getLSWI: calculate LSWI

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

calculate LSWI

Description

calculates land surface water index (LSWI) according to eqn 3 in Mahadevan et al, 2007.

Usage

getLSWI(rho_nir, rho_swir)

Arguments

rho_nir	1xN numeric vector; near-infrared (841-876 nm) band satellite-derived reflectance
rho_swir	1xN numeric vector; 1628-1652 nm band satellite-derived reflectance

Details

LSWI may not exceed 1.0 and may take negative values (Xiao et al 2004)

Value

LSWI: numeric vector same size as rho_nir and rho_swir containing LSWI values.

Author(s)

Timothy W. Hilton

References

Xiangming Xiao, Qingyuan Zhang, Bobby Braswell, Shawn Urbanski, Stephen Boles, Steven Wofsy, Berrien Moore III, Dennis Ojima, Modeling gross primary production of temperate deciduous broadleaf forest using satellite images and climate data, Remote Sensing of Environment, Volume 91, Issue 2, 30 May 2004, Pages 256-270, ISSN 0034-4257, 10.1016/j.rse.2004.03.010.

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)
pfa_df <- as.data.frame( pfa_dd )
LSWI <- getLSWI( rho_nir=pfa_df[['rho_nir']],
                 rho_swir=pfa_df[['rho_swir']] )

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