vprm_calc_GEE: calculate VPRM GEE

In Timothy-W-Hilton/VPRMLandSfcModel: R implementation of VPRM with parameter estimation

calculate VPRM GEE

Description

calculate VPRM GEE according to Mahadevan et al (2008) eq. 9

Usage

vprm_calc_GEE(driver_data, lambda_param = NULL, PAR_0_param = NULL)

Arguments

driver_data	May be a VPRM_driver_data object or a data frame. If a data frame, driver_data must contain the variables Tscale, Pscale, Wscale, EVI, and PAR. The variables lambda, and PAR_0 are optional (see 'details').
lambda_param	numeric, optional; VPRM parameter: maximum light use efficiency.
PAR_0_param	numeric, optional; VPRM parameter (LUE half-saturation value)

Details

Arguments lambda and PAR_0 may be omitted from the function call. In this case they must be present as variables in data frame driver_data. If either of these parameters are present in driver_data *and* specified as parameters in the function call the function parameter values will be used and the values in driver_data will be ignored. If specifed as function parameters lambda and PAR_0 may be single values or numeric vectors the same length as the number of observations in driver_data.

Value

vector of same length as number of rows in driver_data containin VPRM GEE [umol m-2 s-1]

Author(s)

Timothy W. Hilton

References

Mahadevan, P., Wofsy, S., Matross, D., Xiao, X., Dunn, A., Lin, J., Gerbig, C., Munger, J., Chow, V., and Gottlieb, E.: A satellite-based biosphere parameterization for net ecosystem CO2 exchange: Vegetation Photosynthesis and Respiration Model (VPRM), Global Biogeochem. Cy., 22, GB2005, doi:10.1029/2006GB002735, 2008.

Examples

data(Park_Falls)
pfa_dd <- VPRM_driver_data(name_long="Park Falls",
                           name_short = "US-PFa",
                           lat=45.9459,
                           lon=-90.2723,
                           PFT='MF',
                           tower_date=PFa_tower_obs[['date']],
                           NEE_obs=PFa_tower_obs[['FC']],
                           T=PFa_tower_obs[['TA']],
                           PAR=PFa_tower_obs[['PAR']],
                           date_nir = PFa_refl[['date']],
                           rho_nir=PFa_refl[['nir']],
                           date_swir = PFa_refl[['date']],
                           rho_swir = PFa_refl[['swir']],
                           date_EVI = PFa_evi[['date']],
                           EVI=PFa_evi[['evi']],
                           phen=NA)
data(VPRM_parameters)
attach(all_all_VPRM_parameters)
GEE <- vprm_calc_GEE(pfa_dd, lambda=lambda, PAR_0=PAR_0)

Timothy-W-Hilton/VPRMLandSfcModel documentation built on Nov. 17, 2024, 1:56 p.m.