This function searches for SMAP data on a specific date, returning a data.frame describing available data.

find_smap(id, dates, version)

Arguments

id

A character string that refers to a specific SMAP dataset, e.g., "SPL4SMGP" for SMAP L4 Global 3-hourly 9 km Surface and Rootzone Soil Moisture Geophysical Data. See "Details" for a list of supported data types and their associated id codes.

dates

An object of class Date or a character string formatted as To search for one specific date, this can be a Date object of length one. To search over a time interval, it can be a multi-element object of class Date such as produced by seq.Date.

version

Which data version would you like to search for? Version information for each data product can be found at https://nsidc.org/data/smap/data_versions

Value

A data.frame with the names of the data files, the remote directory, and the date.

Details

There are many SMAP data products that can be accessed with this function. Currently, smapr supports level 3 and level 4 data products, each of which has an associated Data Set ID which is specified by the id argument, described at https://nsidc.org/data/smap/smap-data.html and summarized below:

SPL2SMAP_S

SMAP/Sentinel-1 Radiometer/Radar Soil Moisture

SPL3FTA

Radar Northern Hemisphere Daily Freeze/Thaw State

SPL3SMA

Radar Global Daily Soil Moisture

SPL3SMP

Radiometer Global Soil Moisture

SPL3SMAP

Radar/Radiometer Global Soil Moisture

SPL4SMAU

Surface/Rootzone Soil Moisture Analysis Update

SPL4SMGP

Surface/Rootzone Soil Moisture Geophysical Data

SPL4SMLM

Surface/Rootzone Soil Moisture Land Model Constants

SPL4CMDL

Carbon Net Ecosystem Exchange

This function requires a username and password from NASA's Earthdata portal. If you have an Earthdata username and password, pass them in using the set_smap_credentials() function.

If you do not yet have a username and password, register for one here: https://urs.earthdata.nasa.gov/

Examples

if (FALSE) { # looking for data on one day: find_smap(id = "SPL4SMGP", dates = "2015-03-31", version = 4) # searching across a date range start_date <- as.Date("2015-03-31") end_date <- as.Date("2015-04-02") date_sequence <- seq(start_date, end_date, by = 1) find_smap(id = "SPL4SMGP", dates = date_sequence, version = 4) }