A study on the optimization of the deployment of targeted observations using adjoint-based methods

Bergot, Thierry; Doerenbecher, A.

doi:10.1256/00359000260247426

Cited by 5 publications

(6 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Other studies investigated the possibility of evaluating the impact of observations on short‐term forecasts. In particular, the Kalman Filter Sensitivity (KFS; Doerenbecher and Bergot, 2001; Bergot and Doerenbecher, 2002) is used to predict the reduction of error variance of a forecast aspect measured by a specific cost function. Langland and Baker (2004) also proposed an adjoint‐based procedure and Liu and Kalnay (2008) and Kalnay et al (2012) proposed an ensemble‐based counterpart to estimate the impact of observations on short‐range forecast errors: the Forecast Sensitivity to Observations (FSO).…”

Section: Introductionmentioning

confidence: 99%

A posteriori diagnostics of the impact of observations on the AROME‐France convective‐scale data assimilation system

Brousseau

Desroziers

Bouttier

et al. 2013

Quart J Royal Meteoro Soc

View full text Add to dashboard Cite

AROME-France is an operational convective-scale numerical weather prediction system which uses a 3D-Var assimilation scheme in order to determine its initial conditions. In addition to conventional and satellite observations, regional high-resolution observations are assimilated, such as screen-level observations, total zenith delays from ground-based GPS stations and radar measurements (radial winds and reflectivities). The impact of the various observation types on AROME-France analyses is assessed using an a posteriori diagnostic, the reduction of the estimation error variance. This diagnostic, estimated using a randomization technique, allows one to investigate observation impact depending on the control variable field, model levels, date, analysis time, and spatial scales considered. This highlights the importance of screen-level observations (2 m temperature and relative humidity, 10 m wind) for the lowest layers, of aircraft measurements for temperature and wind field analyses and of radar observations for wind and specific humidity in middle and high troposphere. Only the last mentioned observations appear to be informative regarding the horizontal length-scale below 200 km, while all observations are mostly informative for length-scales above 200 km. The results from two diagnostics, namely the variance reduction and the Degrees of Freedom for Signal (DFS), are compared and found to be largely similar. The variance reduction appears to be an interesting diagnostic to improve the understanding of how observations are used. 1 2 χ ) T R −1 (d − HB 1 2 χ).

show abstract

Section: Introductionmentioning

confidence: 99%

A posteriori diagnostics of the impact of observations on the AROME‐France convective‐scale data assimilation system

Brousseau

Desroziers

Bouttier

et al. 2013

Quart J Royal Meteoro Soc

View full text Add to dashboard Cite

show abstract

“…Its potential advantage over the ETKF applied to a set of evolved ensemble perturbations is that it is consistent with the statistics of an operational variational assimilation scheme. The Kalman Filter Sensitivity (KFS, Bergot and Doerenbecher 2002) and the observation sensitivity are so far the only other technique that achieves consistency with an opera tional variational assimilation scheme. The KFS determines the change of variance in one direction of phase space.…”

Section: Resultsmentioning

confidence: 99%

Improved Techniques for Targeting Additional Observations to Improve Forecast Skill

Leutbecher¹,

Joly²,

Palmer³

et al. 2002

View full text Add to dashboard Cite

show abstract

“…Although this paper is focused on a single case of the DTS‐MEDEX‐2009 campaign, and thereby conclusions cannot be generalized to other targeting situations, a wealth of experiments are carried out to extensively test the guidance provided by a wide catalogue of sensitivity computations for a particularly relevant example of Mediterranean HIW. Speciﬁcally, we put under evaluation ﬁve diﬀerent sensitivity products: total energy moist‐TL95 SV based on the ECMWF Integrated Forecast System (Buizza and Montani, 1999); ETKF (Bishop et al , 2001) and KFS (Bergot and Doerenbecher, 2002) from Météo France, both using the ARPEGE model; MM5 adjoint sensitivities computed using ECMWF analysis (Zou et al , 1997) and ensemble sensitivities based on the ECMWF ensemble prediction system (Hakim and Torn, 2008) from the University of the Balearic Islands (hereafter UIB). Several intercomparisons have been performed between guidance provided by diﬀerent sensitivity methods such as the ETKF and SV (Majumdar et al , 2002) or adjoint and ensemble sensitivities (Ancell and Hakim, 2007), diﬀerent models (e.g.…”

Section: Targeting Guidancementioning

confidence: 99%

Are current sensitivity products suﬃciently informative in targeting campaigns? A DTS‐MEDEX‐2009 case study

Garcies

Homar

2013

Quart J Royal Meteoro Soc

View full text Add to dashboard Cite

The DTS‐MEDEX‐2009 campaign was a ﬁeld experiment in which extra observations were adaptively deployed to improve the short‐range forecast of Mediterranean high‐impact weather (HIW) during autumn 2009. For the DTS‐MEDEX‐2009 cases, ﬁve diﬀerent sensitivity analysis techniques were carried out to provide targeting guidance: singular vectors (SV) from the ECMWF; ensemble transform Kalman ﬁlter (ETKF) and Kalman ﬁlter sensitivity (KFS) from Météo France; and ensemble and adjoint sensitivities from the University of the Balearic Islands. However, the value of the targeting guidance provided by such a variety of sensitivity products has never been assessed for a Mediterranean HIW event. Since radiosonde and AMDAR proﬁles were the only observational means available during the DTS‐MEDEX targeting campaign, this study tests the ability of each sensitivity product in identifying the region where a plausible sounding leads to a greater impact on the forecast of a potential high‐impact cyclone over southern Italy on 5 December 2009. All targetable radio‐sounding sites are also tested and a severe‐weather meteorologist is used as a confronting reference. The veriﬁcation testbed comprehends single sounding experiments and multiple sounding strategies by using the WRF Data Assimilation system. Single sounding tests reveal that sensitivity products fail to recognize the best location for a single observation since most of the soundings added over operational radio‐sounding stations have a larger inﬂuence on intense cyclone forecast than the points highlighted by the objective sensitivity calculation methods. Additionally, it is shown that human‐based decisions, after evaluating available sensitivity information, are not optimal, either in single or in multiple sounding strategies.

show abstract

A study on the optimization of the deployment of targeted observations using adjoint-based methods

Cited by 5 publications

References 0 publications

A posteriori diagnostics of the impact of observations on the AROME‐France convective‐scale data assimilation system

A posteriori diagnostics of the impact of observations on the AROME‐France convective‐scale data assimilation system

Improved Techniques for Targeting Additional Observations to Improve Forecast Skill

Are current sensitivity products suﬃciently informative in targeting campaigns? A DTS‐MEDEX‐2009 case study

Contact Info

Product

Resources

About