Post on 06-Jun-2020
transcript
Ph. Ciais , M. Reichstein, N. Viovy
A. Granier , J. Ogée , V. Allard , M. Aubinet , Chr. Bernhofer , A.Carrara , F. Chevallier , T. Conway, N. De Noblet , A. Friend , T.
Grünwald , B. Heinesch , G. Inoue, P. Keronen, A. Knohl, D.Loustau , G. Manca , T. Machida, G. Matteucci , F. Miglietta , J.M.
Ourcival , K. Pilegaard , P. Peylin, S. Rambal , P. Rayner, G.Seufert , J.-F. Soussana , M.-J. Sanz ,
E.D. Schulze , T. Vesala, and R. Valentini
Europe-wide reduction in primary productivitycaused by the heat and drought in 2003
Linking the 2003 European heatwavewith carbon observations
Secular increase in primary productivityfrom satellite NDVI over the past 20 years Nemani et al., Science 2003
% per year
Will the greening trends continue with morefrequent climate extremes ?
Can positive carbon-climate feedbacks come fromtemperate regions ?
Shär et al., Nature 2003
Historical temperaturerecords in Switzerland
Summer temperature reconstructionfrom harvest dates in Burgundy
Chuine et al., Nature, 2003
Precipitation history in BavariaEurope-wide climateSpell : heat & drought
Temperate and Mediterranean forestsshow reduced, GPP, TER, NEE
Towerfluxes
Measured NEE, ETDerived GPP, NPP
Model GPP, TERModel ETModel NPP
Model LAI
ORCHIDEEmodel
Global Climate1900-2003
Hourly 30 -100 km
TowerClimate
hourly
TowerClimate
hourly
TowerClimate
2003-2003hourly
space
time
EOS-MODIS FAPAR
Spatial average
Crop Yield Country
Average / species
Spatialaverage
Model FAPAR
Gridpoint
modelling system
30 min
Climate, andcarbon fluxes insummer 2002
vs.summer 2003
AbnormalClimate and
ModelledProductivity in
2003
EOS-MODISFAPARanomaly
How abnormal is 2003 ?
Verificationagainst
crops yieldnational
data
Interannual variations in CO2 growth rate
70 sitesGrid based inversion(3.5 x 2.5°)
LMDZ model
Interannual winds
Spatial correlations
Anomalies vs. mean97-03
Atmosphere-based inversion estimate
See Peylin et al. Posteralso Patra, Roedenbeck…
Breda et al. 2004
Soil water content variation model andobservations indicate large water stress atall sites in 2003 with Root ExtractableWater REW < 0.
0
50
100
150
200
0 60 120 180 240 300 360
DOY (2003)e
xtra
cta
ble
wa
te
r
(m
m)
Vielsalm
Hyytiala
Hainich
Hesse
SorØ
Tharandt
Braschaat
Fougères
Bray
Lille
Grillenburg
Loobos
Processes
Small Changes in water use efficiency
Effects of high ozone exposure
JJA 2002JJA 2002 JJA 2003JJA 2003
Carboncrashesin therecentpast
• Uniquely dense eddy covariance network to understandclimate-carbon-water interactions at the sub-continentallevel
• Severe drop of transpiration and GPP
• Respiration tailed off with GPP drop rather than increasedwith warming
• forests became net CO2 sources to the atmosphere in July-Aug !
• Anomalous source of 0.5 PgC y-1, undoing years of meansink, enough to explain 50% of the global CO2 growth rateanomaly during 2003
Conclusions (1)
Conclusions (2)
• In the future, adverse impacts of climateextremes may cancel out the benefits ofmoderate climate change
• Forest productivity may be durably reduced ifextremes become more frequent
• In the long run, conifer forest may be moreadapted to future climate conditions in Europe
• And so large uncertainties !
Implications for the future
SummertemperaturesObserved &Modelledby IPSL GCM
2003 2005
FPAR anomalies & recent droughts