Lightning Potential Index

The function computes the lightning potential (LPI) according to Frisbie et al. (2009).

Usage

LPI(
  ta_s,
  hus_s,
  zg_s,
  pa_s,
  ta_pl,
  hus_pl,
  zg_pl,
  pa_pl,
  dz,
  vtc = TRUE,
  nthreads = 1
)

Arguments

ta_s

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

hus_s

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

zg_s

surface geopotential [lon, lat] (m^2/s^2).

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).

zg_pl

geopotential [lon, lat, lev, time] on pressure level (m^2/s^2).

pa_pl

pressure profile [lev] in ascending order from the TOA to the surface (hPa).

dz

height of the layer (m) to search for parcel with the most unstable CAPE. Default is 3000 km

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

LPI

References

• Frisbie, P. R., Colton, J. D., Pringle, J. R., Daniels, J. A., Ramey, J. D., Jr., & Meyers, M. P. (2009). P1. 5 lightning prediction by WFO grand junction using model data and graphical forecast editor smart tools.

• 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_sfc")
ta_s <- ERA5_sfc$t2m
td_s <- ERA5_sfc$t2d
pa_s <- ERA5_sfc$sp / 100
hus_s <- hus_from_td(td_s, pa_s)
dim(hus_s) <- dim(td_s)
zg_s <- ERA5_sfc$z[, , 1]

data("ERA5_pl")
ta_pl <- ERA5_pl$ta
hus_pl <- ERA5_pl$hus
pa_pl <- ERA5_pl$plev / 100
zg_pl <- ERA5_pl$z
dz <- 3000.0
res <- LPI(
  ta_s, hus_s, zg_s, pa_s,
  ta_pl, hus_pl, zg_pl, pa_pl,
  dz
)