPSO (“CC”) data; (b) Exploit the information content of CC observations and products to inform cloud subgrid generator schemes on implementation of better rules of subcolumn generation; (c) Apply the improved schemes to the output of Global Climate Models (GCMs) in order to assess whether their cloud diagnostics are substantially impacted by different subcolumn schemes and whether better agreement to observations can be achieved.

Classifying the world's cloudiness into regimes

Clouds

Cloud Regimes (CRs) have been derived in the past decade through the application of clustering techniques on ISCCP, MODIS, and CloudSat/CALIPSO cloud property distributions. Since their inception, they have been used in numerous studies, which showed that the CRs are an efficient method to separate atmospheric states with distinct radiative, thermodynamic, and dynamic properties, and to examine the evolution of physical processes and evaluate the output of climate models. The project analyzes the combined ISCCP, MODIS, and CloudSat/CALIPSO data records, with the objective to provide to the community a process-resolving coordinate system on which other satellite datasets, such as those coming from additional A-train instrument retrievals, can be mapped and analyzed. The result of such a mapping will be the creation of datasets that will resolve synoptic and mesoscale variability, and will be directly relatable to physical atmospheric states and thus suitable for process understanding explorations, and for physically meaningful model evaluation studies.

Positions/Employment

Supervisory Research Physical Scientist (Lab Chief)

NASA - GSFC, Climate and Radiation Lab

March 2013 - Present

 

Research Physical Scientist

NASA - GSFC, Climate and Radiation Laboratory, Code 613

2008 - March 2013

 

Research Associate Professor

JCET/UMBC - NASA GSFC, Climate and Radiation Branch, Code 613.2

February 2006 - 2008

 

Research Assistant Professor

JCET/UMBC - NASA GSFC, Climate and Radiation Branch, Code 613.2

May 1999 - 2005

 

Assistant Research Scientist

JCET/UMBC - NASA GSFC, Climate and Radiation Branch, Code 613.2

November 1997 - April 1999

 

Research Scientist

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

September 1996 - November 1997

 

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

– Former Member of the Science Steering Committee of GEWEX's GASS (Global Atmospheric System Studies) panel

– Former member of the AMS (American Meteorological Society) Committee on Atmospheric Radiation

– Session Convener and Chair: 3rd I3RC Workshop; 12th AMS Radiation Meeting; AGU Fall 2011 Meeting; AGU Fall 2012 Meeting; AGU Fall 2015 Meeting; AGU Fall 2016 Meeting; AGU Fall 2021 Meeting; IUGG 2015 General Assembly; 2016 Kaufman Memorial Symposium.

– Co-leader of International Intercomparison of 3D Radiation Codes (I3RC)

– Leader of the Continual Intercomparison of Radiation Codes (CIRC)

– Member of NASA’s Radiation Budget Science Working Group for “Recommended Measurement and Instrument Characteristics of an Earth Venture Continuity Earth Radiation Budget Instrument”.

Awards

  • 2001, Award for best paper, NASA-GSFC’s Climate and Radiation Branch
  • 2005, Award for scientific leadership, NASA-GSFC’s Climate and Radiation Branch
  • 2017, Outstanding reviewer recognition by AGU (JGR-Atmospheres)
  • 2018, NASA Exceptional Scientific Achievement Medal
  • 2019, Robert H. Goddard award for Science
  • 2022 NASA Outstanding Leadership Medal

Grants

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

CloudSat and CALIPSO Science Team Recompete - NASA (NNH18ZDA001N) - Awarded: 2019-05-14


Dates: 2019-06-01  - 2022-05-31

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

Precipitation Measurement Missions (PMM) Science Team - NASA (NNH18ZDA001N) - Awarded: 2018-12-05


Dates: 2019-02-01  - 2022-01-31

A unified cloud-defined weather state dataset for process-resolving data analysis and model evaluation

Making Earth System Data Records for Use in Research Environments - NASA (NNH17ZDA001N-MEASURE) - Awarded: 2018-05-01


Dates:  - 

Understanding the links between clouds and their environment by employing MODIS cloud regimes in compositing studies

Science of Terra and Aqua - NASA - Awarded: 2014-04-11


Dates:  - 

 Further enhancement of the cloud prediction capabilities of the GEOS-5 AGCM for radiative and aerosol indirect effect studies

NASA MAP: Modeling Analysis and Prediction - NASA - Awarded: 2013-05-22


Dates:  - 

 Extracting the essence of cloud horizontal and vertical variability from CloudSat for the benefit of Large Scale Models

NASA CloudSat/CALIPSO Science Team Recompete - NASA - Awarded: 2010-05-26


Dates:  - 

 Evaluation of GCM Column Radiation Models under cloudy conditions with the ARM BBHRP Value Added Product

Atmospheric Radiation Measurements Program - Department of Energy - Awarded: 2006-12-07


Dates:  - 

 Cloud detection and avoidance for the Landsat Data Continuity Mission

Science Team for the Landsat Data Continuity Mission - United States Geological Survey - Awarded: 2005-12-12


 Use of new RT schemes and satellite data for more realistic cloud radiative forcing and hydrologic cycle in climate models

Global Water and Energy Cycle - NASA - Awarded: 2002-02-15


Dates:  - 

Special Experience

  • Chief, Climate and Radiation Laboratory (2013-present)
  • Deputy Project Scientist, Aqua (2010-2022)
  • Project Scientist, Aqua (2023-present)
  • Standing Review Board member, Libera, (2021-present)
  • LAADS Users' Working Group member (2018-present)
  • Leader, JCET Atmospheric Radiation Focus Group (2003-2006)

Publications

Refereed

Jin, D., R. J. Kramer, L. Oreopoulos, and D. Lee. 2023. ENSO Disrupts Boreal Winter CRE Feedback Journal of Climate [10.1175/jcli-d-23-0282.1]

Jin, D., D. Kim, S.-W. Son, and L. Oreopoulos. 2023. QBO deepens MJO convection Nature Communications 14 (1): 4088 [10.1038/s41467-023-39465-7]

Yuan, T., H. Song, R. Wood, et al. L. Oreopoulos, S. Platnick, C. Wang, H. Yu, K. Meyer, and E. Wilcox. 2023. Observational evidence of strong forcing from aerosol effect on low cloud coverage Science Advances 9 (45): eadh7716 [10.1126/sciadv.adh7716]

Oreopoulos, L., N. Cho, and D. Lee. 2022. Revisiting cloud overlap with a merged dataset of liquid and ice cloud extinction from CloudSat and CALIPSO Frontiers in Remote Sensing 3 [10.3389/frsen.2022.1076471]

Oreopoulos, L. 2022. Understanding Global Cloud Radiative Impacts Studies of Cloud, Convection and Precipitation Processes Using Satellite Observations Vol. 3 129-149 [10.1142/9789811256912_0008]

Zelinka, M. D., I. Tan, L. Oreopoulos, and G. Tselioudis. 2022. Detailing cloud property feedbacks with a regime-based decomposition Climate Dynamics [10.1007/s00382-022-06488-7]

Chen, Y., J. Haywood, Y. Wang, et al. F. Malavelle, G. Jordan, D. Partridge, J. Fieldsend, J. De Leeuw, A. Schmidt, N. Cho, L. Oreopoulos, S. Platnick, D. Grosvenor, P. Field, and U. Lohmann. 2022. Machine learning reveals climate forcing from aerosols is dominated by increased cloud cover Nature Geoscience [10.1038/s41561-022-00991-6]

Yuan, T., H. Song, R. Wood, et al. C. Wang, L. Oreopoulos, S. E. Platnick, S. von Hippel, K. Meyer, S. Light, and E. Wilcox. 2022. Global reduction in ship-tracks from sulfur regulations for shipping fuel Science Advances 8 (29): [10.1126/sciadv.abn7988]

Jin, D., L. Oreopoulos, D. Lee, J. Tan, and K. Kim. 2022. A New Organization Metric for Synoptic Scale Tropical Convective Aggregation Journal of Geophysical Research: Atmospheres 127 e2022JD036665 [10.1029/2022jd036665]

Lebsock, M., H. Takahashi, R. Roy, M. J. Kurowski, and L. Oreopoulos. 2022. Understanding Errors in Cloud Liquid Water Path Retrievals derived from CloudSat Path Integrated Attenuation Journal of Applied Meteorology and Climatology [10.1175/jamc-d-21-0235.1]

Zhang, Z., L. Oreopoulos, M. D. Lebsock, D. B. Mechem, and J. Covert. 2022. Understanding the Microphysical Control and Spatial‐Temporal Variability of Warm Rain Probability Using CloudSat and MODIS Observations Geophysical Research Letters 49 (10): [10.1029/2022gl098863]

Oreopoulos, L., N. Cho, D. Lee, M. Lebsock, and Z. Zhang. 2022. Assessment of Two Stochastic Cloud Subcolumn Generators Using Observed Fields of Vertically Resolved Cloud Extinction Journal of Atmospheric and Oceanic Technology [10.1175/jtech-d-21-0166.1]

Tan, J., N. Cho, L. Oreopoulos, and P. Kirstetter. 2022. Evaluation of GPROF V05 Precipitation Retrievals under Different Cloud Regimes Journal of Hydrometeorology [10.1175/jhm-d-21-0154.1]

Delgado-Bonal, A., A. Marshak, Y. Yang, and L. Oreopoulos. 2022. Cloud Height Daytime Variability From DSCOVR/EPIC and GOES-R/ABI Observations Frontiers in Remote Sensing 3 [10.3389/frsen.2022.780243]

Marshak, A., A. Ackerman, A. Da Silva, et al. T. Eck, B. Holben, R. Kahn, R. Kleidman, K. Knobelspiesse, R. C. Levy, A. Lyapustin, L. Oreopoulos, L. Remer, O. Torres, T. Varnai, G. Wen, and J. Yorks. 2021. Aerosol properties in cloudy environments from remote sensing observations: a review of the current state of knowledge Bulletin of the American Meteorological Society 1-57 [10.1175/bams-d-20-0225.1]

Mohrmann, J., R. Wood, T. Yuan, et al. H. Song, R. Eastman, and L. Oreopoulos. 2021. Identifying meteorological influences on marine low-cloud mesoscale morphology using satellite classifications Atmospheric Chemistry and Physics 21 (12): 9629-9642 [10.5194/acp-21-9629-2021]

Jin, D., L. Oreopoulos, D. Lee, J. Tan, and N. Cho. 2021. Cloud-Precipitation Hybrid Regimes and their Projection onto IMERG Precipitation Data Journal of Applied Meteorology and Climatology 60 (6): 733-748 [10.1175/jamc-d-20-0253.1]

Cho, N., J. Tan, and L. Oreopoulos. 2021. Classifying planetary cloudiness with an updated set of MODIS Cloud Regimes Journal of Applied Meteorology and Climatology [10.1175/jamc-d-20-0247.1]

Kramer, R. J., H. He, B. J. Soden, et al. L. Oreopoulos, G. Myhre, P. M. Forster, and C. J. Smith. 2021. Observational evidence of increasing global radiative forcing Geophysical Research Letters 48 (7): e2020GL091585 [10.1029/2020gl091585]

Delgado‐Bonal, A., A. Marshak, Y. Yang, and L. Oreopoulos. 2021. Global daytime variability of clouds from DSCOVR/EPIC observations Geophysical Research Letters 48 [10.1029/2020gl091511]

Yuan, T., H. Song, R. Wood, et al. J. Mohrmann, K. Meyer, L. Oreopoulos, and S. Platnick. 2020. Applying deep learning to NASA MODIS data to create a community record of marine low-cloud mesoscale morphology Atmospheric Measurement Techniques 13 (12): 6989-6997 [10.5194/amt-13-6989-2020]

Delgado‐Bonal, A., A. Marshak, Y. Yang, and L. Oreopoulos. 2020. Daytime Variability of Cloud Fraction From DSCOVR/EPIC Observations Journal of Geophysical Research: Atmospheres 125 (10): [10.1029/2019jd031488]

Jin, D., L. Oreopoulos, D. Lee, J. Tan, and K. Kim. 2020. Large‐Scale Characteristics of Tropical Convective Systems Through the Prism of Cloud Regime Journal of Geophysical Research: Atmospheres 125 (6): [10.1029/2019jd031157]

Lee, D., L. Oreopoulos, and N. Cho. 2020. An evaluation of clouds and radiation in a large-scale atmospheric model using a cloud vertical structure classification Geoscientific Model Development 13 (2): 673-684 [10.5194/gmd-13-673-2020]

Oreopoulos, L., N. Cho, and D. Lee. 2020. A Global Survey of Apparent Aerosol‐Cloud Interaction Signals Journal of Geophysical Research: Atmospheres 125 (1): [10.1029/2019jd031287]

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]

Sullivan, S. C., D. Lee, L. Oreopoulos, and A. Nenes. 2016. Role of updraft velocity in temporal variability of global cloud hydrometeor number Proceedings of the National Academy of Sciences 113 (21): 5791-5796 [10.1073/pnas.1514039113]

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 [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]

Woodcock, C. E., R. Allen, M. Anderson, et al. A. Belward, R. Bindschadler, W. Cohen, F. Gao, S. N. Goward, D. Helder, E. Helmer, R. Nemani, L. Oreopoulos, J. Schott, P. S. Thenkabail, E. F. Vermote, J. Vogelmann, M. A. Wulder, and R. Wynne. 2008. Free Access to Landsat Imagery Science 320 (5879): 1011-1011 [10.1126/science.320.5879.1011a]

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

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

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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