Drought in the African Sahel

Alessandra Giannini4 December 2006

http://www.pbs.org/wnet/africa/explore/sahel/sahel_overview.html

the Sahel

r = 0.60

A. Giannini, R. Saravanan and P. Chang, 2003. Science, 302, 1027-1030Also see e.g. Bader and Latif, 2003 (GRL); Lu and Delworth, 2005 (GRL)

OUTLINE:

1. climate dynamics/predictability2. climate change3. education/outreach/science-informed policy

1. climate dynamics/predictability2. climate change3. education/outreach/science-informed policy

Gul

f of

Gui

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patt

ern

Sah

el p

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Giannini et al., 2003 (Science), 2005 (Clim. Dyn.)

Giannini et al., 2003 (Science), 2005 (Clim. Dyn.)

Giannini et al 2003

.

dynamics: warmer oceans v. stronger monsoons?

Giannini et al., 2005 (Clim. Dyn.)

200 hPa h, (u,v)

precipitation

SST, 850hPa (u,v)

Giannini et al., 2005 (Clim. Dyn.)

200 hPa h, (u,v)

precipitation

SST, 850hPa (u,v)

N. Zeng, Science, 7 November 2003

SST

CMAP

ECPCfiltered

SSTanomaly

ECPC

Tippett 2006 (GRL)

August 1984

1. climate dynamics/predictability2. climate change3. education/outreach/science-informed policy

NASA/GISS analysis of surface temp – linear trend 1950-2000Hansen et al. 1999 (J. Geophys. Res.)

regression of NASA/NSIPP1 Sahel PC and sfc tempGiannini et al. 2003, 2005

IPCC 4th Assessment Report (4AR) simulations with 19 modelsBiasutti and Giannini 2006 (GRL)

19 Coupled GCM : XX-PI precipitation/surface temperature changes

Biasutti and Giannini, 2006 (GRL)

Biasutti and Giannini, 2006 (GRL)

Held et al., PNAS 2005

GFDL CM2.0 GMAO(NSIPP1) NCAR CAM3

surface air temperature

(minus global mean)

precipitation

Haarsma et al., GRL 2005 2050-2080 minus 1950-1980

1. climate dynamics/predictability2. climate change3. education/outreach/science-informed policy

Implications:1. “Farmers freed of blame for Sahel drought” (SciDev.Net)2. Policy/intervention issues:

a. spatial scales: from desertification to global warmingb. temporal scales: from early warning to structural change

(lessons have already been learned from the past 30 years or so!)

how to use scientific knowledge?- global/regional policy- local education/outreach

what are local perceptions on the causes of drought?how does Western science relate to them?

Lu and Delworth, 2005 (Geophys. Res. Lett.)

The relative roles of Atlantic, Indian and Pacific SSTs

19 Coupled GCM :Sahel XX-PI Rainfall Change

Biasutti and Giannini, 2006 (GRL)

Courtesy of Isaac Held, Jian Lu, Tom Delworth et al, GFDL

21st century outlook for Sahel precipitation

Indramayu, Jawa Barat

Bali Nusa Tenggara Timur

IRI Asia-Pacific Regional Program project on:“Climate forecast applications for disaster mitigation in Indonesia, Philippines and Vietnam”

SON(0) 1979-2004 JFM(1)

1950-1975

Giannini, Robertson, Qian, Li H. ...

DJF

(1)

SO

N(0

)

RegCM3 at 25km resolution(Joshua Qian, Huilan Li)

DJF

(1)

SO

N(0

)