WESTERN AFRICA MISSION (WAM):WESTERN AFRICA MISSION (WAM):An AURA Collaborative Science An AURA Collaborative Science

MissionMission

Planning Committee: D.J. Jacob, E.V. Browell, W.H. Brune, J.H. Crawford, J.A. Logan, H.B. Singh

AURA Validation WorkshopPasadena, March 19-20, 2002

WESTERN AFRICA MISSION (WAM)WESTERN AFRICA MISSION (WAM)an AURA collaborative science missionan AURA collaborative science mission

OBJECTIVES:• To understand the interactions between biomass burning, the biosphere, human activity, lightning, and dust in determining tropospheric ozone and aerosol production over western Africa;

•To understand the role of deep convection, the monsoon, and other flow patterns in the processing of these emissions;

•To understand the mechanisms for outflow of ozone, aerosols, and their precursors from western Africa to the global troposphere;

• To provide Aura tropospheric validation data in a complex and highly variable tropical environment where TOMS appears to experience unresolved difficulties.

Opportunity for collaboration with European AMMA (African Monsoon Multidisciplinary Analysis) field campaigns in 2005 (ground stations, light aircraft).

Dust

SavannaAnthropogenicBiofuel

Forest

Biomass Burning

Ocean

Monsoon Flux

Harmattan Flux

WESTERN AFRICA IS A PARTICULARLY ACTIVE WESTERN AFRICA IS A PARTICULARLY ACTIVE AND COMPLEX REGION OF THE TROPICSAND COMPLEX REGION OF THE TROPICS

Celine Mari, LA Toulouse

Biomass BurningLightning

ATSR FIRE COUNTS (1997)ATSR FIRE COUNTS (1997)Western Africa is one of the world’s most active Western Africa is one of the world’s most active

biomass burning regions: DJF seasonbiomass burning regions: DJF season

LARGE DIFFERENCE BETWEEN MODEL AND TOMS LARGE DIFFERENCE BETWEEN MODEL AND TOMS TROPOSPHERIC OZONE COLUMNS OVER W. AFRICATROPOSPHERIC OZONE COLUMNS OVER W. AFRICA

GEOS-CHEM - 1997 TOMS (CCD)- 1997

JJA

SON

MAM

DJF

Martin et al. [2002]

OZONE VERTICAL PROFILES OVER ABIDJANOZONE VERTICAL PROFILES OVER ABIDJANNorth African Dec-Feb ozone enhancement from biomass burning Is seen by aircraft observations but not by TOMS (Martin et al., 2002)

MOZAICaircraftdata

GEOS-CHEM

TOMS(distributed w/assumed standard profile)

Note: in situ observations over and around western Africa are exceedingly few!

LIS LIGHTNING FLASHES (2000)LIS LIGHTNING FLASHES (2000)Western Africa is one of the world’s most active Western Africa is one of the world’s most active

lightning regionslightning regions

DJF

JJA

……AND YET MODELS PREDICT MAX. LIGHTNING AND YET MODELS PREDICT MAX. LIGHTNING INFLUENCE ON OZONE OVER S. ATLANTIC YEAR-ROUND INFLUENCE ON OZONE OVER S. ATLANTIC YEAR-ROUND

Difference between standard and no-lightning GEOS-CHEM simulations

Martin et al.[2002]

HIGH AFRICAN BIOGENIC VOC EMISSIONS HIGH AFRICAN BIOGENIC VOC EMISSIONS SEEN BY GOME SEEN BY GOME

T. Kurosu (SAO) and P. Palmer (Harvard)

WESTERN AFRICA IS ONE OF THE DUSTIEST WESTERN AFRICA IS ONE OF THE DUSTIEST REGIONS ON EARTHREGIONS ON EARTH

DUST OVER WESTERN AFRICA CAN HAVEDUST OVER WESTERN AFRICA CAN HAVECOMPLEX EFFECTS ON SATELLITE RETRIEVALSCOMPLEX EFFECTS ON SATELLITE RETRIEVALS

SeaWIFS “true-color” data (obtained from R. Husar)

INTEGRATED OBSERVATIONAL STRATEGYINTEGRATED OBSERVATIONAL STRATEGYFOR WAMFOR WAM

AURA: Ozone, CO, H2O,NO, NO2, HNO3,CH4, HCHO, …

3-D CTM forecasts and analyses

WB-57 and DC-8 aircraft

SATELLITES

AIRCRAFT, SONDES, GROUNDMODELS

Design mission to optimize value of combinedAURA/aircraft data set towards addressing mission objectives and testing relevant CTMs; AURA validation is an essential component of process

Others: CO2, aerosols,surface properties,lightning…

WAM MISSION PLANWAM MISSION PLAN• Two aircraft

• WB-57: vertical profiles to tropopause, convective outflow• DC-8: source region characterization, lower-altitude outflow

• Link with other AURA validation missions• WAM will be part of AVE and may link with TC3 Costa Rica deployment; WAM complements TC3 which focuses on cleaner and simpler regions of the tropics.

•Two seasons• winter (Jan-Feb): biomass burning• summer or shoulder season (Apr-Oct): monsoon, lightning

•Bases of operations• Ivory Coast , Benin, Senegal (link with European planning)

• Ancillary measurements• Ozonesonde launches, ground-based lidar• Coordination with European aircraft, ground-based stations

•Timing• 2005 for summer phase would take advantage of European participation.

WAM AIRCRAFT PAYLOADS AND FLIGHT PLANSWAM AIRCRAFT PAYLOADS AND FLIGHT PLANS

• PAYLOADS– WB-57: AVE payload – DC-8:

• Remote ozone, aerosol, water vapor

• Ozone, CO, CO2, H2O, UV, aerosol properties, NOy species, HOx and HOy species , VOCs, ammonia

• FLIGHT PLANS – Convective flights (WB-57, DC-8): vertical profiles in convective inflow/outflow,

contrast to background– Source characterization flights (DC-8)– Chemical outflow and aging flights (DC-8)

• AURA VALIDATION STRATEGY– Use WB-57 profiling capabilities, support with DC-8 detailed aerosol/chemical

payload and lidars.