LAI

[adrifoster]

Adding another thread about LAI. Now that we are gearing up for concerted SP-mode calibration, are we certain the LAI we are using on the surface datasets to drive SP mode is correct? In my site-level calibrations I have found it to not be very accurate.

We also discussed potentially dividing the input LAI by the clumping factor, @rosiealice maybe you could speak to this.

[lasseke]

Hi! A short comment on this because I ran into the exact same question yesterday. I'm currently working on single-site simulations at a boreal forest site in Finland (Hyytiälä) and they provide a simple time series of LAI measurements in the site description. The prescribed seasonal maximum LAI in FATES-SP is 3, while the measurements (which capture a ~20-year period) range from ~3.0 to ~4.4.

I'm not an expert in LAI measurements but the sampling method seems to have a significant impact on the magnitude: they give estimates based on biomass inventories and radiation measurements. The former consistently gives higher values and seems to better capture ongoing growth (radiation measurements saturate while biomass measurements keep increasing). Hence I have the following questions:

• How can I manipulate the prescribed LAI? I will use the default values for "fates_hlm_pft_map", where my HLM is CLM.
• Would using the biomass inventory estimates be more adequate in terms of model implementation compared to using the radiation measurements?

Thank you all for your great work!

[rosiealice]

Hi Lasse,

These numbers typically come from the surface dataset and (I think @adrifoster has plans to change this) are the same for every year.) so if you modify them (the TLAI fields) there they will get into the FATES SP logic.

On the radiation vs allometric surveys it would be interesting to see the difference in the estimates. Clumping of leaves can potentially be an important factor in the delta between these...