simplecn163

(daily)netphotosynthesis(PSN)and(annual)netprimaryproduction(NPP)PSNandNPP(daily)netphotosynthesis(PSN)(annual)netprimaryproduction(NPP)relatetonetcarbonuptakeimportantforunderstandingglobalcarbonbudget(climatechange)PSNandNPPC02removedfromatmospherephotosynthesisC02releasedbyplant(andanimal)respirationNetPhotosynthesis(PSN)netcarbonexchangeover1day:(photosynthesis-respiration)PSNandNPPNetPrimaryProductivity(NPP)annualnetcarbonexchangequantifiesactualplantgrowth(notjustC02fixation)Algorithms-requiretobemodel-basedsimpleProductionefficiencymodel(PEM)(Monteith,1972;1977)relatePSN,NPPtoAPARAPARfromPARandfAPARPSN=dailytotalphotosynthesisNPP,PSNtypicallyaccum.
ofdrymatter(converttoCbyassumingDM48%C)=efficiencyofconversionofPARtoDM(g/MJ)equationsholdfornon-stressedconditionstocharacterisevegetationneedtoknow:EfficiencyfAPARsoforfixedDeterminingherbaceousvegetation(grasses):av.
1.
0-1.
8gC/MJforC3plantshigherforC4woodyvegetation:0.
2-1.
5gC/MJsimplemodelfor:ReferencesDubayah,R.
(1992)EstimatingnetsolarradiationusingLandsatThematicMapperandDigitalElevationdata.
WaterresourcesRes.
,28:2469-2484.
Monteith,J.
L.
,(1972)Solarradiationandproductivityintropicalecosystems.
J.
Appl.
Ecol,9:747-766.
Monteith,J.
L.
,(1977).
ClimateandefficiencyofcropproductioninBritain.
Phil.
Trans.
RoyalSoc.
London,B281:277-294.
Running,S.
W.
,Nemani,R.
,Glassy,J.
M.
(1996)MOD17PSN/NPPAlgorithmTheoreticalBasisDocument,NASA.