plot_temporal_smos {smosr}

Plot temporal series of BEC-SMOS soil moisture data

Description

This function plots temporal series of BEC-SMOS soil moisture data extracted for specific geographical locations.

Usage

plot_temporal_smos(data, freq = NULL, orbit = NULL, dates = NULL, QA = NULL)

Arguments

data

a data.matrix containing soil moisture data as produced by extract_smos().

freq

an integer specifying temporal frequency of the data. Possible values are: 1 - for daily data, 3 - for 3-day moving averages, and NULL - for cases when data frequency is irrelevant. Default value is NULL.

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, and NULL - for cases when orbit is irrelevant. Default value is NULL.

dates

a object of class Date or a character string formatted as ‘yyyy-mm-dd’ (e.g. ‘2010-06-01’) which specifies the dates to plot the data for. A multiple-element object of class Date or a vector should be passed (e.g. as produced by seq.Date).

QA

a numeric vector specifying the desired data quality to be plotted. Possible values range from 0 (good quality data) to 15. To know the meanings of QA flags, see Details.

Details

This function takes as input temporal series of BEC-SMOS soil moisture estimates extracted for specific geographical locations and plots these data as a line chart. Note that the data characterized by the same frequency and SMOS orbit can be drawn at a time. If the dataset to plot contains a mixture of temporal resolutions and/or SMOS passes, arguments frequency and orbit must be specified. In addition, the dataset can be filtered by desired data quality and specific dates to be plotted.

**** Quality assurance (QA) ****

QA flags are coded by four significant bits as described below:

	--------------	--------------------------------------------------------------------------------
	Bit position	Bit value
	--------------	--------------------------------------------------------------------------------
	[0]	0 - Brightness temperature not affected by sea-land contamination
		1 - Brightness temperature corrected by sea-land contamination
	-------------	--------------------------------------------------------------------------------
	[1]	0 - Radio Frequency Interference (RFI) not flagged in ESA L1C
		brightness temperature
		1 - RFI flagged in ESA L1C brightness temperature
	-------------	--------------------------------------------------------------------------------
	[2]	0 - L3 soil moisture with data obtained from L2 retrievals
		1 - L3 soil moisture with data obtained from a linear model
	-------------	--------------------------------------------------------------------------------
	[3]	0 - L4 soil moisture values within the interval [0,1] m^3/m^3
		1 - L4 soil moisture values outside the interval [0,1] m^3/m^3
	-------------	--------------------------------------------------------------------------------

In case of the 3-day averaged data, each bit of the quality flag is activated if at least one soil moisture estimate during the corresponding time interval is affected.

Value

a line chart

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 plot extracted temporal series of BEC-SMOS soil moisture data produced by extract_smos()
# with the specified frequency, SMOS orbit and QA
smos_files <- list_smos()
lat <- c(40.42, 41.90, 48.86, 52.50, 59.91)
lon <- c(-3.70, 12.50, 2.35, 13.40, 10.75)
sm_estimates <- extract_smos(data = smos_files, lat = lat, lon = lon)
plot_temporal_smos(data = sm_estimates, freq = 3, orbit = "des", QA = 0)

## End(Not run)