Package 'dynatop'

Title: An Implementation of Dynamic TOPMODEL Hydrological Model in R
Description: An R implementation and enhancement of the Dynamic TOPMODEL semi-distributed hydrological model originally proposed by Beven and Freer (2001) <doi:10.1002/hyp.252>. The 'dynatop' package implements code for simulating models which can be created using the 'dynatopGIS' package.
Authors: Paul Smith [aut, cre] , Peter Metcalfe [aut]
Maintainer: Paul Smith <[email protected]>
License: GPL-2
Version: 0.3.0.1010
Built: 2024-12-03 06:13:16 UTC
Source: https://github.com/waternumbers/dynatop

Help Index


R6 Class for Dynamic TOPMODEL

Description

R6 Class for Dynamic TOPMODEL

R6 Class for Dynamic TOPMODEL

Methods

Public methods


Method new()

Creates a dynatop class object from the a list based model description as generated by dynatopGIS.

Usage
dynatop$new(model, map = NULL, use_states = FALSE, delta = 1e-13)
Arguments
model

a dynamic TOPMODEL list object

map

file name of the map layers for the model

use_states

logical if states should be imported

delta

error term in checking redistribution sums

drop_map

logical if the map should be dropped

Details

This function makes some basic consistency checks on a list representing a dynamic TOPMODEL model. The checks performed and basic 'sanity' checks. They do not check for the logic of the parameter values nor the consistency of states and parameters. Sums of the redistribution matrices are checked to be in the range 1 +/- delta.

Returns

invisible(self) suitable for chaining


Method add_data()

Adds observed data to a dynatop object

Usage
dynatop$add_data(obs_data)
Arguments
obs_data

an xts object of observed data

Details

This function makes some basic consistency checks on the observations to ensure they have uniform timestep and all required series are present.

Returns

invisible(self) suitable for chaining


Method clear_data()

Clears all forcing and simulation data except current states

Usage
dynatop$clear_data()
Returns

invisible(self) suitable for chaining


Method initialise()

Initialises a dynatop object in the simplest way possible.

Usage
dynatop$initialise(
  vtol = sqrt(.Machine$double.eps),
  ftol = sqrt(.Machine$double.eps),
  max_it = 1000
)
Arguments
vtol

tolerance for the solution for the saturated zone storage (as volume)

ftol

tolerance for the solution of the saturated zone storage (as difference of function from 0)

max_it

maximum number of iterations to use in the solution of the saturated zone

Returns

invisible(self) suitable for chaining


Method sim()

Simulate the hillslope and channel components of a dynatop object

Usage
dynatop$sim(
  output_defn,
  keep_states = NULL,
  sub_step = NULL,
  vtol = 0.001,
  ftol = sqrt(.Machine$double.eps),
  max_it = 1000
)
Arguments
output_defn

a description of the output series

keep_states

a vector of POSIXct objects (e.g. from xts) giving the time stamp at which the states should be kept

sub_step

simulation timestep in seconds, default value of NULL results in data time step

vtol

tolerance on width of bounds in the numeric search for surface and saturated zone solutions (as volume)

ftol

- not currently used

max_it

maximum number of iterations to use in the solution of the saturated zone

Details

Saving the states at every timestep and keeping the mass balance can generate very large data sets!!

Returns

invisible(self) for chaining


Method get_output()

Return channel inflow as an xts series or list of xts series

Usage
dynatop$get_output(name = colnames(private$time_series$output))
Arguments
name

one or more output series to return


Method plot_output()

Plot the channel inflow

Usage
dynatop$plot_output(name = colnames(private$time_series$output))
Arguments
name

of series to plot


Method get_obs_data()

Get the observed data

Usage
dynatop$get_obs_data()

Method get_model()

Return the model

Usage
dynatop$get_model()

Method get_mass_errors()

Return the model

Usage
dynatop$get_mass_errors()

Method get_states()

Return states

Usage
dynatop$get_states(record = FALSE)
Arguments
record

logical TRUE if the record should be returned. Otherwise the current states returned


Method plot_state()

Plot a current state of the system

Usage
dynatop$plot_state(state = c("s_sf", "s_rz", "s_uz", "s_sz"))
Arguments
state

the name of the state to be plotted


Method clone()

The objects of this class are cloneable with this method.

Usage
dynatop$clone(deep = FALSE)
Arguments
deep

Whether to make a deep clone.

Examples

## the vignettes contains further details of the method calls.

data("Swindale") ## example data
mdl <- Swindale$model
mdl$map <- system.file("extdata","Swindale.tif",package="dynatop",mustWork=TRUE)
ctch_mdl <- dynatop$new(mdl$hru,map=mdl$map) ## create with model
ctch_mdl$add_data(Swindale$obs) ## add observations
ctch_mdl$initialise() ## initialise model
ctch_mdl$sim(Swindale$model$output_flux) ## simulate model

Create sinusoidal time series of potential evapotranspiration input

Description

Generate series of potential evapotranspiration

Usage

evap_est(ts, eMin = 0, eMax = 0)

Arguments

ts

as vector of POSIXct data/times

eMin

Minimum daily PE total (m or mm)

eMax

Maximum daily PE total (m or mm)

Details

Dynamic TOPMODEL requires a time series of potential evapotranspiration in order to calculate and remove actual evapotranspiration from the root zone during a run. Many sophisticated physical models have been developed for estimating potential and actual evapotranspiration, including the Priestly-Taylor (Priestley and Taylor, 1972) and Penman-Monteith (Montieth, 1965) methods. These, however, require detailed meteorological data such as radiation input and relative humidities that are, in general, difficult to obtain. Calder (1983) demonstrated that a simple approximation using a sinusoidal variation in potential evapotranspiration to be a good approximation to more complex schemes.

If the insolation is also taken to vary sinusoidally through the daylight hours then, ignoring diurnal meteorological variations, the potential evapotranspiration during daylight hours for each year day number can be calculated (for the catchment's latitude). Integration over the daylight hours allows the daily maximum to be calculated and thus a sub-daily series generated.

Value

Time series (xts) of potential evapotranspiration totals for the time steps given in same units as eMin and eMax

References

Beven, K. J. (2012). Rainfall-runoff modelling : the primer. Chichester, UK, Wiley-Blackwell.

Calder, I. R. (1986). A stochastic model of rainfall interception. Journal of Hydrology, 89(1), 65-71.

Examples

## Generating daily PET data for 1970
## the values of eMin and eMax may not by not be realistic
st <- as.POSIXct("1970-01-02 00:00:00",tz='GMT')
fn <- as.POSIXct("1971-01-01 00:00:00",tz='GMT')
daily_ts <- seq(st,fn,by=24*60*60)
dpet <- evap_est(daily_ts,0,1)

## create hourly data for the same period
st <- as.POSIXct("1970-01-01 01:00:00",tz='GMT')
fn <- as.POSIXct("1971-01-01 00:00:00",tz='GMT')
hour_ts <- seq(st,fn,by=1*60*60)
hpet <- evap_est(hour_ts,0,1)

## the totals should eb the same...
stopifnot(all.equal(sum(hpet), sum(dpet)))

Functions to resample an xts time series

Description

Takes an xts time series object and resamples then to a new time step.

Usage

resample_xts(obs, dt, is.rate = FALSE)

Arguments

obs

A times series (xts) object with a POSIXct index.

dt

New time interval in seconds

is.rate

If TRUE then these are rates i.e m/h. Otherwise they are absolute values accumulated within the preceding time interval. Values are scaled before returning so resampling is conservative.

Details

Time series of observation data are often of different temporal resolutions, however the input to most hydrological models, as is the case with the Dynamic TOPMODEL, requires those data at the same interval. This provides a method to resample a collection of such data to a single interval.

Because of the methods used the results:

- are not accurate when the input data does not have a constant timestep. The code issues a warning and proceeds assuming the data are equally spaced with the modal timestep. - do not guarantee the requested time step but returns a series with the timestep computed from an integer rounding the ratio of the current and requested time step.

Value

An xts object with the new timestep

Examples

# Resample Swindale Rainfall to hourly intervals
require(dynatop)
data("Swindale")
obs <- Swindale$obs
cobs <- resample_xts(obs, dt=60*60) # hourly data
dobs <- resample_xts(cobs,dt=15*60) # back to 15 minute data
cdobs <- resample_xts(dobs,dt=60*60) # back to hourly data - checks time stamp conversion
obs <- obs[zoo::index(obs)<=max(zoo::index(cobs)),]

# check totals
stopifnot( all.equal(sum(obs),sum(cobs)) )
stopifnot( all.equal(sum(obs),sum(dobs)) )
stopifnot( all.equal(cobs,cdobs) )

Example dynamic TOPMODEL setup

Description

This data set contains a processed model and observation data for Swindale.

Usage

data(Swindale)

Format

An object of class list of length 2.

See Also

dynatop

Examples

require(dynatop)
data(Swindale)

# Show it
# plot(obs)