Most unstable CAPE after Haklander & Van Delden

The function calculates the Convective Available Potential Energy (CAPE) for an air parcel found within the lowest 250 hPa of the atmosphere with the highest equivalent potential temperature. It returns a list containing CAPE, convective inhibition (CIN), pressure at lifted condensation level (LCL), and at level of free convection (LFC).

Usage

CAPE_mu_HVD(
  ta_s,
  hus_s,
  pa_s,
  ta_pl,
  hus_pl,
  pa_pl,
  dp = 250,
  vtc = TRUE,
  nthreads = 1
)

Arguments

ta_s

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

hus_s

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

pa_s

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

ta_pl

air temperature [lon, lat, lev, time] on pressure level (K).

hus_pl

specific humidity [lon, lat, lev, time] on pressure level (kg/kg).

pa_pl

pressure profile [lev] in descending manner (hPa).

dp

Thickness of layer to consider (hPa). Default is 250 hPa

vtc

logical refers to virtual temperature correction due to Doswell and Rasmussen (1994).

nthreads

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

Value

A list containing CAPE, CIN, p_LCL, p_LFC each as [lon, lat, time].

References

• 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 .

• Doswell III, C. A., & Rasmussen, E. N. (1994). The effect of neglecting the virtual temperature correction on CAPE calculations. Weather and forecasting, 9(4), 625-629 doi:10.1175/1520-0434(1994)009<0625:TEONTV>2.0.CO;2 .

Examples

data("ERA5_pl")
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)

ta_pl <- ERA5_pl$ta
hus_pl <- ERA5_pl$hus
pa_pl <- ERA5_pl$plev / 100

res <- CAPE_mu_HVD(ta_s, hus_s, pa_s,
  ta_pl, hus_pl, pa_pl,
  dp = 300,
  vtc = TRUE, nthreads = 1
)

str(res)
#> List of 4
#>  $ CAPE : num [1:9, 1:13, 1:2] 0 0 0 0 0 0 0 0 0 0 ...
#>  $ CIN  : num [1:9, 1:13, 1:2] NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN ...
#>  $ p_LCL: num [1:9, 1:13, 1:2] 550 550 550 550 550 550 550 550 550 550 ...
#>  $ p_LFC: num [1:9, 1:13, 1:2] NaN NaN NaN NaN NaN NaN NaN NaN NaN NaN ...