Retrieval of desert dust aerosol vertical profiles from IASI measurements in the TIR atmospheric window

Abstract. Desert dust aerosols are the most prominent tropospheric aerosols, playing an important role in the earth's climate. However, their radiative forcing is currently not known with sufficient precision to even determine its sign. The sources of uncertainty are multiple, one of them being a poor characterisation of the dust aerosol's vertical profile on a global scale. In this work, we tackle this scientific issue by designing a method for retrieving dust aerosol vertical profiles from Thermal Infrared measurements by Infrared Atmospheric Sounding Interferometer (IASI) instruments onboard the Metop satellite series. IASI offers almost global coverage twice a day, and long (past and future) time series of radiances, therefore being extremely well suited for climate studies. Our retrieval follows Rodger's formalism and is based on a two-step approach, treating separately the issues of low altitude sensitivity and difficult a priori definition. We compare our results for a selected test case above the Atlantic Ocean and North Africa in June 2009, with optical depth data from MODIS, aerosol absorbing index from GOME-2 and OMI, and vertical profiles of extinction coefficients from CALIOP. We also use literature information on desert dust sources to interpret our results above land. Our retrievals provide perfectly reasonable results in terms of optical depth. The retrieved vertical profiles (with on average 1.5 degrees of freedom) show most of the time sensitivity down to the lowest layer, and agree well with CALIOP extinction profiles for medium to high dust optical depth. We conclude that this new method is extremely promising for improving the scientific knowledge about the 3-D distribution of desert dust aerosols in the atmosphere.

[1]  F. Volz,et al.  Infrared refractive index of atmospheric aerosol substances. , 1972, Applied optics.

[2]  F. Volz,et al.  Infrared optical constants of ammonium sulfate, sahara dust, volcanic pumice, and flyash. , 1973, Applied optics.

[3]  E. Shettle,et al.  Models for the aerosols of the lower atmosphere and the effects of humidity variations on their optical properties , 1979 .

[4]  F. X. Kneizys,et al.  AFGL (Air Force Geophysical Laboratory) atmospheric constituent profiles (0. 120km). Environmental research papers , 1986 .

[5]  Steven T. Massie,et al.  Indices of refraction for the hitran compilation , 1994 .

[6]  P. Koepke,et al.  Optical Properties of Aerosols and Clouds: The Software Package OPAC , 1998 .

[7]  Irina N. Sokolik,et al.  Modeling the radiative characteristics of airborne mineral aerosols at infrared wavelengths , 1998 .

[8]  J. Seinfeld,et al.  Radiative forcing by mineral dust aerosols : sensitivity to key variables , 1998 .

[9]  Michael I. Mishchenko,et al.  Bidirectional Reflectance of Flat, Optically Thick Particulate Layers: An Efficient Radiative Transfer Solution and Applications to Snow and Soil Surfaces , 1999 .

[10]  O. Boucher,et al.  Uncertainties in assessing radiative forcing by mineral dust , 1998 .

[11]  Clive D Rodgers,et al.  Inverse Methods for Atmospheric Sounding: Theory and Practice , 2000 .

[12]  Irina N. Sokolik,et al.  Radiative heating rates and direct radiative forcing by mineral dust in cloudy atmospheric conditions , 2000 .

[13]  B. Holben,et al.  Validation of MODIS aerosol retrieval over ocean , 2002 .

[14]  Irina N. Sokolik,et al.  The spectral radiative signature of wind‐blown mineral dust: Implications for remote sensing in the thermal IR region , 2002 .

[15]  Steven T. Massie,et al.  The Infrared Absorption Cross-Section and Refractive-Index Data in HITRAN , 2003 .

[16]  Sundar A. Christopher,et al.  Longwave radiative forcing of Saharan dust aerosols estimated from MODIS, MISR, and CERES observations on Terra , 2003 .

[17]  Alain Chedin,et al.  Dust altitude and infrared optical depth from AIRS , 2004 .

[18]  Axel Lauer,et al.  © Author(s) 2006. This work is licensed under a Creative Commons License. Atmospheric Chemistry and Physics Analysis and quantification of the diversities of aerosol life cycles , 2022 .

[19]  Alain Chedin,et al.  Retrieving the effective radius of Saharan dust coarse mode from AIRS , 2005 .

[20]  Piet Stammes,et al.  Absorbing Aerosol Index: Sensitivity analysis, application to GOME and comparison with TOMS , 2005 .

[21]  J. A. Smith,et al.  Temperature and salinity dependence of sea surface emissivity in the thermal infrared , 2005 .

[22]  Peng Zhang,et al.  Identification and physical retrieval of dust storm using three MODIS thermal IR channels , 2006 .

[23]  R. Betts,et al.  Changes in Atmospheric Constituents and in Radiative Forcing. Chapter 2 , 2007 .

[24]  Lieven Clarisse,et al.  Monitoring of atmospheric composition using the thermal infrared IASI/METOP sounder , 2009 .

[25]  R. Spurr.  LIDORT and VLIDORT: Linearized pseudo-spherical scalar and vector discrete ordinate radiative transfer models for use in remote sensing retrieval problems , 2008 .

[26]  A. Vandaele,et al.  Composition of the Venus mesosphere measured by Solar Occultation at Infrared on board Venus Express , 2008 .

[27]  Sundar A. Christopher,et al.  Vertical and spatial distribution of dust from aircraft and satellite measurements during the GERBILS field campaign , 2009 .

[28]  S. Dewitte,et al.  Dust aerosol optical depth retrieval over a desert surface using the SEVIRI window channels. , 2009 .

[29]  Didier Tanré,et al.  Saharan dust infrared optical depth and altitude retrieved from AIRS: a focus over North Atlantic – comparison to MODIS and CALIPSO , 2009 .

[30]  D. Winker,et al.  Overview of the CALIPSO Mission and CALIOP Data Processing Algorithms , 2009 .

[31]  M. Petters,et al.  Laboratory investigations of the impact of mineral dust aerosol on cold cloud formation , 2010 .

[32]  Didier Tanré,et al.  Infrared retrievals of dust using AIRS: Comparisons of optical depths and heights derived for a North African dust storm to other collocated EOS A‐Train and surface observations , 2010 .

[33]  T. Holzer-Popp,et al.  Thermal infrared remote sensing of mineral dust over land and ocean: a spectral SVD based retrieval approach for IASI , 2011 .

[34]  Seoung-Soo Lee,et al.  Atmospheric science: Aerosols, clouds and climate , 2011 .

[35]  Xu Liu,et al.  Global Land Surface Emissivity Retrieved From Satellite Ultraspectral IR Measurements , 2011, IEEE Transactions on Geoscience and Remote Sensing.

[36]  U. Blahak,et al.  Saharan Dust Event Impacts on Cloud Formation and Radiation over Western Europe , 2011 .

[37]  Zhanqing Li,et al.  Long-term impacts of aerosols on the vertical development of clouds and precipitation , 2011 .

[38]  A. Wiedensohler,et al.  Ground-based off-line aerosol measurements at Praia, Cape Verde, during the Saharan Mineral Dust Experiment: microphysical properties and mineralogy , 2011 .

[39]  Albert Ansmann,et al.  Saharan Mineral Dust Experiments SAMUM–1 and SAMUM–2: what have we learned? , 2011 .

[40]  V. M. Devi,et al.  The 2009 edition of the GEISA spectroscopic database , 2011 .

[41]  Jens Redemann,et al.  The comparison of MODIS-Aqua (C5) and CALIOP (V2 & V3) aerosol optical depth , 2011 .

[42]  David M. Winker,et al.  The global 3-D distribution of tropospheric aerosols as characterized by CALIOP , 2012 .

[43]  T. Holzer-Popp,et al.  Desert dust observation from space – Application of measured mineral component infrared extinction spectra , 2012 .

[44]  Robert J. D. Spurr,et al.  Linearized T-matrix and Mie scattering computations , 2012 .

[45]  Peter Schlüssel,et al.  IASI on Metop-A: Operational Level 2 retrievals after five years in orbit , 2012 .

[46]  A. Chédin,et al.  Characterisation of dust aerosols in the infrared from IASI and comparison with PARASOL, MODIS, MISR, CALIOP, and AERONET observations , 2012 .

[47]  D. Diner,et al.  Intercomparison of desert dust optical depth from satellite measurements , 2012 .

[48]  Maria Rita Perrone,et al.  Dust layer effects on the atmospheric radiative budget and heating rate profiles , 2012 .

[49]  Christopher D. Barnet,et al.  On the effect of dust aerosols on AIRS and IASI operational level 2 products , 2012 .

[50]  Jacques Pelon,et al.  The seasonal vertical distribution of the Saharan Air Layer and its modulation by the wind , 2013 .

[51]  C. Flamant,et al.  The importance of the diurnal cycle of Aerosol Optical Depth in West Africa , 2013 .

[52]  K. Liou,et al.  Improved estimate of global dust radiative forcing using a coupled chemical transport-radiative transfer model , 2013 .