Scheduled Downtime
On Friday 21 April 2023 @ 5pm MT, this website will be down for maintenance and expected to return online the morning of 24 April 2023 at the latest

How to calculate moist Brunt-Vaisala frequency?

This post was from a previous version of the WRF&MPAS-A Support Forum. New replies have been disabled and if you have follow up questions related to this post, then please start a new thread from the forum home page.


Dear Colleges,

The ncl script from is applicable for estimation of dry Brunt-Vaisala frequency.
How to calculate the moist Brunt-Vaisala frequency?

Kind regards,
You need to calculate equivalent potential temperature. It appears NCL does this and can be acquired via calling for "eth" in the get_var function. This requires knowing the temperature of the lifted condensation level for which there are several empirical methods to do so. A better approach would be to make a correction for the moist adiabatic lapse rate so that

N2 = g/t(dt/dz + gamma)

where gamma is the lapse rate, approximated as in the AMS glossary: