Sciences and Exploration Directorate

Andrew Mark Sayer

(Senior Scientist, Earth Sciences)

Andrew Mark Sayer's Contact Card & Information.
Phone: 301.614.6211
Org Code: 616
Mail Code 616.2
Greenbelt, MD 20771

Brief Bio

Andrew Sayer obtained his Ph.D. at the University of Oxford, UK. Following his doctoral thesis, "Aerosol remote sensing using AATSR", he worked as a postdoc in aerosol and cloud remote sensing jointly at Oxford and the Rutherford Appleton Laboratory. In September 2010, Dr. Sayer joined Christina Hsu's group in the Climate and Radiation Laboratory at GSFC to work on aerosol remote sensing as part of the Deep Blue aerosol project. He joined GESTAR in May 2011, and has been in Dr. Jeremy Werdell's group in the Ocean Ecology Laboratory, working on the forthcoming NASA PACE mission, since summer 2018.

A list of publications, citation metrics, reviews, and editorial board memberships can be found on his Publons profile page.

Research Interests

Remote sensing of the Earth's atmosphere and surface using spaceborne imagers

Earth Science: Aerosols

Dr. Sayer's primary research interests include development, validation, and scientific application of aerosol, cloud, and surface property retrievals from passive satellite imaging radiometers. He has been involved in generating data sets from measurements made by the (A)ATSR, AVHRR, MODIS, SeaWiFS, and VIIRS sensors, among others.


Related to this, he is also interested in Sun-photometry, aerosol microphysical/optical properties, statistical techniques, and radiative transfer.

Professional Service

Dr. Sayer is an Associate Editor for the journal Atmospheric Measurement Techniques.



2023. "Simultaneous retrieval of aerosol and ocean properties from PACE HARP2 with uncertainty assessment using cascading neural network radiative transfer models." Atmospheric Measurement Techniques 16 (23): [] [Journal Article/Letter]

2023. "Calibration of the SNPP and NOAA 20 VIIRS sensors for continuity of the MODIS climate data records." Remote Sensing of Environment 295 113717 [10.1016/j.rse.2023.113717] [Journal Article/Letter]

2023. "Assessment of the impact of discontinuity in satellite instruments and retrievals on global PM2.5 estimates." Remote Sensing of Environment 294 113624 [10.1016/j.rse.2023.113624] [Journal Article/Letter]

2023. "Reducing Aerosol Forcing Uncertainty By Combining Models with Satellite and Within‐the‐Atmosphere Observations: A Three‐Way Street." Reviews of Geophysics [10.1029/2022rg000796] [Journal Article/Letter]

2023. "The CHROMA cloud-top pressure retrieval algorithm for the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) satellite mission." Atmospheric Measurement Techniques 16 (4): 969-996 [10.5194/amt-16-969-2023] [Journal Article/Letter]

2022. "Effective uncertainty quantification for multi-angle polarimetric aerosol remote sensing over ocean." Atmos. Meas. Tech. 15 (16): 4859–4879 [10.5194/amt-15-4859-2022] [Journal Article/Letter]

2022. "Estimating pixel-level uncertainty in ocean color retrievals from MODIS." Optics Express 30 (17): 31415 [10.1364/oe.460735] [Journal Article/Letter]

2022. "Optimal Estimation Framework for Ocean Color Atmospheric Correction and Pixel-level Uncertainty Quantification." Applied Optics Vol. 61 No. 20 [10.1364/ao.461861] [Journal Article/Letter]

2021. "Adaptive Data Screening for Multi-Angle Polarimetric Aerosol and Ocean Color Remote Sensing Accelerated by Deep Learning." Frontiers in Remote Sensing 2 [10.3389/frsen.2021.757832] [Journal Article/Letter]

2021. "Monthly Global Estimates of Fine Particulate Matter and Their Uncertainty." Environmental Science & Technology [10.1021/acs.est.1c05309] [Journal Article/Letter]

2021. "A practical guide to writing a radiative transfer code." Computer Physics Communications 271 108198 [10.1016/j.cpc.2021.108198] [Journal Article/Letter]

2021. "Effects of COVID-19 lockdowns on fine particulate matter concentrations." Science Advances 7 (26): eabg7670 [10.1126/sciadv.abg7670] [Journal Article/Letter]

2021. "Evaluation of Novel NASA Moderate Resolution Imaging Spectroradiometer and Visible Infrared Imaging Radiometer Suite Aerosol Products and Assessment of Smoke Height Boundary Layer Ratio During Extreme Smoke Events in the Western USA." Journal of Geophysical Research: Atmospheres 126 (11): [10.1029/2020jd034180] [Journal Article/Letter]

2020. "Direct and semi-direct radiative forcing of biomass-burning aerosols over the southeast Atlantic (SEA) and its sensitivity to absorbing properties: a regional climate modeling study." Atmospheric Chemistry and Physics 20 (21): 13191-13216 [10.5194/acp-20-13191-2020] [Journal Article/Letter]

2020. "An AeroCom–AeroSat study: intercomparison of satellite AOD datasets for aerosol model evaluation." Atmospheric Chemistry and Physics 20 (21): 12431-12457 [10.5194/acp-20-12431-2020] [Journal Article/Letter]

2020. "Global Estimates and Long-Term Trends of Fine Particulate Matter Concentrations (1998–2018)." Environmental Science & Technology 54 (13): 7879-7890 [10.1021/acs.est.0c01764] [Journal Article/Letter]

2020. "Merging regional and global aerosol optical depth records from major available satellite products." Atmospheric Chemistry and Physics 20 (4): 2031-2056 [10.5194/acp-20-2031-2020] [Journal Article/Letter]

2020. "A review and framework for the evaluation of pixel-level uncertainty estimates in satellite aerosol remote sensing." Atmospheric Measurement Techniques 13 (2): 373-404 [10.5194/amt-13-373-2020] [Journal Article/Letter]

2019. "A geometry-dependent surface Lambertian-equivalent reflectivity product for UV-Vis retrievals - Part 2: Evaluation over open ocean." Atmospheric Measurement Techniques 12 (12): 6749-6769 [10.5194/amt-12-6749-2019] [Journal Article/Letter]

2019. "How should we aggregate data? Methods accounting for the numerical distributions, with an assessment of aerosol optical depth." Atmospheric Chemistry and Physics 19 15023-15048 [10.5194/acp-19-15023-2019] [Journal Article/Letter]

2019. "Two decades observing smoke above clouds in the south-eastern Atlantic Ocean: Deep Blue algorithm updates and validation with ORACLES field campaign data." Atmospheric Measurement Techniques 12 (7): 3595-3627 [10.5194/amt-12-3595-2019] [Journal Article/Letter]

2019. "Validation, Stability, and Consistency of MODIS Collection 6.1 and VIIRS Version 1 Deep Blue Aerosol Data Over Land." Journal of Geophysical Research: Atmospheres 124 (8): 4658-4688 [10.1029/2018jd029598] [Journal Article/Letter]

2019. "Simulation of the transport, vertical distribution, optical properties and radiative impact of smoke aerosols with the ALADIN regional climate model during the ORACLES-2016 and LASIC experiments." Atmospheric Chemistry and Physics 19 (7): 4963-4990 [10.5194/acp-19-4963-2019] [Journal Article/Letter]

2019. "VIIRS Deep Blue Aerosol Products Over Land: Extending the EOS Long‐Term Aerosol Data Records." Journal of Geophysical Research: Atmospheres 124 (7): 4026-4053 [10.1029/2018jd029688] [Journal Article/Letter]

2018. "Harnessing remote sensing to address critical science questions on ocean-atmosphere interactions." Elem Sci Anth 6 [10.1525/elementa.331] [Journal Article/Letter]

2018. "Observations of the Interaction and Transport of Fine Mode Aerosols with Cloud and/or Fog in Northeast Asia from Aerosol Robotic Network (AERONET) and Satellite Remote Sensing." Journal of Geophysical Research: Atmospheres [10.1029/2018JD028313] [Journal Article/Letter]

2018. "Satellite Ocean Aerosol Retrieval (SOAR) Algorithm Extension to S-NPP VIIRS as Part of the “Deep Blue” Aerosol Project." Journal of Geophysical Research: Atmospheres 123 (1): 380-400 [10.1002/2017jd027412] [Journal Article/Letter]

2017. "AERONET-Based Nonspherical Dust Optical Models and Effects on the VIIRS Deep Blue/SOAR Over Water Aerosol Product." Journal of Geophysical Research: Atmospheres 122 (19): 10,384-10,401 [10.1002/2017jd027258] [Journal Article/Letter]

2017. "Evaluation of NASA Deep Blue/SOAR aerosol retrieval algorithms applied to AVHRR measurements." Journal of Geophysical Research: Atmospheres 122 (18): 9945-9967 [10.1002/2017jd026934] [Journal Article/Letter]

2017. "Retrieving near-global aerosol loading over land and ocean from AVHRR." Journal of Geophysical Research: Atmospheres 122 (18): 9968-9989 [10.1002/2017jd026932] [Journal Article/Letter]

2017. "Cross-calibration of S-NPP VIIRS moderate-resolution reflective solar bands against MODIS Aqua over dark water scenes." Atmospheric Measurement Techniques 10 (4): 1425-1444 [10.5194/amt-10-1425-2017] [Journal Article/Letter]

2016. "COMMIT in 7-SEAS/BASELInE: Operation of and Observations from a Novel, Mobile Laboratory for Measuring In-Situ Properties of Aerosols and Gases." Aerosol Air Qual. Res. 16 (11): 2728-2741 [10.4209/aaqr.2015.11.0630] [Journal Article/Letter]

2016. "Satellite-Surface Perspectives of Air Quality and Aerosol-Cloud Effects on the Environment: An Overview of 7-SEAS/BASELInE." Aero. Air Qual. Res. 16 (11): 2581-2602 [10.4209/aaqr.2016.08.0350] [Journal Article/Letter]

2016. "Evaluating the Height of Biomass Burning Smoke Aerosols Retrieved from Synergistic Use of Multiple Satellite Sensors over Southeast Asia." Aero. Air Qual. Res. 16 2897-2906 [10.4209/aaqr.2015.08.0506] [Journal Article/Letter]

2016. "Development of an operational land water mask for MODIS Collection 6, and influence on downstream data products." International Journal of Digital Earth 10 (2): 207-218 [10.1080/17538947.2016.1232756] [Journal Article/Letter]

2016. "The Sensitivity of SeaWiFS Ocean Color Retrievals to Aerosol Amount and Type." J. Atmos. and Oceanic Tech 33 (6): 1185–1209 [10.1175/JTECH-D-15.0121.1] [Journal Article/Letter]

2016. "Satellite-Based Spatiotemporal Trends in PM2.5 Concentrations: China, 2004–2013." Environmental Health Perspectives 124 (2): 184-192 [10.1289/ehp.1409481] [Journal Article/Letter]

2016. "Coupled Aerosol-Cloud Systems over Northern Vietnam during 7-SEAS/BASELInE: A Radar and Modeling Perspective." Aerosol Air Qual. Res. 16 2768-2785 [10.4209/aaqr.2015.11.0631] [Journal Article/Letter]

2015. "Implications of MODIS bow-tie distortion on aerosol optical depth retrievals, and techniques for mitigation." Atmos. Meas. Tech 8 5277-5288 [10.5194/amt-8-5277-2015] [Journal Article/Letter]

2015. "Effect of MODIS Terra radiometric calibration improvements on Collection 6 Deep Blue aerosol products: Validation and Terra/Aqua consistency." J. Geophys. Res. Atmos. 120 12,157-12,174 [10.1002/2015JD023878] [Journal Article/Letter]

2015. "In-situ and remotely-sensed observations of biomass burning aerosols at Doi Ang Khang Thailand during 7-SEAS/BASELInE 2015." Aerosol and Air Quality Research 16 2768-2801 [10.4209/aaqr.2015.08.0500] [Journal Article/Letter]

2014. "MODIS Collection 6 aerosol products: Comparison between Aqua's e-Deep Blue, Dark Target, and “merged” data sets, and usage recommendations." J. Geophys. Res.-Atmos 119 (24): 13,965-13,989 [10.1002.2014JD022453] [Journal Article/Letter]

2014. "AERONET-based models of smoke-dominated aerosol near source regions and transported over oceans, and implications for satellite retrievals of aerosol optical depth." Atmospheric Chemistry and Physics 14 11493-11523 [doi:10.5194/acp-14-11493-2014] [Journal Article/Letter]

2014. "Systematic satellite observations of the impact of aerosols from passive volcanic degassing on local cloud properties." Atmos. Chem. Phys 14 10601-10618 [doi:10.5194/acp-14-10601-2014] [Journal Article/Letter]

2014. "Interactions between biomass-burning aerosols and clouds over Southeast Asia: Current status, challenges, and perspectives." Environmental Pollution 195 292-307 [doi:10.1016/j.envpol.2014.06.036] [Journal Article/Letter]

2014. "Multi-decadal aerosol variations from 1980 to 2009: a perspective from observations and a global model." Atmos. Chem. Phys. 14 (7): 3657-3690 [10.5194/acp-14-3657-2014] [Journal Article/Letter]

2014. "Current and Future Perspectives of Aerosol Research at NASA Goddard Space Flight Center." Bulletin of the American Meteorological Society early view [10.1175/ BAMS-D-13-00153.1] [Journal Article/Letter]

2013. "Validation and uncertainty estimates for MODIS Collection 6 “Deep Blue” aerosol data." J. Geophys. Res. Atmos. 118 (14): 7864-7872 [10.1002/jgrd.50600] [Journal Article/Letter]

2013. "An overview of regional experiments on biomass burning aerosols and related pollutants in Southeast Asia: From BASE-ASIA and the Dongsha Experiment to 7-SEAS." Atmospheric Environment 78 1-19 [10.1016/j.atmosenv.2013.04.066] [Journal Article/Letter]

2013. "Intercomparison of satellite dust retrieval products over the west African Sahara during the Fennec campaign in June 2011." Remote Sensing of Environment 136 99-116 [10.1016/j.rse.2013.05.003] [Journal Article/Letter]

2013. "From BASE-ASIA toward 7-SEAS: A satellite-surface perspective of boreal spring biomass-burning aerosols and clouds in Southeast Asia." Atmospheric Environment 78 20-34 [10.1016/j.atmosenv.2012.12.013] [Journal Article/Letter]

2013. "Retrieval of aerosol optical depth under thin cirrus from MODIS: Application to an ocean algorithm." J. Geophys. Res. Atmos. 118 (17): 10,111-10,124 [10.1002/jgrd.50806] [Journal Article/Letter]

2013. "Enhanced Deep Blue aerosol retrieval algorithm: The second generation." J. Geophys. Res. Atmos. 118 (16): 9296–9315 [10.1002/jgrd.50712] [Journal Article/Letter]

2013. "Production mechanisms, number concentration, size distribution, chemical composition, and optical properties of sea spray aerosols." Atmos. Sci. Lett. 14 (4): 207-213 [10.1002/asl2.441] [Journal Article/Letter]

2013. "The Collection 6 MODIS Aerosol Products over Land and Ocean." Atmos Meas Tech 6 2989-3034 [10.5194/amt-6-2989-2013] [Journal Article/Letter]

2012. "Can Asian dust trigger phytoplankton blooms in the oligotrophic northern South China Sea?." Geophysical Research Letters 39 (5): L05811 [Full Text] [10.1029/2011GL050415] [Journal Article/Letter]

2012. "Estimating marine aerosol particle volume and number from Maritime Aerosol Network data." Atmos. Chem. Phys. 12 (18): 8889-8909 [10.5194/acp-12-8889-2012] [Journal Article/Letter]

2012. "A pure marine aerosol model, for use in remote sensing applications." J. Geophys. Res. 117 (D5): D05213 [10.1029/2011JD016689] [Journal Article/Letter]

2012. "Intercomparison of desert dust optical depth from satellite measurements." Atmos. Meas. Tech. 5 (8): 1973-2002 [10.5194/amt-5-1973-2012] [Journal Article/Letter]

2012. "Estimating marine aerosol particle volume and number from Maritime Aerosol Network data." Atm Chem Phys 12 8889-8909 [Journal Article/Letter]

2012. "SeaWiFS Ocean Aerosol Retrieval (SOAR): Algorithm, validation, and comparison with other data sets." J. Geophys. Res. 117 (D3): D03206 [10.1029/2011JD016599] [Journal Article/Letter]

2012. "Smoke aerosol and its radiative effects during extreme fire event over Central Russia in summer 2010." Atmos Meas Tech 5 (3): 557-568 [10.5194/amt-5-557-2012] [Journal Article/Letter]

2012. "Seven years of global retrieval of cloud properties using space-borne data of GOME." Atmos Meas Tech 5 (7): 1551-1570 [10.5194/amt-5-1551-2012] [Journal Article/Letter]

2012. "Global and regional evaluation of over-land spectral aerosol optical depth retrievals from SeaWiFS." Atmos Meas Tech 5 (7): 1761-1778 [10.5194/amt-5-1761-2012] [Journal Article/Letter]

2012. "Global and regional trends of aerosol optical depth over land and ocean using SeaWiFS measurements from 1997 to 2010." Atmos. Chem. Phys. 12 (17): 8037-8053 [10.5194/acp-12-8037-2012] [Journal Article/Letter]

2012. "Effect of wind speed on aerosol optical depth over remote oceans, based on data from the Maritime Aerosol Network." Atmos Meas Tech 5 (2): 377-388 [10.5194/amt-5-377-2012] [Journal Article/Letter]

2012. "Use of MODIS-derived surface reflectance data in the ORAC-AATSR aerosol retrieval algorithm: Impact of differences between sensor spectral response functions." Rem Sens Environ 116 177-188 [10.1016/j.rse.2011.02.029] [Journal Article/Letter]

2012. "Cloud retrievals from satellite data using optimal estimation: evaluation and application to ATSR." Atmospheric Measurement Techniques 5 (8): 1889-1910 [10.5194/amt-5-1889-2012] [Journal Article/Letter]

2011. "Global retrieval of ATSR cloud parameters and evaluation (GRAPE): dataset assessment." Atmos. Chem. Phys. 11 (8): 3913-3936 [10.5194/acp-11-3913-2011] [Journal Article/Letter]

2010. "Validation of the GRAPE single view aerosol retrieval for ATSR-2 and insights into the long term global AOD trend over the ocean." Atmos. Chem. Phys. 10 (10): 4849-4866 [10.5194/acp-10-4849-2010] [Journal Article/Letter]

2010. "A sea surface reflectance model for (A)ATSR, and application to aerosol retrievals." Atmos Meas Tech 3 (4): 813-838 [10.5194/amt-3-813-2010] [Journal Article/Letter]

2010. "Some implications of sampling choices on comparisons between satellite and model aerosol optical depth fields." Atmos. Chem. Phys. 10 (22): 10705-10716 [10.5194/acp-10-10705-2010] [Journal Article/Letter]

2009. "Aerosol indirect effects – general circulation model intercomparison and evaluation with satellite data." Atmos. Chem. Phys. 9 (22): 8697-8717 [10.5194/acp-9-8697-2009] [Journal Article/Letter]