Unstable LAI with dynamic vegetation in NoahMP

[tpartrid]

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

 

[Ming Chen]

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.

 

[tpartrid]

Hi Ming,

Thank you for the response. I'll definitely be keeping me eyes open for progress on the dynamic veg. module.

 

[yangliu_WRF]

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?

 

[Ming Chen]

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.

 

[caoyer]

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.

 

[Ming Chen]

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.

 

[marose]

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.

 

[Ming Chen]

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.

 

[marose]

Thanks for the swift response Ming, this is very helpful.