Delta Theta_E Index — Delta_thetaE • MeteoMate

It is the difference between the equivalent potential temperature at the surface and at 300 hPa to assess the potential for wet microbursts.

Usage

Delta_thetaE(ta_s, hus_s, pa_s, hus300, ta300, 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).
hus300: specific humidity [lon, lat, time] at 300 hPa (kg/kg).
ta300: air temperature [lon, lat, time] at 300 hPa (K).
nthreads: an integer specifying the number of threads to use for computation (OpenMP). Default is 1.

Value

Delta Theta_E Index [lon, lat, time] (K).

References

Wakimoto, R. M. (1991). Wet microburst activity over the Southeastern United States: Implications for forecasting. Wea. Forecasting, 6, 470–482.
Kunz, M. (2007). The skill of convective parameters and indices to predict isolated and severe thunderstorms. Natural Hazards and Earth System Science, 7(2), 327–342 doi:10.5194/nhess-7-327-2007 .

Examples

data("ERA5_sfc")
ta_s <- ERA5_sfc$t2m
pa_s <- ERA5_sfc$sp / 100
hus_s <- hus_from_td(
  ERA5_sfc$t2d,
  pa_s
)[, , , 1]
data("ERA5_pl")
pa <- ERA5_pl$plev / 100 # convert to hPa
hus <- ERA5_pl$hus
ta <- ERA5_pl$ta
l300 <- which(pa == 300)

res <- Delta_thetaE(
  ta_s, hus_s, pa_s,
  hus[, , l300, ], ta[, , l300, ]
)