Sciences and Exploration Directorate

Lok N Lamsal


Lok N Lamsal's Contact Card & Information.
Phone: 301.614.5160
Org Code: 614
Mail Code 614
Greenbelt, MD 20771

Brief Bio

Dr. Lok N.  Lamsal is a GESTAR-affiliated Research Scientist at NASA Goddard Space Flight Center. His current research areas include development/improvement of retrieval algorithm for atmospheric trace gases from orbital and suborbital UV-visible sensors, validation of algorithm/products, and interpretation of satellite observations using in-situ data and model simulations. Prior to joining NASA, he was a postdoctoral fellow at Dalhousie University, Halifax, Canada. He received a Ph.D. in Atmospheric Science from the Institute of Remote Sensing, University of Bremen, Germany.


Senior Research Scientist

Goddard Earth Sciences Technology and Research (GESTAR) II, University of Maryland Baltimore County, Baltimore, MD 21250 - NASA Goddard Space Flight Center, Greenbelt, MD 20771

November 2021 - Present

Senior Scientist (Earth Science)

Goddard Earth Sciences Technology & Research, Universities Space Research Association - NASA Goddard Space Flight Center, Greenbelt, MD 20771

May 2018 - November 2021

Scientist II/Scientist III

Goddard Earth Sciences Technology & Research, Universities Space Research Association - NASA Goddard Flight Center, Greenbelt, MD 20771

2011 - 2018

Postdoctoral Fellow

Dalhousie University - Dalhousie University, Halifax, Nova Scotia, Canada B3H 4R2

2006 - 2011

Research Assistant

University of Bremen - University of Bremen, Otto-Hahn-Allee 1, D-28359, Bremen, Deutschland

2002 - 2006

Lecturer (Physics)

Tribhuvan University - Tribhuvan University, Kathmandu, Nepal

1999 - 2001


- NASA Robert H. Goddard Science Team Award (2021)

- NASA Goddard Earth Science Division Best Science Highlight or Nugget Award (2020)

- NASA Goddard Earth Science Division Distinguished Contribution Group Award


- AMS Special Award – OMI Team (2020)

- William T. Pecora Award - OMI International Team (2018)

- NASA DISCOVER-AQ Group Achievement Award (2017)

- USRA President's Individual Excellence Award (2016)

- NASA Robert H. Goddard Exceptional Achievement Science Award (2015)

- NASA Goddard Laboratory for Atmospheres Outstanding Performance in Science

Award (2015)

- GESTAR Excellence Award (2014)

- Graduate scholarship – University of Bremen (2001-2002)

- M.Sc. Dissertation Grants, Nepal Academy of Science and Technology (1998)




2023. "Use of machine learning and principal component analysis to retrieve nitrogen dioxide (NO2) with hyperspectral imagers and reduce noise in spectral fitting." Atmospheric Measurement Techniques 16 (2): 481-500 [10.5194/amt-16-481-2023] [Journal Article/Letter]

2022. "Change in Tropospheric Ozone in the Recent Decades and Its Contribution to Global Total Ozone." Journal of Geophysical Research: Atmospheres 127 (22): [10.1029/2022jd037170] [Journal Article/Letter]

2022. "NASA Satellite Measurements Show Global‐Scale Reductions in Free Tropospheric Ozone in 2020 and Again in 2021 During COVID‐19." Geophysical Research Letters 49 (15): [10.1029/2022gl098712] [Journal Article/Letter]

2022. "Polarization Performance Simulation for the GeoXO Atmospheric Composition Instrument: NO2 Retrieval Impacts." Atmospheric Measurement Techniques 15 (15): 4489–4501 [] [Journal Article/Letter]

2022. "Global fine-scale changes in ambient NO2 during COVID-19 lockdowns." Nature 601 (7893): 380-387 [10.1038/s41586-021-04229-0] [Journal Article/Letter]

2022. "Use of Hyper-Spectral Visible and Near-Infrared Satellite Data for Timely Estimates of the Earth’s Surface Reflectance in Cloudy and Aerosol Loaded Conditions: Part 1–Application to RGB Image Restoration Over Land With GOME-2." Frontiers in Remote Sensing 2 [10.3389/frsen.2021.716430] [Journal Article/Letter]

2021. "CHAPS: a sustainable approach to targeted air pollution observation from small satellites." Sensors, Systems, and Next-Generation Satellites XXV [10.1117/12.2600175] [Proceedings]

2021. "Comprehensive evaluations of diurnal NO2 measurements during DISCOVER-AQ 2011: effects of resolution-dependent representation of NOx emissions." Atmospheric Chemistry and Physics 21 (14): 11133-11160 [10.5194/acp-21-11133-2021] [Journal Article/Letter]

2021. "Observations of Lightning NOx Production From GOES‐R Post Launch Test Field Campaign Flights." Journal of Geophysical Research: Atmospheres 126 (8): [10.1029/2020jd033769] [Journal Article/Letter]

2021. "Explicit and consistent aerosol correction for visible wavelength satellite cloud and nitrogen dioxide retrievals based on optical properties from a global aerosol analysis." Atmospheric Measurement Techniques 14 (4): 2857-2871 [10.5194/amt-14-2857-2021] [Journal Article/Letter]

2021. "Ozone Monitoring Instrument (OMI) Aura nitrogen dioxide standard product version 4.0 with improved surface and cloud treatments." Atmospheric Measurement Techniques 14 455-479 [10.5194/amt-14-455-2021] [Journal Article/Letter]

2020. "Surface and Satellite Observations of Air Pollution in India during COVID-19 Lockdown: Implication to Air Quality." Sustainable Cities and Society 102688 [10.1016/j.scs.2020.102688] [Journal Article/Letter]

2020. "Impact of COVID-19 on the Air Quality over China and India Using Long-term (2009-2020) Multi-satellite Data." Aerosol and Air Quality Research 21 (3): 200295 [10.4209/aaqr.2020.06.0295] [Journal Article/Letter]

2020. "Abrupt decline in tropospheric nitrogen dioxide over China after the outbreak of COVID-19." Science Advances 6 (28): eabc2992 [10.1126/sciadv.abc2992] [Journal Article/Letter]

2020. "Assessment of NO2; observations during DISCOVER-AQ and KORUS-AQ field campaigns." Atmospheric Measurement Techniques 13 (5): 2523-2546 [10.5194/amt-13-2523-2020] [Journal Article/Letter]

2020. "A methodology to constrain carbon dioxide emissions from coal-fired power plants using satellite observations of co-emitted nitrogen dioxide." Atmospheric Chemistry and Physics 20 99-116 [10.5194/acp-20-99-2020] [Journal Article/Letter]

2019. "Exploiting OMI NO2 satellite observations to infer fossil-fuel CO2 emissions from U.S. megacities." Science of The Total Environment 695 133805 [10.1016/j.scitotenv.2019.133805] [Journal Article/Letter]

2019. "Using satellite observations of tropospheric NO2 columns to infer long-term trends in US NOx emissions: the importance of accounting for the free tropospheric NO2 background." Atmospheric Chemistry and Physics 19 (13): 8863-8878 [10.5194/acp-19-8863-2019] [Journal Article/Letter]

2019. "High-Resolution Mapping of Nitrogen Dioxide With TROPOMI: First Results and Validation Over the Canadian Oil Sands." Geophysical Research Letters 46 (2): 1049-1060 [10.1029/2018gl081095] [Journal Article/Letter]

2018. "Atmospheric Trace Gas (NO2 and O3) Variability in South Korean Coastal Waters, and Implications for Remote Sensing of Coastal Ocean Color Dynamics." Remote Sensing 10 (10): 1587 [10.3390/rs10101587] [Journal Article/Letter]

2018. "Estimates of the Global Burden of Ambient PM2.5, Ozone, and NO2 on Asthma Incidence and Emergency Room Visits." Environmental Health Perspectives 126 (10): 107004 [10.1289/ehp3766] [Journal Article/Letter]

2018. "A cloud algorithm based on the O2-O2 477 nm absorption band featuring an advanced spectral fitting method and the use of surface geometry-dependent Lambertian-equivalent reflectivity." Atmospheric Measurement Techniques 11 (7): 4093-4107 [10.5194/amt-11-4093-2018] [Journal Article/Letter]

2017. "A decade of changes in nitrogen oxides over regions of oil and natural gas activity in the United States." Elem Sci Anth 5 (0): 76 [10.1525/elementa.259] [Journal Article/Letter]

2017. "The version 3 OMI NO2 standard product." Atmospheric Measurement Techniques 10 (9): 3133-3149 [10.5194/amt-10-3133-2017] [Journal Article/Letter]

2017. "Structural uncertainty in air mass factor calculation for NO2 and HCHO satellite retrievals." Atmospheric Measurement Techniques 10 (3): 759-782 [10.5194/amt-10-759-2017] [Journal Article/Letter]

2017. "High-resolution NO2 observations from the Airborne Compact Atmospheric Mapper: Retrieval and validation." Journal of Geophysical Research: Atmospheres 122 (3): 1953-1970 [10.1002/2016jd025483] [Journal Article/Letter]

2017. "What factors control the trend of increasing AAOD over the United States in the last decade?." Journal of Geophysical Research: Atmospheres 122 (3): 1797-1810 [10.1002/2016jd025472] [Journal Article/Letter]

2017. "Accounting for the effects of surface BRDF on satellite cloud and trace-gas retrievals: a new approach based on geometry-dependent Lambertian equivalent reflectivity applied to OMI algorithms." Atmospheric Measurement Techniques 10 (1): 333-349 [10.5194/amt-10-333-2017] [Journal Article/Letter]

2016. "Comparison of OMI NO2 observations and their seasonal andweekly cycles with ground-based measurements in Helsinki." Atmospheric Measurement Techniques 9 (10): 5203-5212 [10.5194/amt-9-5203-2016] [Journal Article/Letter]

2016. "Tropospheric emissions: Monitoring of pollution (TEMPO)." Journal of Quantitative Spectroscopy and Radiative Transfer 186 17-39 [10.1016/j.jqsrt.2016.05.008] [Journal Article/Letter]

2016. "Aura OMI observations of regional SO2 and NO2 pollution changes from 2005 to 2015." Atmos. Chem. Phys. 16 (7): 4605-4629 [10.5194/acp-16-4605-2016] [Journal Article/Letter]

2016. " A space-based, high-resolution view of notable changes in urban NO x pollution around the world (2005-2014) ." J. Geophys. Res. Atmos. 121 (2): 976–996 [10.1002/2015jd024121] [Journal Article/Letter]

2015. "Aura OMI observations of regional SO2 and NO2 pollution changes from 2005 to 2014." Atmos. Chem. Phys. 16 4605-4629 [10.5194/acp-16-4605-2016] [Journal Article/Letter]

2015. "Emissions of nitrogen oxides from US urban areas: estimation from Ozone Monitoring Instrument retrievals for 2005–2014 ." Atmos. Chem. Phys. 15 10367-10383 [10.5194/acp-15-10367-2015] [Journal Article/Letter]

2015. "Trends and variability in surface ozone over the United States." Journal of Geophysical Research: Atmospheres 120 [10.1002/2014JD022784] [Journal Article/Letter]

2015. "U.S. NO2 trends (2005–2013): EPA Air Quality System (AQS) data versus improved observations from the Ozone Monitoring Instrument (OMI)." Atmos. Env. 110 130-143 [10.1016/j.atmosenv.2015.03.055] [Journal Article/Letter]

2015. "Influence of satellite-derived photolysis rates and NOx emissions on Texas ozone modeling." Atmos. Chem. Phys. 15 (4): 1601-1619 [10.5194/acp-15-1601-2015] [Journal Article/Letter]

2014. "Evaluation of OMI operational standard NO2 column retrievals using in situ and surface-based NO2 observations." Atmos. Chem. Phys. 14 11,587-11,609 [10.5194/acp-14-11587-2014] [Journal Article/Letter]

2014. "Relationship between column-density and surface mixing ratio: Statistical analysis of O3 and NO2 data from the July 2011 Maryland DISCOVER-AQ mission." Atmospheric Environment 92 429-441 [10.1016/j.atmosenv.2014.04.041] [Journal Article/Letter]

2014. "Improved satellite retrievals of NO2 and SO2 over the Canadian oil sands and comparisons with surface measurements." Atmospheric Chemistry and Physics 14 (7): 3637-3656 [10.5194/acp-14-3637-2014] [Journal Article/Letter]

2014. "Using Satellite Observations to Measure." Environmental Manager 64 16-21 [Journal Article/Letter]

2013. "Emissions estimation from satellite retrievals: A review of current capability." Atmospheric Environment 77 1011-1042 [10.1016/j.atmosenv.2013.05.051] [Journal Article/Letter]

2013. "A new stratospheric and tropospheric NO2 retrieval algorithm for nadir-viewing satellite instruments: applications to OMI." Atmospheric Measurement Techniques 6 (10): 2607-2626 [10.5194/amt-6-2607-2013] [Journal Article/Letter]

2013. "Scaling Relationship for NO2 Pollution and Urban Population Size: A Satellite Perspective." Environmental Science & Technology 47 (14): 7855-7861 [10.1021/es400744g] [Journal Article/Letter]

2013. "The observed response of Ozone Monitoring Instrument (OMI) NO2 columns to NOx emission controls on power plants in the United States: 2005–2011." Atmospheric Environment 81 102-111 [10.1016/j.atmosenv.2013.08.068] [Journal Article/Letter]

2013. "Airborne MAX-DOAS measurements over California: Testing the NASA OMI tropospheric NO₂ product." J. Geophys. Res. Atmos. 118 (13): 7400–7413 [10.1002/jgrd.50550] [Journal Article/Letter]