1. A regional-model « climatology » of vertical mass and water-vapour transport for the Hibiscus-Troccinox-Troccibras campaign 2004 F. Gheusi, J.-P. Cammas, J.-P. Chaboureau, J. Duron, C. Mari, P. Mascart and J.-P. Pinty Laboratoire d’Aérologie Toulouse (France)

2. Meso-NH forecast support during the campaign (1) Resolution = 30 km Domain 3000 km x 3000 km « Radar » rectangle Mass budget (arbitrarily) restricted to this area

3. Meso-NH forecast support during the campaign (2) Daily time-period considered for vertical air-displacement integration of mass budgets 06 UTC 24 UTC Set of 30 simulations from 05 Feb to 05 Mar Makes possible some statistics !

4. Wind-strength @ z = 1500 m Some climatological features (30-day averaged fields) P + wind @ z = 3000 m Temp. °C (colorscale) -2 PVU tropopause (dashed) Zonal wind (dotted) SACZ vertical cross-section

5. Mean daily vertical motion (06-24 UTC) S-N cross-section:  z = z – z 0 (km) z 0 (m) @ z = 6000 m SACZ

6. Mass budget computation: a post-processing method z Surface = air-parcels with common initial altitude z 0 x z0z0 Upward mass flux through z 0 between t 0 and t: Air-parcels that were initially below z 0 are finally above z 0 Mass flux between t 0 and t = Mass of the colored volume Model run: transport of a passive tracer initialized with the altitude, then …

7. Mass budget computation: what was performed 3000 m 6000 m 9000 m 12000 m 15000 m 18000 m 21000 m = flux 06-24 UTC (up / down) Net flux = up - down For each day (simulation Day 1) Computation for 30 days: few seconds on a Linux PC ! Mass flux = dry air or water-vapour

8. Qualitative comparison against rain satellite-retrievals (TRMM, 125x125 km²) Mixed results, better with sub-grid cloud fraction ? To be tested… 06 February heavy-rain over Bauru, good forecast ! 14 February active front, forecasted too late… 28 February good ! diurnal convection period, not good… 3-4 March not so bad

9. Dry-air mass budget

10. Criterion: Max( flux(9000m) + flux (12000m) )

11. Dry-air mass budget Criterion: Min( flux(9000m) + flux (12000m) )

12. Water-vapor flux: qualitative comparison against rain satellite retrievals (TRMM, 125x125 km²) Better correlation with the « observed » precipitation

13. Water-vapour mass budget

14. Conclusions Numerical aspects 30 MesoNH runs in forecast mode: statistical approach over the period 05 Feb – 05 Mar 2004. Flux computation based on –On-line passive transport of initial-coordinate tracers –Low-cost and highly adaptable post-processing (PC) Vertical motion « model climatology » Subsidence in the lower troposphere, S of the SACZ Largest ascent just below the tropopause, N of the SACZ Slight but significant subsidence above the tropopause  convergence in the TTL, no export in the stratosphere Vertical mass budget Downward flux in the lower stratosphere Upward flux maximum at 9000m (6000m for WV) Mass and humidity convergence in the TTL

15. Future work Work with better simulation sets Compare findings and observations Investigate the diurnal evolution of the vertical transport