IASI temperature and water vapor retrievals – error assessment and validation

Abstract. The METOP-A satellite Infrared Atmospheric Sounding Interferometer (IASI) Level 2 products comprise retrievals of vertical profiles of temperature and water vapor. The error covariance matrices and biases of the most recent version (4.3.1) of the L2 data were assessed, and the assessment was validated using radiosonde data for reference. The radiosonde data set includes dedicated and synoptic time launches at the Lindenberg station in Germany. For optimal validation, the linear statistical Validation Assessment Model (VAM) was used. The VAM uses radiosonde profiles as input and provides optimal estimate of the nominal IASI retrieval by utilizing IASI averaging kernels and statistical characteristics of the ensembles of the reference radiosondes. For temperatures above 900 mb and water retrievals above 700 mb, level expected and assessed errors are in good agreement. Below those levels, noticeable excess in assessed error is observed, possibly due to inaccurate surface parameters and undetected clouds/haze.

[1]  C. Rodgers,et al.  Retrieval of atmospheric temperature and composition from remote measurements of thermal radiation , 1976 .

[2]  Xiangqian Wu,et al.  Recent activities and achievements of the Global Space-based Inter-Calibration System (GSICS) research working group , 2008, Optical Engineering + Applications.

[3]  C. Rodgers.  Characterization and Error Analysis of Profiles Retrieved From Remote Sounding Measurements , 1990 .

[4]  J. R. Eyre,et al.  Variational Assimilation of Remotely-Sensed Observations of the Atmosphere , 1997 .

[5]  David J. Lary,et al.  Using probability distribution functions for satellite validation , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[6]  William L. Smith,et al.  IASI spectral radiance performance validation: case study assessment from the JAIVEx field campaign , 2009 .

[7]  L. Larrabee Strow,et al.  Atmospheric Radiation Measurement site atmospheric state best estimates for Atmospheric Infrared Sounder temperature and water vapor retrieval validation , 2006 .

[8]  William L. Smith,et al.  All weather IASI single field-of-view retrievals: case study – validation with JAIVEx data , 2008 .

[9]  Peter Schlüssel,et al.  Validation of the operational IASI level 2 processor using AIRS and ECMWF data , 2006 .

[10]  William L. Smith,et al.  The NPOESS Airborne Sounding Testbed Interferometer—Remotely Sensed Surface and Atmospheric Conditions during CLAMS , 2005 .

[11]  B. Connor,et al.  Intercomparison of remote sounding instruments , 1999 .

[12]  Nikita Pougatchev,et al.  Validation of atmospheric sounders by correlative measurements. , 2008, Applied optics.

[13]  William L. Smith,et al.  Retrieval of atmospheric profiles and cloud properties from IASI spectra using super-channels , 2009 .

[14]  E. Mahieu,et al.  Ground-based FTIR measurements of CO from the Jungfraujoch: characterisation and comparison with in situ surface and MOPITT data , 2003 .

[15]  EUMETSAT Am Kavalleriesand,et al.  THE OPERATIONAL IASI LEVEL 2 PROCESSOR , 2003 .

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

[17]  Clive D. Rodgers,et al.  Intercomparison of direct and indirect measurements: Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) versus sonde ozone profiles , 2004 .