Extreme eventsExtreme events

ObjectiveObjective: characterizing ecosystem/carbon : characterizing ecosystem/carbon response to extreme climate events; response to extreme climate events; understanding the processes and mechanisms understanding the processes and mechanisms that will be useful for future projectionsthat will be useful for future projections

MethodMethod: using a suite of models and data: : using a suite of models and data: foward/inversion/flux/satellitefoward/inversion/flux/satellite

Forcings: PDSI, P, Temp, …Forcings: PDSI, P, Temp, … Correlation analysisCorrelation analysis Sensitivity experimentsSensitivity experiments

Processes: NPP, Rh, …Processes: NPP, Rh, …

Which events: 2002 (also 2007?, 3+ models)Which events: 2002 (also 2007?, 3+ models)

Site flux measurementsForest/agriculture inventory

A

Carbon fluxes

Observed Climate+

ForcingPrecipitation, temp, radiation, etc.CO2

Land use

Mechanistic carbon models

InversionCarbon data assimilation

NEEGPP, ReNPP

Satellite: NDVI EVI LAI Fire and derived C-fluxes

Fire

LAI, NPP

Comparison, validation, synthesis

Inversion

Forward

NEE anomalies with 2000-05 mean removed

2002: drought2004: ?

Inversion

Forward

MODIS GPP

MODIS LAI

Variability of the North American Variability of the North American Carbon CycleCarbon Cycle

Ning Zeng and Jinho YoonNing Zeng and Jinho Yoon

Dept. Atmospheric and Oceanic Science andDept. Atmospheric and Oceanic Science andEarth System Science Interdisciplinary Center Earth System Science Interdisciplinary Center

University of MarylandUniversity of Maryland

Collaborators: G. J. Collatz, M. Heimman, C. Roedenbeck, H. Qian, R. Joseph,A. Kumar, A. Vintzileos, A. Mariotti, A. Busalacchi, S. Lord

The big question is, how much would it really cost

Photosynthesis Autotrophic respiration

Carbon allocation

Turnover

Heterotrophic respiration

4 Plant Functional Types:Broadleaf treeNeedleleaf treeC3 Grass (cold)C4 Grass (warm)

3 Vegetation carbon pools:LeafRootWood

3 Soil carbon pools:FastIntermediateSlow

Atmospheric CO2

The VEgetation-Global Atmosphere-Soil Model (VEGAS)

VEGAS IIVEGAS IIPhotosynthesis: Photosynthesis:

Light (PAR, LAI, Height), soil moisture, temperature, CO2Light (PAR, LAI, Height), soil moisture, temperature, CO2

Respiration: Respiration:

temperature, soil moisture, lower soil pools slower decaytemperature, soil moisture, lower soil pools slower decay

Competition:Competition:

Net growth, shading => fractional coverNet growth, shading => fractional cover

Fire: Fire:

moisture, fuel load, PFT dependent resistancemoisture, fuel load, PFT dependent resistance

Wetland/CH4: Wetland/CH4:

moisture, topography gradientmoisture, topography gradient

Carbon 13:Carbon 13:

C3/C4 competition: temperature, CO2C3/C4 competition: temperature, CO2

ConclusionsConclusions There is large differences in the spatial and temporal variability There is large differences in the spatial and temporal variability

on continental-regional scale among the modelson continental-regional scale among the models There is some agreement, especially associated with major There is some agreement, especially associated with major

climatic events such as drought among forward, inversion and climatic events such as drought among forward, inversion and satellite datasatellite data