Observation of entrainment at the interface between monsoon flow and the Saharan Air Layer

Quarterly Journal of the Royal Meteorological Society

Volumn 136, Issue SUPPL. 1, 2010, Pages 34-46

  Canut, G ^a   Lothon, M ^a   Said F ^a   Lohou, F ^a  

^a UNIVERSITÉ DE TOULOUSE   (France)

Author keywords

AMMA; Atmospheric boundary layer; Dry tongues; West African Monsoon

Indexed keywords

BUOYANCY FLUXES; ENTRAINMENT PROCESS; FAST MEASUREMENT; LOWER TROPOSPHERE; MOISTURE FLUXES; NIGER; PLANETARY BOUNDARY LAYERS; SAHARAN AIR LAYERS; SURFACE FLUX; TURBULENCE SCALE; WATER VAPOUR; WEST AFRICAN MONSOON;

AIR ENTRAINMENT; AIRCRAFT INSTRUMENTS; ATMOSPHERIC HUMIDITY; ATMOSPHERIC THERMODYNAMICS; INTERPLANETARY SPACECRAFT; MOISTURE; PHASE INTERFACES; TROPOSPHERE;

ATMOSPHERIC BOUNDARY LAYER;

AIR TEMPERATURE; AIRBORNE SURVEY; BUOYANCY; ENTRAINMENT; FIELD METHOD; HUMIDITY; INTERFACE; MOISTURE FLUX; MONSOON; SKEWNESS; TURBULENCE; TURBULENT BOUNDARY LAYER; TURBULENT FLOW; WATER VAPOR; WIND MEASUREMENT;

NIGER [WEST AFRICA]; SAHARA;

EID: 77949388133     PISSN: 00359009     EISSN: 1477870X     Source Type: Journal    
DOI: 10.1002/qj.471     Document Type: Article

References (40)

1. Burpee RW. 1972. The origin and structure of easterly waves in the lower troposphere of North Africa. J. Atmos. Sci. 29: 77-90.
2. Cook K. 1999. Generation of the African Easterly Jet and its role in determining West African precipitation. J. Climate 12: 1165-1184.
3. Couvreux F, Guichard F, Redelsperger J-L, Kiemle C, Masson V, Lafore J-P, Flamant C. 2005. Water-vapour variability within a convective boundary layer assessed by large-eddy simulations and ihop-2002 observations. Q. J. R. Meteorol. Soc. 131: 2665-2693.
4. Couvreux F, Guichard F, Redelsperger J-L, Masson V. 2007. Negative water vapour skewness and dry tongues in the convective boundary layer: Observations and LES budget analysis. Boundary-Layer Meteorol. 123: 269-294.
5. Couvreux F, Guichard F, Bock O, Campistron B, Lafore J-P, Redelsperger J-L. 2009. Intraseasonal variability of the monsoon flux over West Africa prior to the monsoon onset. Q. J. R. Meteorol. Soc. 136(s1): 160-174.
6. Cuesta J, Lavaysse C, Flamant C, Mimuni M, Knippertz P. 2009. Northward bursts of the West African monsoon leading to rainfall over the Hoggar massif, Algeria. Q. J. R. Meteorol. Soc. submitted.
7. Fedorovich E, Conzemius R. 2008. Effects of wind shear on the atmospheric convective boundary-layer structure and evolution. Acta Geophysica 56: 114-141.
8. Flamant C, Pelon J, Flamant P-H, Durand P. 1997. Lidar determination of the entrainment zone thickness at the top of the unstable marine atmospheric boundary layer. Boundary-Layer Meteorol. 83: 247-284.
9. Flamant C, Knippertz P, Parker DJ, Chaboureau J-P, Lavaysse C, Agusti-Panareda A, Kergoat L. 2009. The impact of a mesoscale convective system cold pool on the northward propagation of the intertropical discontinuity over West Africa. Q. J. R. Meteorol. Soc. 135: 139-159.
10. Garratt JR. 1992. The atmospheric boundary layer. Cambridge atmospheric and space science series.
11. Grossman RL, Nimal G. 1995. Moisture flux and mixing processes in the daytime continental convective boundary layer. J. Geophys. Res. 100: 25665-25674.
12. Kalapureddy MC, Lothon M, Campistron B, Lohou F, Said F. 2009. Wind profiler observations of the African Easterly Jet and its interactions with the boundary layer and Saharan heat low. Q. J. R. Meteorol. Soc. 136(s1): 77-91
13. Kim S-W, Park S-U, Pino D, Vilà-Guerau de Arellano J. 2006. Parameterization of entrainment in a sheared convective boundary layer using a first-order jump model. Boundary-Layer Meteorol. 120: 445-475.
14. Lavaysse C, Flamant C, Janicot S, Parker DJ, Lafore J-P, Sultan B, Pelon J. 2009. Seasonal evolution of the West African Heat Low: A climatological perspective. Clim. Dyn. In press. DOI: 10.1007/s00382-009-0553-4.
15. Lee Y, Campistron B, Kim KE. 2007. 'Preliminary results obtained from the 3D analysis of the AMMA wind-profiler radar synoptic network'. Second International AMMA Conference, Karlsruhe, 26-30 November 2007.
16. Lenschow DH, Stephens PL. 1980. The role of thermals in the convective boundary layer. Boundary-Layer Meteorol. 19: 509-532.
17. Lenschow DH, Mann J, Kristensen L. 1994. How long is long enough when measuring fluxes and other turbulence statistics? J. Atmos. Oceanic Technol. 11: 661-673.
18. Lenschow DH, Krummel PB, Siems ST. 1999. Measuring entrainment, divergence and vorticity on the mesoscale from aircraft. J. Atmos. Oceanic Technol. 16: 1384-1400.
19. Lilly DK. 1968. Models of cloudy-topped mixed layers under a strong inversion. Q. J. R. Meteorol. Soc. 94: 292-309.
20. Lohou F, Said F, Lothon M, Durand P, Serça D. 2009. Planetary boundary-layer processes signatures on turbulent characteristics and heat fluxes at surface. Boundary-Layer Meteorol. submitted
21. Lothon M, Couvreux F, Donier S, Guichard F, Lacarrère P, Noilhan J, Said F. 2007. Impact of the coherent eddies on airborne measurements of vertical turbulent fluxes. Boundary-Layer Meteorol. 124: 425-447.
22. Lothon M, Said F, Lohou F, Campistron B. 2008. Observation of the diurnal cycle in the low troposphere of West Africa. Mon. Weather Rev. 136: 3477-3500.
23. Lothon M, Lenschow DH, Mayor S. 2009. Doppler lidar measurements of vertical velocity spectra in the convective boundary layer. Boundary-Layer Meteorol. DOI: 10.1007/s10546-009-9398-y.
24. Mahrt L, Lenschow DH. 1976. Growth dynamics of the convective mixed layer. J. Atmos. Sci. 33: 41-51.
25. Miao Q, Geerts B. 2006. Vertical velocity and buoyancy characteristics of coherent echo plumes in the convective boundary layer, detected by a profiling airborne radar. J. Appl. Meteorol. Climatol. 45: 838-855.
26. Miller J, Thomas A, Bannon P. 2001. A shallow-water model of the diurnal dryline. J. Atmos. Sci. 58: 3508-3524.
27. Nicholls S. 1989. The structure of radiatively driven convection in stratocumulus. Q. J. R. Meteorol. Soc. 115: 487-510.
28. Parker DJ, Burton RR, Diongue-Niang A, Ellis RJ, Felton MA, Taylor CM, Thorncroft CD, Bessemoulin P, Tompkins A. 2005. The diurnal cycle of the West African Monsoon circulation. Q. J. R. Meteorol. Soc. 131: 2839-2860.
29. Peyrillé P. 2005. 'Etude idéalisée de la mousson ouest-africaine à partir d'un modèle numérique bi-dimensionnel'. PhD thesis, Université Toulouse III, France.
30. Peyrillé P, Lafore J-P. 2007. An idealized two-dimensional framework to study the West African Monsoon. Part II: Large-scale advection and the diurnal cycle. J. Atmos. Sci. 64: 2783-2803.
31. Pino D. 2006. Role of shear and the inversion strength during sunset turbulence over land: Characteristic length scales. Boundary-Layer Meteorol. 121: 537-556.
32. Redelsperger J, Thorncroft C, Diedhiou A, Lebel T, Parker DJ, Polcher J. 2006. African Monsoon Multidisciplinary Analysis (AMMA): An international research project and field campaign. Bull. Amer. Meteorol. Soc. 87: 1739-1746.
33. Roca R, Lafore J-P, Piriou C, Redelsperger J-L. 2005. Extratropical dry-air intrusions into the West African monsoon midtroposphere: An important factor for the convective activity over the Sahel. J. Atmos. Sci. 62: 390-407.
34. Saïd F, Canut G, Durand P, Lohou F, Lothon M. 2009. Seasonal evolution of the boundary-layer turbulence measured by aircraft during the AMMA 2006 Special Observation Period. Q. J. R. Meteorol. Soc. 136(s1): 47-65
35. Stevens B. 2002. Entrainment in stratocumulus-topped mixed layers. Q. J. R. Meteorol. Soc. 128: 2663-2690.
36. Stevens B, Lenschow DH, Faloona I, Moeng C-H, Lilly DK, Blomquist B, Vali G, Bandy A, Campos T, Gerber H, Haimov S, Morley B, Thornton D. 2003. On entrainment rates in nocturnal marine stratocumulus. Q. J. R. Meteorol. Soc. 129: 3469-3492.
37. Sultan B, Janicot S. 2000. Abrupt shift of the ITCZ over West Africa. Geophys. Res. Lett. 27: 3353-3356.
38. Tennekes H. 1973. A model for the dynamics of the inversion above a convective boundary layer. J. Atmos. Sci. 30: 538-567.
39. Träumner K, Wieser A, Kottmeier C, Corsmeier U. 2009. 'Short-time fluctuations of the convective boundary-layer height and entrainment processes observed with Doppler lidar'. Proceedings of the 4th Symposium on Lidar Atmospheric Applications, Phoenix, Arizona. Amer. Meteorol. Soc: Boston.
40. 20 project (IHOP 2002) and some preliminary highlights. Bull. Amer. Meteorol. Soc. 85: 253-277.