ODINAFRICA/GLOSS ODINAFRICA/GLOSS Sea Level Training CourseSea Level Training Course

Regional Oceanography and Climate (West Africa)

13-24 November 2006, Oostende

Angora AMAN

Niger à Malanville: 106 km²

Humid

Dry

Ind

ice

plu

vio

mét

riq

ue

Sah

el

Sahel Rainfall index Recall: why AMMA ?

The Gulf of Guinea is very badly simulated in numerical models…

-Pb with fluxes; (eg wind stress, local air-sea interaction, convective heating over land of S. America and W. Africa)

-Pb with mixing processes;

- Pb with horizontal advection + interactions with subsurface

-Pb with effect of waves;

SST Surface fluxes

Pb mostly in the GG…

WEST AFRICA CLIMATEWEST AFRICA CLIMATE

Importance of the GG in the West Africa Importance of the GG in the West Africa ClimatologyClimatology

- Principal source of the WV which is Principal source of the WV which is advected by the atmospheric advected by the atmospheric circulation. It can constitute most of circulation. It can constitute most of precipitations on the continentprecipitations on the continent

- The SST in the GG is also one of the The SST in the GG is also one of the factors, with continental surface which factors, with continental surface which conditions the intensity of the monsoon conditions the intensity of the monsoon of West Africa.of West Africa.

Atmospheric circulation (averaged winds)Circulation atmosphérique (vents moyens)

Wauthy, 1983

January

April

July

October

Cersat,Année 2005

Annual cycle of precipitation / Cycle annuel des précipitations

(Nicholson)

: PIRATA (needed for AMMA)

(Pilot Research moored Array in the Tropical Atlantic) (1997 - 200??)(African Monsoon Multidisciplinary Analyses)

Tripartite Programme as a contribution to CLIVAR, GCOS and GOOS :

- FRANCE (IRD/LEGOS, Météo-France)- BRESIL (INPE, DHN)- USA (NOAA/PMEL)

Photo: A.Kartavtseff

PIRATA ATLAS buoys network

in October 2005

yearly dedicated cruises needed for replacement/deployment of mooorings

PIRATA ATLAS buoys:

Measured Parameters :Atmosphere: - wind (direction, speed) - relative humidity - air temperature - precipitation - incident radiation Ocean: - temperature (11 levels from surface to 500m) - salinity (4 levels; 0,20,40,120m) - pressure (at 300 & 500m)

- Daily averaged data transmitted in real time by Argos;- High frequency data (10mn) available after servicing operations

http://www.brest.ird.fr/pirata/piratafr.html

Web sites: http://www.pmel.noaa.gov/pirata/

What is AMMA?

Scientists from more than 25 agencies/institutions in more than 20 countries in Africa, Europe and the US are involved: Algeria, Benin, Burkina Faso, Cameroon, Chad, Denmark, France, Germany, Ghana, Italy, Ivory Coast, Mali, Niger, Nigeria, Senegal, Spain, Togo, UK, US

International Science and Implementation Working Groups are formed

Endorsement received from WCRP (CLIVAR & GEWEX), GCOS, …

French, UK & USA funding agencies have declared support

2. A coordinated international effort

2: International program

AMMAAfrican Monsoon Multidisciplinary Analyses

2nd ODINAFRICA Seminar ; Ostende, April 24, 2006

Egée 1 trackline (June-July 2005) Egée 2 trackline (September 2005)

(Repeated sections at 10°W, 3°E; Contribution to PIRATA, ARGO (Coriolis), GODAE (Mercator)…. + opportunities for other programs as JGOF (CO2, biogeochemistry…)

EGEE / AMMA cruises:

French EGEE program : => 6 cruises, 2 per year in 2005, 2006 & 2007 interannual variability (Egée 1->6) + intra-annual (Egée 3)

 

Measurements at São Tomé Island (0°N, 6°E)

2) Tide gauge maintained by IRD since 1980s.- Pressure, Atm. pressure + SST & SSS.- Part of GLOOS. - GPS positioned (in December 2002)

1) Installation ofa meteorological

station in October 2003 + ONSET autonomous

temperature sensor in September 2005

EGEE:EGEE:

Meteorological Station + Tide gauge

SST annual evolution from in situ records

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1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Date

Pointe Noire

Abidjan

Cotonou

Tema

San Pedro

Lagos

Pointe Noire – Cotonou- Tema - Abidjan

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24

25

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1955 1960 1965 1970 1975 1980 1985

Date

Pointe Noire

Abidjan

Cotonou

Tema

Comparison Tabou - Lagos

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30

1975 1980 1985 1990 1995 2000 2005

Date

SS

T Lagos

Tabou

Comparison between in situ and satellite SST measurements (Tema)

TEMA

y = 0,6359x + 9,6278

R2 = 0,8517

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25

26

27

28

29

30

16 18 20 22 24 26 28 30 32

données in situ

do

nn

ées

sat

Série1

Linéaire (Série1)

Comparison between in situ and satellite SST measurements (Tabou)

TABOU

y = 0.6424x + 10.052

R2 = 0.7567

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30

18 20 22 24 26 28 30

situ

sat Série1

Linéaire (Série1)

Comparison between in situ and satellite SST measurements (Abidjan)

comparison de données sat et in situ Abidjan

y = 0.5855x + 11.326

R2 = 0.8644

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30

18 20 22 24 26 28 30 32

situ

sa

t Série1

Linéaire (Série1)

Comparison SST and SL (r =0.75)

moyenne par quinzaine de la TSM et du NM 1991 à 1996

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30

J J F F M M A A M M J J J J A A S S O O N N D D Mois

TSM

(°C

)

95

100

105

110

115

120

NM

(cm

)

TSM

NM

Comparison SST and SL (r=0.93)

moyenne par quinzaine de la TSM et du NM (NM retardé de 15 jours)

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20

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28

30

J J F F M M A A M M J J J J A A S S O O N N D D Mois

TSM

(°C)

95

100

105

110

115

120

NM (c

m) TSM

NM

SST and SL anomalies (San Pedro)

ODINAFRICA CONTRIBUTION

Information from African coast is needed to Information from African coast is needed to contribute to the global sea level monitoring network contribute to the global sea level monitoring network that understands the climate change. Better that understands the climate change. Better understanding on the futures of the GG.understanding on the futures of the GG.

Contribution of ODINAFRICA to:Contribution of ODINAFRICA to:

- the World Ocean Circulation Experiment (WOCE).- the World Ocean Circulation Experiment (WOCE).

Climate Variability (CLIVAR)Climate Variability (CLIVAR)

African Multidisciplinary Monsoon Analysis (AMMA)African Multidisciplinary Monsoon Analysis (AMMA)

GLOSSGLOSS