geopressure_timeseries: Request and download pressure time series at a given location

In Rafnuss/GeoPressureR: Global Positioning by Atmospheric Pressure

Request and download pressure time series at a given location

Description

This function returns the surface atmospheric pressure time series from ERA5 at any requested location.

If the location queried is over water, the location will be moved to the closest onshore location.

The ERA5 pressure time series of the response P_{ERA} will be provided on a hourly basis between start_time and end_time or the same as pressure$date if pressure is supplied.

If you supply the pressure of the geolocator P_{gl}, the function will additionally return the altitude of the geolocator above sea level z_{gl} using the barometric equation,

z_{{gl}}(x)=z_{ERA5}(x) + \frac{T_{ERA5}(x)}{L_b} \left( \frac{P_{gl}}{P_{ERA5}(x)} \right)^{\frac{RL_b}{g M}-1},

where z_{ERA}, T_{ERA}, and P_{ERA} respectively correspond to the ground level elevation, temperature at 2m, and ground level pressure of ERA5, L_b is the standard temperature lapse rate, R is the universal gas constant, g is the gravity constant and M is the molar mass of air. See more information at the GeoPressureAPI documentation.

To be able to compare the temporal variation of the retrieved pressure of ERA5 P_{ERA} to the geolocator pressure P_{gl}, the function also returns the ERA pressure normalized with the geolocator mean pressure measurement as surface_pressure_norm.

P_{ERA5,0}(\boldsymbol{x})[t] = \left( P_{ERA5}(\boldsymbol{x})[t]-P_{gl}[t]\right) - \left( \frac{1}{n}\sum_{i=1}^{n} P_{ERA5}(\boldsymbol{x})[i]-P_{gl}[i] \right).

Usage

geopressure_timeseries(
  lat,
  lon,
  pressure = NULL,
  start_time = NULL,
  end_time = NULL,
  timeout = 60 * 5,
  quiet = FALSE,
  debug = FALSE
)

Arguments

lat	Latitude to query (0° to 90°).
lon	Longitude to query (-180° to 180°).
pressure	A data.frame of pressure time series, containing at least a "date" and "value" column.
start_time	If pressure is not provided, start_time defines the start time of the time series as POSIXlt.
end_time	If pressure is not provided, end_time defines the end time of the time series as POSIXlt.
timeout	duration before the code is interrupted both for the request on GeoPressureAPI and on GEE (in seconds, see httr2::req_timeout()).
quiet	logical to hide messages about the progress
debug	logical to display additional information to debug a request

Value

A data.frame containing

• date POSIXct date time

• surface_pressure pressure (hPa)

• lon same as input lon except if over water

• lat same as input lat except if over water.

• surface_pressure_norm only if pressure is provided as input

• altitude only if pressure is provided as input

References

Nussbaumer, Raphaël, Mathieu Gravey, Martins Briedis, and Felix Liechti. 2023. Global Positioning with Animal‐borne Pressure Sensors. Methods in Ecology and Evolution, 14, 1118–1129 https://doi.org/10.1111/2041-210X.14043.

See Also

Other pressurepath: plot_pressurepath(), pressurepath_create()

Examples

# Request pressure at a given location
pressurepath <- geopressure_timeseries(
  lat = 46, lon = 6,
  start_time = "2017-01-01 00:00",
  end_time = "2017-01-02 00:00",
  quiet = TRUE
)

str(pressurepath)

plot(pressurepath$date, pressurepath$surface_pressure,
  type = "b", ylab = "Pressure (hPa)", xlab = "Datetime"
)

# Retrieve the altitude of a bird being at this location adding random noise on the sensor.
pressurepath <- geopressure_timeseries(
  lat = 46, lon = 6,
  pressure = data.frame(
    data.frame(
      date = pressurepath$date,
      value = pressurepath$surface_pressure + rnorm(nrow(pressurepath))
    )
  ),
  quiet = TRUE
)

str(pressurepath)

plot(pressurepath$date, pressurepath$altitude,
  type = "b", ylab = "Altitude (m)", xlab = "Datetime"
)

Rafnuss/GeoPressureR documentation built on April 17, 2025, 12:58 p.m.