Calculates the classification of the main weather types
for the 16-points defined in get_lamb_points. Wind-flow characteristics
are computed for the daily pressure field according to the rules proposed by the original
Jenkinson and Collison classification (see Jenkinson and Collison, 1977; Jones et al., 2013) (1), and
to the rules proposed by Trigo and DaCamara, 2000 (2).
Usage
lamb_clas(points, msl, U = FALSE, thr = c(6, 6))Arguments
- points
16 point pair of coordinates obtained from
get_lamb_points.- msl
Mean Sea Level pressure gridded data.
- U
Logical. If T, Jones et al. 2013 approach is applied, maintaining the U-type in the classification. If F, U is removed as detailed in Trigo and DaCamara, 2000.
- thr
threshold used for Unclassified days (total shear vorticity and total flow, respectively). Default c(6,6).
Value
A list with:
A data.frame containing the dates and the weather types.
A data frame containing the gridded data grouped by circulation types.
References
Jenkinson, A.F., Collison F.P (1977) An initial climatology of gales over the North Sea Synoptic Climatology Branch Memorandum, No. 62.Meteorological Office: Bracknell, England.Jones, P. D., Hulme M., Briffa K. R. (1993) A comparison of Lamb circulation types with an objective classification scheme Int. J. Climatol. 13: 655–663.Jones, P. D., Harpham C, Briffa K. R. (2013) Lamb weather types derived from Reanalysis products Int. J. Climatol. 33: 1129–1139.
Trigo, R., DaCamara C. (2000) Circulation weather types and their impact on the precipitation regime in Portugal Int. J. Climatol. 20: 1559-1581.
Examples
data(msl)
msl$value <- msl$value/100
points <- get_lamb_points(x = 5,y = 40)
lamb_clas(points = points, msl = msl)
#> $clas
#> # A tibble: 1,096 × 2
#> time WT
#> <date> <chr>
#> 1 2000-01-01 A
#> 2 2000-01-02 ANE
#> 3 2000-01-03 A
#> 4 2000-01-04 A
#> 5 2000-01-05 A
#> 6 2000-01-06 A
#> 7 2000-01-07 A
#> 8 2000-01-08 A
#> 9 2000-01-09 C
#> 10 2000-01-10 NE
#> # ℹ 1,086 more rows
#>
#> $grid_clas
#> # A tibble: 5,746 × 4
#> x y WT mean_WT_value
#> <dbl> <dbl> <chr> <dbl>
#> 1 -10 30 A 1018.
#> 2 -10 30 AE 1015.
#> 3 -10 30 AN 1017.
#> 4 -10 30 ANE 1015.
#> 5 -10 30 ANW 1020.
#> 6 -10 30 AS 1017.
#> 7 -10 30 ASE 1016.
#> 8 -10 30 ASW 1019.
#> 9 -10 30 AW 1019.
#> 10 -10 30 C 1016.
#> # ℹ 5,736 more rows
#>