metpy.calc.total_totals_index(pressure, temperature, dewpoint)#

Calculate Total Totals Index from the pressure temperature and dewpoint.

Total Totals Index formula derived from [Miller1972]: TT = (T850 + Td850) - (2 * T500)


T850 is the temperature at 850 hPa T500 is the temperature at 500 hPa Td850 is the dewpoint at 850 hPa

Calculation of the Total Totals Index is defined as the temperature at 850 hPa plus the dewpoint at 850 hPa, minus twice the temperature at 500 hPa. This index consists of two components, the Vertical Totals (VT) and the Cross Totals (CT).

  • pressure (pint.Quantity) – Pressure level(s), in order from highest to lowest pressure

  • temperature (pint.Quantity) – Temperature corresponding to pressure

  • dewpoint (pint.Quantity) – Dewpoint temperature corresponding to pressure


pint.Quantity – Total Totals Index