Regional Analysis of West African Monsoonal Convective Systems During 2006 Nick Guy, Steven. A. Rutledge, and Brenda Dolan Colorado State University

N/AMMA 2006 Observational Campaign Radar Common Operating Period: 19 Aug – 16 Sep 2006 MIT Radar (UTC+1) Niamey, Niger NPOL Radar (UTC+0) Kawsara, Senegal TOGA Radar (UTC-1) Praia, Cape Verde

Evidence of propagating modes Disturbance generation over east Africa Propagates westward with various points of regeneration How does this contribute locally? What do local diurnal cycles look like at these three locations? Averaged over 12-17°N

Environmental Characteristics CAPE CIN 0 – 6 km Shear

VAD Analysis E NE ESW NE SEE Con Div

Precipitation Feature Analysis Grouped precipitation features –MCS and Sub-MCS spatial scale Producing 1-hour statistics Common time binned into hour of day to produce diurnal representation MCSSub-MCS Season

Diurnal Characteristics MCS Convective MCS Stratiform Precipitation Convective vs. Stratiform Vertical Structure of total common period Total

Wave vs. No Wave Common time frame shows a distinct separation of characteristics due to convective spatial scale Deep convection has been shown to be modulated by African Easterly Waves What differences are seen at the local scale? Partition data in terms of wave and non-wave influence Berry et al algorithm definition of trough tracking used

Vertical Reflectivity

Diurnal Characteristics Precipitation Convective Vs. Stratiform MCS Feature Size AEWNo Wave

Summary Characteristic zonal differences in convection are observed between the three unique sites attributable to: –AEW activity –Zonal variability environmental characteristics Continental site shows most favorable environment for linearly organized convection, though the coastal site also displays this behavior Coastal site maintains most abundant reservoir of available convective energy Large cap and shear at continental site results in explosive organized convective growth Continental and maritime sites show similar vertical growth, though the continental site exhibits much larger reflectivity values at low levels

Summary Wave forcing at the continental and coastal sites show the greatest differences in stratiform extent and precipitation Wave organization results in greater precipitation feature size and therefore precipitation Vertical growth does not show strong wave dependence at the maritime and coastal sites Diurnal peaks show variability in distribution and magnitude due to “wave influence”