Impact of singular‐vector‐based satellite data thinning on NWP

Bauer, Péter; Buizza, Roberto; Cardinali, Carla; Thépaut, J.-N.

doi:10.1002/qj.733

Cited by 24 publications

(27 citation statements)

References 42 publications

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“…Sensitive areas, whether they are determined by forecasters or by objective algorithms, can potentially be monitored more closely by turning on the rapid-scan feature on geostationary satellites and then assimilating a denser network of motion vectors, such as in Berger et al (2011). Perhaps a denser network of radiance data can be assimilated in sensitive regions (Bauer et al 2011). Copyright of Monthly Weather Review is the property of American Meteorological Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.…”

Section: Discussionmentioning

confidence: 99%

Impact of Targeted Winter Storm Reconnaissance Dropwindsonde Data on Midlatitude Numerical Weather Predictions

Hamill

Yang

Cardinali

et al. 2013

Monthly Weather Review

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The impact of assimilating data from the 2011 Winter Storm Reconnaissance (WSR) program on numerical weather forecasts was assessed. Parallel sets of analyses and deterministic 120-h numerical forecasts were generated using the ECMWF four-dimensional variational data assimilation (4D-Var) and Integrated Forecast System. One set of analyses was generated with all of the normally assimilated data plus WSR targeted dropwindsonde data, the other with only the normally assimilated data. Forecasts were then generated from the two analyses. The comparison covered the period from 10 January to 28 March 2011, during which 98 flights and 776 total dropwindsondes were deployed from four different air bases in the Pacific basin and the United States. The dropwindsondes were deployed in situations where guidance indicated the potential for high-impact weather and/or the potential for large subsequent forecast errors. Downstream target verification regions where the high-impact weather was expected were identified for each case. Forecast errors around the target verification regions were evaluated using an approximation to the total-energy norm. Precipitation forecasts were also evaluated over the contiguous United States using the equitable threat score and bias.Forecast impacts were generally neutral and thus smaller than reported in previous studies, most from over a decade ago, perhaps because of the improved forecast and assimilation system and the somewhat denser observation network. Target areas may also have been undersampled in this study. The neutral results from 2011 suggest that it may be more beneficial to explore other targeted observation concepts for the midlatitudes, such as assimilation of a denser set of cloud-drift winds and radiance data in dynamically sensitive regions.

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Section: Discussionmentioning

confidence: 99%

Impact of Targeted Winter Storm Reconnaissance Dropwindsonde Data on Midlatitude Numerical Weather Predictions

Hamill

Yang

Cardinali

et al. 2013

Monthly Weather Review

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“…The third experiment, EXP-ATOVS*2, aims to investigate other data targeting strategies in HIRLAM DA, in particular a non-uniform data thinning for the satellite data located in the target region, following the work of Bauer et al (2011) with ECMWF global model. With EXP-ATOVS2, we seek to test the potential additional improvement obtained with an enhanced sampling of ATOVS data located in the sensitive regions over the ocean and sea areas to complement the extra radiosondes mostly launched in Europe.…”

Section: Experiments Descriptionmentioning

confidence: 99%

“…Dando et al (2007) investigated the impact on forecast skill of using additional ATOVS (Advanced TIROS Operational Vertical Sounders) data in targeted regions for some case studies. Selective satellite data thinning was applied by Bauer et al (2011) to reduce analysis uncertainty and forecast error in the Southern Hemisphere extratropics, increasing data density in singular vector (SV)-based sensitive regions.…”

Section: Introductionmentioning

confidence: 99%

Influence of targeted observations on short-term forecasts of high-impact weather events in the Mediterranean

Campins

Navascués

Santos

et al. 2013

Nat. Hazards Earth Syst. Sci.

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Abstract. The influence of targeted observations on shortrange forecasts is tested over two different periods of PRE-VIEW (2008) and MEDEX (2009) data targeting field campaigns for a set of Mediterranean high-impact weather events. As targeted observations we have used not only extra radiosondes, but also enhanced satellite data observed in singular vector (SV)-based sensitive regions. Three parallel observing system experiments, based on the High-Resolution Limited-Area Model (HIRLAM) data assimilation and forecast system, have been conducted. Forecasts of the three experiments have been assessed using both verifying analyses for upper-air fields, and surface observations for several meteorological parameters. Furthermore, quantitative precipitation forecasts (QPF) have been objectively verified using the novel feature oriented Structure-Amplitude-Location (SAL) method.The results obtained show that extra radiosondes have an overall positive impact on the forecasts (average improvement of all upper-air variables and vertical levels studied is 3.6 %). When in addition to extra radiosonde data also enhanced satellite data are assimilated, the overall forecast skill is almost doubled. However, a distinct behaviour is found between the PREVIEW and MEDEX cases. While for MEDEX cases the improvement is slight, for PREVIEW cases the improvement is significant (average improvements of 1.7 % and 8.9 %, respectively, for the experiment with enhanced satellite data). It is suggested that this is due to the location of the target areas and the spatial distribution of the composite observing system and to the different atmospheric predictability in these two periods.

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“…• at the European Centre for Medium-Range Weather Forecasts (ECMWF; Bauer et al, 2011), before they are assimilated and as a result the resolution of the assimilated data may be too low to properly represent polar lows. Therefore there is a lack of near-surface observations which may be important due to the role of low-level development and surface fluxes to polar low genesis through either the conditional instability of the second kind (CISK) or wind-induced surface heat exchange (WISHE) mechanism (e.g.…”

Section: Introductionmentioning

confidence: 99%

Targeted observations of a polar low in the Norwegian Sea

Irvine

Gray

Methven

2011

Quart J Royal Meteoro Soc

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A developing polar low is targeted with dropsonde observations to improve the forecast of its landfall. Accurately forecasting a polar low's strength and location remains a challenge; polar lows form over the ocean in poorly observed regions, therefore initial condition errors may contribute significantly to forecast error. The targeted polar low formed in the Norwegian Sea on 3 March 2008, during the Norwegian IPY-THORPEX field campaign. Two flights, six hours apart, released dense networks of dropsondes into a sensitive region covering the polar low and Arctic front to its west. The impact of the targeted observations is assessed using the limited-area Met Office Unified Model and three-dimensional variational (3D-Var) data assimilation scheme. Forecasts were verified using ECMWF analysis data, which show good agreement with both dropsonde data from a flight through the mature polar low, and 10 m QuikSCAT winds. The impact of the targeted data moved southwards with the polar low as it developed and then hit the Norwegian coast after 24 hours. The results show that the forecast of the polar low is sensitive to the initial conditions; targeted observations from the first flight did not improve the forecast, but those from the second flight clearly improved the forecast polar low position and intensity. However, caution should be applied to attributing the forecast improvement to the assimilation of the targeted observations from a single case-study, especially in this case as the forecast improvement is moderate relative to the spread from an operational ensemble forecast.

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Impact of singular‐vector‐based satellite data thinning on NWP

Cited by 24 publications

References 42 publications

Impact of Targeted Winter Storm Reconnaissance Dropwindsonde Data on Midlatitude Numerical Weather Predictions

Impact of Targeted Winter Storm Reconnaissance Dropwindsonde Data on Midlatitude Numerical Weather Predictions

Influence of targeted observations on short-term forecasts of high-impact weather events in the Mediterranean

Targeted observations of a polar low in the Norwegian Sea

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