Atmospheric Measurement Techniques Discussions www.atmos-meas-tech-discuss.net 1867-8610 2 2 2009 10.5194/amtd-2-981-2009 http://www.atmos-meas-tech-discuss.net/2/981/2009/ http://www.atmos-meas-tech-discuss.net/2/981/2009/amtd-2-981-2009.html http://www.atmos-meas-tech-discuss.net/2/981/2009/amtd-2-981-2009.pdf 981 1026 2009-04-08 The GRAPE aerosol retrieval algorithm G. E. Thomas gthomas@atm.ox.ac.uk C. A. Poulsen A. M. Sayer S. H. Marsh S. M. Dean E. Carboni R. Siddans R. G. Grainger B. N. Lawrence Atmospheric, Oceanic and Planetary Physics, University of Oxford, Oxford, UK Space Science and Technology Department, Rutherford Appleton Laboratory, Chilton, Didcot, UK now at: Department of Medical Physics and Bioengineering, Christchurch Hospital, New Zealand now at: National Institute of Water and Atmospheric Research, Wellington, New Zealand The aerosol component of the Oxford-Rutherford Aerosol and Cloud (ORAC) combined cloud and aerosol retrieval scheme is described and the theoretical performance of the algorithm is analysed. ORAC is an optimal estimation retrieval scheme for deriving cloud and aerosol properties from measurements made by imaging satellite radiometers and, when applied to cloud free radiances, provides estimates of aerosol optical depth at a wavelength of 550 nm, aerosol effective radius and surface reflectance at 550 nm. The aerosol retrieval component of ORAC has several incarnations – this paper addresses the version which operates in conjunction with the cloud retrieval component of ORAC (described by Watts et al., 1998), as applied in producing the Global Retrieval of ATSR Cloud Parameters and Evaluation (GRAPE) data-set. <br><br> The algorithm is described in detail and its performance examined. This includes a discussion of errors resulting from the formulation of the forward model, sensitivity of the retrieval to the measurements and <i>a priori</i> constraints, and errors resulting from assumptions made about the atmospheric/surface state. Aminou,~D., Jacquet,~B., and Pasternak,~F.: Characteristics of the Meteosat Second Generation radiometer/imager SEVIRI, Proc. SPIE, Europto series 3221, 19–31, 1997. Berk,~A., Bernstein,~L S., Anderson,~G P., Acharya,~P K., Robertson,~D C., Chetwynd,~J H., and Adler-Golden,~S M.: MODTRAN cloud and multiple scattering upgrades with application to AVIRIS, Remote Sens. Environ., 65, 367–375, 1998. Grey,~W M F., North,~P R J., Los,~S O., and Mitchell,~R M.: Aerosol optical depth and land surface reflectance from multiangle AATSR measurements: global validation and intersensor comparisons, IEEE T. Geosci. Remote, 44, 2184–2197, 2006. Hess,~M., Koepke,~P., and Schult,~I.: Optical Properties of Aerosols and Clouds: The software package OPAC, B. Am. Meteorol. Soc., 79, 831–844, 1998. von~Hoyningen-Huene,~W., Freitag,~M., and Burrows,~J P.: Retrieval of aerosol optical thickness over land surfaces from top-of-atmosphere radiance, J. Geophys. Res., 108, D94269, doi:10.1029/2001JD002018, 2003. IPCC: Climate Change 2007: The physical science basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Solomon,~S., Qin~D., Manning~M., Chen~Z., Marquis~M., Averyt~K B., Tignor~M., and Miller~H L.] , Cambridge University Press, Cambridge and New York, 2007. Jin,~Y., Schaaf,~C B., Woodcock,~C E., Gao,~F., Li,~X., Strahler,~A H., Lucht,~W., and Liang,~S.: Consistency of MODIS surface BRDF/Albedo retrievals: 1. Algorithm performance, J. Geophys. Res., 108, D54158, doi:10.1029/2002JD002803, 2003. Kokhanovsky,~A A., Breon,~F.-M.,Cacciari,~A., Carboni,~E., Diner,~D., Di~Nicolantonio,~W., Grainger,~R G., Grey,~W M F., Höller,~R., Lee,~K.-H., North,~P R J., Sayer,~A., Thomas,~G., and von~Hoyningen-Huene,~W.: Aerosol remote sensing over land: satellite retrievals using different algorithms and instruments, Atmos. Res., 85, 372–294, 2007. Levenberg,~K.: A method for the solution of certain nonlinear problems in least squares, Quart. Appl. Math., 2, 164–168, 1944. Llewellyn-Jones,~D., Edwards,~M C., Mutlow,~C T., Birks,~A R., Barton,~L J. and Tait,~H.: AATSR:Global-change and surface-temperature measurements from Envisat, ESA Bull., 105, 10–21, 2001. Lohmann, U. and Feichter, J.: Global indirect aerosol effects: a review, Atmos. Chem. Phys., 5, 715–737, 2005. Marquardt,~D W.: An algorithm for least-squares estimation of nonlinear parameters, SIAM J. Appl. Math., 11, 431–441, 1963. Marsh,~S H., Dean,~S M., Grainger,~R G., Quijano,~A L., Thomas,~G E., and Lawrence,~B N.: An optimal estimation aerosol retrieval scheme for ATSR-2, Atmospheric, Oceanic and Planetary Physics Technical Memorandum, University of Oxford, online available at: http://www.atm.ox.ac.uk/main/research/technical/2004.2.pdf, 2004. Martonchik,~J V., Diner,~D J., Kahn,~R A., Ackerman,~T P., Verstaete,~M M., Pinty,~B., and Gordon,~H R.: Techniques for the retrieval of aerosol properties over land and ocean using multiangle imaging, IEEE T. Geosci. Remote, 36, 1212–1227, 1998. Martonchik,~J V., Diner,~D J., Crean,~K A., and Bull,~M A.: Regional aerosol retrieval results from MISR, IEEE T. Geosci. Remote, 40, 1520–1531, 2002. Mishchenko,~M I., Geogdzhayev,~I V., Cairns,~B., Rossow,~W B., and Lacis,~A A.: Aerosol retrievals over the ocean by use of channels 1 and 2 AVHRR data: sensitivity analysis and preliminary results, Appl. Optics, 38, 7325–7341, 1999. Mutlow,~C T., Murray,~M J., Bailey,~P., Birks,~A R., and Smith,~D L.: ATSR-1/2 user guide issue 1, ESA User Guide, 1999. Remer,~L A., Kaufman,~Y J., Tanré,~D., Mattoo,~S., Chu,~D A., Martins,~J V., Li,~R.-R., Ichoku,~C., Levy,~R C., Kleidman,~R G., Eck,~T F., Vermote,~E., and Holben,~B N.: The MODIS aerosol algorithm, products and validation, J. Atmos. Sci., 62, 947–972, 2005. Rodgers, C. D.: Inverse methods for atmospheric sounding: Theory and practice, World Scientific, Singapore, 2000. Sayer,~A.: A sea surface reflectance model suitable for use with AATSR aerosol retrieval, Atmospheric, Oceanic and Planetary Physics Technical Memorandum, University of Oxford, online available at: http://www.atm.ox.ac.uk/main/research/technical/2007.2.pdf, 2007. Smith,~D L., Mutlow,~C T., and Nagaraja~Rao,~C R.: Calibration monitoring of the visible and near-infrared channels of the Along-Track Scanning Radiometer-2 by use of stable terrestrial sites, Appl. Optics, 41, 515–523, 2002. Stamnes,~K., Tsay,~S.-C., Wiscombe~W., and Jayweera,~K.: Numerically stable algorithm for discrete-ordinate-method radiative transfer in multiple scattering and emitting layered media, Appl. Optics, 24, 2502–2509, 1988. Thomas,~G E., Dean,~S M., Carboni,~E., Grainger,~R G., Poulsen,~C A., Siddans,~R., and Kerridge,~B J.: An optimal estimation aerosol retrieval scheme for (A)ATSR, Atmospheric, Oceanic and Planetary Physics Technical Memorandum, University of Oxford, online available at: http://www.atm.ox.ac.uk/main/research/technical/2007.1.pdf, 2007. Thomas,~G E., Poulsen,~C A., Curier,~R L., de~Leeuw,~G., Marsh,~S H., Carboni,~E., Grainger,~R G., and Siddans,~R.: Comparison of AATSR and SEVIRI aerosol retrievals over the Northern Adriatic, Q. J. Roy. Meteor. Soc., 133, 85–95, 2007. Thomas,~G E., Carboni,~E., Sayer,~A M., Poulsen,~C A., Siddans,~R., and Grainger,~R G.: Oxford-RAL Aerosol and Cloud (ORAC): Aerosol retrievals from satellite radiometers, in: Aerosol Remote Sensing Over Land, edited by:~Kokhanovsky, A A. and~de~Leeuw, G., Springer, Berlin, Germany, 2009. Veefkind,~J P. and de~Leeuw,~G.: A new algorithm to determine the spectral aerosol optical depth from satellite radiometer measurements, J. Aerosol Sci., 29, 1237–1248, 1998. Watts,~P D., Mutlow,~C T., Baran,~A J., and Zavody,~A M.: Study on cloud properties derived from Meteosat Second Generation observations, EUMETSAT ITT no. 97/181, 1998.