The assimilation of Cross‐track Infrared Sounder radiances at ECMWF

Eresmaa, Reima; Letertre-Danczak, Julie; Lupu, Cristina; Bormann, Niels; McNally, A. P.

doi:10.1002/qj.3171

Cited by 57 publications

(48 citation statements)

References 18 publications

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“…Over the years significant improvements in the measurement capabilities of satellite instruments such as Atmospheric Infrared Sounder, Cross-track Infrared Sounder, Advanced Microwave Sounding Unit, and Advanced Technology Microwave Sounder as states of the art advanced infrared microwave sounding systems have revolutionized the temperature and moisture observations, undoubtedly (Strow et al, 2006;Susskind et al, 2006;Zheng et al, 2015). With increasing usage of sounding retrieval products in data assimilation for general circulation models (GCMs), regional climate models (RCMs), and NWPs, atmospheric reanalysis has improved the operational capabilities (Barker et al, 2004;Chahine et al, 2006;Dee et al, 2011;Eresmaa et al, 2017). It is difficult to obtain realistic absolute temperature estimates for basin-scale application from these models due to coarse resolution (10 to 100 km), improper representation of topography and lack of subgrid parameterization for small scale processes and surface characteristics (Dimri, 2014).…”

Section: Citationmentioning

confidence: 99%

Distributed Hydrological Modeling Framework for Quantitative and Spatial Bias Correction for Rainfall, Snowfall, and Mixed‐Phase Precipitation Using Vertical Profile of Temperature

et al. 2019

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Mountain snowpack and its distribution both have intimate connections to regional hydrology by preserving winter precipitation to sustain streamflows during the summer months. One of the key knowledge gaps in mountainous region is the interplay of precipitation and temperature with changing altitudes. Three‐dimensional temperature distribution is pivotal for the realistic temporal and spatial distribution of precipitation with pattern (rain/snow). The environmental/linear lapse rates are inadequate to address snow processes, resulting in significant uncertainties. An effort is made in this study to develop a vertical profile of temperature (VPT) and apply it as a dynamic temperature lapse rate to curtail uncertainties. The VPT was used for the spatiotemporal bias correction of precipitation by targeting accessible data sources based on the quantitative and spatial analysis in a distributed hydrologic modeling framework with a logical calibration and validation. The water and energy budget‐based distributed hydrological model with snow was utilized to simulate the streamflows and spatial distribution of snow cover based on VPT and corrected precipitation. During calibration and validation phase, the simulated discharge resulted with Nash‐Sutcliffe Efficiency over 0.76 and 0.71, respectively. Moreover, the output for the spatial distribution of snow cover evaluated against Moderate Resolution Imaging Spectroradiometer‐derived 8‐day maximum snow cover extents by employing pixel‐by‐pixel analysis with average model accuracy over 88.28% and 85.89%. To the authors' knowledge, it is the first study to integrate VPT in hydrologic modeling with robust potential for optimal water resource management in the data scarce region.

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Section: Citationmentioning

confidence: 99%

Distributed Hydrological Modeling Framework for Quantitative and Spatial Bias Correction for Rainfall, Snowfall, and Mixed‐Phase Precipitation Using Vertical Profile of Temperature

et al. 2019

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“…To implement the estimated nondiagonal OECMs of radiance observations including interchannel correlations on a 4DVar DAS, the direct inverse calculation approach can be used, which calculates the inverse of OECMs for each observation profile and 4DVar iteration. This approach has been used in previous studies (Weston et al 2014;Bormann et al 2016;Eresmaa et al 2017) to introduce interchannel correlations of HSS and ATMS. The inverse calculations for every horizontal observation points and 4DVar iterations are necessary to treat different channel selection for each profile and to avoid large computer memory use.…”

Section: ) Interchannel Correlationsmentioning

confidence: 99%

“…The first experiment (named EXP-BR-A5) is an experiment using the estimated OECMs for all observations and an estimated BECM by the D05 method, where the nondiagonal OECMs are used for the TBB, while other OECMs and the BECM are refined only for variances. The nondiagonal OECMs for the TBB are introduced by the direct matrix inverse calculation approach (Weston et al 2014;Bormann et al 2016;Eresmaa et al 2017) as described in section 2b(1). The thinning distance for the AMSU-A data is also refined according to the estimated horizontal correlation structure, as follows.…”

Section: Experimental Design Of Ecm Estimation and Cycle Experimentsmentioning

confidence: 99%

“…Furthermore, the use of estimated OECMs in DASs for NWP has been started. Interchannel observation error correlation of data from infrared sounders [AIRS, IASI, and the Cross-track Infrared Sounder (CrIS)] are operationally used with readjusted eigenvalues or variances (Weston et al 2014;Bormann et al 2016;Eresmaa et al 2017). These studies were performed on the model space four-dimensional variational (4DVar) DASs at ECMWF and the Met Office.…”

Section: Introductionmentioning

confidence: 99%

“…is 1.75,Weston et al (2014) used about 1.65,Eresmaa et al (2017) used 2.75, Campbell et al (2017 used the values between 1.2 and 3.0 (this is read from theirFig. 1).…”

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confidence: 99%

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Improvement of Accuracy of Global Numerical Weather Prediction Using Refined Error Covariance Matrices

Ishibashi

2020

Monthly Weather Review

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In data assimilation for NWP, accurate estimation of error covariance matrices (ECMs) and their use are essential to improve NWP accuracy. The objective of this study is to estimate ECMs of all observations and background variables using sampling statistics, and improve global NWP accuracy by using them. This study presents the first results of such all ECM refinement. ECM diagnostics combining multiple methods, and analysis and forecast cycle experiments were performed on the JMA global NWP system, where diagonal components of all ECMs and off-diagonal components of radiance observations are refined. The ECM diagnostic results are as follows: 1) the diagnosed error standard deviations (SDs) are generally much smaller than those of the JMA operational system (CNTL); 2) interchannel correlations in humidity-sensitive radiance errors are much larger than 0.2; and 3) horizontal correlation distances of AMSU-A are ;50 km, excluding channel 4. The experimental results include the following: 1) the diagnosed ECMs generally improve forecast accuracy over CNTL even without additional tunings; 2) the supplemental tuning parameter, which is the deflation factor (0.6 in SD) applied for the estimated ECMs of nonsatellite conventional data and GPS radio occultation data, statistically significantly improves forecast accuracy; 3) this value 0.6 is set as the same value as the ratio of the estimated background error SD to that in CNTL; 4) high-density assimilation (10 times) of AMSU-A is better than CNTL, not better than that with 5 times; and 5) ECMs estimated using boreal summer data can improve forecast accuracy in winter, which indicates their robustness.

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Improved scheme for Cross‐track Infrared Sounder geolocation assessment and optimization

Wang

Zhang

Tremblay³

et al. 2017

JGR Atmospheres

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An improved scheme for Cross‐track Infrared Sounder (CrIS) geolocation assessment for all scan angles (from −48.5° to 48.5°) is developed in this study. The method uses spatially collocated radiance measurements from the Visible Infrared Imaging Radiometer Suite (VIIRS) image band I5 to evaluate the geolocation performance of the CrIS Sensor Data Records (SDR) by taking advantage of its high spatial resolution (375 m at nadir) and accurate geolocation. The basic idea is to perturb CrIS line‐of‐sight vectors along the in‐track and cross‐track directions to find a position where CrIS and VIIRS data matches more closely. The perturbation angles at this best matched position are then used to evaluate the CrIS geolocation accuracy. More importantly, the new method is capable of performing postlaunch on‐orbit geometric calibration by optimizing mapping angle parameters based on the assessment results and thus can be further extended to the following CrIS sensors on new satellites. Finally, the proposed method is employed to evaluate the CrIS geolocation accuracy on current Suomi National Polar‐orbiting Partnership satellite. The error characteristics are revealed along the scan positions in the in‐track and cross‐track directions. It is found that there are relatively large errors (~4 km) in the cross‐track direction close to the end of scan positions. With newly updated mapping angles, the geolocation accuracy is greatly improved for all scan positions (less than 0.3 km). This makes CrIS and VIIRS spatially align together and thus benefits the application that needs combination of CrIS and VIIRS measurements and products.

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The assimilation of Cross‐track Infrared Sounder radiances at ECMWF

Cited by 57 publications

References 18 publications

Distributed Hydrological Modeling Framework for Quantitative and Spatial Bias Correction for Rainfall, Snowfall, and Mixed‐Phase Precipitation Using Vertical Profile of Temperature

Distributed Hydrological Modeling Framework for Quantitative and Spatial Bias Correction for Rainfall, Snowfall, and Mixed‐Phase Precipitation Using Vertical Profile of Temperature

Improvement of Accuracy of Global Numerical Weather Prediction Using Refined Error Covariance Matrices

Improved scheme for Cross‐track Infrared Sounder geolocation assessment and optimization

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