Tuesday 14 August update

Summary

• Wednesday  - DIAMET flight in the afternoon with BBC crew onboard.

• Friday         - possible flying day if there is strong scientific interest
  
  

Details

Wednesday looks very promising, while low pressure area over Ireland and seas west of UK is gradually deepening. There is tightly-packed warm and cold front coming from southwest, passing during the day over UK and Ireland.

As was already mentioned on Monday telecon, we were interested in flying on Wednesday, possibly even double flight. Due to missing pieces of information about dropsonde clearance and other projects (TOTAL) interested in Wednesday, there were more possible scenarios.

Plans has become pretty clear with 10:20 telecon when Steven from TOTAL project declared interest in morning flight over **** oil platform. Therefore DIAMET team will load on board TOTAL flight in the morning (0830), and DIAMET flight itself will take off 1300-1330 from Prestwick.

Most of the flight will take place in the afternoon in the 'area B' and over Northern Ireland.
Flight would consist (according to Ian's later email) something relatively simple with in-situ leg, diagonally across front, then a pattern of stacked legs over Northern Ireland at a various heights, before heading north for a long north to south dropsonde leg. Peter Knippertz suggesting less levels and longer flight legs.

BBC One Show has previously showed interest in DIAMET flights. Long story told short, there will be a camera crew on board our flight.

Monday 13 August Update

Although Tuesday was originally expected to be a flight day, weather forecast from Monday morning shows just wide and shallow low pressure system over Atlantic west from UK. Althought there might be some strong showers, fronts are week and therefore there is no interest in Tuesday flight.

Wednesday seems more promissing. According to Met Office Unified Model, low presure over Ireland and seas west of UK is gradually deepening. Double cold front is coming from southwest, and might be associated with groups of strong showers when passing over Southest, and then Midlands, Wales and East of Ireland.

However some doubts persist due to high uncertainty present in ensemble forecasts. MOGREPS forecast shows high spread in ensemble results, substantialy more then what is usual for +48 & + 56.
ECMF 850 hPa shows double temperature structure coming from southwest, so there is clearly some parity between models.
There might be areas of diabatically generated PV, and this scaenario is yet to be further evaluated.

Thursday 19th July Update

We are having a few days off while the plane is used for MAMM flying until Monday (23rd).  It has been a busy last couple of days for the DIAMET team though with yet another interesting flight yesterday!

18th July Flight

Safe to say we have been having a very wet summer with much of the rain a result of stationary or slow moving fronts, yesterday we got one when we could fly so up we went again.

The analysis chart from 1200UTC is shown below.  The long warm and occluded front can be seen streching across central Scotland, this was producing the rain we were aiming for.

Along with the rainband a potential vorticity anomaly was predicted to extend in behind the fronts so a dropsonde leg on the way back was planned to profile this.  Below is the fight track overlayed on a MODIS image from 1322.  The first part of science observations came from a dropsonde leg heading north from a point east of Edinburgh, including a brief gap to avoid the busy Aberdeen flight lanes below.  A total of 8 sondes were dropped on this leg allowing us to develop a decent idea of the warm front.  Following this we did multiple stacked legs within the cloud aiming for the improtant temperature regions aound -11°, -5° and 0°C.  We were hoping to do a low level leg but low cloud prevented us from going below 1500ft.  The microphysics readings from the stacked legs showed up the fact that the front had two distinct rainbands. 

On the return leg we ascended up to 33000ft well into stratospheric air with ozone readings of over 390ppb.  Three aditional sondes were dropped off the north east coast to profile the forecasted PV feature within the dry slot.

All in all this was yet another interesting and successful DIAMET flight!

Friday 06 July update

Conference call today to get discussions going again for flights whenever anything looks promising.  Aircraft available from next week.

Today

Would be perfect Diamet case – low spinning up over Wales, possibly diabatically forced.

Weekend

Low moving southwest over UK. Looking interesting over Cornwall tomorrow so may be worth releasing extra sondes from Camborne.

Next week

Low moving east, putting us in northerly airstream between that and Atlantic ridge. Not looking like a flight in early part of the week but to be discussed on Monday.

Phase 3 1-18th May

Written by Ali Rudd

Friday, 27 April 2012 09:38

We're about to start Phase 3 of the DIAMET flight campaign. This time we have the aircraft from 1-18 May. 1-10th it wil be based from Cranfield and 11-18th from Benson. Watch this space for further updates!

B662 (2011-12-12)

Written by Jenny Owen

Thursday, 15 December 2011 14:10

This flight was sadly the last flight of DIAMET 2011. It aimed to investigate the structure fo the warm front that was over the Celtic Sea. In the forecasts, there was a complex double frontal structure (see below). The science aim of this flight was to investigate whether the latent heat release from condensation of water vapour into liquid drops and freezing into ice heats the surrounding air sufficiently to change the weather associated with the front. Particularly, it could enhance the along-front wind shear (how wind speed differs with height) and alter the rate at which rain falls from it.

Image from MetOffice 48h forecast chart, valid 2011-12-12 12:00.

Image from MetOffice analysis chart, valid 2011-12-12 12:00

It was a much more leisurely morning than the previous flight we did, as take-off was 12:00. The first leg of the flight was at high altitude dropsonde leg, through the warm front and warm sector, to get an accurate picture of how the altitude of the frontal surface varied with distance. Then we doubled back along the latitude line and decreased altitude, to investigate the various cloud levels in the front. We did this three times, so passed through the front at four different altitudes (including the dropsonde leg). Each of these later three lega looked at the ice and water that was in or falling from each layer of the cloud. The last of these was just at the cloud base at about 1000ft, which was pretty exciting (and a little bumpy!).

The final section of the flight continued along the latitude we'd already covered, and went upwards to profile the warm front. This means we can get an idea of the vertical structure of the warm front, in terms of the winds, ice & water, humidity and temperature. Overall, not the most photogenic flight, as we were mainly deep in cloud! However, we are quietly optimistic that the data that was collected will help ascertain the extent to which microphysics affects the weather in warm frontal regions.