Dr. Ziauddin Ahmad

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Dr. Ziauddin Ahmad

  • SENIOR SCIENTIST
  • 301.286.1404 | 301.286.0268
  • NASA/GSFC
  • Mail Code: 616.2
  • Greenbelt , MD 20771
  • Employer: Science Application International Corp.
  • Publications

    Refereed

    Jamet, C., A. Ibrahim, Z. Ahmad, et al. F. Angelini, M. Babin, M. J. Behrenfeld, E. Boss, B. Cairns, J. Churnside, J. Chowdhary, A. B. Davis, D. Dionisi, L. Duforêt-Gaurier, B. Franz, R. Frouin, M. Gao, D. Gray, O. Hasekamp, X. He, C. Hostetler, O. V. Kalashnikova, K. Knobelspiesse, L. Lacour, H. Loisel, V. Martins, E. Rehm, L. Remer, I. Sanhaj, K. Stamnes, S. Stamnes, S. Victori, J. Werdell, and P.-W. Zhai. 2019. "Going Beyond Standard Ocean Color Observations: Lidar and Polarimetry." Frontiers in Marine Science, 6: [10.3389/fmars.2019.00251]

    Ibrahim, A., B. A. Franz, Z. Ahmad, and S. W. Bailey. 2019. "Multiband Atmospheric Correction Algorithm for Ocean Color Retrievals." Frontiers in Earth Science, 7: [10.3389/feart.2019.00116]

    Ibrahim, A., B. Franz, Z. Ahmad, et al. R. Healy, K. Knobelspiesse, B.-C. Gao, C. Proctor, and P.-W. Zhai. 2018. "Atmospheric correction for hyperspectral ocean color retrieval with application to the Hyperspectral Imager for the Coastal Ocean (HICO)." Remote Sensing of Environment, 204: 60-75 [10.1016/j.rse.2017.10.041]

    Pahlevan, N., J.-C. Roger, and Z. Ahmad. 2017. "Revisiting short-wave-infrared (SWIR) bands for atmospheric correction in coastal waters." Opt. Express, 25 (6): 6015--6035.

    Kahn, R. A., A. M. Sayer, Z. Ahmad, and B. A. Franz. 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]

    Sayer, A. M., N.-Y. C. Hsu, C. Bettenhausen, et al. Z. Ahmad, B. N. Holben, A. Smirnov, G. E. Thomas, and J. Zhang. 2012. "SeaWiFS Ocean Aerosol Retrieval (SOAR): Algorithm, validation, and comparison with other data sets." J. Geophys. Res., 117 (D3): D03206 [10.1029/2011JD016599]

    Ahmad, Z., B. A. Franz, C. R. Mc Clain, et al. E. J. Kwiatkowska, P. J. Werdell, E. P. Shettle, and B. N. Holben. 2010. "New aerosol models for the retrieval of aerosol optical thickness and normalized water-leaving radiances from the SeaWiFS and MODIS sensors over coastal regions and open oceans." Applied Optics, 49 (29): 5545 [10.1364/AO.49.005545]

    Ahmad, Z., C. R. Mc Clain, J. R. Herman, et al. B. A. Franz, E. Kwiatkowska, W. D. Robinson, E. Buscela, and M. A. Tzortziou. 2007. "Atmospheric correction for NO2 absorption in retrieving water-leaving reflectances from the SeaWiFS and MODIS measurements." Applied Optics, 46 (26): 6504 [10.1364/AO.46.006504]

    Tzortziou, M. A., J. R. Herman, C. Gallegos, et al. P. Neale, A. Subramaniam, L. Harding, and Z. Ahmad. 2006. "Bio-optics of the Chesapeake Bay from measurements and radiative transfer closure." Estuarine, Coastal and Shelf Science, 68 (1-2): 348-362 [10.1016/j.ecss.2006.02.016]

    Vasilkov, A. P., J. R. Herman, Z. Ahmad, M. Kahru, and G. Mitchell. 2005. "Assessment of the ultraviolet radiation field in ocean waters from space-based measurements and full radiative-transfer calculations." Appl Optics, 44 (14): 2863-2869 [10.1364/AO.44.002863]

    Ahmad, Z., P. Bhartia, and N. Krotkov. 2004. "Spectral properties of backscattered UV radiation in cloudy atmospheres." J. Geophys. Res., 109 (D1): D01201 [10.1029/2003JD003395]

    Remer, L., D. Tanre, Y. Kaufman, et al. C. Ichoku, S. Matto, R. Levy, D. Chu, B. N. Holben, O. Dubovik, A. Smirnov, J. Martins, R. Li, and Z. Ahmad. 2002. "Validation of MODIS aerosol retrieval over ocean." Geophys Res Lett, 29 (12): [10.1029/2001GL013204]

    Heath, D., Z. Ahmad, and Z. Wei. 2002. "Applications of ultraviolet absolute radiometry in satellite and surface-based remote sensing of atmospheric ozone." Opt Eng, 41 (12): 3104-3110 [10.1117/1.1516825]

    Qin, W., J. Herman, and Z. Ahmad. 2001. "A fast, accurate algorithm to account for non-Lambertian surface effects on TOA radiance." J. Geophys. Res., 106 (D19): 22,671-22,684 [10.1029/2001JD900215]

    Gao, B., M. Monte, Z. Ahmad, and C. Davis. 2000. "Atmospheric Correction Algorithm for Hyperspectral Remote Sensing of Ocean Color from Space." Applied Optics, 39 (6): 887-896 [10.1364/AO.39.000887]

    Torres, O., P. Bhartia, J. R. Herman, Z. Ahmad, and J. F. Gleason. 1998. "Derivation of aerosol properties from satellite measurements of backscattered ultraviolet radiation. Theoretical basis." J Geophys Res, 103 (D14): 17099-17110 [10.1029/98JD00900]

    Herman, J., P. Bhartia, J. Ziemke, Z. Ahmad, and D. Larko. 1996. "UV-B increases (1979-1992) from decrease in total ozone." Geophys Res Lett, 23: 21107-21120.

    Torres, O., J. R. Herman, P. K. Bhartia, and Z. Ahmad. 1995. "Properties of Mt. Pinatubo Aerosols as derived from Nimbus 7 TOMS measurements." J. Geophys. Res., 100: 14043 14055.

    Ahmad, Z., and P. K. Bhartia. 1995. "Effect of molecular anisotropy on backscattered ultraviolet radiance." Applied Optics, 34 (36): 8309 [10.1364/AO.34.008309]

    Ahmad, Z., M. T. Deland, R. P. Cebula, et al. H. Weiss, C. Wellemeyer, W. Planet, J. Lienesch, H. D. Bowman, A. Miller, and R. Nagatani. 1994. "Accuracy of total ozone retrieval from NOAA SBUV/2 measurements: Impact of instrument performance." J Geophys Res, 99 (D11): 22,975-22,984 [10.1029/94JD01528]

    Toress, O., J. Herman, P. Bhartia, and Z. Ahmad. 1994. "Properties of mount Pinatubo aerosols as derived from Nimbus-TOMS measurements." J Geophys Res, 100: 14043-14055.

    Torres, O., Z. Ahmad, and J. R. Herman. 1992. "Optical Effects of Polar Stratospheric Clouds on the Retrieval of TOMS Total Ozone." J. Geophys. Res., 97: 13015 13024.

    Toress, O., Z. Ahmad, and J. Herman. 1992. "Optical effects of polar stratosphere clouds on the retrieval of toms total ozone." J Geophys Res, 97: 13015-13024.

    Herman, J., R. Hudson, R. D. Mc Peters, et al. R. S. Stolarski, Z. Ahmad, X. Gu, S. Taylor, and C. Wellemeyer. 1991. "A new self-calibration method applied to TOMS and SBUV backscattered ultraviolet data to determine long-term global ozone change." J Geophys Res, 94 (D4): 7531-7545 [10.1029/90JD02662]

    Ahmad, Z., and R. Fraser. 1983. "Satellite measurements of cloud reflectance and optical thickness." Adv Space Res, 2: 29-34.

    McClain, E., W. Pichel, C. Walton, and Z. Ahmad. 1982. "Multi-channel improvements to satellite derived global sea surface temperatures." Adv Space Res, 2 (6): 43-47.

    Ahmad, Z., and R. Fraser. 1982. "An iterative radiative transfer code for ocean-atmospheric systems." J Atmos Sci, 39 (3): 656-665 [10.1175/1520-0469(1982)039<0656:AIRTCF>2.0.CO;2]

    Non-Refereed

    Meister, G., C. R. Mc Clain, Z. Ahmad, et al. S. W. Bailey, R. A. Barnes, S. Brown, G. E. Eplee, B. A. Franz, A. Holmes, W. B. Monosmith, F. S. Patt, R. P. Stumpf, K. R. Turpie, and P. J. Werdell. 2011. "Requirements for an Advanced Ocean Radiometer ." NASA Tech Memo 37:

    Franz, B. A., P. J. Werdell, G. Meister, et al. E. J. Kwiatkowska, S. W. Bailey, Z. Ahmad, and C. R. Mc Clain. 2006. "MODIS Land Bands for Ocean Remote Sensing Applications." Proc. Ocean Optics XVIII

    Ahmad, Z., J. R. Herman, A. P. Vasilkov, et al. M. A. Tzortziou, B. G. Mitchell, and M. Kahru. 2003. "Seasonal variation of UV radiation in the ocean under clear and cloudy conditions." Proc. SPIE 5156, Ultraviolet Ground- and Space-based Measurements, Models, and Effects III 5156: 63-73 [10.1117/12.505298]

    Publications

    Refereed

    Jamet, C., A. Ibrahim, Z. Ahmad, et al. F. Angelini, M. Babin, M. J. Behrenfeld, E. Boss, B. Cairns, J. Churnside, J. Chowdhary, A. B. Davis, D. Dionisi, L. Duforêt-Gaurier, B. Franz, R. Frouin, M. Gao, D. Gray, O. Hasekamp, X. He, C. Hostetler, O. V. Kalashnikova, K. Knobelspiesse, L. Lacour, H. Loisel, V. Martins, E. Rehm, L. Remer, I. Sanhaj, K. Stamnes, S. Stamnes, S. Victori, J. Werdell, and P.-W. Zhai. 2019. "Going Beyond Standard Ocean Color Observations: Lidar and Polarimetry." Frontiers in Marine Science 6 [10.3389/fmars.2019.00251]

    Ibrahim, A., B. A. Franz, Z. Ahmad, and S. W. Bailey. 2019. "Multiband Atmospheric Correction Algorithm for Ocean Color Retrievals." Frontiers in Earth Science 7 [10.3389/feart.2019.00116]

    Ibrahim, A., B. Franz, Z. Ahmad, et al. R. Healy, K. Knobelspiesse, B.-C. Gao, C. Proctor, and P.-W. Zhai. 2018. "Atmospheric correction for hyperspectral ocean color retrieval with application to the Hyperspectral Imager for the Coastal Ocean (HICO)." Remote Sensing of Environment 204 60-75 [10.1016/j.rse.2017.10.041]

    Pahlevan, N., J.-C. Roger, and Z. Ahmad. 2017. "Revisiting short-wave-infrared (SWIR) bands for atmospheric correction in coastal waters." Opt. Express 25 (6): 6015--6035

    Kahn, R. A., A. M. Sayer, Z. Ahmad, and B. A. Franz. 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]

    Sayer, A. M., N.-Y. C. Hsu, C. Bettenhausen, et al. Z. Ahmad, B. N. Holben, A. Smirnov, G. E. Thomas, and J. Zhang. 2012. "SeaWiFS Ocean Aerosol Retrieval (SOAR): Algorithm, validation, and comparison with other data sets." J. Geophys. Res. 117 (D3): D03206 [10.1029/2011JD016599]

    Ahmad, Z., B. A. Franz, C. R. Mc Clain, et al. E. J. Kwiatkowska, P. J. Werdell, E. P. Shettle, and B. N. Holben. 2010. "New aerosol models for the retrieval of aerosol optical thickness and normalized water-leaving radiances from the SeaWiFS and MODIS sensors over coastal regions and open oceans." Applied Optics 49 (29): 5545 [10.1364/AO.49.005545]

    Ahmad, Z., C. R. Mc Clain, J. R. Herman, et al. B. A. Franz, E. Kwiatkowska, W. D. Robinson, E. Buscela, and M. A. Tzortziou. 2007. "Atmospheric correction for NO2 absorption in retrieving water-leaving reflectances from the SeaWiFS and MODIS measurements." Applied Optics 46 (26): 6504 [10.1364/AO.46.006504]

    Tzortziou, M. A., J. R. Herman, C. Gallegos, et al. P. Neale, A. Subramaniam, L. Harding, and Z. Ahmad. 2006. "Bio-optics of the Chesapeake Bay from measurements and radiative transfer closure." Estuarine, Coastal and Shelf Science 68 (1-2): 348-362 [10.1016/j.ecss.2006.02.016]

    Vasilkov, A. P., J. R. Herman, Z. Ahmad, M. Kahru, and G. Mitchell. 2005. "Assessment of the ultraviolet radiation field in ocean waters from space-based measurements and full radiative-transfer calculations." Appl Optics 44 (14): 2863-2869 [10.1364/AO.44.002863]

    Ahmad, Z., P. Bhartia, and N. Krotkov. 2004. "Spectral properties of backscattered UV radiation in cloudy atmospheres." J. Geophys. Res. 109 (D1): D01201 [10.1029/2003JD003395]

    Remer, L., D. Tanre, Y. Kaufman, et al. C. Ichoku, S. Matto, R. Levy, D. Chu, B. N. Holben, O. Dubovik, A. Smirnov, J. Martins, R. Li, and Z. Ahmad. 2002. "Validation of MODIS aerosol retrieval over ocean." Geophys Res Lett 29 (12): [10.1029/2001GL013204]

    Heath, D., Z. Ahmad, and Z. Wei. 2002. "Applications of ultraviolet absolute radiometry in satellite and surface-based remote sensing of atmospheric ozone." Opt Eng 41 (12): 3104-3110 [10.1117/1.1516825]

    Qin, W., J. Herman, and Z. Ahmad. 2001. "A fast, accurate algorithm to account for non-Lambertian surface effects on TOA radiance." J. Geophys. Res. 106 (D19): 22,671-22,684 [10.1029/2001JD900215]

    Gao, B., M. Monte, Z. Ahmad, and C. Davis. 2000. "Atmospheric Correction Algorithm for Hyperspectral Remote Sensing of Ocean Color from Space." Applied Optics 39 (6): 887-896 [10.1364/AO.39.000887]

    Torres, O., P. Bhartia, J. R. Herman, Z. Ahmad, and J. F. Gleason. 1998. "Derivation of aerosol properties from satellite measurements of backscattered ultraviolet radiation. Theoretical basis." J Geophys Res 103 (D14): 17099-17110 [10.1029/98JD00900]

    Herman, J., P. Bhartia, J. Ziemke, Z. Ahmad, and D. Larko. 1996. "UV-B increases (1979-1992) from decrease in total ozone." Geophys Res Lett 23 21107-21120

    Torres, O., J. R. Herman, P. K. Bhartia, and Z. Ahmad. 1995. "Properties of Mt. Pinatubo Aerosols as derived from Nimbus 7 TOMS measurements." J. Geophys. Res. 100 14043 14055

    Ahmad, Z., and P. K. Bhartia. 1995. "Effect of molecular anisotropy on backscattered ultraviolet radiance." Applied Optics 34 (36): 8309 [10.1364/AO.34.008309]

    Ahmad, Z., M. T. Deland, R. P. Cebula, et al. H. Weiss, C. Wellemeyer, W. Planet, J. Lienesch, H. D. Bowman, A. Miller, and R. Nagatani. 1994. "Accuracy of total ozone retrieval from NOAA SBUV/2 measurements: Impact of instrument performance." J Geophys Res 99 (D11): 22,975-22,984 [10.1029/94JD01528]

    Toress, O., J. Herman, P. Bhartia, and Z. Ahmad. 1994. "Properties of mount Pinatubo aerosols as derived from Nimbus-TOMS measurements." J Geophys Res 100 14043-14055

    Torres, O., Z. Ahmad, and J. R. Herman. 1992. "Optical Effects of Polar Stratospheric Clouds on the Retrieval of TOMS Total Ozone." J. Geophys. Res. 97 13015 13024.

    Toress, O., Z. Ahmad, and J. Herman. 1992. "Optical effects of polar stratosphere clouds on the retrieval of toms total ozone." J Geophys Res 97 13015-13024

    Herman, J., R. Hudson, R. D. Mc Peters, et al. R. S. Stolarski, Z. Ahmad, X. Gu, S. Taylor, and C. Wellemeyer. 1991. "A new self-calibration method applied to TOMS and SBUV backscattered ultraviolet data to determine long-term global ozone change." J Geophys Res 94 (D4): 7531-7545 [10.1029/90JD02662]

    Ahmad, Z., and R. Fraser. 1983. "Satellite measurements of cloud reflectance and optical thickness." Adv Space Res 2 29-34

    McClain, E., W. Pichel, C. Walton, and Z. Ahmad. 1982. "Multi-channel improvements to satellite derived global sea surface temperatures." Adv Space Res 2 (6): 43-47

    Ahmad, Z., and R. Fraser. 1982. "An iterative radiative transfer code for ocean-atmospheric systems." J Atmos Sci 39 (3): 656-665 [10.1175/1520-0469(1982)039<0656:AIRTCF>2.0.CO;2]

    Non-Refereed

    Meister, G., C. R. Mc Clain, Z. Ahmad, et al. S. W. Bailey, R. A. Barnes, S. Brown, G. E. Eplee, B. A. Franz, A. Holmes, W. B. Monosmith, F. S. Patt, R. P. Stumpf, K. R. Turpie, and P. J. Werdell. 2011. "Requirements for an Advanced Ocean Radiometer ." NASA Tech Memo 37

    Franz, B. A., P. J. Werdell, G. Meister, et al. E. J. Kwiatkowska, S. W. Bailey, Z. Ahmad, and C. R. Mc Clain. 2006. "MODIS Land Bands for Ocean Remote Sensing Applications." Proc. Ocean Optics XVIII

    Ahmad, Z., J. R. Herman, A. P. Vasilkov, et al. M. A. Tzortziou, B. G. Mitchell, and M. Kahru. 2003. "Seasonal variation of UV radiation in the ocean under clear and cloudy conditions." Proc. SPIE 5156, Ultraviolet Ground- and Space-based Measurements, Models, and Effects III 5156 63-73 [10.1117/12.505298]

                                                                                                                                                                                            
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