CO2Exchange, Part 1•Philosophy/BackgroundPhilosophy/Background• Processing•Time Series AnalysisTime Series Analysis– Diurnal–Seasonal– Interannual• Flux Partitioningg– Canopy photosynthesis– Ecosystem RespirationESPM 129 BiometeorologyPhilosophy/Background• Philosophy– What, How, Why, Will be?•BioPhysical Processesy– Meteorology/Microclimate• Light, temperature, wind, humidity, pressure– Vegetation• Structure (height, leaf area index, leaf size)• Physiology (photosynthetic capacity, stomatal conductance) –Soil• Roots• Microbes•Abiotic conditions (soil moisture temperature chemistry texture)•Abiotic conditions (soil moisture, temperature, chemistry, texture)• Spatial-Temporal Variability– Spatial• Vertical (canopy) and Horizontal (footprint, landscape, functional type, disturbance)yp , )– Temporal• Dynamics• Diurnal• SeasonalItlESPM 129 Biometeorology•Inter-annualWhat a Tower SeesRRRRPNEEFFESPM 129 BiometeorologymicrobesrootswoodleafnetstoragecRRRRPNEEFFWhat the Atmosphere SeesS h l 2006 Bi iESPM 129 BiometeorologySchulze, 2006 BiogeosciencesEddy CovarianceyF''Fwc''MeanFluctuationFhFSzdzh()()()z0ESPM 129 BiometeorologyFhFSzdzzzB()()()z00Time Series Analysis: Raw DataVaira Grassland 200115510mol m-2 s-1)-50Fc (-15-100 50 100 150 200 250 300 350-25-20ESPM 129 BiometeorologyDay/Hour-15 -10 -5 Time Series: FingerPrintCO2 Exchange (mol m-2 s-1)Grassland, 2002240 2024our1216Ho81204ESPM 129 BiometeorologyDay0 50 100 150 200 250 300 3500Time Series: Diurnal Pattern15Temperate Deciduous ForestD2152 s-1)05105c (mol m-210-50Fc-20-15-100 400 800 1200 1600 2000 240020ESPM 129 BiometeorologyRealityCloudCloudESPM 129 BiometeorologyTime Series: Mean Diurnal PatternTemperate ForestDays 150 to 250, 199710Ne: measured (-4.84 gC m-2 day-1)Ne: computed (-5.09 gC m-2 day-1)Fwpl+Storage: measured (-5.96 gC m-2 day-1)Fwpl: measured (-6.12 gC m-2 day-1)sity0510CO2 Flux Densmol m-2 s-1-15-10-5tim e (hours)0 4 8 12162024-25-20neemdtst.spwp2/10/99arazaBhwczcdzwcSzdzr''()''()()zz0ESPM 129 BiometeorologyaraaBt()()()zz00Night time Biased RespirationNight time Biased RespirationVaira, D296-366, 20001078r ² 0.325Canopy Respiration8to13CWheat, Columbia River Valley, Oregonmol m-2 s-1)468mol m-2 s-1)45678 to 13 CFc (m-202Fco2 (123u* (m s-1)0.0 0.1 0.2 0.3 0.42u* (m s-1)0.00.20.40.60.81.00ESPM 129 BiometeorologyhcdtzCO2Storage ‘Flux’150Deciduous Forest1995atdtz0day-1)0.751.001.251.50ge (g C m-2 d-0.250.000.250.50CO2 Stora125-1.00-0.75-0.500.25DAY0 50 100 150 200 250 300 350-1.50-1.25ESPM 129 BiometeorologyD141-154: well-wateredStress factor > 1D197-210: moderate soil moisture deficitStress factor = 0.8430D239-252: droughtStress factor = 0.72D225-238: soil moisture deficitstress factor = 0.77D168-182: well-wateredstress factor > 11995 Growing SeasonBroad-leaved Temperate Forest202530mol m-2 s-1)1015NE (05Time (hours)0 4 8 12162024-10-5ESPM 129 BiometeorologyTime (hours)Deciduous Broadleaved ForestsForestsTBdldTemperate Broadleaved Deciduous Forest45LAI=0now:d-1)123GPP=0;Litterfall (+)Reco=f(litterfall)(+)snow:Tsoil(+)GPP=0; Reco(+)GPP=f(LAIlate spNEE (gC m-2 d-3-2-10no snowTsoil (-)Reco (-)AI, Vcmax)pringearly sprDrought:(-)GPP(-); Re(-)-6-5-4pringGPP( ); Re( )Clouds:PAR(-) GPP=f(PAR)(+)ESPM 129 BiometeorologyDay0 50 100 150 200 250 300 350-7ECifFEvergreen Conifer ForestsTemperate/Boreal Ecosystems2BlClitT il( )2 d-1)01frostGPP(-)Boreal ClimateGPP=0Tsoil(-)Reco(-)Tmin > 0 oCGPP>0NEE (gC m-2-2-1/Humid ClimatesMaritime/HumidCGPP=f(PAR)Drought, (-)Reco(-), GPP(-)VPD(++)GPP( )-4-3Maritime/Hd ClimatesGPP(-)ESPM 129 BiometeorologyDay0 50 100 150 200 250 300 3504Mediterranean Evergreen ForestMediterranean Evergreen Forest0.40.6m-2 d-1)0.00.2Summer Drought-), Reco(-)rain eventsReco(++)NEE (gC -0.4-0.2Spring/Su(-); GPP(-)Autumn RainsGPP(+), Reco (+)0 50 100 150 200 250 300 350-0.8-0.6ESPM 129 BiometeorologyDayGrasslands24Spring/Summer Drought(-)GPP(-); Reco(-)Rain PulseReco(++)GPP=0Autumn Rains:T(-),  (++)GPP(+), Reco(-)snow covereddormant grassGPP=0, R>0gC m-2 d-1)0espring rains+)GPP 0, Reco 0NEE (g-4-2Late sGPP(+)GPP > 0;AM Frost:GPP(-)Tmin > 0 oCGPP f(LAI) ( )Day0 50 100 150 200 250 300 350-6GPP =f(LAI) (+)ESPM 129 BiometeorologyyMediterranean GrasslandTemperate C4 grasslandData sources: Valentini et al. 1996; Baldocchi + Xu, unpublished; Verma +SuykerAgricultural Cropgp23Planting Datetime when GPP>0Tsoil(+), Residual Matter(+)Reco(+)GPP=0Winter fallowGPP=0C m-2 d-1)01Late SnowTil(-)HarvestGPP=0Reco=f(Tsoil,)GPPRNEE (gC-2-1Grain FillingR(++)Tsoil()Reco(-)PP=f(aPAR)Reco<<GPP0 50 100 150 200 250 300 350-4-3Reco()ESPM 129 BiometeorologyDayNorthern Wetlands/Tundra060.81.0Snow Coversnow meltGPP > 0 m-2 d-1)000.20.40.6Tsoil< 0GPP=0Reco ~> 0snow meltGPP > 0Tmin < 0; SenescenceGPP~0NEE (gC06-0.4-0.20.0Tair(+)Reco (++); GPP(+)Reco > GPP140 160 180 200 220 240 260-1.0-0.8-0.6water table(-)Reco(+)NEE > 0ESPM 129 BiometeorologyDayTime Series: Interannual VariabilityHarvard Forest12GEEReco1)4812Col 1 vs gC m-2 d-1 Flux (gC m-2 d-1-40CO2 F-16-12-8Year1992 1994 1996 1998 2000 2002 2004-20ESPM 129 BiometeorologyData of Wofsy, Munger, Goulden, Harvard UnivIntern-annual Lag Effects Due to Drought/Heat Stressg01020NEEm-2 week-1]40-30-20-10[g C -70-60-50-40HainichLeinefelde2002 2003 2004 2005-8070ESPM 129 BiometeorologyKnohl et al Max Planck,