1. 2.4 Some observations from the JET2000 experiment Thorncroft et al, 2003 BAMS Parker et al, 2005 QJRMS

2. C130 aircraft flew 4 legs over this region: 25-30 August 2000 Dropsondes every 0.5-1 degree Low level flights on north-south transect Met Office C-130 At Niamey Airport, Niger Experimental Details

3. JET2000 Period Weak AEW activity 2-5 day filtered V at 700mb (from ECMWF)

4. Dropsonde locations – on the 28 th August 2000

5. ECMWF PBL fields compared to observations Potential temperature Equivalent potential temperature

6. Zonal Wind 28 th August 2000

7. Thermodynamic Profiles 28 th August 2000

9. Height of AEJ

10. Saturated equivalent potential temperature 28 th August 2000 Close to dry adiabatic Closer to moist adiabatic

11. Equivalent Potential Temperature 28 th August 2000 Elevated SAL is a region of lateral mixing (e.g. q, aerosol) Variability in boundary layer θe (surface conditions)

12. Boundary Layer Buoyancy 28 th August 2000 Larger CIN and +ve buoyancy Smaller CIN and +ve buoyancy