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SUMMARY:Science and technology seminar: Aircraft data\, Covid-19 and globa
 l weather forecasting
DTSTART:20210120T160000Z
DTEND:20210120T170000Z
DTSTAMP:20260415T004200Z
UID:indico-event-230@events.ecmwf.int
CONTACT:events@ecmwf.int
DESCRIPTION:\n\nSpeaker\n\nBruce Ingleby\, ECMWF Senior Scientist\n\nBruce
  Ingleby works on the processing and assimilation of in situ observations.
   He has over 30 years experience in many different aspects of data assim
 ilation. He worked at the UK Met Office and has been at ECMWF for the last
  seven years.\n\nAbstract\n\nMeteorological reports from aircraft are an i
 mportant source of data for Numerical Weather Prediction (NWP).  From a '
 no aircraft' experiment run in 2019 the largest impact is in the upper tro
 posphere at short-range. The number of aircraft reports reduced by about 7
 5% between mid-March and mid-April 2020 due to the disruption caused by Co
 vid-19\, recovering to almost 50% of normal by July 2020. Despite the hiat
 us it is difficult to see any evidence of a drop in forecast skill - partl
 y because forecast skill is very variable\, showing both day-to-day noise 
 and lower frequency trends. Satellite data are very important for NWP and 
 several new sources became available during 2020.\n\nAmong the measures ta
 ken at ECMWF to mitigate the data loss was the assimilation of European Mo
 de-S aircraft winds - these are still very dense and only 5% of them are u
 sed. The use of Mode-S winds improves the 12-hour forecasts over Europe as
  measured against radiosondes - with the largest impact around 250 hPa aga
 in. A separate change to try to correct wind direction errors in a subset 
 of B787 reports was also introduced. Although only about 10% of the affect
 ed winds are in the southern hemisphere the forecast improvement is larges
 t there.\n\nAircraft temperatures are biased (usually between 0.3 and 1 de
 gree too high) and NWP centres have to bias correct them. More metadata\, 
 such as aircraft type\, would help with this and other quality issues. Fin
 ally\, efforts to "fill in the gaps" - provide aircraft reports in current
 ly data sparse regions were mentioned.\n\nhttps://events.ecmwf.int/event/2
 30/
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URL:https://events.ecmwf.int/event/230/
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