ECMWF IFS

Rnet (net radiation)

Met station Agoufou, 1.5W,15.3N

MJJA 2005

weaker seasonal dynamic of Rnet in the model (MJJA mean values rather close)

* IFS Rnet larger in May, smaller during the monsoon* also, less day to day variability (just a bit of caution, not exactly same time sampling/smoothing here, + maybe effect of 1 point versus ~(40 km)**2 area)

decomposition in SW, LW, up & down fluxes, next slidesseasonal dynamics explained mostly by upward fluxes monsoon trends (both SW and LW)

more differences between IFS and Met station in 2005 (these plots) than in 2004 (dry year) because of weaker seasonal dynamics of measured radiative fluxes for dry years

24-h avg values 3-day running

mean

Observations provided by the CESBIO team: Mougin, Timouk, Kergoat et al

Rnet

SWnet

ECMWF IFS

Rnet

SW cloud forcing

clear sky SW net

LWnet

-20-LW cloud forcing

clear sky LW netLWnet

SWnet

Met station Agoufou, 1.5W,15.3N

MJJA 2005 24-h avg values 3-day running

mean

SW dow

n

LW dow

n

SW up

LW up

Met station Agoufou, 1.5W,15.3N

MJJA 2005

day of year 2005 day of year 2005

ECMWF IFS

24-h avg values 3-day running

mean

JunJulAugSep

Met station Agoufou 1.5W,15.3N

2002, Rnet

This slide and next ones for 2003 to 2006 illustrate interannual variability and show how the differences between years take place mostly during daytime

JunJulAugSep

Met station Agoufou 1.5W,15.3N

2003, Rnet

JunJulAugSep

Met station Agoufou 1.5W,15.3N

2004, Rnet

JunJulAugSep

Met station Agoufou 1.5W,15.3N

2005, Rnet

JunJulAugSep

Met station Agoufou 1.5W,15.3N

2006, Rnet

variations along latitude (North Sahel)

weel, with 2 met stations only, 15.3N & 17N, in 2004

interannual variability

with 2004 and 2005, met station at 15.3N

note: there is a meaningful seasonal variation of albedo in the IFS, in terms of shape but it is less than 0.02 in amplitude – I have just drawn a line to indicate the avg value in the IFS.

2004 Bamba, 1.5W , 17.0N

0.4

Albedo ECMWF ~ 0.38

Rnet ECMWF IFS

Rnet Met station

2004 Agoufou 1.5W , 15.3N

0.4

Albedo ECMWF ~ 0.27

Rnet ECMWF IFS

Rnet Met station

2005 Agoufou 1.5W , 15.3N

Albedo ECMWF ~ 0.28

Rnet ECMWF IFS

Rnet Met station

Cloud cover and rainfall in the IFS Sahel, 2 next slides

an example with 1 met station 15.3N , in 2004 24-h average values, except rainfall: 24-h cumulative (also shown, surface heat fluxes H and LE) ok I made them with 24h starting each day something like 6 or 9 hours after the model start, i.e. Possibly a bit early with respect to spin-uo-down but it may be less of a pb at this latitude (?)

then a slide showing some characteristics of the measured rainfall

overall, in the IFS it does not seem to me that there is a clear underestimation of rainfall events but there is an underestimation of rainfall per rainfall event (I base this argument on more than these examples of course)the stratiform rainfall being negligible in the IFS does not seems wrong to me

note: simulated stratiform rainfall negligible

composite precipitation events Agoufou 2002,2003,2005,2006from met station, for Jun Jul Aug Sep, other colours=other months

duration

Rang

e of

fluc

tuat

ions

OBS

ECMWF IFS

LWnet+cstA,SWnet+cstB

Rnet

Distinct interannual signatures of Rnet in OBS & ECMWF IFS, qualitatively similar LW & SW differences for wet (2003) versus dry (2004) monsoon seasons but the sum LW+SW reflect the quantitative differences

SWnet

SWnet LWnet

LWnet