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Unstable LAI with dynamic vegetation in NoahMP

tpartrid

New member
Hi all,

I'm finding that LAI is unstable and eventually goes to zero over a multi-year simulation when I turn on dynamic vegetation in Noah-MP. The attached image shows 5 years of LAI over a grid cell defined as an Evergreen Needleleaf Forest and another as Savannah. I've run with dynamic vegetation in the past, but never for a multi-year simulation, has anyone else experienced this behavior? Any ideas for troubleshooting?

Thank you for the help!
-Trevor

Screenshot 2022-05-24 093649.png
 
Trevor,
I am sorry to tell that the dynamic option in noahMP doesn't work as expected. We have to suggest that users avoid using this option. The developers haven't made any progress/improvement regarding issue at present.
 
Hi Ming,

Thank you for the response. I'll definitely be keeping me eyes open for progress on the dynamic veg. module.
 
Trevor,
I am sorry to tell that the dynamic option in noahMP doesn't work as expected. We have to suggest that users avoid using this option. The developers haven't made any progress/improvement regarding issue at present.
Hi Ming,
I would like to ask, is it possible to obtain the LAI and FVEG information of a certain area in China in the 1930s/1950s by coupling the dynamic veg. module with WRF?
 
I don't think so. This is because the dynamic vegetation option in WRF doesn't work well and we have no verification to confirm it can yield reasonable results.
 
Hi,
I'm now using dynamic vegetation option simulating the development of LAI in india,
i encounter the same problem, even the simulation period was not that long (3 months),
in most area, the value of LAI eventually stay at a very low level, which is not consistent with observed data
from MODIS.
 
We are aware of the issue related to dynamic vegetation option in NoahMP. Unfortunately we cannot fix this issue at present. Please don't use this option.
 
Hi. This is slightly off-topic but I would be happy if you could provide me with some clarifications. I am running the WRF model with noahmp for surface physics. I saw about 10 options to use for noahmp. Currently, I am using my own input LAI and Fveg downloaded from copernicus. My questions pertain to how noahmp would use these datasets based on the options I choose:

1. If LAI is from tables, does it mean the noahmp uses the LAI found in the MPTABLE.TBL file?
2. If I choose the LAI and Fveg from input option, does it mean noahmp would use these datasets which have been processed in the geo_em.d01.nc file or perhaps that in the met_em files?

Looking forward to read any clarifications. Thanks in advance.
 
Please see my answers below:

(1) If LAI is from tables, does it mean the noahmp uses the LAI found in the MPTABLE.TBL file?

yes it is.

(2). If I choose the LAI and Fveg from input option, does it mean noahmp would use these datasets which have been processed in the geo_em.d01.nc file or perhaps that in the met_em files?

With DVEG = 7, WRF will read data from input file. In this case if you provide LAI and FVEG, the model will use them.
 
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