MERIS in‐flight spectral calibration

Delwart, Steven; Preusker, R.; Bourg, Ludovic; Santer, R.; Ramon, Didier; Fischer, Jürgen

doi:10.1080/01431160600821119

Cited by 55 publications

(33 citation statements)

References 10 publications

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“…For example, the relation between AVHRR and MODIS radiances has already been examined in depth [9,10]. Furthermore, the radiances from the two European Space Agency Environment Satellite ENVISAT sensors were continuously monitored through comparisons with surface site reflectances and through inter-comparisons with other sensors measuring over the same locations [11][12][13]. Special studies of the involved visible channel radiances have also been carried out within the framework of the Infrared and Visible Optical Sensors Subgroup (IVOS) of the Committee on Earth Observation Satellites (CEOS) Working Group on Calibration and Validation (WGCV, [14]).…”

Section: Purpose and Backgroundmentioning

confidence: 99%

Multi-Sensor Calibration Studies of AVHRR-Heritage Channel Radiances Using the Simultaneous Nadir Observation Approach

Karlsson

Johansson

2014

Remote Sensing

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-18), AATSR, and MERIS channel radiances were evaluated using the simultaneous nadir (SNO) approach. Results show generally agreeing radiances within approximately 3% for channels at 0.6 µm and 0.8 µm . Larger deviations (+5%) were found for the corresponding AATSR channel at 0.6 µm. Excessive deviations but with opposite sign were also indicated for AATSR 1.6 µm and MERIS 0.8 µm radiances. Observed differences may largely be attributed to residual temporal and spatial matching differences while excessive AATSR and MERIS deviations are likely partly attributed to incomplete compensation for spectrally varying surface and atmospheric conditions. However, very good agreement was found for all infrared channels among all the studied sensors. Here, deviations were generally less than 0.2% for the measured brightness temperatures with the exception of some remaining non-linear deviations at extreme low and high temperatures.

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Section: Purpose and Backgroundmentioning

confidence: 99%

Multi-Sensor Calibration Studies of AVHRR-Heritage Channel Radiances Using the Simultaneous Nadir Observation Approach

Karlsson

Johansson

2014

Remote Sensing

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“…11). Since, depending on the instrument construction type, the central wavelengths of spectral channels can vary with time or the view angle (as an example see Delwart et al, 2007), it is important to account for these spectral effects to avoid temporal or view angle dependent biases in derived products. …”

Section: Radiance Approximationmentioning

confidence: 99%

On the efficient treatment of temperature profiles for the estimation of atmospheric transmittance under scattering conditions

Lindstrot

Preusker

2012

Atmos. Meas. Tech.

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Abstract. The vertical temperature profile of the atmosphere has an influence on the width and intensity of gaseous absorption lines. In the visible and near infrared part of the spectrum, this poses a problem for the fast forward simulation of the radiative transfer, needed in algorithms for the retrieval of any atmospheric or surface-related parameter from satellite measurements. We show that the main part of the global variability of temperature profiles can be described by their first 2 to 6 eigenvectors, depending on the accuracy requirement, by performing a Principal Component Analysis (PCA) on a global set of temperature profiles from the Global Forecast System (GFS). Furthermore, we demonstrate the possibility to approximate the atmospheric transmittance in the O 2 A band for any temperature profile with almost perfect accuracy by a linear combination of the transmittances attributed to each of the significant temperature eigenvectors. For the retrieval of surface pressure from O 2 A band measurements, this reduces the global root mean square error from > 30 hPa to better than 1 hPa by strongly reducing the regional bias of surface pressure, retrieved on the assumption of an average temperature profile. The technique can be applied under scattering conditions to eliminate temperatureinduced errors in, e.g., simulated radiances. In principal, the method can be useful for any problem including gaseous absorption or emission with a significant influence of the temperature profile, such as the retrieval of total water vapour content or sea surface temperature.

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“…The latter is needed to account for the variable spectral centre wavelength of the absorption channel (Delwart et al, 2007;Lindstrot et al, 2010), while knowledge of the surface pressure is required to optimize the use of the pressure information carried by the oxygen absorption. The ANNs were trained with radiative transfer simulations of MERIS radiances, performed with the Matrix Operator Model (MOMO; Fell and Fischer, 2001;Hollstein and Fischer, 2012).…”

Section: Meris Cloud Screeningmentioning

confidence: 99%

A global climatology of total columnar water vapour from SSM/I and MERIS

Lindstrot

Stengel

Schröder

et al. 2014

Earth Syst. Sci. Data

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Abstract.A global time series of total columnar water vapour from combined data of the Medium Resolution Imaging Spectrometer (MERIS) onboard ESA's Environmental Satellite (ENVISAT) and the Special Sensor Microwave/Imager (SSM/I) onboard the satellite series of the US Defense Meteorological Satellite Program (DMSP) is presented. The unique data set, generated in the framework of the ESA Data User Element (DUE) GlobVapour project, combines atmospheric water vapour observations over land and ocean, derived from measurements in the near-infrared and the microwave range, respectively. Daily composites and monthly means of total columnar water vapour are available as global maps on rectangular latitude-longitude grids with a spatial resolution of 0.05 • × 0.05 • over land and 0.5 • × 0.5 • over ocean for the years 2003 to 2008. The data are stored in NetCDF files and is fully compliant with the NetCDF Climate Forecast convention. Through the combination of high-quality microwave observations and near-infrared observations over ocean and land surfaces, respectively, the data set provides global coverage. The combination of both products is carried out such that the individual properties of the microwave and near-infrared products, in particular their uncertainties, are not modified by the merging process and are therefore well defined. Due to the global coverage and the provided uncertainty estimates this data set is potentially of high value for climate research. The SSM/I-MERIS TCWV data set is freely available via the GlobVapour project web page (www.globvapour.info) with associated doi:10.5676/DFE/WV_COMB/FP.In this paper, the details of the data set generation, i.e. the satellite data used, the retrieval techniques and merging approaches, are presented. The derived level 3 products are compared to global radiosonde data from the GCOS upper air network (GUAN), showing a high agreement with a root-mean-square deviation of roughly 4.4 kg m −2 and a small wet bias well below 1 kg m −2 . Furthermore, the data set is shown to be free of seasonal biases. The consistency of the MERIS and SSM/I retrievals is demonstrated by applying the MERIS retrieval to sun glint areas over ocean.

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MERIS in‐flight spectral calibration

Cited by 55 publications

References 10 publications

Multi-Sensor Calibration Studies of AVHRR-Heritage Channel Radiances Using the Simultaneous Nadir Observation Approach

Multi-Sensor Calibration Studies of AVHRR-Heritage Channel Radiances Using the Simultaneous Nadir Observation Approach

On the efficient treatment of temperature profiles for the estimation of atmospheric transmittance under scattering conditions

A global climatology of total columnar water vapour from SSM/I and MERIS

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