Gareth’s modeling extravaganza.

Approach. - Using a full-physics mesoscale model to simulate AEW cases. - Analysis of model output will be subjected to synoptic analysis with an emphasis put upon the evolution of the potential vorticity (PV) field to identify the dominant physical processes. Problem. - We don’t know enough about the physical processes that occur within an AEW, especially how those on different scales interact. - Recent research (e.g. Berry and Thorncroft, 2005) has suggested that the synoptic scale AEW and mesoscale convection can feedback on one another and promote mutual growth.

Model details. - Using the Weather Research and Forecasting (WRF) model (Version 3) with full physics suite to simulate the continental life cycles of AEWs. - The case shown in this presentation is from 2004 and was chosen for being an ‘average’ AEW based on the analysis of Berry, Thorncroft and Hewson (2006). - Using a 50km horizontal resolution with 30 levels between surface and 10hPa on a large domain (14000x5000km): - Model run with a 120s timestep out 144hr. - Domain initial conditions and 6-hourly lateral boundary conditions come from NCEP FNL analysis.

700hPa Curvature vorticity.

4/9 12UTC 5/9 12UTC 6/9 12UTC 7/9 12UTC 8/9 12UTC 9/9 12UTC

S = diabatic heating

Snapshots at t+6days  at 1km W-E PV and  cross-section. (A-A’) N-S PV and  cross- section. (B-B’) OLR, 3km wind (barbs), 1km winds (streamlines), 3.5km objective trough and jet axes E-W section Meridional wind, Diabatic heating (K/day) cross- section. (A-A’) N-S section Meridional wind, Diabatic heating (K/day) cross- section. (B-B’) AA’A B B’ B AA’A BB’ B

Simulate surface reflectivity T+66hrs A B A B Cross-section of hydrometeor mixing ratio (black contour), MP diabatic heating (red/blue), winds and 0C isotherm. Ongoing research (i): More detailed look at mesoscale PV maxima using a cloud resolving model.

AEW26 Parcel buoyancy (coloured), PV and circulation (vectors), averaged 7-17N at t+70 Ongoing research (ii): Linking triggering and maintenance of deep convection to synpotic structure: Synoptic scale cold core?????