An update on the DIAMET flight campaign

At the beginning of term, Tom Frame contributed this excellent post about the ongoing DIAMET field campaign.  In this blog entry, I’ll provide an update on some of the more exciting and stomach-turning developments from the past few weeks of flying into storms around the British Isles.

Backing up for just a moment, you may recall that the purpose of DIAMET (DIAbatic influences on Mesoscale structures in ExtraTtropical storms) is to improve our understanding of and ability to model the interactions between cloud microphysical processes and mesoscale flow structures in midlatitude cyclones. What does this mean? In and around  clouds, water changes phase between ice, liquid, and vapour. The phase transitions are accompanied by heating and cooling of the air, sometimes over very large regions such as along a synoptic scale front. All of this heating and cooling leads to changes in temperature and pressure, which in turn can influence the flow of air in and around clouds. Many questions remain unanswered concerning how the interaction between diabatic heating and mesoscale flow influence the evolution of heavy precipitation and severe wind events. In a numerical weather prediction model, this interaction involves communication between subgridscale processes and the explicitly resolved flow. Does a model represent this interaction correctly? This is a difficult question to answer, but a field campaign such as DIAMET can help us to find out.

Over the past three weeks, the FAAM (Facility for Airborne Atmospheric Measurement) BAe-146 research aircraft has been flying into storms and collecting data that will be analysed to determine microphysical heating and cooling rates as well as the dynamical structure of the storms. When the campaign was planned over a year ago, we couldn’t possibly know if the weather regime would lend itself to supporting the kinds of storms that we wanted.  Fortunately for everyone who has invested their time and energy in this project, the weather did indeed comply. For a complete run down on all of the field campaign happenings, visit the DIAMET blog.

On 8th December , our very own John “The Intrepid”  Methven led a mission into the centre of an explosively developing cyclone that appears to have produced a sting jet. This was quite a rare opportunity to sample one of the most violent types of cold season wind phenomena. The Scottish Sun has written an article about the flight here, and the Met Office issued this press release. Rumor has it that the 160+mph winds and associated turbulence were too much for one Reading scientist who flew on this mission. Some lunch may have been lost, but we won’t be telling the Sun about that. Before you pass judgment, have a look at this video posted to Youtube by a member of the flight crew on the 1st December mission north of Scotland :

Flying at 150 ft above 70 ft waves

The purpose of this particular sortie was to collect enough data to infer the heat and moisture flux from the ocean surface into the boundary layer of an intense cyclone.

In summary, both the September and December flying periods were a big success. The weather gifted us more cases than we could have hoped for. Now begins the real heart-pounding phase of work when we scatter back to our desks and analyse the data!

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