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

Surface/Soil Data Assimilation

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.


New member

Here again. First of all congratulations for such nice GSI user guide, it is really clear and useful.

Secondly, I only want to confirm my thoughts. I have downloaded, compiled and ran the "reference" analysis for WRF-ARW, with GSI, using only conventional obs, and it seems I am running a 3DVAR Upper Air analysis were the updated variables are U,V,Q,T and PS in all the vertical levels. I have computed analysis increments and I don't see any update for any other variable, in particular, T2m, Q2m and Soil Temperature and Humidity.

My thought I would like someone to confirm (if possible) is that GSI does not update soil variables (and probably T2m/Q2m) in the analysis step, correct? E.g, these variables are only updated during the forecast step?

A related question is, specially for people who is running GSI operationally, do you think this "reference" 3DVAR configuration is the optimal for your operational runs? I mean if you run 3DVAR... In principle I want to stay with 3DVAR, not to go to 4DVAR or Hybrid methods.

Many thanks!!