WEST AFRICAN MONSOON EXPERIMENT WAM Focuses on both
WEST AFRICAN MONSOON EXPERIMENT (WAM) • Focuses on both dynamical and chemical aspects of monsoon • European leadership (France, UK), U. S. involvement through NCAR (dynamics) • white paper is available • Chemical objective: What is the impact of the West African Monsoon on tropical chemistry and climate at local, regional and global scale? • biogenic, lightning, dust, biomass burning, growing urban emissions • convective processing SOP 3 • Three intensives planned during 2005 • monsoon onset (April) • monsoon maximum (August) • late monsoon (October) SOP 1 and 2
WESTERN AFRICA IS AN ACTIVE AND COMPLEX REGION OF THE TROPICS Dust Anthropogenic Biofuel Ocean Monsoon Flux Harmattan Flux Savanna Forest Biomass Burning Celine Mari, LA Toulouse
ATSR FIRE COUNTS
TROPOSPHERIC OZONE COLUMNS (Sep’ 96 -Aug’ 97) [Martin et. , 2002] GEOS-CHEM TOMS (CCD) DJF MAM JJA SON R = 0. 75, BIAS = -1 DU
OZONE VERTICAL PROFILES OVER ABIDJAN North African Dec-Feb ozone enhancement from biomass burning Is seen by aircraft observations but not by TOMS GEOSCHEM TOMS (distributed w/assumed standard profile) MOZAIC aircraft data Martin et al. [2002]
LOW SENSITIVITY OF TOMS IN LOWER TROPOSPHERE HAMPERS DETECTION OF OZONE ENHANCEMENTS FROM BIOMASS BURNING IN N AFRICA AND SE ASIA TOMS sensitivity to ozone (LIDORT radiative transfer model) TOMS standard profiles S. Atlantic profile Abidjan profile Martin et al. [2002]
MAXIMUM OZONE ENHANCEMENT FROM LIGHTNING PREDICTED OVER THE SOUTH ATLANTIC YEAR-ROUND Difference between standard and no-lightning GEOS-CHEM simulations Martin et al. [2002]
PROPOSAL: TWO NASA WAM TROPICAL MINI-MISSIONS (January and August) • Scientific objective: quantify biomass burning and lightning influences on ozone and related species over western Africa, investigate convective processing during monsoon • Aura validation objective: obtain vertical profiles of ozone, H 2 O, CO, aerosols, other species (see Stan’s list) over western Africa under range of conditions – understand bias in solar UV backscatter instruments (TOMS). Expect high complementarity with TC 3. • Need DC-8 + higher-flying aircraft (WB-57) operating from west coast of Africa (Ivory Coast, Benin). Minimum instrumentation includes ozone and precursors, aerosols • minimum of 40 flight hours per aircraft per deployment
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