Calculates a new scan parameter from a combination of existing scan parameters. Useful for calculating quantities that are defined in terms of other basic radar moments, like linear reflectivity eta, depolarization ratio (Kilambi et al. 2018), or for applying clutter corrections (CCORH) to uncorrected reflectivity moments (TH), as in TH+CCORH
calculate_param(x, ...) # S3 method for pvol calculate_param(x, ...) # S3 method for scan calculate_param(x, ...)
x | an object of class |
---|---|
... | an expression defining the new scan parameter in terms of existing scan parameters |
an object of the same class as x
, either class pvol
or class scan
pvol
: Calculate a new scan parameter for all scans in a polar volume.
scan
: Calculate a new scan parameter for a scan
Kilambi, A., Fabry, F., and Meunier, V., 2018. A simple and effective method for separating meteorological from nonmeteorological targets using dual-polarization data. Journal of Atmospheric and Oceanic Technology, 35, 1415–1424. https://doi.org/10.1175/JTECH-D-17-0175.1
# locate example volume file: pvolfile <- system.file("extdata", "volume.h5", package = "bioRad") # load the file: example_pvol <- read_pvolfile(pvolfile) # calculate linear reflectivity ETA from reflectivity factor DBZH: radar_wavelength <- example_pvol$attributes$how$wavelength # example_pvol <- calculate_param(example_pvol,ETA=dbz_to_eta(DBZH,radar_wavelength)) # add depolarization ratio (DR) as a scan parameter (see Kilambi 2018): example_pvol <- calculate_param(example_pvol, DR = 10 * log10((ZDR + 1 - 2 * ZDR^0.5 * RHOHV) / (ZDR + 1 + 2 * ZDR^0.5 * RHOHV))) # calculate_param operates on both pvol and scan objects: calculate_param(example_scan, DR = 10 * log10((ZDR + 1 - 2 * ZDR^0.5 * RHOHV) / (ZDR + 1 + 2 * ZDR^0.5 * RHOHV)))#> Polar scan (class scan) #> #> parameters: VRADH DBZH ZDR RHOHV PHIDP DR #> elevation angle: 0.5 deg #> dims: 480 bins x 360 rays