The impact on weather forecasts of targeted observations during A-TReC

G. N. Petersen, A. J. Thorpe

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


The impact of the additional observations from the Atlantic THORPEX Regional Campaign (A-TReC) on forecasts made with the UK Met Office operational forecast system is assessed. A total of 38 forecasts are analysed in which the forecasts range is between 30 and 78 hours. The absolute observational impact is evaluated as well as the effect on forecast error.

The results show that in most events, irrespective of whether there was a forecast improvement or not, the additional observations were made in the correct locations as the impact of the observations reached the verification areas at verification time. Thus, the guidance of the sensitive-area prediction techniques was generally very successful in identifying sensitive regions. The observational impact resulted in a general improvement of the forecasts in 32% of the events, but in about half of the events there were improvements in some fields. These results need to be considered in the light of the fact that during the A-TReC period, forecast errors were generally small. Thus, there was little room for improvements and consequently, as anticipated from previously published research, there was a significant risk of forecast deterioration. A detailed examination of four events demonstrates a complex range of behaviour in the role of targeted observations in realising forecast improvements. It is proposed that forecast improvements due to targeted observations are critically dependent on the properties of the data assimilation scheme, whilst predictions of the location of sensitive regions are successful using current techniques.
Original languageEnglish
Pages (from-to)417-431
Number of pages15
JournalQuarterly Journal of the Royal Meteorological Society
Issue number623
Publication statusPublished - Jan 2007

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