find_smos {smosr}

Find BEC-SMOS soil moisture data on the server

Description

This function searches for BEC-SMOS soil moisture data available on Barcelona Expert Center (BEC) server for the frequency, orbit, and dates specified by the user.

Usage

find_smos(freq, orbit, dates)

Arguments

freq

an integer specifying temporal frequency of the data. Possible values are: 1 - for daily data, or 3 - for 3-day moving averages. No default value is provided.

orbit

a character (or character string) specifying SMOS orbit corresponding to the data. Possible values are: ‘a’, ‘asc’, and ‘ascending’ - for an ascending pass, or ‘d’, ‘des’, or ‘descending’ - for a descending pass. No default value is provided.

dates

an object of class Date or a character string formatted as ‘yyyy-mm-dd’ (e.g. ‘2010-06-01’) which specifies the date(s) to search through. To look for a specific date, it can be a Date object or a character vector of length 1. To iterate over various dates or a time interval, a multiple-element object of class Date or a vector should be passed (e.g. as produced by seq.Date).

Details

BEC-SMOS soil moisture (SM) data is a regional root zone SM product that covers Europe and Mediterranean countries. Particularly, smosr package works with the reprocessed SMOS Level 4 (L4) SM estimates downscaled to ~1 km spatial resolution (EASE-grid v.2). The data is computed for two time periods (argument frequency): daily and 3-day moving averages produced by a temporal aggregation of the daily products. Note that SMOS ascending and descending passes (argument orbit) are processed separately. The data is available starting from June 1st, 2010 throughout the end of 2022. The currently supported version is 6.0. For more details about the BEC-SMOS SM products, see the technical note available at https://digital.csic.es/handle/10261/303808.

Note that the registration as a user on the Barcelona Expert Center (BEC) webpage is required to access the server. See set_credentials() for details.

Value

a character vector containing full links to the data files on the server.

References

Pablos M, Gonzalez-Haro C, Portal G, Piles M, Vall-llossera M, Portabella M (2022). SMOS L4 Surface Soil Moisture downscaled maps at 1 km EASE-2 (reprocessed mode) (V.6.0) [Dataset].

Examples

## Not run: 
# to look for BEC-SMOS data on a specific date
smos_data <- find_smos(freq = 1, orbit = "a", dates = "2022-12-31")
# to search data over a date range
start_date <- as.Date("2022-01-01")
end_date <- as.Date("2022-12-31")
date_range <- seq(start_date, end_date, by = 10)
smos_data <- find_smos(freq = 3, orbit = "descending", dates = date_range)

## End(Not run)