an objective composite of the african easterly wave lifecycle
Post on 23-Feb-2016
42 Views
Preview:
DESCRIPTION
TRANSCRIPT
An Objective Composite of the African Easterly Wave Lifecycle
Matthew Janiga
What is an AEW?
From the YOTC 0.225° analysis
African easterly waves (AEWs) are defined as disturbances of the mid-level PV strip. These disturbances interact with the low-level baroclinic zone perturbing the surface θ field.
Since the July-September 1989-2005 ERA-Interim mean PV strip is best defined at 700 hPa this level is used for tracking.
Tracking Procedure
Raw ERA-Interim 700 hPa PV
After 2 day low-passAfter application of Gaussian smoothing with a radius of 6°
and one standard deviation at 3°.
1. Look for maxima within a radius of 6° which exceed 0.15 PVU and the average of that radius by 0.02 PVU.2. Continuation is determined by matching closest maxima within 6°. 3. Tracks are 1-2-1 smoothed and trimmed for continuous westward propagation.4. We select those trimmed tracks lasting > 3 days and with 15° westward movement.
Hovmöller Validation
top related