Santiago Gassó

Santiago Gassó

  • RESEARCH ASSOCIATE
  • 301.614.6244 | 301.614.6307
  • NASA/GSFC
  • Mail Code: 613
  • Greenbelt , MD 20771
  • Employer: MORGAN STATE UNIV.
  • Brief Bio

    Dr. Gassó specializes in observational studies of aerosols, clouds and their interactions using a combination of satellite detectors. He has extensive knowledge of the aerosol retrieval algorithms of the detectors MODIS and OMI and their performance.

    He is an University of Washington graduate in geophysics (Atmospheric Science track) with thesis work on in-situ observations of aerosols, their optical properties in relation to remote sensing and evaluation of the first versions of the MODIS aerosol algorithm. In his post-doctoral work, he acquired aerosol global modeling experience with the design of a (currently operational) module of the optical and radiative aerosol properties in the Navy Aerosol Assimilation Prediction System (NAAPS) model. Then, he was awarded a NASA grant to evaluate NAAPS model outputs and compare with satellite retrievals of mass concentration and then an ONR grant to evaluate sulfate emission inventories in NAAPS. Also, he has participated as aerosol scientist in the NPOESS Preparatory Project science team (2005-08) . Since 2008, he is an Ozone Monitoring Instrument (OMI) science team and a member of the OMI aerosol remote sensing group led by Dr. Omar Torres. During 2009 to 2011, he lead the Aerosol-Ocean Interactions working group, one of the science working groups for the Aerosol, Clouds and Ecosystems (ACE) mission, a proposed NASA mission to fulfill the NRC Decadal Survey requirements.

    In addition to the operational aspects of remote sensing retrievals, his research interests include study of dust at high latitudes. In particular, characterization of its production and long range transport as well as its impacts in biogeochemical and paleo-climate studies. This is an activity he has carried out for the last 15 years. He has been a collaborator and Co-I in internationally funded projects to survey and monitor dust activity in Patagonia. He made the first dedicated satellite and model studies of dust activity in Patagonia. In 2007 , he chaired and organized the Multidisciplinary Workshop on Southern South American Dust held in Puerto Madryn, Argentina, 2007 for which obtained NSF funding and had an attendance 60 participant (~20 international). Between 2010 and 2013, he participated as co-I in a NASA-IDS funded project to characterize dust transport from Alaska glaciers and has been monitoring the area with remote sensing tools since then. Since 2014, he is part of the High Latitude Dust and Cold Environment Network, a working group supported by The Leverhulme Trust (UK). He has authored or co-authored 23 peer-reviewed journal articles many on the subject of dust transport at high latitudes as characterized by satellite, model and surface observations.

    Also, he developed an interest in studying volcanoes through a discovery he made in 2006. He found that low levels volcanic activity (non-explosive passive degassing activity VEI<2) can be detected in cloudy conditions by studying the change in properties in nearby water clouds. The discovery provides an excellent opportunity for studying aerosol-cloud interactions as well as provides a way to detect volcanic activity in cloudy conditions.

    See the ranking of publications : http://www.researcherid.com/rid/H-9571-2014

    Research Interests

    Remote sensing of absorbing aerosols in the UV-NIR wavelength range

    In addition to scatter light, airborne particulate matter such as smoke and dust (also known as aerosols) absorb solar energy. This absorbed energy does not reach the surface and the reduction (or redistribution) of this energy can impact photosynthetic processes in both land and ocean ecosystems. In addition, this energy is returned to the environment in the form of heat and changing the ambient temperature in the atmospheric column. This results in, for example, cloud dissipation among other effects. Thus characterization of these aerosols from space is very important because it will enable a better understanding of their energy balance in the atmosphere as well the processes modulate cloud formation and dissipation. The observation absorbing aerosols is most effective in the ultra-violet range of the electromagnetic spectrum. Currently, very few space sensors have the capability to detect these aerosols. One of them is the Ozone Monitoring Instrument on board the NASA’s Aura satellite. As member of the aerosol science team of OMI (lead by Dr. Omar Torres), I work to improve existing and new approaches to observe these aerosols.

    High Latitude Dust in Cold Environments

    High Latitude Dust refers to dust generated in mid to high latitudes such as in cold deserts (Patagonia desert in South America) and in the vicinity of glaciers (Alaska, Iceland). The deserts are distinctive in the sense they occur in cold environments, normally not associated with warmer places (such as the Saharan desert) but they do have low precipitation, dry conditions and high winds all necessary conditions for dust production. Satellite images confirm that dust production per event can be abundant. However, the frequency of the events and the abundance of the material produced in these cold environments is much lower than the mid-latitude counterparts. Yet, because their location, they could have a disproportionate and indirect effects in climate. The reason is that most of these sources are located upwind of ocean ecosystems known to be deficient of the micronutrient iron (Fe). Since it is abundant in dust, it is possible that the deposition of Fe may impact the marine ecosystem downwind (specifically via the ingest of nutrients by phytoplankton). Also the study of high latitude dust in modern times can provide clues of the dynamics of atmospheric transport during previous ice-ages. The reason is that the dust is commonly found in ice cores in both poles and it is well known the most of it originated from high latitude sources. By understanding the production and transport patterns of modern dust transport, it will be possible to better understand how past climates evolved.

    Observations of the Impact of Passive Volcanic Activity on Clouds

    Volcanic activity from space is most easily detectable when the eruption is powerful enough to send ashes above clouds. However, most of the active volcanoes emit gases, water vapor and ash in rather unenergetic eruptions where the emissions stay at cloud level or do not penetrate through the cloud layer aloft. Consequently, the vast majority of volcanic activity remains undetected unless the volcano is nearby a human settlement or a surface remote sensor. In addition, volcanoes are a source of aerosol and aerosol precursors (such as sulfur dioxide) and they are regularly emitted and mixed with clouds in the environment. Because the injection of these materials into the cloud, the cloud micro- and macro-physical properties of these clouds change accordingly. The extent of this impact is rather unclear. However, passive volcanic activity provides a natural laboratory to study the indirect effect of aerosols in clouds such as the change of the cloud’s reflective and precipitation properties.

    Positions/Employment

    5/2013 - Present

    Associate Research Scientist

    GEST/Morgan State University, GFSC/NASA
    5/2011 - 5/2013

    Research Scientist

    GEST/Morgan State University, GFSC/NASA
    5/2003 - 4/2011

    Research Scientist

    GESTAR/University of Maryland Baltimore County, GSFC/NASA
    8/2001 - 8/2003

    Post-Doctoral Researcher

    GESTAR/University of Maryland Baltimore County, GSFC/NASA

    Education

    Ph. D ,Geophysics. University of Washington, Seattle (2001).
    M. Sc, Geophysics. University of Washington, Seattle (1997).
    M. Sc, Physics. University of Buenos Aires, Buenos Aires, Argentina (1992).

    Publications

    Refereed

    Schroth, A. W., J. Crusius, S. Gassó, et al. C. M. Moy, N. J. Buck, J. A. Resing, and R. W. Campbell. 2017. "Atmospheric deposition of glacial iron in the Gulf of Alaska impacted by the position of the Aleutian Low." Geophysical Research Letters, 44 (10): 5053-5061 [10.1002/2017gl073565]

    Colarco, P. R., S. Gassó, C. Ahn, et al. V. Buchard, A. M. da Silva, and O. Torres. 2017. "Simulation of the Ozone Monitoring Instrument aerosol index using the NASA Goddard Earth Observing System aerosol reanalysis products." Atmospheric Measurement Techniques, 10 (11): 4121-4134 [10.5194/amt-10-4121-2017]

    Gasso, S., and O. Torres. 2016. "The role of cloud contamination, aerosol layer height and aerosol model in the assessment of the OMI near-UV retrievals over the ocean." Atmospheric Measurements Techniques, 9: 3031-3052 [10.5194/amt-9-3031-2016]

    Bullard, J. E., M. Baddock, T. Bradwell, et al. J. Crusius, E. Darlington, D. Gaiero, S. Gassó, G. Gisladottir, R. Hodgkins, R. McCulloch, C. M. Neuman, T. Mockford, H. Stewart, and T. Thorsteinsson. 2016. "High Latitude Dust in the Earth System." Review of Geophysics, 54: [10.1002/2016RG000518]

    Dawson, K. W., N. Meskhidze, D. Josset, and S. Gassó. 2015. "Spaceborne observations of the lidar ratio of marine aerosols ." Atmos. Chem. Phys., 15: 3241-3255 [10.5194/acp-15-3241-2015]

    Gaiero, D., S. Gassó, L. Simonella, and A. F. Stein. 2013. "Ground/satellite observations and atmospheric modeling of dust storms originating in the high Puna-Altiplano deserts (South America): Implications for the interpretation of paleo-climatic archives." J. Geophys. Res. Atmos., 118 (9): 3817–3831 [10.1002/jgrd.50036]

    Crucius, J., A. Schroth, S. Gassó, and R. C. Levy. 2011. "Glacial flour dust storms in the Gulf of Alaska: Hydrologic and meteorological controls and their importance as a source of bioavailable iron." Geophysical Research Letters, 38 (6): L06602 [10.1029/2010GL046573]

    Johnson, M., N. Meskhidze, V. Kiliyanpilakkil, and S. Gassó. 2011. "Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean." Atmos. Chem. Phys., 11 (6): 2487-2502 [10.5194/acp-11-2487-2011]

    Johnson, M., N. Meskhidze, F. Solmon, et al. S. Gassó, P. Chuang, D. Gaiero, Y. Robert, S. Wu, Y. Wang, and C. Carouge. 2010. "Modeling Dust and Soluble Iron Deposition to the South Atlantic Ocean." J. Geophys. Res., 115: 15202 [10.1029/2009JD013311]

    Gassó, S., V. Grassian, and R. L. Miller. 2010. "Interactions between Mineral Dust, Climate, and Ocean Ecosystems." Elements, 6 (4): 247-252 [Full Text (Link)] [10.2113/gselements.6.4.247]

    Gassó, S., A. Stein, F. Marino, et al. E. Castellano, R. Udisti, and J. Ceratto. 2010. "A combined observational and modeling approach to study modern dust transport from the Patagonia desert to East Antarctica." Atmos. Chem. Phys., 10 (17): 8287-8303 [10.5194/acp-10-8287-2010]

    Gassó, S. 2008. "Satellite observations of the impact of weak volcanic activity on marine clouds." J. Geophys. Res., 113 (D14): D14S19 [10.1029/2007JD009106]

    Gassó, S., and A. F. Stein. 2007. "Does dust from Patagonia reach the sub-Antarctic Atlantic Ocean?" Geophysical Research Letters, 34 (1): L01801 [10.1029/2006GL027693]

    Vallina, S., R. Simó, and S. Gassó. 2007. "Analysis of a potential “solar radiation dose-dimethylsulfide-cloud condensation nuclei” link from globally mapped seasonal correlations." Global Biogeochem. Cycles, 21 (2): GB2004 [10.1029/2006GB002787]

    Gassó, S., and N. O'Neill. 2006. "Comparisons of remote sensing retrievals and in situ measurements of aerosol fine mode fraction during ACE-Asia." Geophysical Research Letters, 33 (5): L05807 [10.1029/2005GL024926]

    Vallina, S., R. Simó, and S. Gassó. 2006. "What controls CCN seasonality in the Southern Ocean? A statistical analysis based on satellite-derived chlorophyll and CCN and model-estimated OH radical and rainfall." Global Biogeochem. Cycles, 20 (1): GB1014 [10.1029/2005GB002597]

    Gassó, S., and D. Hegg. 2003. "On the Retrieval of Columnar Aerosol Mass and CCN Concentration by MODIS." J. of Geophys. Res., 108 (D1): 4010 [Full Text (Link)] [10.1029/2002JD002382]

    Husar, R., D. Tratt, B. Schichtel, et al. S. Falke, F. Li, D. Jaffe, S. Gassó, T. Gill, N. Laulainen, M. Reheis, Y. Chun, D. Westphal, B. N. Holben, C. Gueymard, I. McKendry, N. A. Kuring, G. C. Feldman, C. R. Mcclain, R. Frouin, J. Merrill, D. DuBois, F. Vignola, T. Murayama, S. Nickovic, W. Wilson, K. Sassen, N. Sugimoto, W. Malm, and S. Gassó. 2001. "Asian dust events of April 1998." Journal of Geophysical Research-Atmospheres, 106 (16): 18317-18330 [10.1029/2000JD900788]

    Schmid, B., J. Livingston, P. B. Russell, et al. P. Durkee, H. Jonsson, D. Collins, R. Flagan, J. Seinfeld, S. Gassó, D. Hegg, E. Öström, K. Noone, E. J. Welton, K. Voss, H. Gordon, P. Formenti, and M. Andreae. 2000. "Clear-sky closure studies of lower tropospheric aerosol and water vapor during ACE-2 using airborne sunphotometer, airborne in-situ, space-borne, and ground-based measurements." Tellus B, 52 (2): 568-593 [10.1034/j.1600-0889.2000.00009.x]

    Gassó, S., and D. Hegg. 1998. "Comparison of columnar aerosol optical properties measured by the MODIS airborne simulator with in situ measurements: A case study." Rem. Sens. Env, 66 (2): 138-152 [Full Text (Link)] [10.1016/S0034-4257(98)00052-2]

    Remer, L., S. Gassó, D. Hegg, Y. Kauffman, and B. Holben. 1997. "Urban/Industrial Aerosol: Ground-Based Sun/Sky Radiometer and Airborne In Situ Measurements." J. of Geophys. Res., 102 (D14): 16849-16859 [Full Text (Link)] [10.1029/96JD01932]

    Hegg, D., P. V. Hobbs, S. Gassó, J. Nance, and A. Rangno. 1996. "Aerosol Measurements in the Arctic Relevant to Direct and Indirect Radiative Forcing." J. of Geophys. Res., 101 (D18): 23349-23363 [Full Text (Link)] [10.1029/96JD02246]

    Brief Bio

    Dr. Gassó specializes in observational studies of aerosols, clouds and their interactions using a combination of satellite detectors. He has extensive knowledge of the aerosol retrieval algorithms of the detectors MODIS and OMI and their performance.

    He is an University of Washington graduate in geophysics (Atmospheric Science track) with thesis work on in-situ observations of aerosols, their optical properties in relation to remote sensing and evaluation of the first versions of the MODIS aerosol algorithm. In his post-doctoral work, he acquired aerosol global modeling experience with the design of a (currently operational) module of the optical and radiative aerosol properties in the Navy Aerosol Assimilation Prediction System (NAAPS) model. Then, he was awarded a NASA grant to evaluate NAAPS model outputs and compare with satellite retrievals of mass concentration and then an ONR grant to evaluate sulfate emission inventories in NAAPS. Also, he has participated as aerosol scientist in the NPOESS Preparatory Project science team (2005-08) . Since 2008, he is an Ozone Monitoring Instrument (OMI) science team and a member of the OMI aerosol remote sensing group led by Dr. Omar Torres. During 2009 to 2011, he lead the Aerosol-Ocean Interactions working group, one of the science working groups for the Aerosol, Clouds and Ecosystems (ACE) mission, a proposed NASA mission to fulfill the NRC Decadal Survey requirements.

    In addition to the operational aspects of remote sensing retrievals, his research interests include study of dust at high latitudes. In particular, characterization of its production and long range transport as well as its impacts in biogeochemical and paleo-climate studies. This is an activity he has carried out for the last 15 years. He has been a collaborator and Co-I in internationally funded projects to survey and monitor dust activity in Patagonia. He made the first dedicated satellite and model studies of dust activity in Patagonia. In 2007 , he chaired and organized the Multidisciplinary Workshop on Southern South American Dust held in Puerto Madryn, Argentina, 2007 for which obtained NSF funding and had an attendance 60 participant (~20 international). Between 2010 and 2013, he participated as co-I in a NASA-IDS funded project to characterize dust transport from Alaska glaciers and has been monitoring the area with remote sensing tools since then. Since 2014, he is part of the High Latitude Dust and Cold Environment Network, a working group supported by The Leverhulme Trust (UK). He has authored or co-authored 23 peer-reviewed journal articles many on the subject of dust transport at high latitudes as characterized by satellite, model and surface observations.

    Also, he developed an interest in studying volcanoes through a discovery he made in 2006. He found that low levels volcanic activity (non-explosive passive degassing activity VEI<2) can be detected in cloudy conditions by studying the change in properties in nearby water clouds. The discovery provides an excellent opportunity for studying aerosol-cloud interactions as well as provides a way to detect volcanic activity in cloudy conditions.

    See the ranking of publications : http://www.researcherid.com/rid/H-9571-2014

    Publications

    Refereed

    Schroth, A. W., J. Crusius, S. Gassó, et al. C. M. Moy, N. J. Buck, J. A. Resing, and R. W. Campbell. 2017. "Atmospheric deposition of glacial iron in the Gulf of Alaska impacted by the position of the Aleutian Low." Geophysical Research Letters 44 (10): 5053-5061 [10.1002/2017gl073565]

    Colarco, P. R., S. Gassó, C. Ahn, et al. V. Buchard, A. M. da Silva, and O. Torres. 2017. "Simulation of the Ozone Monitoring Instrument aerosol index using the NASA Goddard Earth Observing System aerosol reanalysis products." Atmospheric Measurement Techniques 10 (11): 4121-4134 [10.5194/amt-10-4121-2017]

    Gasso, S., and O. Torres. 2016. "The role of cloud contamination, aerosol layer height and aerosol model in the assessment of the OMI near-UV retrievals over the ocean." Atmospheric Measurements Techniques 9 3031-3052 [10.5194/amt-9-3031-2016]

    Bullard, J. E., M. Baddock, T. Bradwell, et al. J. Crusius, E. Darlington, D. Gaiero, S. Gassó, G. Gisladottir, R. Hodgkins, R. McCulloch, C. M. Neuman, T. Mockford, H. Stewart, and T. Thorsteinsson. 2016. "High Latitude Dust in the Earth System." Review of Geophysics 54 [10.1002/2016RG000518]

    Dawson, K. W., N. Meskhidze, D. Josset, and S. Gassó. 2015. "Spaceborne observations of the lidar ratio of marine aerosols ." Atmos. Chem. Phys. 15 3241-3255 [10.5194/acp-15-3241-2015]

    Gaiero, D., S. Gassó, L. Simonella, and A. F. Stein. 2013. "Ground/satellite observations and atmospheric modeling of dust storms originating in the high Puna-Altiplano deserts (South America): Implications for the interpretation of paleo-climatic archives." J. Geophys. Res. Atmos. 118 (9): 3817–3831 [10.1002/jgrd.50036]

    Crucius, J., A. Schroth, S. Gassó, and R. C. Levy. 2011. "Glacial flour dust storms in the Gulf of Alaska: Hydrologic and meteorological controls and their importance as a source of bioavailable iron." Geophysical Research Letters 38 (6): L06602 [10.1029/2010GL046573]

    Johnson, M., N. Meskhidze, V. Kiliyanpilakkil, and S. Gassó. 2011. "Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean." Atmos. Chem. Phys. 11 (6): 2487-2502 [10.5194/acp-11-2487-2011]

    Johnson, M., N. Meskhidze, F. Solmon, et al. S. Gassó, P. Chuang, D. Gaiero, Y. Robert, S. Wu, Y. Wang, and C. Carouge. 2010. "Modeling Dust and Soluble Iron Deposition to the South Atlantic Ocean." J. Geophys. Res. 115 15202 [10.1029/2009JD013311]

    Gassó, S., V. Grassian, and R. L. Miller. 2010. "Interactions between Mineral Dust, Climate, and Ocean Ecosystems." Elements 6 (4): 247-252 [Full Text (Link)] [10.2113/gselements.6.4.247]

    Gassó, S., A. Stein, F. Marino, et al. E. Castellano, R. Udisti, and J. Ceratto. 2010. "A combined observational and modeling approach to study modern dust transport from the Patagonia desert to East Antarctica." Atmos. Chem. Phys. 10 (17): 8287-8303 [10.5194/acp-10-8287-2010]

    Gassó, S. 2008. "Satellite observations of the impact of weak volcanic activity on marine clouds." J. Geophys. Res. 113 (D14): D14S19 [10.1029/2007JD009106]

    Gassó, S., and A. F. Stein. 2007. "Does dust from Patagonia reach the sub-Antarctic Atlantic Ocean?" Geophysical Research Letters 34 (1): L01801 [10.1029/2006GL027693]

    Vallina, S., R. Simó, and S. Gassó. 2007. "Analysis of a potential “solar radiation dose-dimethylsulfide-cloud condensation nuclei” link from globally mapped seasonal correlations." Global Biogeochem. Cycles 21 (2): GB2004 [10.1029/2006GB002787]

    Gassó, S., and N. O'Neill. 2006. "Comparisons of remote sensing retrievals and in situ measurements of aerosol fine mode fraction during ACE-Asia." Geophysical Research Letters 33 (5): L05807 [10.1029/2005GL024926]

    Vallina, S., R. Simó, and S. Gassó. 2006. "What controls CCN seasonality in the Southern Ocean? A statistical analysis based on satellite-derived chlorophyll and CCN and model-estimated OH radical and rainfall." Global Biogeochem. Cycles 20 (1): GB1014 [10.1029/2005GB002597]

    Gassó, S., and D. Hegg. 2003. "On the Retrieval of Columnar Aerosol Mass and CCN Concentration by MODIS." J. of Geophys. Res. 108 (D1): 4010 [Full Text (Link)] [10.1029/2002JD002382]

    Husar, R., D. Tratt, B. Schichtel, et al. S. Falke, F. Li, D. Jaffe, S. Gassó, T. Gill, N. Laulainen, M. Reheis, Y. Chun, D. Westphal, B. N. Holben, C. Gueymard, I. McKendry, N. A. Kuring, G. C. Feldman, C. R. Mcclain, R. Frouin, J. Merrill, D. DuBois, F. Vignola, T. Murayama, S. Nickovic, W. Wilson, K. Sassen, N. Sugimoto, W. Malm, and S. Gassó. 2001. "Asian dust events of April 1998." Journal of Geophysical Research-Atmospheres 106 (16): 18317-18330 [10.1029/2000JD900788]

    Schmid, B., J. Livingston, P. B. Russell, et al. P. Durkee, H. Jonsson, D. Collins, R. Flagan, J. Seinfeld, S. Gassó, D. Hegg, E. Öström, K. Noone, E. J. Welton, K. Voss, H. Gordon, P. Formenti, and M. Andreae. 2000. "Clear-sky closure studies of lower tropospheric aerosol and water vapor during ACE-2 using airborne sunphotometer, airborne in-situ, space-borne, and ground-based measurements." Tellus B 52 (2): 568-593 [10.1034/j.1600-0889.2000.00009.x]

    Gassó, S., and D. Hegg. 1998. "Comparison of columnar aerosol optical properties measured by the MODIS airborne simulator with in situ measurements: A case study." Rem. Sens. Env 66 (2): 138-152 [Full Text (Link)] [10.1016/S0034-4257(98)00052-2]

    Remer, L., S. Gassó, D. Hegg, Y. Kauffman, and B. Holben. 1997. "Urban/Industrial Aerosol: Ground-Based Sun/Sky Radiometer and Airborne In Situ Measurements." J. of Geophys. Res. 102 (D14): 16849-16859 [Full Text (Link)] [10.1029/96JD01932]

    Hegg, D., P. V. Hobbs, S. Gassó, J. Nance, and A. Rangno. 1996. "Aerosol Measurements in the Arctic Relevant to Direct and Indirect Radiative Forcing." J. of Geophys. Res. 101 (D18): 23349-23363 [Full Text (Link)] [10.1029/96JD02246]

                                                                                                                                                                                            
    NASA Logo, National Aeronautics and Space Administration