energy.closure: Energy Balance Closure

In bigleaf: Physical and Physiological Ecosystem Properties from Eddy Covariance Data

Energy Balance Closure

Description

Calculates the degree of the energy balance non-closure for the entire time span based on the ratio of two sums (energy balance ratio), and ordinary least squares (OLS).

Usage

energy.closure(
  data,
  Rn = "Rn",
  G = NULL,
  S = NULL,
  LE = "LE",
  H = "H",
  instantaneous = FALSE,
  missing.G.as.NA = FALSE,
  missing.S.as.NA = FALSE
)

Arguments

data	Data.frame or matrix containing all required variables.
Rn	Net radiation (W m-2)
G	Ground heat flux (W m-2); optional
S	Sum of all storage fluxes (W m-2); optional
LE	Latent heat flux (W m-2)
H	Sensible heat flux (W m-2)
instantaneous	should the energy balance be calculated at the time step of the observations (TRUE), or over the entire time period provided as input (FALSE)
missing.G.as.NA	if TRUE, missing G are treated as NAs ,otherwise set to 0.
missing.S.as.NA	if TRUE, missing S are treated as NAs, otherwise set to 0.

Details

The energy balance ratio (EBR) is calculated as:

EBR = sum(LE + H)/sum(Rn - G - S)

the sum is taken for all time steps with complete observations (i.e. where all energy balance terms are available).

Value

a named vector containing:

n	number of complete (all energy balance terms available) observations
intercept	intercept of the OLS regression
slope	slope of the OLS regression
r_squared	r^2 of the OLS regression
EBR	energy balance ratio

if instantaneous = TRUE, only EBR is returned.

References

Wilson K., et al. 2002: Energy balance closure at FLUXNET sites. Agricultural and Forest Meteorology 113, 223-243.

Examples

## characterize energy balance closure for DE-Tha in June 2014
energy.closure(DE_Tha_Jun_2014,instantaneous=FALSE)

## look at half-hourly closure 
EBR_inst <- energy.closure(DE_Tha_Jun_2014,instantaneous=TRUE)
summary(EBR_inst)

bigleaf documentation built on Aug. 22, 2022, 9:09 a.m.