The Experts below are selected from a list of 183 Experts worldwide ranked by ideXlab platform
William L. Smith - One of the best experts on this subject based on the ideXlab platform.
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Technical Note: Evolution, current capabilities, and future advance in Satellite nadir viewing ultra-spectral IR Sounding of the lower atmosphere
Atmospheric Chemistry and Physics, 2009Co-Authors: William L. Smith, Allen M. Larar, D. K. Zhou, H. Revercomb, G. Bingham, Hung-lung Huang, Xu Liu, Stanislav KireevAbstract:Abstract. Infrared ultra-spectral spectrometers have brought in a new era in Satellite remote atmospheric Sounding capability. During the 1970s, after the implementation of the first Satellite Sounding instruments, it became evident that much higher vertical resolution Sounding information was needed to be able to forecast life and property threatening localized severe weather. The demonstration of the ultra-spectral radiance measurement technology required to achieve higher vertical resolution began in 1985, with the aircraft flights of the High resolution Interferometer Sounder (HIS) instrument. The development of Satellite instruments designed to have a HIS-like measurement capability was initiated in the late 1980's. Today, after more than a decade of development time, the Atmospheric Infrared Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI) are now operating successfully from the Aqua and MetOp polar orbiting Satellites. The successful development and ground demonstration of the Geostationary Imaging Fourier Transform Spectrometer (GIFTS), during this decade, is now paving the way toward the implementation of the ultra-spectral Sounding capability on the international system of geostationary environmental Satellites. This note reviews the evolution of the Satellite ultra-spectral Sounding systems, shows examples of current polar Satellite Sounding capability, and discusses future advances planned for geostationary orbit.
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evolution current capabilities and advances in Satellite ultra spectral ir Sounding
CURRENT PROBLEMS IN ATMOSPHERIC RADIATION (IRS 2008): Proceedings of the International Radiation Symposium (IRC IAMAS), 2009Co-Authors: William L. SmithAbstract:Infrared ultra‐spectral spectrometers have brought on a new era in Satellite remote atmospheric Sounding capability. During the 1970’s, after the implementation of the first Satellite Sounding instruments, it became evident that much higher vertical resolution Sounding information was needed to be able to forecast life and property threatening localized severe weather. The ultra‐spectral resolution Sounding technology demonstration began in 1985, with the airborne High‐resolution Interferometer Sounder (HIS) instrument. Today, after more than a decade of development time, the Atmospheric Infrared Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI) are now operating successfully from the Aqua and MetOp Polar orbiting Satellites. The successful development and ground demonstration of the Geostationary Imaging Fourier Transform Spectrometer (GIFTS), during this decade, is now paving the way toward the implementation of the ultra‐spectral Sounding capability on the international system ...
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EAQUATE: An International Experiment for Hyper-Spectral Atmospheric Sounding Validation
Bulletin of the American Meteorological Society, 2008Co-Authors: Jonathan P. Taylor, William L. Smith, Vincenzo Cuomo, Allen M. Larar, D. K. Zhou, Carmine Serio, Tiziano Maestri, Rolando Rizzi, Stuart M. Newman, Paolo AntonelliAbstract:The international experiment called EAQUATE (European AQUA Thermodynamic Experiment) was held this past September in Italy and the United Kingdom to demonstrate certain ground-based and airborne systems useful for validating hyperspectral Satellite Sounding observations.
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Future hybrid infrared and microwave Satellite Sounding system - A theoretical analysis of its capability
1991Co-Authors: H.-l. Huang, William L. Smith, George R. Diak, Harold M. WoolfAbstract:The expected atmospheric Sounding accuracy and the vertical resolution performance of the Sounding system selected by NASA to fly aboard the Earth Observing System polar platform, the Atmospheric Infrared Sounder combined with the Advanced Microwave Sounding Unit, are evaluated under various weather conditions. The performance of the combined system is compared to that of current polar orbiting systems. The complementary nature of the IR component provides high vertical resolution, and the microwave information permits Sounding through nonprecipitating clouds.
Stephen English - One of the best experts on this subject based on the ideXlab platform.
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The Importance of Accurate Skin Temperature in Assimilating Radiances From Satellite Sounding Instruments
IEEE Transactions on Geoscience and Remote Sensing, 2008Co-Authors: Stephen EnglishAbstract:An error analysis has been performed, which shows that skin temperature errors are important for Sounding channels. An approach for estimating skin temperature and emissivity errors from the dependence of differences between observed and calculated radiances on surface-to-space transmittance is described. Estimates of emissivity and skin temperature error for the operational Met Office data assimilation system are presented as an example, and the implications are discussed, in terms of use of data over different surfaces and in different conditions (e.g., day/night). The results highlight the need for a better emissivity estimate over sea ice than that used at the Met Office and the inaccuracy of the land surface skin temperature that was derived from radiative flux balance at the surface.
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a comparison of the impact of tovs arid atovs Satellite Sounding data on the accuracy of numerical weather forecasts
Quarterly Journal of the Royal Meteorological Society, 2000Co-Authors: Stephen English, Richard Renshaw, P C Dibben, Andrew Smith, Peter Rayer, C Poulsen, F W Saunders, John EyreAbstract:The Advanced TIROS Operational Vertical Sounder (ATOVS) was launched on the NOAA-15 Satellite in May 1998. This provided a very significant improvement in the information available from meteorological polar-orbiting Satellites compared with the previous TIROS Operational Vertical Sounder system, particularly for humidity and vertical resolution of temperature in cloudy areas. In preparation for assimilation of the observations into a three-dimensional analysis of atmospheric temperature and humidity, the observations have been compared with calculated top-of-atmosphere brightness temperatures computed from numerical weather prediction model profiles of temperature and humidity. Differences between observed and modelled brightness temperature are small. In some parts of the tropics and northern hemisphere the standard deviation of these differences for the tropospheric Advanced Microwave Sounding Unit Sounding channels is only marginally higher than the radiometric noise of the observations. Early in 1999 a series of observation-system experiments were completed in which ATOVS observations were assimilated using a one-dimensional variational analysis. No use of the new humidity information could be made because of interference problems experienced by the microwave humidity sounder on ATOVS. Nonetheless, these experiments showed that the assimilation of the new temperature information provided by the radiance observations reduces forecast errors by as much as 20% in the southern hemisphere and 5% in the northern hemisphere. Further improvements have been found by assimilating more data over land. The major impact arises from the microwave channels. Whilst forward-model errors may be slightly lower for the microwave channels than the infrared channels the primary reason is the provision of Sounding information in active weather systems, which are usually cloudy.
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a cloud detection scheme for use with Satellite Sounding radiances in the context of data assimilation for numerical weather prediction
Quarterly Journal of the Royal Meteorological Society, 1999Co-Authors: Stephen English, J. R. Eyre, J A SmithAbstract:A scheme for detecting cloud-affected radiances is described. the method is used to determine the probability of cloud-free conditions given the observations and the prior knowledge we have about the atmosphere from a numerical weather prediction (NWP) model. This is achieved using a likelihood method. It combines the strengths of some alternative methods (e.g. comparison of infra-red and microwave channels Sounding the lower troposphere and comparison of infra-red window channels with sea surface temperature) in a powerful and flexible method. It is powerful because it uses different types of information simultaneously. It is flexible because it makes no assumption about which instrument is being processed, or what type of prior information (NWP, climatology etc.) is used. Therefore, it can readily be extended to new situations and data types (e.g. Advanced TIROS Operational Vertical Sounder (ATOVS)). It is suitable for use on general cloud-detection problems, using combined microwave and infra-red data. It has been tested using TIROS Operational Vertical Sounder (TOVS) radiances. the new method has been compared with an alternative cloud-detection method tailored specifically for TOVS and has been developed to a level of robustness adequate for operational use. the new method gave very similar results to the alternative method, especially over the ocean. the differences that did occur have been investigated by comparing with cloud information derived from the Advanced Very High Resolution Radiometer (AVHRR). Both the alternative method and the new scheme were found to have deficiencies when dealing with very low cloud. Some cloud missed by the existing scheme is identified by the new scheme. Over land, cloud detection is more difficult. the two schemes disagree more often, but validation using AVHRR is also more difficult because of increased surface heterogeneity and more variable emissivity and surface temperature errors. the new method is therefore shown to perform at least as well as an alternative method in operational use, whilst gaining the flexibility required for future systems. the implications for ATOVS are discussed.
Stanislav Kireev - One of the best experts on this subject based on the ideXlab platform.
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Technical Note: Evolution, current capabilities, and future advance in Satellite nadir viewing ultra-spectral IR Sounding of the lower atmosphere
Atmospheric Chemistry and Physics, 2009Co-Authors: William L. Smith, Allen M. Larar, D. K. Zhou, H. Revercomb, G. Bingham, Hung-lung Huang, Xu Liu, Stanislav KireevAbstract:Abstract. Infrared ultra-spectral spectrometers have brought in a new era in Satellite remote atmospheric Sounding capability. During the 1970s, after the implementation of the first Satellite Sounding instruments, it became evident that much higher vertical resolution Sounding information was needed to be able to forecast life and property threatening localized severe weather. The demonstration of the ultra-spectral radiance measurement technology required to achieve higher vertical resolution began in 1985, with the aircraft flights of the High resolution Interferometer Sounder (HIS) instrument. The development of Satellite instruments designed to have a HIS-like measurement capability was initiated in the late 1980's. Today, after more than a decade of development time, the Atmospheric Infrared Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI) are now operating successfully from the Aqua and MetOp polar orbiting Satellites. The successful development and ground demonstration of the Geostationary Imaging Fourier Transform Spectrometer (GIFTS), during this decade, is now paving the way toward the implementation of the ultra-spectral Sounding capability on the international system of geostationary environmental Satellites. This note reviews the evolution of the Satellite ultra-spectral Sounding systems, shows examples of current polar Satellite Sounding capability, and discusses future advances planned for geostationary orbit.
Richard Renshaw - One of the best experts on this subject based on the ideXlab platform.
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a comparison of the impact of tovs arid atovs Satellite Sounding data on the accuracy of numerical weather forecasts
Quarterly Journal of the Royal Meteorological Society, 2000Co-Authors: Stephen English, Richard Renshaw, P C Dibben, Andrew Smith, Peter Rayer, C Poulsen, F W Saunders, John EyreAbstract:The Advanced TIROS Operational Vertical Sounder (ATOVS) was launched on the NOAA-15 Satellite in May 1998. This provided a very significant improvement in the information available from meteorological polar-orbiting Satellites compared with the previous TIROS Operational Vertical Sounder system, particularly for humidity and vertical resolution of temperature in cloudy areas. In preparation for assimilation of the observations into a three-dimensional analysis of atmospheric temperature and humidity, the observations have been compared with calculated top-of-atmosphere brightness temperatures computed from numerical weather prediction model profiles of temperature and humidity. Differences between observed and modelled brightness temperature are small. In some parts of the tropics and northern hemisphere the standard deviation of these differences for the tropospheric Advanced Microwave Sounding Unit Sounding channels is only marginally higher than the radiometric noise of the observations. Early in 1999 a series of observation-system experiments were completed in which ATOVS observations were assimilated using a one-dimensional variational analysis. No use of the new humidity information could be made because of interference problems experienced by the microwave humidity sounder on ATOVS. Nonetheless, these experiments showed that the assimilation of the new temperature information provided by the radiance observations reduces forecast errors by as much as 20% in the southern hemisphere and 5% in the northern hemisphere. Further improvements have been found by assimilating more data over land. The major impact arises from the microwave channels. Whilst forward-model errors may be slightly lower for the microwave channels than the infrared channels the primary reason is the provision of Sounding information in active weather systems, which are usually cloudy.
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Global processing of Satellite Sounding radiances in a numerical weather prediction system
Quarterly Journal of the Royal Meteorological Society, 1995Co-Authors: A. J. Gadd, B.r. Barwell, S. J. Cox, Richard RenshawAbstract:This paper gives an account of the global Soundings system (GLOSS), which is the new method introduced at the Meteorological Office at Bracknell for the processing of global TOVS radiance data for assimilation into numerical weather prediction (NWP) models. The assimilating NWP models themselves provide the prior information necessary to infer temperature and humidity information from radiances. After a brief summary of the historical background, the GLOSS processing is described, noting in particular the differences from similar work elsewhere. Results are then presented from NWP impact studies of the assimilation of temperature profiles derived from Satellite Soundings. An advantage is demonstrated for the GLOSS temperature retrievals relative to the retrievals distributed by NESDIS and produced from the same radiance data. The advantage of GLOSS is clear and consistent in the extratropical regions of the northern hemisphere and, especially, of the southern hemisphere. In the tropics the results are more mixed. The paper concludes with a note of additional work required before operational implementation of GLOSS, and with an outline of other expected future developments.
D. K. Zhou - One of the best experts on this subject based on the ideXlab platform.
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Technical Note: Evolution, current capabilities, and future advance in Satellite nadir viewing ultra-spectral IR Sounding of the lower atmosphere
Atmospheric Chemistry and Physics, 2009Co-Authors: William L. Smith, Allen M. Larar, D. K. Zhou, H. Revercomb, G. Bingham, Hung-lung Huang, Xu Liu, Stanislav KireevAbstract:Abstract. Infrared ultra-spectral spectrometers have brought in a new era in Satellite remote atmospheric Sounding capability. During the 1970s, after the implementation of the first Satellite Sounding instruments, it became evident that much higher vertical resolution Sounding information was needed to be able to forecast life and property threatening localized severe weather. The demonstration of the ultra-spectral radiance measurement technology required to achieve higher vertical resolution began in 1985, with the aircraft flights of the High resolution Interferometer Sounder (HIS) instrument. The development of Satellite instruments designed to have a HIS-like measurement capability was initiated in the late 1980's. Today, after more than a decade of development time, the Atmospheric Infrared Sounder (AIRS) and the Infrared Atmospheric Sounding Interferometer (IASI) are now operating successfully from the Aqua and MetOp polar orbiting Satellites. The successful development and ground demonstration of the Geostationary Imaging Fourier Transform Spectrometer (GIFTS), during this decade, is now paving the way toward the implementation of the ultra-spectral Sounding capability on the international system of geostationary environmental Satellites. This note reviews the evolution of the Satellite ultra-spectral Sounding systems, shows examples of current polar Satellite Sounding capability, and discusses future advances planned for geostationary orbit.
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EAQUATE: An International Experiment for Hyper-Spectral Atmospheric Sounding Validation
Bulletin of the American Meteorological Society, 2008Co-Authors: Jonathan P. Taylor, William L. Smith, Vincenzo Cuomo, Allen M. Larar, D. K. Zhou, Carmine Serio, Tiziano Maestri, Rolando Rizzi, Stuart M. Newman, Paolo AntonelliAbstract:The international experiment called EAQUATE (European AQUA Thermodynamic Experiment) was held this past September in Italy and the United Kingdom to demonstrate certain ground-based and airborne systems useful for validating hyperspectral Satellite Sounding observations.
