scholarly journals The Radiometric Sensitivity Requirements for Satellite Microwave Temperature Sounding Instruments for Numerical Weather Prediction

2010 ◽  
Vol 27 (3) ◽  
pp. 443-456 ◽  
Author(s):  
William Bell ◽  
Sabatino Di Michele ◽  
Peter Bauer ◽  
Tony McNally ◽  
Stephen J. English ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Weather Prediction ◽  
Forecast Accuracy ◽  
Forecast Errors ◽  
Atmospheric Infrared Sounder ◽  
Microwave Sounding Unit ◽  
Atmospheric Sounding ◽  
Microwave Sounding ◽  
Satellite Microwave ◽  
The Impact

Abstract The sensitivity of NWP forecast accuracy with respect to the radiometric performance of microwave sounders is assessed through a series of observing system experiments at the Met Office and ECMWF. The observing system experiments compare the impact of normal data from a single Advanced Microwave Sounding Unit (AMSU) with that from an AMSU where synthetic noise has been added. The results show a measurable reduction in forecast improvement in the Southern Hemisphere, with improvements reduced by 11% for relatively small increases in radiometric noise [noise-equivalent brightness temperature (NEΔT) increased from 0.1 to 0.2 K for remapped data]. The impact of microwave sounding data is shown to be significantly less than was the case prior to the use of advanced infrared sounder data [Atmospheric Infrared Sounder (AIRS) and Infrared Atmospheric Sounding Interferometer (IASI)], with microwave sounding data now reducing Southern Hemisphere forecast errors by approximately 10% compared to 40% in the pre-AIRS/IASI period.

scholarly journals The Impact of MetOp and Other Satellite Data within the Met Office Global NWP System Using an Adjoint-Based Sensitivity Method

2013 ◽  
Vol 141 (10) ◽  
pp. 3331-3342 ◽  
Author(s):  
Sangwon Joo ◽  
John Eyre ◽  
Richard Marriott
Keyword(s):  
Satellite Data ◽  
Forecast Error ◽  
Weather Prediction ◽  
Satellite System ◽  
Error Reduction ◽  
Forecast Errors ◽  
Data Types ◽  
Satellite Platform ◽  
Atmospheric Sounding ◽  
The Impact

Abstract The role of observations in reducing 24-h forecast errors is evaluated using the adjoint-based forecast sensitivity to observations (FSO) method developed within the Met Office global numerical weather prediction (NWP) system. The impacts of various subsets of observations are compared, with emphasis on space-based observations, particularly those from instruments on board the European Organisation for the Exploitation of Meteorological Satellites Meteorological Operational-A (MetOp-A) platform. Satellite data are found to account for 64% of the short-range global forecast error reduction, with the remaining 36% coming from the assimilation of surface-based observation types. MetOp-A data are measured as having the largest impact of any individual satellite platform (about 25% of the total impact on global forecast error reduction). Their large impact, compared to that of NOAA satellites, is mainly due to MetOp's additional sensors [Infrared Atmospheric Sounding Interferometer (IASI), Global Navigation Satellite System (GNSS) Receiver for Atmospheric Sounding (GRAS), and the Advanced Scatterometer (ASCAT)]. Microwave and hyperspectral infrared sounding techniques are found to give the largest total impacts. However, the GPS radio occultation technique is measured as having the largest mean impact per profile of observations among satellite types. This study demonstrates how the FSO technique can be used to assess the impact of individual satellite data types in NWP. The calculated impacts can be used to guide improvements in the use of currently available data and to contribute to discussions on the evolution of future observing systems.

scholarly journals Reducing Uncertainties of SNO-Estimated Intersatellite AMSU-A Brightness Temperature Biases for Surface-Sensitive Channels

2008 ◽  
Vol 25 (6) ◽  
pp. 1048-1054 ◽  
Author(s):  
Robert A. Iacovazzi ◽  
Changyong Cao
Keyword(s):  
Brightness Temperature ◽  
Nearest Neighbor ◽  
Weather Prediction ◽  
Microwave Radiometer ◽  
Surface Radiation ◽  
Bias Estimation ◽  
Microwave Sounding Unit ◽  
Collocation Technique ◽  
Microwave Sounding ◽  
Microwave Radiometers

Abstract In this study, a technique has been developed to improve collocation of two passive-microwave satellite instrument datasets at a simultaneous nadir overpass (SNO). The technique has been designed for the purpose of reducing uncertainties related to SNO-inferred intersatellite brightness temperature (Tb) biases, and it involves replacing the current “nearest-neighbor pixel matching” collocation technique with quality-controlled bilinear interpolation. Since the largest Tb bias estimation uncertainties of the SNO method are associated with highly variable earth scenes and window channels of microwave radiometers that have relatively large (∼50 km) separation between measurements, the authors have used Advanced Microwave Sounding Unit A (AMSU-A) data to develop the technique. It is found that using the new data collocation technique reduces SNO ensemble mean Tb bias confidence intervals in the SNO method, as applied to surface-sensitive channels of AMSU-A, by nearly 70% on average. This improvement in the SNO method enhances its ability to quantify intersatellite Tb biases at microwave radiometer channels that are sensitive to surface radiation, which is necessary to advance the sciences of numerical weather prediction and climate change detection.

Characterizing the FY-3A Microwave Temperature Sounder Using the ECMWF Model

2011 ◽  
Vol 28 (11) ◽  
pp. 1373-1389 ◽  
Author(s):  
Qifeng Lu ◽  
William Bell ◽  
Peter Bauer ◽  
Niels Bormann ◽  
Carole Peubey
Keyword(s):  
Weather Prediction ◽  
Quadratic Function ◽  
Climate Science ◽  
Brightness Temperatures ◽  
Microwave Sounding Unit ◽  
Satellite Sensors ◽  
Microwave Sounding ◽  
Data Source ◽  
Nwp Model ◽  
Ecmwf Model

Abstract China’s Feng-Yun-3A (FY-3A), launched in May 2008, is the first in a series of seven polar-orbiting meteorological satellites planned for the next decade by China. The FY-3 series is set to become an important data source for numerical weather prediction (NWP), reanalysis, and climate science. FY-3A is equipped with a microwave temperature sounding instrument (MWTS). This study reports an assessment of the MWTS instrument using the ECMWF NWP model, radiative transfer modeling, and comparisons with equivalent observations from the Advanced Microwave Sounding Unit-A (AMSU-A). The study suggests the MWTS instrument is affected by biases related to large shifts, or errors, in the frequency of the channel passbands as well as radiometer nonlinearity. The passband shifts, relative to prelaunch measurements, are 55, 39, and 33 MHz for channels 2–4, respectively. Relative to the design specification the shifts are 60, 80, and 83 MHz, with uncertainties of ±2.5 MHz. The radiometer nonlinearity results in a positive bias in measured brightness temperatures and is manifested as a quadratic function of measured scene temperatures. By correcting for both of these effects the quality of the MWTS data is improved significantly, with the standard deviations of the (observed minus simulated) differences based on short-range forecast fields reduced by 30%–50% relative to simulations using prelaunch measurements of the passband, to values close to those observed for AMSU-A-equivalent channels. The new methodology could be applied to other microwave temperature sounding instruments and illustrates the value of NWP fields for the on-orbit characterization of satellite sensors.

scholarly journals Using MetOp-A AVHRR Clear-Sky Measurements to Cloud-Clear MetOp-A IASI Column Radiances

2011 ◽  
Vol 28 (9) ◽  
pp. 1104-1116 ◽  
Author(s):  
Eric S. Maddy ◽  
Thomas S. King ◽  
Haibing Sun ◽  
Walter W. Wolf ◽  
Christopher D. Barnet ◽  
...  
Keyword(s):  
High Spatial Resolution ◽  
Zero Bias ◽  
Clear Sky ◽  
Microwave Sounding Unit ◽  
Atmospheric Sounding ◽  
Microwave Sounding ◽  
Ecmwf Model ◽  
Skin Temperatures ◽  
Very High ◽  
Better Than

Abstract High spatial resolution measurements from the Advanced Very High Resolution Radiometer (AVHRR) on the Meteorological Operation (MetOp)-A satellite that are collocated to the footprints from the Infrared Atmospheric Sounding Interferometer (IASI) on the satellite are exploited to improve and quality control cloud-cleared radiances obtained from the IASI. For a partial set of mostly ocean MetOp-A orbits collected on 3 October 2010 for latitudes between 70°S and 75°N, these cloud-cleared radiances and clear-sky subpixel AVHRR measurements within the IASI footprint agree to better than 0.25-K root-mean-squared difference for AVHRR window channels with almost zero bias. For the same dataset, surface skin temperatures retrieved using the combined AVHRR, IASI, and Advanced Microwave Sounding Unit (AMSU) cloud-clearing algorithm match well with ECMWF model surface skin temperatures over ocean, yielding total uncertainties ≤1.2 K for scenes with up to 97% cloudiness.

scholarly journals A simulated observation database to assess the impact of the IASI-NG hyperspectral infrared sounder

2018 ◽  
Vol 11 (2) ◽  
pp. 803-818 ◽  
Author(s):  
Javier Andrey-Andrés ◽  
Nadia Fourrié ◽  
Vincent Guidard ◽  
Raymond Armante ◽  
Pascal Brunel ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Weather Prediction ◽  
Simulated Data ◽  
The Public ◽  
Impact Studies ◽  
New Instrument ◽  
Atmospheric Sounding ◽  
Common Framework ◽  
New Generation ◽  
The Impact

Abstract. The highly accurate measurements of the hyperspectral Infrared Atmospheric Sounding Interferometer (IASI) are used in numerical weather prediction (NWP), atmospheric chemistry and climate monitoring. As the second generation of the European Polar System (EPS-SG) is being developed, a new generation of IASI instruments has been designed to fly on board the MetOp-SG constellation: IASI New Generation (IASI-NG). In order to prepare the arrival of this new instrument, and to evaluate its impact on NWP and atmospheric chemistry applications, a set of IASI and IASI-NG simulated data was built and made available to the public to set a common framework for future impact studies. This paper describes the information available in this database and the procedure followed to run the IASI and IASI-NG simulations. These simulated data were evaluated by comparing IASI-NG to IASI observations. The result is also presented here. Additionally, preliminary impact studies of the benefit of IASI-NG compared to IASI on the retrieval of temperature and humidity in a NWP framework are also shown in the present work. With a channel dataset located in the same wave numbers for both instruments, we showed an improvement of the temperature retrievals throughout the atmosphere, with a maximum in the troposphere with IASI-NG and a lower benefit for the tropospheric humidity.

scholarly journals Contribuição de diversos sistemas de observação na previsão de tempo no CPTEC/INPE

2008 ◽  
Vol 23 (2) ◽  
pp. 219-238 ◽  
Author(s):  
Rita V. Andreoli ◽  
Sérgio Henrique S. Ferreira ◽  
Luiz F. Sapucci ◽  
Rodrigo Augusto F. de Souza ◽  
Renata Weissmann B. Mendonça ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Physical Space ◽  
Total Precipitation ◽  
Atmospheric Infrared Sounder ◽  
Statistical Analysis System ◽  
Microwave Sounding Unit ◽  
Precipitation Water ◽  
Microwave Sounding ◽  
Advanced Microwave Sounding Unit ◽  
Analysis System

Experimentos utilizando sistemas de observação global, foram realizados excluindo um ou mais tipos de observação do esquema global de assimilação de dados/previsão de tempo do Centro de Previsão de Tempo e Estudos Climáticos do Instituto Nacional de Pesquisas Espaciais - CPTEC/INPE (Global Physical-space Statistical Analysis System - GPSAS). Estes experimentos indicam como efetivamente as observações são usadas no GPSAS. Os sistemas de observação testados foram o conjunto de dados convencionais, que incluem informações de superfície (estações em superfície, bóias, navios e plataformas oceânicas) e de ar superior (radiossondagem, aeronaves e balões piloto), os sistemas de sondagem Advanced TIROS-N/NOAA Operational Vertical Sounder (ATOVS) e AQUA, composto pelos sensores Atmospheric Infrared Sounder e Advanced Microwave Sounding Unit (AIRS/AMSU), dados de vento de satélite, estimados a partir do deslocamento de nuvens (Cloud Track Wind), dados de vento em superfície sobre o oceano (QuikScat) e água precipitável (Total Precipitation water - TPW). Todos os sistemas testados mostram um impacto positivo na qualidade da previsão. Os dados convencionais têm um maior impacto na região do Hemisfério Norte devido à maior disponibilidade dessas informações sobre esta região. Por outro lado, as sondagens AIRS/AMSU são fundamentais para uma boa previsão sobre o Hemisfério Sul. Sobre a América do Sul, os perfis inferidos pelo sistema de sondagem AQUA contribuem com a mesma ordem de grandeza dos dados convencionais e apresentam um impacto positivo para todos os períodos de previsões analisados. Dados de vento e água precipitável estimados por satélites têm maior impacto nas regiões tropical e da América do Sul, nas primeiras horas de previsão (1-3 dias). Todavia, a utilização de um conjunto completo de observações é crucial para se obter, operacionalmente, uma boa condição inicial do estado atmosférico para ser utilizada nos modelos de previsão numérica de tempo do CPTEC/INPE.

scholarly journals A simulated observation database to assess the impact of IASI-NG hyperspectral infrared sounder

2017 ◽  
Author(s):  
Javier Andrey-Andrés ◽  
Nadia Fourrié ◽  
Vincent Guidard ◽  
Raymond Armante ◽  
Pascal Brunel ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Weather Prediction ◽  
Simulated Data ◽  
The Public ◽  
Impact Studies ◽  
New Instrument ◽  
Atmospheric Sounding ◽  
Common Framework ◽  
New Generation ◽  
The Impact

Abstract. The highly accurate measurements of the hyperspectral Infrared Atmospheric Sounding Interferometer (IASI) are used in Numerical Weather Prediction (NWP), atmospheric chemistry and climate monitoring. As the second generation of the European Polar System (EPS-SG) is being developed, a new generation of IASI instruments has been designed to fly on board the MetOp-SG constellation: IASI New Generation (IASI-NG). In order to prepare the arrival of this new instrument, and to evaluate its impact on NWP and atmospheric chemistry applications, a set of IASI and IASI-NG simulated data was built and made available to the public to set a common framework for future impact studies. This paper describes the information available in this database and the procedure followed to run the IASI and IASI-NG simulations. These simulated data were evaluated by comparing IASI-NG to IASI observations. The result is also presented here. Additionally, preliminary impact studies of the benefit of IASI-NG compared to IASI on the retrieval of temperature and humidity in a NWP framework are also shown in the present work. With a channel dataset located in the same wave numbers for both instruments, we showed an improvement of the temperature retrievals along all the atmosphere with a maximum in the troposphere with IASI-NG and a lower benefit for the tropospheric humidity.

scholarly journals Combining FY-3D MWTS-2 with AMSU-A Data for Inter-Decadal Diurnal Correction and Climate Trends of Atmospheric Temperature

2021 ◽  
Vol 13 (16) ◽  
pp. 3148
Author(s):  
Xinlu Xia ◽  
Xiaolei Zou
Keyword(s):  
Warming Trend ◽  
Atmospheric Temperature ◽  
Double Difference ◽  
Target Area ◽  
Climate Trends ◽  
Microwave Sounding Unit ◽  
Microwave Sounding ◽  
Cooling Trend ◽  
The Impact ◽  
Diurnal Correction

Microwave temperature sounding observations from polar-orbiting meteorological satellites have been widely used for research on climate trends of atmospheric temperature at different heights around the world. Taking the Amazon rainforest as the target area, this study combined the Microwave Temperature Sounder-2 (MWTS-2) data onboard the Chinese FengYun-3D (FY-3D) satellite with the Advanced Microwave Sounding unit-A (AMSU-A) data onboard the National Oceanic and Atmospheric Administration (NOAA) and the European Meteorological Operational (MetOp) polar-orbiting meteorological satellites (i.e., NOAA-15, −18, −19, MetOp-A, -B). The double difference method was used to estimate and thus eliminate the inter-sensor bias, and a decadal diurnal correction was used to reduce the impact of different local equator crossing times on climate trends. The “no-rain” conditions were determined for AMSU-A data by channels 1 and 15, and for MWTS-2 data by channels 1 and 7. Finally, the decadal linear trends of atmospheric temperature from 1998 to 2020 were obtained after applying the inter-sensor bias calibration and inter-decadal diurnal correction to AMSU-A and MWTS-2 data from NOAA-15, −18, −19; MetOp-A, -B; and FY-3D. A warming trend was found in the AMSU-A window and tropospheric channels (1–9 and 15) and a cooling trend in stratospheric channels (10–14). The warming (cooling) trends of channels 7–9 (10) were relatively small. The warming (cooling) trends of AMSU-A channels 1–6 (14–15) were significantly reduced after the inter-decadal diurnal correction.

scholarly journals The Impact of Big Data on Firm Performance: An Empirical Investigation

2019 ◽  
Vol 109 ◽  
pp. 33-37 ◽  
Author(s):  
Patrick Bajari ◽  
Victor Chernozhukov ◽  
Ali Hortaçsu ◽  
Junichi Suzuki
Keyword(s):  
Big Data ◽  
Firm Performance ◽  
Empirical Investigation ◽  
Forecast Accuracy ◽  
Forecast Errors ◽  
Retail Sales ◽  
Sales Data ◽  
Empirical Results ◽  
Time Periods ◽  
The Impact

We examine the impact of “big data” on firm performance in the context of forecast accuracy using proprietary retail sales data obtained from Amazon. We measure the accuracy of forecasts in two relevant dimensions: the number of products (N), and the number of time periods for which a product is available for sale (T). Theory suggests diminishing returns to larger N and T, with relative forecast errors diminishing at rate 1/sqrt(N)+1/sqrt(T). Empirical results indicate gains in forecast improvement in the T dimension but essentially flat N effects.

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