regional trends in the land carbon cycle and the underlying mechanisms over the period, 1980-2009 s....
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Regional trends in the land carbon cycle and the underlying mechanisms
over the period, 1980-2009
S. Sitch, P. Friedlingstein, G. Bonan, P. Canadell, P. Ciais, P.M. Cox, P. Foster, E. Gloor, K. Goldewijk, C. Huntingford, G. Hurtt, C. D. Jones, S. Piao, I.C. Prentice, C. Le Quere, P. Levy, M. R. Lomas, L. Mercado, B.
Mueller, M. Reichstein, S. Running, S. I. Seneviratne, E. Shevliakova, P. Thornton, N. Viovy , G. van der Werf, F. I. Woodward, S. Zaehle, M. Zhao
Photosynthesis
CO2
Plant respiration
CO2
CO2
Soil respiration
(heterotrophic)
RH
Net ecosystem exchange NEE
Terminology
Net Primary productivity (NPP)=
GPP-Plant respiration
RH - NPP
Gross Primary productivity (GPP)=
Photosynthesis +leaf respiration
Total CO2 emissions
Atmosphere
Data: NOAA, CDIAC; Le Quéré et al. 2009, Nature-geoscience
CO2 P
artit
ioni
ng (P
gC y
-1)
1960 20101970 1990 20001980
10
8
6
4
2
Key Diagnostic of the Carbon CycleEvolution of the fraction of total emissions that remain in the atmosphere
Fate of Anthropogenic CO2 Emissions (2000-2008)
Le Quéré et al. 2009, Nature-geoscience; Canadell et al. 2007, PNAS, updated
1.4 PgC y-1
+7.7 PgC y-1
3.0 PgC y-1
29%
4.1 PgC y-1
45%
26%2.3 PgC y-1
Modelled Natural CO2 Sinks
Le Quéré et al. 2009, Nature-geoscience
Global Annual Budget Regional Trends in Land C-Sinks (Trendy)Compare DGVM-based estimates with other
evidence- Satellite derived data
- Fluxtower data
- Atmospheric Monitoring Stations
Regional Trends in C-sinks and Annual Global Budget
GCP- Land trends: modelling protocol Contact: Stephen Sitch ([email protected]) & Pierre Friedlingstein ([email protected])Goal: To investigate the trends in NEE over the period 1980-2009
Participating modelsJULES, LPX, ORCHIDEE, O-CN, HyLand, SDGVM, NCAR CLM4, GFDL/Princeton
Model simulationsThe models will be forced over the 1860-2009 period with changing CO2, climate (CRU/NCEP)
and land use:
S1: CO2 onlyS2: CO2 and climateS3 (optional): CO2, climate and land use
Trendy Protocol
Land Source trend
positive NPP trend < positive RESP trend
negative NPP trend < negative RESP trend
negative NPP trend, positive RESP trend
Land Sink trend
positive NPP trend > positive RESP trend
negative NPP trend > negative RESP trend
positive NPP trend, negative RESP trend
Trends in Land Processes
Land Sink trend
positive NPP trend > positive RESP trend
negative NPP trend > negative RESP trend
positive NPP trend, negative RESP trend
Land Source trend
positive NPP trend < positive RESP trend
negative NPP trend < negative RESP trend
negative NPP trend, positive RESP trend
Climatic Drivers of Trends in Land Processes
B. Mueller, ETH Zurich
Satellite Evidence: Trends in Soil Moisture
0.95
1
1.05
1.1
1.15
1.2
1.25
1.3
1.35
1900 1920 1940 1960 1980 2000
Frac
tion
al N
PP C
hang
e
Year
TRIF FNPP
LPJ FNPP
SDGVM FNPP
Remarkable Similarity between NPP evolution from DGVMs
Global NPP explains most of the NEE variability
DGVM sink vs MODIS-NPP)
M Zhao
Alternative Upscaling Approaches Multidimensional flux patterns...
0 2000LE [MJ m-2 yr-1]
0
2000
H [
MJ
m-2
yr-
1]
Color: GPP
... models to be cross-evaluated against.Reichstein
remote sensingof CO2
Tem
pora
l sc
ale
Spatial scale [km]
hour
day
week
month
year
decade
century
local 0.1 1 10 100 1000 10 000 global
forestinventory
plot
Countries EUplot/site
talltowerobser-
vatories
Forest/soil inventories
Eddycovariance
towers
Landsurface remote sensing
JJA
Stippled areas > 90% of the models agree in the sign of the change
http://www.ipcc.ch/
Future Precipitation Changes (Summer Droughts?)
Use set-up to produce global/regional annual C-budgetsDrought may be an important driver of the present-day
trends in the land carbon cycleClimate Models Project Summer Drought in Continental
RegionsDrought may be an important driver of the future trends
in the land carbon cycleCritical to understand Ecosystem Response to Drought
for future Earth System feedbacks
Summary