Synoptic Structure of AEWs

Matthew Janiga

Tracking Methodology

• Apply a 2-day low-pass filter with a 100 day window to circulation calculated within a 4.5 degree radius of each grid point.

• Locate disturbances exceeding 1x10-5 s-1 which are a maximum within a 9 degree radius. Match to disturbances at subsequent times within 7.5 degrees of the extrapolated position of past maxima. – For disturbances older than 3 time steps the last 3 times

are used for extrapolation otherwise no extrapolation is attempted.

Only composite tracks with at least 2000 km of continuous westward propagation in the domain 0-20°N, 35°E-35°W, JAS 1989-2005, before TC.

Organization of rainfallTC Precursors

TCs

700 hPa 2-10 Day Filtered Potential Vorticity and WindWind (m/s, vectors), PV (0.1 PVU, shaded)

700 hPa 2-10 Day Filtered Temperature and WindWind (m/s, vectors), Temperature (K, shaded)