Global Hydrological Balance — hb

Computes the global hydrological balance of a water basin from the measurements of water level, outflows, and precipitation/evapotranspiration. For analyzing Albufera data, you should not need to directly run this function, and you can instead use the albufera_hb_global wrapper, that calls hb_global() with the right arguments, extracted from the built-in datasets.

Usage

hb_global(
  level,
  rain_mm,
  evapotranspiration_mm,
  outflows,
  ...,
  storage_curve = erahumed::linear_storage_curve(slope = 1, intercept = 0),
  petp_surface = erahumed::linear_petp_surface(surface_P = 1, surface_ETP = 1)
)

Arguments

level: numeric vector. Time series of lake levels, in meters.
rain_mm: numeric vector. Time series of precipitation values, in millimiters.
evapotranspiration_mm: numeric vector. Time series of evapotranspiration values, in millimiters.
outflows: a data.frame whose columns are the time series of outflows, expressed in cube meters per second.
...: additional columns to be appended in the returned data-frame. Each of these additional (named) arguments should be a vector of the same length implied by the previous arguments.
storage_curve: a function that takes a numeric vector as input, and returns a numeric vector of the same length. Function that converts lake levels (passed through the level argument) into lake volumes.
petp_surface: a function that takes two numeric vectors of common length as inputs, and returns a numeric vector of the same length. Function that converts precipitation and evapotranspiration values (passed through the rain_mm and evapotranspiration_mm arguments) into an overall volume change.

Value

An object of class hb_global, a lightweight wrapper of data.frame with a few additional visualization methods (most prominently plot.hb_global). The underlying data-frame contains as columns the input time series, as well as the following calculated columns:

volume Volume time series, obtained from the storage curve.
volume_change Differenced time series of volume. The \(n\)-th is given by \(\Delta V _n \equiv V_{n+1}-V_n\), where \(V_n\) is volume at time step \(n\).
petp_change Time series. The amount \(\Delta V _n ^\text{P-ETP}\) of volume change due to precipitation and evapotranspiration, obtained from the P-ETP surface.
outflow_total Time series of total outflows, measured in cube meters per second. This is the sum \(\sum _i O_i\) of time series passed through the outflows argument, plus an extra term \(\delta O\) of unaccounted outflow. The correction term is defined by \(\delta O = \frac{\Delta V _n - \Delta V _n ^\text{P-ETP}}{24 \times 60 \times 60} -\sum _i O_i\) and is chosen in such a way to ensure that the total inflow is always non-negative.
outflow_extra Time series. The unaccounted outflow term \(\delta O\) described above.
inflow_total Time serie of total inflows, in cube meters per second. This is computed as \(I = \sum _{i} O_i + \delta O + \frac{\Delta V _n - \Delta V _n ^\text{P-ETP}}{24 \times 60 \times 60}\).
residence_time_days. Residence time, as modeled by hbg_residence_time.