Bias in 2m and surface temperature

[mmaoyi]

Hi MPAS users

I was doing model validation and noticed that MPAS 7 grossly underestimates the 2m temperature ( t2m see temperature.png) as well as surface temperature (temperature_surface not attached- similar with t2m) as compared to CRU and University of Delware observational data (I also tried comparing to various reanalysis datasets but the outcome is the same). The composite is for JFM years 1983, 1992, 1998 and 2010. I performed 10 ensembles for each of the years but each individual ensemble still shows a cold bias similar to the composite. I used restart files to create the ensembles (warm start) and I was careful to convert the T2M in Kelvins to celcius degrees by calculting New_T2M=T2M - 273.15.

When I check other fields like rainfall (see rainfall.png) and geopotential height, they are comparable with observations/reanalysis (with some bias), however both the temperature at surface and the 2m temperature are quite low.

Has anybody encountered this ? Are there any papers on MPAS which have dealt with this similar problem?

Kind Regards
Linda

 

[mgduda]

Apologies for the silence on this issue. For my part, I don't have any good suggestions on where the issue might lie, so I've refrained from posting in hopes that others might be able to offer some insight or suggestions.

Is this still an issue under investigation?

 

[mmaoyi]

Greetings Michael

I have decided not to use the 2m temperature in terms of my current work, however, it still remains under investigation
by my research group as we use MPAS extensively.

I suspect that it has to do with topography. I compared the MPAS topography with etop observed topography (MPAS-etop) and the MPAS
topography was lower in areas with higher elevation (mountains) and but showed higher values over the low-lying regions as compared with etop.
I have not yet gone deep into it but I think that's a start.