Lok Lamsal, Research Scientist III

Lok Lamsal


NASA Goddard Space Flight Center
Bldg. 33
Greenbelt, MD 20771

Phone: 301-614-5160
Fax: 301-614-5903


Retrieval and validation of trace gases from satellite measurements, Interpretation of satellite observations and model simulation for surface air quality and emissions, Radiative transfer.


Dr. Lok N. Lamsal received a Ph.D. in Atmospheric Science from the Institute of Remote Sensing, University of Bremen, Germany in 2006. His doctoral research focused on developing improved total ozone retrieval algorithm for hyper-spectral satellite instrument: GOME and SCIAMACHY. From 2006 to 2010, he worked as a postdoctoral fellow at Dalhousie University, Halifax, Canada, where his research focus was on interpreting NO2 observations from satellite using in-situ measurements and a chemistry transport model (GEOS-Chem). He developed methods to infer ground-level NO2 concentration and to timely update bottom-up NOx emission using satellite data, and helped improve tropospheric NO2 retrievals from the OMI satellite instrument. In 2011, he joined GEST/UMBC and later GESTAR/USRA working at NASA/GSFC. His current research areas include development/improvement of retrieval algorithm for OMI and future satellite instruments, validation of algorithm/product, and interpretation of satellite observations using in-situ data and model simulations.


54) Nickolay Krotkov, Lok Lamsal, Edward Celarier, William Swartz, Sergey Marchenko, Eric Bucsela, Ka Lok Chan, and Mark Wenig, The version 3 OMI NO2 standard product, Atmos. Meas. Tech. Discuss., in review, 2016.

53) Lorente, A., Boersma, K. F., Yu, H., Dörner, S., Hilboll, A., Richter, A., Liu, M., Lamsal, L. N., Barkley, M., De Smedt, I., Van Roozendael, M., Wang, Y., Wagner, T., Beirle, S., Lin, J. T., Kroktov, N., Stammes, P., Wang, P., Eskes, H. J., and Krol, M.: Structural uncertainty in air mass factor calculation for NO2 and HCHO satellite retrievals, Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-306, in review, 2016.

52) Ialongo, I., Herman, J., Krotkov, N., Lamsal, L., Boersma, K. F., Hovila, J., and Tamminen, J.: Comparison of OMI NO2 observations and their seasonal and weekly cycles with ground-based measurements in Helsinki, Atmos. Meas. Tech., 9, 5203-5212, doi:10.5194/amt-9-5203-2016, 2016.

51) P. Zoogman, X. Liu, R.M. Suleiman, W.F. Pennington, D.E. Flittner, J.A. Al-Saadi, B.B. Hilton, D.K. Nicks, M.J. Newchurch, J.L. Carr, S.J. Janz, M.R. Andraschko, A. Arola, B. D. Baker, B.P. Canova, C. Chan Miller, R.C. Cohen, J.E. Davis, M.E. Dussault, D.P. Edwards, J. Fishman, A. Ghulam, G. González Abad, M. Grutter, J.R. Herman, J. Houck, D.J. Jacob, J. Joiner, B.J. Kerridge, J. Kim, N.A. Krotkov, L. Lamsal, C. Li, A. Lindfors, R.V. Martin, C.T. McElroy, C. McLinden, V. Natraj, D.O. Neil, C.R. Nowlan, E.J. O’Sullivan, P.I. Palmer, R. B. Pierce, M.R. Pippin, A. Saiz-Lopez, R.J.D. Spurr, J.J. Szykman, O. Torres, J.P. Veefkind, B. Veihelmann, H. Wang, J. Wang, K. Chance, Tropospheric Emissions: Monitoring of Pollution (TEMPO), JQSRT, DOI: 10.1016/j.jqsrt.2016.05.008, 2016.

50) Lok Lamsal, Scott Janz, Nickolay A. Krotkov, Kenneth Pickering, Robert Spurr, Matthew Kowalewski, Christopher Loughner, James Crawford, William Swartz, Jay Herman, High-resolution NO2 observations from the Airborne Compact Atmospheric Mapper: Retrieval and validation, J. Geophys. Res., 122, doi:10.1002./2016JD025483, 2017.

49) Li Zhang, Daven Henze, Georg A. Grell, Omar Torres, Hiren Jethva, Lok Lamsal, What factors control the trend of increasing AAOD over the United States in the last decade?, J. Geophys. Res., 122, doi:10.1002/2016JD025472, 2017.

48) Rasool, Q. Z., Zhang, R., Lash, B., Cohan, D. S., Cooter, E., Bash, J., and Lamsal, L. N.:
Enhanced representation of soil NO emissions in the Community Multiscale Air Quality (CMAQ) model version 5.0.2, Geosci. Model Dev., 9, 3177-3197, doi:10.5194/gmd-9-3177-2016, 2016.

47) A. Vasilkov, W. Qin, N. Krotkov, L. Lamsal, R. Spurr, D. Haffner, J. Joiner, E.-S. Yang, and S. Marchenko, 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, Atmos. Meas. Tech., 10, 333-349, doi:10.5194/amt-10-333-2017, 2017.

46) Daniel Tong, Li Pan, Weiwei Chen, Lok Lamsal, Pius Lee, Youhua Tang, Hyuncheol Kim, Shobha Kondragunta, and Ivanka Stajner, Impact of the 2008 Global Recession on air quality over the United States: Implications for surface ozone level, Geophys. Res. Lett, 43,
doi:10.1002/2016GL069885, 2016.

45) Can Li, N. Christina Hsu, Andrew M. Sayer, Nickolay A. Krotkov, Joshua S. Fu, Lok N. Lamsal, Jaehwa Lee, Si-Chee Tsay, Satellite observation of pollutant emissions from gas flaring activities near the Arctic, Atmos. Env., Vol. 133, p. 1-11, 2016.

44) Bryan N. Duncan, Lok N. Lamsal, Anne M. Thompson, Yasuko Yoshida, Zifeng Lu, David G. Streets, Margaret M. Hurwitz, Kenneth E. Pickering, A space-based, high-resolution view of notable changes in urban NOx pollution around the world (2005-2014), J. Geophys. Res., 121, 976–996, doi:10.1002/2015JD024121, 2016.

43) N. A. Krotkov, C. A. McLinden, C. Li, L. N. Lamsal, E. A. Celarier, S. V. Marchenko, W. H. Swartz, E. J. Bucsela, J. Joiner, B. N. Duncan, K. F. Boersma, J. P. Pepijn, P. F. Levelt, V. E. Fioletov, R. R. Dickerson, H. He, Z. Lu, and D. G. Streets, Aura OMI observations of regional SO2 and NO2 pollution changes from 2005 to 2015, 16, 4605-4629, Atmos. Chem. Phys., doi:10.5194/acp-16-4605-2016, 2016.

42) C. Liu, X. Liu, M. G. Kowalewski, S. J. Janz, G. González Abad, K. E. Pickering, K. Chance, and L. N. Lamsal, Analysis of ACAM Data for Trace Gas Retrievals during the 2011 DISCOVER-AQ Campaign, J. Spec., Vol. 2015, 827160, 2015.

41) Lu, Z., Streets, D. G., de Foy, B., Lamsal, L. N., Duncan, B. N., and Xing, J.: Emissions of nitrogen oxides from US urban areas: estimation from Ozone Monitoring Instrument retrievals for 2005–2014, Atmos. Chem. Phys., 15, 10367-10383, doi:10.5194/acp-15-10367-2015, 2015.

40) S. K. Kharol, R. V. Martin, S. Philip, B. Boys, L. N. Lamsal, M. Jerrett, M. Brauer, D. L. Crouse, C. McLinden, R. T. Burnett, Assessment of the Magnitude and Recent Trends in Satellite-Derived Ground-Level Nitrogen Dioxide over North America, Atmos. Env., 118, 236–245, doi:10.1016/j.atmosenv.2015.08.011, 2015.

39) Benjamin de Foy, Zifeng Lu, David G Streets, Lok N Lamsal, Bryan N Duncan, Obtaining accurate estimates of power plant NOx emissions from satellite data, Atmos. Env., 116, 1–11, doi:10.1016/j.atmosenv.2015.05.056, 2015.

38) Lok N. Lamsal, Bryan N. Duncan, Yosuko Yoshida, Nickolay A. Krotkov, Kenneth E. Pickering, David G Streets, Zifeng Lu, U.S. NO2 trends (2005–2013): EPA Air Quality System (AQS) data versus improved observations from the Ozone Monitoring Instrument (OMI), Atmos. Env., 110, pp:130-143, doi:10.1016/j.atmosenv.2015.03.055, 2015.

37) S. A. Strode, J. M. Rodriguez, J. A. Logan, O. R. Cooper, J. C. Witte, L. N. Lamsal, M. Damon, B. Van Aartsen, S. D. Steenrod, S. E. Strahan, Trends and variability in surface ozone over the United States, J. Geophys. Res., DOI: 10.1002/2014JD022784, 2015.

36) S. Marchenko, N.A. Krotkov, L.N. Lamsal, E.A. Celarier, W.H. Swartz, E.J. Bucsela, Revising the slant- column density retrieval of nitrogen dioxide observed by the Ozone Monitoring Instrument, J. Geophys. Res., DOI: 10.1002/2014JD022913, 2015.

35) Daniel Tong, Lok N. Lamsal, Li Pan, Hyuncheol Kim, Pius Lee, Tianfeng Chai, Kenneth E. Pickering, Long-term NOx trends over large cities in the United States during the Great Recession: Intercomparison of satellite retrievals, ground observations, and emission inventories, Atmos. Env., 109, DOI: 10.1016/j.atmosenv.2015.01.035, 2015.

34) Liu, C., Liu, X., Kowalewski, M. G., Janz, S. J., González Abad, G., Pickering, K. E., Chance, K., and Lamsal, L. N.: Characterization and verification of ACAM slit functions for trace gas retrievals during the 2011 DISCOVER-AQ flight campaign, Atmos. Meas. Tech., 8, 751-759, doi:10.5194/amt-8-751-2015, 2015.

33) Tang, W., Cohan, D. S., Pour-Biazar, A., Lamsal, L. N., White, A. T., Xiao, X., Zhou, W., Henderson, B. H., and Lash, B. F.: Influence of satellite-derived photolysis rates and NOx emissions on Texas ozone modeling, Atmos. Chem. Phys., 15, 1601-1619, doi:10.5194/acp-15-1601-2015, 2015.

32) Lamsal, L. N., Krotkov, N. A., Celarier, E. A., Swartz, W. H., Pickering, K. E., Bucsela, E. J., Gleason, J. F., Martin, R. V., Philip, S., Irie, H., Cede, A., Herman, J., Weinheimer, A., Szykman, J. J., and Knepp, T. N.: Evaluation of OMI operational standard NO2 column retrievals using in situ and surface-based NO2 observations, Atmos. Chem. Phys., 14, 11587-11609, doi:10.5194/acp-14-11587-2014, 2014.

31) Bryan N. Duncan, Ana I. Prados, Lok N. Lamsal, Yang Liu, David Streets, Pawan Gupta, Ernest Hilsenrath, Ralph Kahn, J. Eric Nielsen, Andreas Beyersdorf, Sharon Burton, Arlene M. Fiore, Jack Fishman, Daven Henze, Chris Hostetler, Nickolay A. Krotkov, Pius Lee, Meiyun Lin, Steven Pawson, Gabriele Pfister, Kenneth E. Pickering, Brad Pierce, Yasuko Yoshida, Luke Ziemba, Satellite Data for U.S. Air Quality Applications: Examples of Applications, Summary of Data End-User Resources, Answers to FAQs, and Common Mistakes to Avoid, Atmos. Environ., 94, 647-662, 2014.

30) Nowlan, C. R., R. V. Martin, S. Philip, L.N. Lamsal, N. A. Krotkov, E. A. Marais, S. Wang, and Q. Zhang, Global Dry Deposition of Nitrogen Dioxide and Sulfur Dioxide Inferred from Space-Based Measurements, Global Biogeochemical Cycles, 28, 10, doi: 10.1002/2014GB004805, 2014.

29) Flynn, C.M., K.E. Pickering, J.H. Crawford, L.N. Lamsal, N.A. Krotkov, J. Herman, A. Weinheimer, G. Chen, X. Liu, J. Szykman, S.-C. Tsay, C. Loughner, J. Hains, P. Lee, R.R. Dickerson, J. Stehr, L. Brent, The relationship between column-density and surface mixing ratio: statistical analysis of O3 and NO2 data from the July 2011 Maryland DISCOVER-AQ mission, Atmos. Environ., 92, 429-441, 2014.

28) David G. Streets, Benjamin de Foy, Bryan N. Duncan, Lok N. Lamsal, Can Li, Zifeng Lu, Using satellite observations to measure power-plant emissions and their trends, Air & Waste Management Association, 16, em, Feb, 2014.

27) McLinden, C.A., V. Fioletov, K.F. Boersma, S. Kharol, N.A. Krotkov, L.N. Lamsal, P.A. Makar, R.V. Martin, J.P. Veefkind, K. Yang, Improved satellite retrievals of NO2 and SO2 over the Canadian oil sands and comparisons with surface measurements, Atmos. Chem. Phys., 14, 3637-3656, 2014.

26) Philip, S., R. V. Martin, J. R. Pierce, J. L. Jimenez, Q. Zhang, M. R. Canagaratna, D. V. Spracklen, C. R. Nowlan, L. N. Lamsal, M. J. Cooper, and N. A. Krotkov, Spatially and seasonally resolved estimate of the ratio of global organic matter to organic carbon, Atmos. Environ., 87, 34-40, 2014.

25) Duncan, B.N., Y. Yoshida, B. de Foy, L.N. Lamsal, D. Streets, Zifeng Lu, K. E. Pickering, and N. A. Krotkov, The observed response of the Ozone Monitoring Instrument (OMI) NO2 column to NOx emission controls on power plants in the United States: 2005-2011, Atmos. Environ., 81, 102-111, 2013.

24) Prud’homme, G., N.A. Dobbin, L. Sun, R.T. Burnett, R.V. Martin, A. Davidson, S. Cakmak, P.J. Villeneuve, L.N. Lamsal, A. van Donkelaar, P.A. Peters, M. Johnson, Comparison of remote sensing and fixed-site monitoring approaches for examining health effects on a national study population, Atmos. Environ., 161-171, 2013.

23) Tang, W., D. Cohan, L.N. Lamsal, X. Xiao, W. Zhou, Inverse modeling of Texas NOx emissions using space-based and ground-based NO2 observations, Atmos. Chem. Phys., 13, 11005-11018, 2013.

22) Lamsal, L.N., R.V. Martin, D.D. Parrish, N.A. Krotkov, Scaling relationship for NO2 pollution and population size: A satellite perspective, Environ. Sci. Technol, 47, 7855-7861, 2013.

21) Streets, D.G., G.R. Carmichael, B. de Foy, R. R. Dickerson, B.N. Duncan, D.P. Edwards, J.A. Haynes, D.K. Henze, M.R. Houyoux, D.J. Jacob, N.A. Krotkov, L.N. Lamsal, Y. Liu, Z. Lu, R.V. Martin, G.G. Pfister, R.W. Pinder, K.J. Wecht, Emissions estimation from satellite retrievals: A review of current capability, Atmos. Environ., 77, 1011-1042, 2013.

20) Oetjen, H., S. Baidar, N.A. Krotkov, L.N. Lamsal, M. Lechner, R. Volkamer, Airborne MAX-DOAS measurements over California: testing the NASA OMI tropospheric NO2 product, J. Geophys. Res., 118, DOI: 10.1002/jgrd.50550, 2013.

19) Bucsela, E. J., Krotkov, N. A., Celarier, E. A., Lamsal, L. N., Swartz, W. H., Bhartia, P. K., Boersma, K. F., Veefkind, J. P., Gleason, J. F., and Pickering, K. E.: A new stratospheric and tropospheric NO2 retrieval algorithm for nadir-viewing satellite instruments: applications to OMI, Atmos. Meas. Tech., 6, 2607-2626, doi:10.5194/amt-6-2607-2013, 2013.

18) Cooper, M.J., R.V. Martin, A. van Donkelaar, L. N. Lamsal, M. Brauer, J. R. Brook, A satellite-based multi-pollutant index of global air quality, Environ. Sci. Technol., pp 8523-8524, doi: 10.1021/es302672p, 2012.

17) Walter, D., K.-P. Heue, A. Rauthe-Schoech, C.A.M. Brenninkmeijer, L.N. Lamsal, N. Krotkov, U. Platt , Flux calculation using CARIBIC DOAS aircraft measurements – SO2 emissions of Norilsk, J. Geophys. Res., doi:10.1029/2011JD017335, 2012.

16) Wang, S.W., Q. Zhang, D.G. Streets, K.B. He, R.V. Martin, L.N. Lamsal, D. Chen, Y. Lei, and Z. Lu, Growth in NOx emissions from power plants in China: bottom-up estimates and satellite observations, Atmos. Chem. Phys., 12, 4429-4447, 2012.

15) Anderson, H.R., B. Butland, A. van Donkelaar, M. Bauer, D.P. Strachan, T. Clayton, R. van Dingenen, M. Amann, B. Brunekreef, A. Cohen, F. Dentener, C. Lai, L.N. Lamsal, R.V. Martin, and the ISAAC Phase One and Phase Three study groups, Satellite-based estimates of ambient air pollution and global variation in childhood asthma prevalence, Environ. Health Perspec., doi:10.1289/ehp.1104724, 2012.

14) Hystad, P. P.A. Semers, K.C. Johnson, J. Brook, A. van Donkelaar, L.N. Lamsal, R. Martin, and M. Brauer, Spatiaotemporal air pollution exposure assessment for a Canadian population-based lung cancer case-control study, Env. Health, 11:22, doi:10.1186/1476-069X-11-22, 2012.

13) Matus, K., K.-M. Nam, N.E. Selin, L.N. Lamsal, J.M. Reilly, and S. Paltsev, Health Damages from Air Pollution in China, Glob. Env. Change, 22(1), 55-66, 2012.

12) Hystad, P., E. Setton, A. Cervantes, K. Poplawski, S. Deschenes, M. Brauer, A. van Donkelaar, L. Lamsal, R.V. Martin, M. Jerrett, and P. Demers, Creating National Air Pollution Models for Population Exposure Assessment in Canada, Environ. Health Perspec., 119:1123-1129., 2011.

11) Lamsal, L.N., R.V. Martin, A. Padmanabhan, A. van Donkelaar, Q. Zhang, C.E. Sioris, K. Chance, T.P. Kurosu, and M.J. Newchurch, Application of satellite observations for timely updates to global anthropogenic NOx emission inventories, Geophys. Res. Lett, 38, L05810, doi:10.1029/2010GL046476, 2011.

10) Duncan, B., Y. Yoshida, J. Olson, S. Sillman, R.V. Martin, L.N. Lamsal, Y. Hu, K. Pickering, C. Retscher, D. Allen, and J. Crawford, Application of OMI observations to a space-based indicator of NOx and VOC controls on surface ozone formation, Atmos. Environ., 44, 2213-2223, 2010.

9) Lamsal, L.N., R.V. Martin, A. van Donkelaar, E.A. Celarier, E.J. Bucsela, K.F. Boersma, R. Dirksen, C. Luo, and Y. Wang, Indirect validation of tropospheric nitrogen dioxide retrieved from the OMI satellite instrument: Insight into the seasonal variation of nitrogen oxides at northern midlatitude, J. Geophys. Res., 115, doi:10.1029/2009JD013351, 2010.

8) Lamsal, L.N., R.V. Martin, M. Steinbacher, E.A. Celarier, E. Bucsela, E.J. Dunlea, and J. Pinto, Ground level nitrogen dioxide concentrations inferred from the satellite-borne Ozone Monitoring Instrument, J. Geophys. Res., 113, doi:10:1029/2007DJ009235, 2008.

7) Lamsal. L.N., M. Weber, G. Labow, and J.P. Burrows, Influence of ozone and temperature climatology on the accuracy of total ozone retrieval, J. Geophys. Res., 112, doi:10.1029/2005JD006865, 2007.

6) Kokhanovsky, A. A., B. Mayer, V.V. Rozanov, K. Wapler, L.N. Lamsal, M. Weber, J.P. Burrows, and U. Schumann, Satellite ozone retrieval under broken cloud conditions: An error analysis based on Monte-Carlo simulations, IEEE Trans. Geo. Rem. Sens., 45, 187-194, 2007.

5) Amekudzi, L.K., B.-M. Sinnhuber, N.V. Sheode, J. Meyer, A. Rozanov, L.N. Lamsal, H. Bovensmann, and J.P. Burrows, Retrieval of stratospheric NO3 vertical profiles from SCIAMACHY lunar accultation measurement over the Antarctic, J. Geophys. Res., 110, doi:10.1029/2004JD005748, 2005.

4) Bracher, A., L.N. Lamsal, M. Weber, K. Bramstedt, M. Coldewey, and J.P. Burrows, Global satellite validation of SCIAMACHY O3 columns with GOME WFDOAS, Atmos. Chem. Phys., Sref-ID: 1680-7324/acp/2005-5-2357, 2005.

3) Coldewey-Egbers, M., M. Weber, L.N. Lamsal, R. de Beek, M. Buchwitz, and J. P. Burrows, Total ozone retrieval from GOME UV spectral data using the weighting function DOAS approach”, M. Coldewey-Egbers, Atmos. Chem. Phys., Sref-ID: 1680-7324/acp/2005-5-1015, 2005.

2) Weber, L.N. Lamsal, M. Coldewey-Egbers, K. Bramstedt, and J.P. Burrows, Pole-to-pole validation of GOME WFDOAS total ozone with groundbased data, Atmos. Chem. Phys., Sref-ID: 1680-7324/acp/2005-5-1341, 2005.

1) Lamsal, L.N., M. Weber, S. Tellmann, and J.P. Burrows, Ozone column classified climatology of ozone and temperature profiles based on ozonesonde and satellite data, J. Geophy. Res., 109, doi:10.1029/2004JD004680, 2004.