A new approach to sensitivity climatologies: the DTS-MEDEX-2009 campaign

A Jansa,D Richardson,L Garcies,S Klink,P Arbogast,V Homar,A Genoves,C Sahin,A Doerenbecher

doi:10.5194/nhess-11-2381-2011

Abstract

Abstract. Adaptive observation is an approach to improving the quality of numerical weather forecasts through the optimization of observing networks. It is sometimes referred to as Data Targeting (DT). This approach has been applied to high impact weather during specific field campaigns in the past decade. Adaptive observations may involve various types of observations, including either specific research observing platforms or routine observing platforms employed in an adaptive way. The North-Atlantic TReC 2003 and the EURORISK-PREVIEW 2008 exercises focused on the North-Atlantic and Western Europe areas using mainly routine observing systems. These campaigns also included Mediterranean cases. The most recent campaign, DTS-MEDEX-2009, is the first campaign in which the DT method has been used to address exclusively Mediterranean high impact weather events. In this campaign, which is an important stage in the MEDEX development, only operational radiosonde stations and commercial aircraft data (AMDAR) have provided additional observations. Although specific diagnostic studies are needed to assess the impact of the extra-observations on forecast skill and demonstrate the effectiveness of DTS-MEDEX-2009, some preliminary findings can be deduced from a survey of this targeting exercise. After a description of the data targeting system and some illustrations of particular cases, this paper attempts some comparisons of additional observation needs (through effectively deployed radio-soundings) with sensitivity climatologies in the Mediterranean. The first step towards a sensitivity climatology for Mediterranean cases of high impact weather is indirectly given by the frequency of extra-soundings launched from the network of radiosonde stations involved in the DTS-MEDEX-2009 campaign.

Highlights

One of the main sources of errors in numerical weather prediction is the inaccuracy in the description of the model’s initial conditions (Zhu and Thorpe, 2006)
It can be concluded that the sample of cases provided by the campaign represents quite well the type of high impact weather that is frequent in the Mediterranean area, because the proportion between cases of heavy rain, strong wind and intense cyclone in the campaign is not very different from the proportion between cases included in the list of MEDEX selected cases
The distribution of the types of events can be considered as reasonably representative for the high impact phenomena in the Mediterranean, the geographical distribution of the events seems to be quite biased: the concentration of phenomena in the central Mediterranean area looks excessive, when compared to the number of events affecting the western Mediterranean basin and countries. Is this due to the peculiar 2009 season? This bias has to be accounted for when interpreting the sensitivity climatology we present

Summary

Introduction

One of the main sources of errors in numerical weather prediction is the inaccuracy in the description of the model’s initial conditions (Zhu and Thorpe, 2006). The DTS (for Data Targeting System) is based on this philosophy, oriented towards the improvement of specific weather forecast cases. 4. Section 5 describes the inference about the climatology of sensitive areas by considering the geographical distribution of the frequency of additional observations (extra-soundings).

Results

Conclusion