showalter_index#
- metpy.calc.showalter_index(pressure, temperature, dewpoint)#
Calculate Showalter Index.
Showalter Index derived from [Galway1956]:
\[SI = T500 - Tp500\]where:
\(T500\) is the measured temperature at 500 hPa
\(Tp500\) is the temperature of the parcel at 500 hPa when lifted from 850 hPa
- Parameters:
pressure (
pint.Quantity
) – Atmospheric pressure, in order from highest to lowest pressuretemperature (
pint.Quantity
) – Ambient temperature corresponding topressure
dewpoint (
pint.Quantity
) – Ambient dew point temperatures corresponding topressure
- Returns:
pint.Quantity
– Showalter index
Examples
>>> from metpy.calc import dewpoint_from_relative_humidity, showalter_index >>> from metpy.units import units >>> # pressure >>> p = [1008., 1000., 950., 900., 850., 800., 750., 700., 650., 600., ... 550., 500., 450., 400., 350., 300., 250., 200., ... 175., 150., 125., 100., 80., 70., 60., 50., ... 40., 30., 25., 20.] * units.hPa >>> # temperature >>> T = [29.3, 28.1, 23.5, 20.9, 18.4, 15.9, 13.1, 10.1, 6.7, 3.1, ... -0.5, -4.5, -9.0, -14.8, -21.5, -29.7, -40.0, -52.4, ... -59.2, -66.5, -74.1, -78.5, -76.0, -71.6, -66.7, -61.3, ... -56.3, -51.7, -50.7, -47.5] * units.degC >>> # relative humidity >>> rh = [.85, .65, .36, .39, .82, .72, .75, .86, .65, .22, .52, ... .66, .64, .20, .05, .75, .76, .45, .25, .48, .76, .88, ... .56, .88, .39, .67, .15, .04, .94, .35] * units.dimensionless >>> # calculate dewpoint >>> Td = dewpoint_from_relative_humidity(T, rh) >>> # compute the showalter index >>> showalter_index(p, T, Td) <Quantity([0.48421285], 'delta_degree_Celsius')>
Examples using metpy.calc.showalter_index
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Sounding Calculation Examples