bauru november 2004 modelling interpretation of in situ h2o, ch4 and co2 measured by sdla balloon...
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Bauru November 2004
Modelling interpretation of in situ H2O, CH4 and CO2 measured by
SDLA balloon borne instrument (SF2 and SF4 flights).
N. Huret(1),G. Durry (2),S. Freitas(3),M.Pirre(1) , A. Hauchcorne(2)
(1) LPCE/CNRS,France(2)IPSL, Service d’Aéronomie du CNRS,France
(3)CPTEC, Brazil
Bauru November 2004
OBJECTIVES
• To understand how the convection can modify the Upper Troposphere (UT) and the Tropical Transition Layer (TTL) ?
• What type of model we have to use to investigate the tropical UT and TTL ?
• Previously in polar region and at mid-latitude we used insentropic trajectories from ECMWF
Bauru November 2004
Mesoscale interpretation
• RAMS/CPTEC model outputsOperational mesoscale model (40 km x 40
km)
• 3D trajectory code (Freitas et al. 2000)
– 4 days backward trajectories – 10-20 km every km– Temperature, pressure, water vapor,
liquid water content, solid water content, vertical velocity
Bauru November 2004
• SF2 flight, 13 February 2004
•Upper troposphere : Air mass ascent from 8 to 10.5 km, 20h before the measurements
•Tropical Transition Layer : nothing special
Bauru November 2004
• SF4 flight, 24 February 2004
•Tropical Transition Layer : very strong uplifting from the ground to 17 km 80h before the measurements
Bauru November 2004
Is SF4 17km trajectory realistic ?
• Very strong uplifting from the ground to 17 km, 80h before the measurements
• Does a strong convective system exist ?
•Accumulated precipitation map from RAMS and TRMM satellite data
•GOES-E satellite cloud MAP
• Does RAMS mesocale model predict this convective system at the good location ?
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3 days before the SF4 measurements
A strong convective system exists at the location of the uplifting
SF4 RAMS Validation
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• RAMS validation : accumulated
precipitation• RAMS outputs / TRMM satellite data
•This case was very convective because of the South Atlantic Convergence Zone activity• RAMS predictions are validated
Bauru November 2004
SDLA water vapor measurementsSF2/ SF4 comparison
• a water vapor bubble from SDLA (17 km) for SF4
• can be due to a deep convective system seen on GOES satellite maps and simulated using RAMS mesocale model
• The convection affects the TTL
Bauru November 2004
RAMS(40 km) grid close to BauruProfiles extracted at each grid point in this region
Bauru
Bauru November 2004
RAMS water vapor profiles
Water vapor excess in the TTL
Very dry layerIn the UT :
SF4
Good agreement between RAMS simulation and measurementsExcept : between 14 and 16 km but not critical
between 8-10km in the UT
Bauru November 2004
SDLA-RAMS temperature profiles comparisons
Bauru November 2004
Mixing ratio RAMS fields
Bauru
Strong water vapor gradient south of Bauru The dry layer is predicted by the RAMS model
Bauru
Bauru November 2004
MIMOSA PV contour advection model
Hauchecorne et al. 2001• On isentropic surfaces MIMOSA
calculates the Potential vorticity evolution from ECMWF wind fields.
• Global scale transport
340 K isentropic surface
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MIMOSA Outputs
PV filament coming from low stratopshere mid-latitude with PVU > 2Large scale isentropic transport
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SF4 : CH4 , CO2 , H2O and O3 (sonde)
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CONCLUSIONS SF4 flightStrong uplifting from the ground to the TTL (17 km) due to convectionMesoscale transport process
Isentropic transport from mid- latitude to the tropical UT (8-10 km)Large scale transport
SF4 profiles
Bauru November 2004
Many thanks
• TROCCIBRAS partners• team from USP and CPTEC
– S. Freitas – P. Leite da Silva Dias
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