Modified KO Index after Haklander & Van Delden

Modified KO Index after Haklander & Van Delden

Usage

ModKO_Index(
  ta500,
  hus500,
  ta700,
  hus700,
  ta850,
  hus850,
  ta1000,
  hus1000,
  ta_s,
  hus_s,
  pa_s,
  nthreads = 1
)

Arguments

ta500

air temperature [lon, lat, time] at 500 hPa (K).

hus500

specific humidity [lon, lat, time] at 500 hPa (kg/kg).

ta700

air temperature [lon, lat, time] at 700 hPa (K).

hus700

specific humidity [lon, lat, time] at 700 hPa (kg/kg).

ta850

air temperature [lon, lat, time] at 850 hPa (K).

hus850

specific humidity [lon, lat, time] at 850 hPa (kg/kg).

ta1000

air temperature [lon, lat, time] at 1000 hPa (K).

hus1000

specific humidity [lon, lat, time] at 1000 hPa (kg/kg).

ta_s

air temperature [lon, lat, time] at 2 meter above the surface (K).

hus_s

specific humidity [lon, lat, time] at 2 meter above the surface (kg/kg).

pa_s

surface pressure [lon, lat, time] (hPa).

nthreads

an integer specifying the number of threads to use for computation (OpenMP). Default is 1.

Value

the computed modified KO Index (K).

References

• Andersson, T., Andersson, M., Jacobsson, C., Nilsson, S., 1989. Thermodynamic indices for forecasting thunder- storms in southern Sweden. Meteorol. Mag. 116, 141–146

• Haklander, A. J., & Van Delden, A. (2003). Thunderstorm predictors and their forecast skill for the Netherlands. Atmospheric Research, 67–68, 273–299. doi:10.1016/S0169-8095(03)00056-5 .

Examples

data("ERA5_pl")
pa <- ERA5_pl$plev / 100 # convert to hPa
hus <- ERA5_pl$hus
ta <- ERA5_pl$ta


data("ERA5_sfc")
ta_s <- ERA5_sfc$t2m
td_s <- ERA5_sfc$t2d
pa_s <- ERA5_sfc$sp / 100
hus_s <- hus_from_td(td_s, pa_s)
dim(hus_s) <- dim(ta_s)

l500 <- which(pa == 500)
l700 <- which(pa == 700)
l850 <- which(pa == 850)
l1000 <- which(pa == 1000)
res <- ModKO_Index(
  ta[, , l500, ], hus[, , l500, ],
  ta[, , l700, ], hus[, , l700, ],
  ta[, , l850, ], hus[, , l850, ],
  ta[, , l1000, ], hus[, , l1000, ],
  ta_s, hus_s, pa_s
)