Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

Introduction

Meteorological evaluation of the OpenIFS outputs is demonstrated here on case studies. Two weather events have been chosen in order to show the model's capabilities on the one hand, and on the other hand, to provide reference cases for the users (to compare the results of their installed model version with the ones run at the ECMWF or to inter-compare the results of different model versions). Important aspects at selection of the cases were their geographical scope and their physical background, i.e., those storm events were preferred which had severe impact over Europe and were governed by large-scale dynamical forces. Cases both with weak and good operational forecast skill were considered.

Case studies

Storm Desmond


Column
width43%

Storm Desmond caused severe flooding, travel disruption and a power outage across northern England, parts of Scotland and Ireland on 5 December 2015. Cumbria in northwestern part of England is one of the worst affected regions with more than 200 mm of rain in 24 hours recorded in that area. Storm Desmond broke the United Kingdom's 24-hour rainfall record, with 341.4 mm of rain falling in Honister Pass, Cumbria. On Saturday, 5 December, UK Met office issued a red warning of heavy rain for Cumbria. The cyclone also led to flooding in southern Norway.

Orographical enhancement of precipitation played a major role in the event and the operational model of the ECMWF picked well the highest rainfall amounts over the orographical barriers. However, the forecast underestimated the peak values of about 100 mm in 24 hours in Cumbria and overestimated the precipitation amount in lee of the hills.

Several OpenIFS experiments have been conducted for this case with the aim to test the effect of starting date and forecast length, initial condition as well as spatial resolution to the forecast quality. The details of experiments are summarized in Table 1.


Column
width2%


Column
width15%

Observations

Image Modified

ForecastsForecastImage Modified

Panel
borderStylesolid

Figure 1: 24-hour precipitation amount (mm) between 6 UTC 5 December and 6 UTC 6 December 2013, based on observations (top) and ECMWF operational IFS forecast (bottom).






Panel
borderStylesolid

Table 1:  Settings of the experiments achieved for Storm Desmond.



Initial conditionResolutionStarting dateTime stepOutput frequency
1.ERA-InterimT255L91

   

2700 s3h
2.ERA-InterimT639L137

 

900 s3h
3.ERA-InterimT1279L137

600 s3h
4.ERA5T255L91

2700 s3h
5.ERA5T639L137

900 s3h

- download from download.ecmwf.int/openifs/evalution

Storm Xavier


On the 5 December 2013 the cyclone swept from Scotland, over the North Sea and hit Denmark, Germany and Sweden. Problems were caused both by the wind and the following storm surge. The surged reached 6 metres in Hamburg for example and was the highest along the England east-coast for 60 years. In the aftermaths of the cyclone a blizzard hit Sweden. The cyclone was presented in the forecasts 8-9 days before the event and the forecasts indicated the very strong winds 3-4 days in advance.

Several OpenIFS experiments have been conducted for this case with the aim to test the effect of starting date and forecast length, initial condition as well as spatial resolution to the forecast quality. The details of experiments are summarized in Table 2.

Table 2: Settings of the experiments achieved for Storm Xavier.




Initial conditionResolutionStarting dateTime stepOutput frequency
1.ERA-InterimT255L91

2700 s3h
2.ERA-InterimT639L137


900 s3h
3.ERA5T255L91
2700 s3h
4.ERA5T639L137
900 s3h




Post-processing step

- how to prepare data for plotting

- precipitation.


Metview macros

- where they are, how to set them up .. etc


Catalogue



Excerpt Include
Credits
Credits
nopaneltrue

 

 

 


...