Changes between Version 83 and Version 84 of Documentation/TrunkFunctionality4

03/12/21 14:26:21 (3 months ago)



  • Documentation/TrunkFunctionality4

    v83 v84  
    342342* While parameterizing CAN, the response to k_latosa appeared almost linear. More recent tests with r6818 and a focus on PFT4 showed a clear nonlinear relationship between '''k_latosa''' and annual mean LAI. LAI saturated when k_latosa increased: 2500 to 4500 in steps of 500. 
     343* Around r7124 we think we understand this saturation. GPP is the input of carbon.  We can only allocate to tissue if we have enough N.  If we don't, it goes to reserve pool.  If we have too much in the reserves, then we reduce GPP with sugar loading.  Higher LAIs will initially result in higher GPP but if the system lacks N to allocate the feedback through sugar loading may reduce the GPP on the long term. The model needs a way to "burn off" the GPP that could be allocated. Leaching of labile carbon to the soil (thought to be responsible for up to 20-30% of the NPP - textbook by Chapin 2012) comes to mind. As leaching has not been implemented yet, we could add leaching artificially by turning over the roots.  So now we have high GPP, same amount of C goes to tissue, but rather than the excess going to the reserves (and decreasing GPP through the sugar loading) it turns over the roots.  This could also increase the soil carbon, which is still desirable around r7113.  
    344345'''Parameter compensations'''