The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
J. F. Meirink - One of the best experts on this subject based on the ideXlab platform.
-
The impact of SCIAMACHY near-infrared Instrument Calibration on CH4 and CO total columns
Atmospheric Chemistry and Physics, 2005Co-Authors: A. M. S. Gloudemans, H. Schrijver, Q. Kleipool, M. M. P. Van Den Broek, A. G. Straume, G. Lichtenberg, R. M. Van Hees, I. Aben, J. F. MeirinkAbstract:The near-infrared spectra measured with the SCIAMACHY Instrument on board the ENVISAT satellite suffer from several Instrument Calibration problems. The effects of three important Instrument Calibration issues on the retrieved methane (CH4) and carbon monoxide (CO) total columns have been investigated: the effects of the growing ice layer on the near-infrared detectors, the effects of the orbital variation of the Instrument dark signal, and the effects of the dead/bad detector pixels. Corrections for each of these Instrument Calibration issues have been defined. The retrieved CH4 and CO total columns including these corrections show good agreement with CO measurements from the MOPITT satellite Instrument and with CH4 model calculations by the chemistry transport model TM3. Using a systematic approach, it is shown that all three Instrument Calibration issues have a significant effect on the retrieved CH4 and CO total columns. However, the impact on the CH4 total columns is more pronounced than for CO, because of its smaller variability. Results for three different wavelength ranges are compared and show good agreement. The growing ice layer and the orbital variation of the dark signal show a systematic, but time-dependent effect on the retrieved CH4 and CO total columns, whereas the effect of the dead/bad pixels is rather unpredictable: some dead pixels show a random effect, some more systematic, and others no effect at all. The importance of accurate corrections for each of these Instrument Calibration issues is illustrated using examples where inaccurate corrections lead to a wrong interpretation of the results.
-
The impact of SCIAMACHY near-infrared Instrument Calibration on CH 4 and CO total columns
Atmospheric Chemistry and Physics, 2005Co-Authors: A. M. S. Gloudemans, H. Schrijver, Q. Kleipool, M. M. P. Van Den Broek, A. G. Straume, G. Lichtenberg, R. M. Van Hees, I. Aben, J. F. MeirinkAbstract:Abstract. The near-infrared spectra measured with the SCIAMACHY Instrument on board the ENVISAT satellite suffer from several Instrument Calibration problems. The effects of three important Instrument Calibration issues on the retrieved methane (CH4) and carbon monoxide (CO) total columns have been investigated: the effects of the growing ice layer on the near-infrared detectors, the effects of the orbital variation of the Instrument dark signal, and the effects of the dead/bad detector pixels. Corrections for each of these Instrument Calibration issues have been defined. The retrieved CH4 and CO total columns including these corrections show good agreement with CO measurements from the MOPITT satellite Instrument and with CH4 model calculations by the chemistry transport model TM3. Using a systematic approach, it is shown that all three Instrument Calibration issues have a significant effect on the retrieved CH4 and CO total columns. However, the impact on the CH4 total columns is more pronounced than for CO, because of its smaller variability. Results for three different wavelength ranges are compared and show good agreement. The growing ice layer and the orbital variation of the dark signal show a systematic, but time-dependent effect on the retrieved CH4 and CO total columns, whereas the effect of the dead/bad pixels is rather unpredictable: some dead pixels show a random effect, some more systematic, and others no effect at all. The importance of accurate corrections for each of these Instrument Calibration issues is illustrated using examples where inaccurate corrections lead to a wrong interpretation of the results.
-
The impact of SCIAMACHY near-infrared Instrument Calibration on CH4 and CO total columns
Atmospheric Chemistry and Physics Discussions, 2005Co-Authors: A. M. S. Gloudemans, H. Schrijver, Q. Kleipool, M. M. P. Van Den Broek, A. G. Straume, G. Lichtenberg, R. M. Van Hees, I. Aben, J. F. MeirinkAbstract:The effects of three important SCIAMACHY near-infrared Instrument Calibration issues on the retrieved methane (CH4) and carbon monoxide (CO) total columns have been investigated: the effects of the growing ice layer on the near-infrared detectors, the effects of the orbital variation of the Instrument dark signal, and the effects of the dead/bad detector pixels. Corrections for each of these Instrument Calibration issues have been defined. The retrieved CH4 and CO total columns including these corrections show good agreement with CO measurements from the MOPITT satellite Instrument and with CH4 model calculations by the chemistry transport model TM3. Using a systematic approach, it is shown that all three Instrument Calibration issues have a significant effect on the retrieved CH4 and CO total columns, although the impact on the CH4 total columns is more pronounced than for CO. Results for three different wavelength ranges are compared and show good agreement. The growing ice layer and the orbital variation of the dark signal show a systematic, but time-dependent effect on the retrieved CH4 and CO total columns, whereas the dead/bad pixels show a more random effect. The importance of accurate corrections for each of these Instrument Calibration issues is illustrated using examples where inaccurate corrections lead to a wrong interpretation of the results.
-
The impact of SCIAMACHY near-infrared Instrument Calibration on CH<sub>4</sub> and CO total columns
2005Co-Authors: A. M. S. Gloudemans, H. Schrijver, Q. Kleipool, M. M. P. Van Den Broek, A. G. Straume, G. Lichtenberg, R. M. Van Hees, I. Aben, J. F. MeirinkAbstract:Abstract. The effects of three important SCIAMACHY near-infrared Instrument Calibration issues on the retrieved methane (CH4) and carbon monoxide (CO) total columns have been investigated: the effects of the growing ice layer on the near-infrared detectors, the effects of the orbital variation of the Instrument dark signal, and the effects of the dead/bad detector pixels. Corrections for each of these Instrument Calibration issues have been defined. The retrieved CH4 and CO total columns including these corrections show good agreement with CO measurements from the MOPITT satellite Instrument and with CH4 model calculations by the chemistry transport model TM3. Using a systematic approach, it is shown that all three Instrument Calibration issues have a significant effect on the retrieved CH4 and CO total columns, although the impact on the CH4 total columns is more pronounced than for CO. Results for three different wavelength ranges are compared and show good agreement. The growing ice layer and the orbital variation of the dark signal show a systematic, but time-dependent effect on the retrieved CH4 and CO total columns, whereas the dead/bad pixels show a more random effect. The importance of accurate corrections for each of these Instrument Calibration issues is illustrated using examples where inaccurate corrections lead to a wrong interpretation of the results.
Raju V. Datla - One of the best experts on this subject based on the ideXlab platform.
-
System level approach to satellite Instrument Calibration
Proceedings of SPIE, 2006Co-Authors: Joe Tansock, Alan Thurgood, Nikita Pougatchev, Victor Privalsky, E. Knight, Gail E. Bingham, V. N. Krutikov, Randy Jost, Raju V. Datla, Vyacheslav IvanovAbstract:The state-of-the-art electro-optical sensors being designed for today's space-based environmental applications require a complete characterization and thorough Calibration. This is especially true for sensors designed to assess global climate change, which require very small uncertainties. This paper describes a system-level approach that addresses each phase of Calibration, from planning to on-orbit operations. This approach encourages early planning and continuity of effort throughout the lifetime of the project (pre- and post-flight) to promote an optimum Calibration approach that will minimize uncertainty for the intended application. This paper also discusses considerations for component level characterization, ground Calibration and standards, in-flight Calibration sources and trending, and in-flight validation assessment.
-
satellite Instrument Calibration for measuring global climate change report of a workshop
Bulletin of the American Meteorological Society, 2005Co-Authors: George Ohring, Bruce A Wielicki, Bill Emery, Roy W Spencer, Raju V. DatlaAbstract:Measuring the small changes associated with long-term global climate change from space is a daunting task. The satellite Instruments must be capable of observing atmospheric and surface temperature trends as small as 0.1°C decade−1, ozone changes as little as 1% decade−1, and variations in the sun's output as tiny as 0.1% decade−1. To address these problems and recommend directions for improvements in satellite Instrument Calibration, the National Institute of Standards and Technology (NIST), National Polar-orbiting Operational Environmental Satellite System–Integrated Program Office (NPOESS-IPO), National Oceanic and Atmospheric Administration (NOAA), and National Aeronautics and Space Administration (NASA) organized a workshop at the University of Maryland Inn and Conference Center, College Park, Maryland, 12–14 November 2002. Some 75 scientists participated including researchers who develop and analyze long-term datasets from satellites, experts in the field of satellite Instrument Calibration, and phy...
-
satellite Instrument Calibration for measuring global climate change report of a workshop
Bulletin of the American Meteorological Society, 2005Co-Authors: George Ohring, Bruce A Wielicki, Bill Emery, Roy W Spencer, Raju V. DatlaAbstract:Measuring the small changes associated with long-term global climate change from space is a daunting task. The satellite Instruments must be capable of observing atmospheric and surface temperature trends as small as 0.1°C decade−1, ozone changes as little as 1% decade−1, and variations in the sun's output as tiny as 0.1% decade−1. To address these problems and recommend directions for improvements in satellite Instrument Calibration, the National Institute of Standards and Technology (NIST), National Polar-orbiting Operational Environmental Satellite System–Integrated Program Office (NPOESS-IPO), National Oceanic and Atmospheric Administration (NOAA), and National Aeronautics and Space Administration (NASA) organized a workshop at the University of Maryland Inn and Conference Center, College Park, Maryland, 12–14 November 2002. Some 75 scientists participated including researchers who develop and analyze long-term datasets from satellites, experts in the field of satellite Instrument Calibration, and phy...
-
Satellite Instrument Calibration for Measuring Global Climate Change. Report of a Workshop at the University of Maryland Inn and Conference Center, College Park, MD. , November 12-14, 2002
2004Co-Authors: George Ohring, Bruce A Wielicki, Bill Emery, Roy W Spencer, Raju V. DatlaAbstract:Measuring the small changes associated with long-term global climate change from space is a daunting task. To address these problems and recommend directions for improvements in satellite Instrument Calibration some 75 scientists, including researchers who develop and analyze long-term data sets from satellites, experts in the field of satellite Instrument Calibration, and physicists working on state of the art Calibration sources and standards met November 12 - 14, 2002 and discussed the issues. The workshop defined the absolute accuracies and long-term stabilities of global climate data sets that are needed to detect expected trends, translated these data set accuracies and stabilities to required satellite Instrument accuracies and stabilities, and evaluated the ability of current observing systems to meet these requirements. The workshop's recommendations include a set of basic axioms or overarching principles that must guide high quality climate observations in general, and a roadmap for improving satellite Instrument characterization, Calibration, inter-Calibration, and associated activities to meet the challenge of measuring global climate change. It is also recommended that a follow-up workshop be conducted to discuss implementation of the roadmap developed at this workshop.
A. M. S. Gloudemans - One of the best experts on this subject based on the ideXlab platform.
-
The impact of SCIAMACHY near-infrared Instrument Calibration on CH4 and CO total columns
Atmospheric Chemistry and Physics, 2005Co-Authors: A. M. S. Gloudemans, H. Schrijver, Q. Kleipool, M. M. P. Van Den Broek, A. G. Straume, G. Lichtenberg, R. M. Van Hees, I. Aben, J. F. MeirinkAbstract:The near-infrared spectra measured with the SCIAMACHY Instrument on board the ENVISAT satellite suffer from several Instrument Calibration problems. The effects of three important Instrument Calibration issues on the retrieved methane (CH4) and carbon monoxide (CO) total columns have been investigated: the effects of the growing ice layer on the near-infrared detectors, the effects of the orbital variation of the Instrument dark signal, and the effects of the dead/bad detector pixels. Corrections for each of these Instrument Calibration issues have been defined. The retrieved CH4 and CO total columns including these corrections show good agreement with CO measurements from the MOPITT satellite Instrument and with CH4 model calculations by the chemistry transport model TM3. Using a systematic approach, it is shown that all three Instrument Calibration issues have a significant effect on the retrieved CH4 and CO total columns. However, the impact on the CH4 total columns is more pronounced than for CO, because of its smaller variability. Results for three different wavelength ranges are compared and show good agreement. The growing ice layer and the orbital variation of the dark signal show a systematic, but time-dependent effect on the retrieved CH4 and CO total columns, whereas the effect of the dead/bad pixels is rather unpredictable: some dead pixels show a random effect, some more systematic, and others no effect at all. The importance of accurate corrections for each of these Instrument Calibration issues is illustrated using examples where inaccurate corrections lead to a wrong interpretation of the results.
-
The impact of SCIAMACHY near-infrared Instrument Calibration on CH 4 and CO total columns
Atmospheric Chemistry and Physics, 2005Co-Authors: A. M. S. Gloudemans, H. Schrijver, Q. Kleipool, M. M. P. Van Den Broek, A. G. Straume, G. Lichtenberg, R. M. Van Hees, I. Aben, J. F. MeirinkAbstract:Abstract. The near-infrared spectra measured with the SCIAMACHY Instrument on board the ENVISAT satellite suffer from several Instrument Calibration problems. The effects of three important Instrument Calibration issues on the retrieved methane (CH4) and carbon monoxide (CO) total columns have been investigated: the effects of the growing ice layer on the near-infrared detectors, the effects of the orbital variation of the Instrument dark signal, and the effects of the dead/bad detector pixels. Corrections for each of these Instrument Calibration issues have been defined. The retrieved CH4 and CO total columns including these corrections show good agreement with CO measurements from the MOPITT satellite Instrument and with CH4 model calculations by the chemistry transport model TM3. Using a systematic approach, it is shown that all three Instrument Calibration issues have a significant effect on the retrieved CH4 and CO total columns. However, the impact on the CH4 total columns is more pronounced than for CO, because of its smaller variability. Results for three different wavelength ranges are compared and show good agreement. The growing ice layer and the orbital variation of the dark signal show a systematic, but time-dependent effect on the retrieved CH4 and CO total columns, whereas the effect of the dead/bad pixels is rather unpredictable: some dead pixels show a random effect, some more systematic, and others no effect at all. The importance of accurate corrections for each of these Instrument Calibration issues is illustrated using examples where inaccurate corrections lead to a wrong interpretation of the results.
-
The impact of SCIAMACHY near-infrared Instrument Calibration on CH4 and CO total columns
Atmospheric Chemistry and Physics Discussions, 2005Co-Authors: A. M. S. Gloudemans, H. Schrijver, Q. Kleipool, M. M. P. Van Den Broek, A. G. Straume, G. Lichtenberg, R. M. Van Hees, I. Aben, J. F. MeirinkAbstract:The effects of three important SCIAMACHY near-infrared Instrument Calibration issues on the retrieved methane (CH4) and carbon monoxide (CO) total columns have been investigated: the effects of the growing ice layer on the near-infrared detectors, the effects of the orbital variation of the Instrument dark signal, and the effects of the dead/bad detector pixels. Corrections for each of these Instrument Calibration issues have been defined. The retrieved CH4 and CO total columns including these corrections show good agreement with CO measurements from the MOPITT satellite Instrument and with CH4 model calculations by the chemistry transport model TM3. Using a systematic approach, it is shown that all three Instrument Calibration issues have a significant effect on the retrieved CH4 and CO total columns, although the impact on the CH4 total columns is more pronounced than for CO. Results for three different wavelength ranges are compared and show good agreement. The growing ice layer and the orbital variation of the dark signal show a systematic, but time-dependent effect on the retrieved CH4 and CO total columns, whereas the dead/bad pixels show a more random effect. The importance of accurate corrections for each of these Instrument Calibration issues is illustrated using examples where inaccurate corrections lead to a wrong interpretation of the results.
-
The impact of SCIAMACHY near-infrared Instrument Calibration on CH<sub>4</sub> and CO total columns
2005Co-Authors: A. M. S. Gloudemans, H. Schrijver, Q. Kleipool, M. M. P. Van Den Broek, A. G. Straume, G. Lichtenberg, R. M. Van Hees, I. Aben, J. F. MeirinkAbstract:Abstract. The effects of three important SCIAMACHY near-infrared Instrument Calibration issues on the retrieved methane (CH4) and carbon monoxide (CO) total columns have been investigated: the effects of the growing ice layer on the near-infrared detectors, the effects of the orbital variation of the Instrument dark signal, and the effects of the dead/bad detector pixels. Corrections for each of these Instrument Calibration issues have been defined. The retrieved CH4 and CO total columns including these corrections show good agreement with CO measurements from the MOPITT satellite Instrument and with CH4 model calculations by the chemistry transport model TM3. Using a systematic approach, it is shown that all three Instrument Calibration issues have a significant effect on the retrieved CH4 and CO total columns, although the impact on the CH4 total columns is more pronounced than for CO. Results for three different wavelength ranges are compared and show good agreement. The growing ice layer and the orbital variation of the dark signal show a systematic, but time-dependent effect on the retrieved CH4 and CO total columns, whereas the dead/bad pixels show a more random effect. The importance of accurate corrections for each of these Instrument Calibration issues is illustrated using examples where inaccurate corrections lead to a wrong interpretation of the results.
George Ohring - One of the best experts on this subject based on the ideXlab platform.
-
achieving satellite Instrument Calibration for climate change
Eos Transactions American Geophysical Union, 2007Co-Authors: George Ohring, Bruce A Wielicki, Joe Tansock, L E Flynn, Karen St. Germain, Fuzhong Weng, James J. Butler, Mitchell D Goldberg, William J. Emery, Jack XiongAbstract:For the most part, satellite observations of climate are not presently sufficiently accurate to establish a climate record that is indisputable and hence capable of determining whether and at what rate the climate is changing. Furthermore, they are insufficient for establishing a baseline for testing long-term trend predictions of climate models. Satellite observations do provide a clear picture of the relatively large signals associated with interannual climate variations such as El Nino-Southern Oscillation (ENSO), and they have also been used to diagnose gross inadequacies of climate models, such as their cloud generation schemes. However, satellite contributions to measuring long-term change have been limited and, at times, controversial, as in the case of differing atmospheric temperature trends derived from the U.S. National Oceanic and Atmospheric Administration's (NOAA) microwave radiometers.
-
achieving satellite Instrument Calibration for climate change
Eos Transactions American Geophysical Union, 2007Co-Authors: George Ohring, Bruce A Wielicki, Joe Tansock, L E Flynn, Karen St. Germain, Fuzhong Weng, James J. Butler, Mitchell D Goldberg, William J. Emery, Jack XiongAbstract:For the most part, satellite observations of climate are not presently sufficiently accurate to establish a climate record that is indisputable and hence capable of determining whether and at what rate the climate is changing. Furthermore, they are insufficient for establishing a baseline for testing long-term trend predictions of climate models. Satellite observations do provide a clear picture of the relatively large signals associated with interannual climate variations such as El Nino-Southern Oscillation (ENSO), and they have also been used to diagnose gross inadequacies of climate models, such as their cloud generation schemes. However, satellite contributions to measuring long-term change have been limited and, at times, controversial, as in the case of differing atmospheric temperature trends derived from the U.S. National Oceanic and Atmospheric Administration's (NOAA) microwave radiometers.
-
satellite Instrument Calibration for measuring global climate change report of a workshop
Bulletin of the American Meteorological Society, 2005Co-Authors: George Ohring, Bruce A Wielicki, Bill Emery, Roy W Spencer, Raju V. DatlaAbstract:Measuring the small changes associated with long-term global climate change from space is a daunting task. The satellite Instruments must be capable of observing atmospheric and surface temperature trends as small as 0.1°C decade−1, ozone changes as little as 1% decade−1, and variations in the sun's output as tiny as 0.1% decade−1. To address these problems and recommend directions for improvements in satellite Instrument Calibration, the National Institute of Standards and Technology (NIST), National Polar-orbiting Operational Environmental Satellite System–Integrated Program Office (NPOESS-IPO), National Oceanic and Atmospheric Administration (NOAA), and National Aeronautics and Space Administration (NASA) organized a workshop at the University of Maryland Inn and Conference Center, College Park, Maryland, 12–14 November 2002. Some 75 scientists participated including researchers who develop and analyze long-term datasets from satellites, experts in the field of satellite Instrument Calibration, and phy...
-
satellite Instrument Calibration for measuring global climate change report of a workshop
Bulletin of the American Meteorological Society, 2005Co-Authors: George Ohring, Bruce A Wielicki, Bill Emery, Roy W Spencer, Raju V. DatlaAbstract:Measuring the small changes associated with long-term global climate change from space is a daunting task. The satellite Instruments must be capable of observing atmospheric and surface temperature trends as small as 0.1°C decade−1, ozone changes as little as 1% decade−1, and variations in the sun's output as tiny as 0.1% decade−1. To address these problems and recommend directions for improvements in satellite Instrument Calibration, the National Institute of Standards and Technology (NIST), National Polar-orbiting Operational Environmental Satellite System–Integrated Program Office (NPOESS-IPO), National Oceanic and Atmospheric Administration (NOAA), and National Aeronautics and Space Administration (NASA) organized a workshop at the University of Maryland Inn and Conference Center, College Park, Maryland, 12–14 November 2002. Some 75 scientists participated including researchers who develop and analyze long-term datasets from satellites, experts in the field of satellite Instrument Calibration, and phy...
-
Satellite Instrument Calibration for Measuring Global Climate Change. Report of a Workshop at the University of Maryland Inn and Conference Center, College Park, MD. , November 12-14, 2002
2004Co-Authors: George Ohring, Bruce A Wielicki, Bill Emery, Roy W Spencer, Raju V. DatlaAbstract:Measuring the small changes associated with long-term global climate change from space is a daunting task. To address these problems and recommend directions for improvements in satellite Instrument Calibration some 75 scientists, including researchers who develop and analyze long-term data sets from satellites, experts in the field of satellite Instrument Calibration, and physicists working on state of the art Calibration sources and standards met November 12 - 14, 2002 and discussed the issues. The workshop defined the absolute accuracies and long-term stabilities of global climate data sets that are needed to detect expected trends, translated these data set accuracies and stabilities to required satellite Instrument accuracies and stabilities, and evaluated the ability of current observing systems to meet these requirements. The workshop's recommendations include a set of basic axioms or overarching principles that must guide high quality climate observations in general, and a roadmap for improving satellite Instrument characterization, Calibration, inter-Calibration, and associated activities to meet the challenge of measuring global climate change. It is also recommended that a follow-up workshop be conducted to discuss implementation of the roadmap developed at this workshop.
R. M. Van Hees - One of the best experts on this subject based on the ideXlab platform.
-
The impact of SCIAMACHY near-infrared Instrument Calibration on CH4 and CO total columns
Atmospheric Chemistry and Physics, 2005Co-Authors: A. M. S. Gloudemans, H. Schrijver, Q. Kleipool, M. M. P. Van Den Broek, A. G. Straume, G. Lichtenberg, R. M. Van Hees, I. Aben, J. F. MeirinkAbstract:The near-infrared spectra measured with the SCIAMACHY Instrument on board the ENVISAT satellite suffer from several Instrument Calibration problems. The effects of three important Instrument Calibration issues on the retrieved methane (CH4) and carbon monoxide (CO) total columns have been investigated: the effects of the growing ice layer on the near-infrared detectors, the effects of the orbital variation of the Instrument dark signal, and the effects of the dead/bad detector pixels. Corrections for each of these Instrument Calibration issues have been defined. The retrieved CH4 and CO total columns including these corrections show good agreement with CO measurements from the MOPITT satellite Instrument and with CH4 model calculations by the chemistry transport model TM3. Using a systematic approach, it is shown that all three Instrument Calibration issues have a significant effect on the retrieved CH4 and CO total columns. However, the impact on the CH4 total columns is more pronounced than for CO, because of its smaller variability. Results for three different wavelength ranges are compared and show good agreement. The growing ice layer and the orbital variation of the dark signal show a systematic, but time-dependent effect on the retrieved CH4 and CO total columns, whereas the effect of the dead/bad pixels is rather unpredictable: some dead pixels show a random effect, some more systematic, and others no effect at all. The importance of accurate corrections for each of these Instrument Calibration issues is illustrated using examples where inaccurate corrections lead to a wrong interpretation of the results.
-
The impact of SCIAMACHY near-infrared Instrument Calibration on CH 4 and CO total columns
Atmospheric Chemistry and Physics, 2005Co-Authors: A. M. S. Gloudemans, H. Schrijver, Q. Kleipool, M. M. P. Van Den Broek, A. G. Straume, G. Lichtenberg, R. M. Van Hees, I. Aben, J. F. MeirinkAbstract:Abstract. The near-infrared spectra measured with the SCIAMACHY Instrument on board the ENVISAT satellite suffer from several Instrument Calibration problems. The effects of three important Instrument Calibration issues on the retrieved methane (CH4) and carbon monoxide (CO) total columns have been investigated: the effects of the growing ice layer on the near-infrared detectors, the effects of the orbital variation of the Instrument dark signal, and the effects of the dead/bad detector pixels. Corrections for each of these Instrument Calibration issues have been defined. The retrieved CH4 and CO total columns including these corrections show good agreement with CO measurements from the MOPITT satellite Instrument and with CH4 model calculations by the chemistry transport model TM3. Using a systematic approach, it is shown that all three Instrument Calibration issues have a significant effect on the retrieved CH4 and CO total columns. However, the impact on the CH4 total columns is more pronounced than for CO, because of its smaller variability. Results for three different wavelength ranges are compared and show good agreement. The growing ice layer and the orbital variation of the dark signal show a systematic, but time-dependent effect on the retrieved CH4 and CO total columns, whereas the effect of the dead/bad pixels is rather unpredictable: some dead pixels show a random effect, some more systematic, and others no effect at all. The importance of accurate corrections for each of these Instrument Calibration issues is illustrated using examples where inaccurate corrections lead to a wrong interpretation of the results.
-
The impact of SCIAMACHY near-infrared Instrument Calibration on CH4 and CO total columns
Atmospheric Chemistry and Physics Discussions, 2005Co-Authors: A. M. S. Gloudemans, H. Schrijver, Q. Kleipool, M. M. P. Van Den Broek, A. G. Straume, G. Lichtenberg, R. M. Van Hees, I. Aben, J. F. MeirinkAbstract:The effects of three important SCIAMACHY near-infrared Instrument Calibration issues on the retrieved methane (CH4) and carbon monoxide (CO) total columns have been investigated: the effects of the growing ice layer on the near-infrared detectors, the effects of the orbital variation of the Instrument dark signal, and the effects of the dead/bad detector pixels. Corrections for each of these Instrument Calibration issues have been defined. The retrieved CH4 and CO total columns including these corrections show good agreement with CO measurements from the MOPITT satellite Instrument and with CH4 model calculations by the chemistry transport model TM3. Using a systematic approach, it is shown that all three Instrument Calibration issues have a significant effect on the retrieved CH4 and CO total columns, although the impact on the CH4 total columns is more pronounced than for CO. Results for three different wavelength ranges are compared and show good agreement. The growing ice layer and the orbital variation of the dark signal show a systematic, but time-dependent effect on the retrieved CH4 and CO total columns, whereas the dead/bad pixels show a more random effect. The importance of accurate corrections for each of these Instrument Calibration issues is illustrated using examples where inaccurate corrections lead to a wrong interpretation of the results.
-
The impact of SCIAMACHY near-infrared Instrument Calibration on CH<sub>4</sub> and CO total columns
2005Co-Authors: A. M. S. Gloudemans, H. Schrijver, Q. Kleipool, M. M. P. Van Den Broek, A. G. Straume, G. Lichtenberg, R. M. Van Hees, I. Aben, J. F. MeirinkAbstract:Abstract. The effects of three important SCIAMACHY near-infrared Instrument Calibration issues on the retrieved methane (CH4) and carbon monoxide (CO) total columns have been investigated: the effects of the growing ice layer on the near-infrared detectors, the effects of the orbital variation of the Instrument dark signal, and the effects of the dead/bad detector pixels. Corrections for each of these Instrument Calibration issues have been defined. The retrieved CH4 and CO total columns including these corrections show good agreement with CO measurements from the MOPITT satellite Instrument and with CH4 model calculations by the chemistry transport model TM3. Using a systematic approach, it is shown that all three Instrument Calibration issues have a significant effect on the retrieved CH4 and CO total columns, although the impact on the CH4 total columns is more pronounced than for CO. Results for three different wavelength ranges are compared and show good agreement. The growing ice layer and the orbital variation of the dark signal show a systematic, but time-dependent effect on the retrieved CH4 and CO total columns, whereas the dead/bad pixels show a more random effect. The importance of accurate corrections for each of these Instrument Calibration issues is illustrated using examples where inaccurate corrections lead to a wrong interpretation of the results.