How to set Kplantinit, gsmax in a coordinated manner

**How to set the many parameters that set E_max. I think we should collectively work on a general procedure that would help to set/calibrate smartly some parameters based on others :  In the case of Jarvis four parameters can help to set maximum transpiration :  Basically E = 1/(1/gs+1/gcrown) * VPD_leaf ; gs = gs_max (RegulFact) and Regulfact = f(P_Leaf_sym) and starts to decrease as soon as P_Leaf_sym < P_12gs. gCrown is in fact a function of many things but to make it simple we can use sureau formulation: gCrown = gCrown0 * windSpeed ^ 0.6 with gCrown0 = 150  If we neglect the capacitance and skip some complexe details of the numerical solver we can writte : P_Leaf_sym = P_all_Soil – E/Kplant_init  Thus here is what we could do when we have some data (such as our costa-rica case) to estimate key parameters and match the maximum transpiration : 1- Based on sapflow data select E_max under well watered (saturated soil) and high VPD and light (this should be natrurally the case) 2- Assuming that at Emax, gs= Gsmax and gcrown =Grownmax, P_all_Soil = 0 and that P_Leaf_sym = P_gs_12 (stomata are at the limit to start to close):  we can first estimate Kplant_init: Kplant_init = Emax/P_gs_12. I know you don’t have P_gs_12, but you have TLP (I provided it thorugh my database). In general TLP match well with P_gs88. If we assume that stomata start to close at midway between saturation and TLP e can assume that P_gs_12=TLP/2 (we’ll talk about this later).  we can then estimate gs_max : Emax= 1/(1/gs_max+1/gcrown) *VPD/Atmopheric pressure.

Note that E is here expressed in mmol/m2leaf/s . Obviously this method works only if we have concurrent data of E and VPD. If we don’t, we could assume E is constant (2mmol/m2_leaf/s) and take maximum VPD during a “well-watered” period to compute K_plant_init and Gsmax.

Gcrown remains something we should one day work on..