Adding In-Canopy Features in UFS-SRW-AQM

[drnimbusrain]

Systematic ozone overpredictions in CTMs are linked to distinct vertical gradients of ozone measured within dense forest canopies of the U.S. (Makar et al., 2017). For example, the typical ozone overpredictions in the eastern U.S. and Pacific Northwest in our operational NAQFC are found in regions of contiguous canopies, where the effects of canopy shading are not explicitly taken into account using the widely applied "big-leaf" approach.

Here we are incorporating new canopy parameters and simple parameterizations in the AQM component of Online-CMAQ, which are associated with the attenuation of light based on Makar et al. (2017).

We have already integrated and tested the code in the CONUS 13 km Online-CMAQ domain, and have performed a 10-day evaluation for August 01 - 10, 2019 that shows improved ozone model performance. More background and results found here: https://docs.google.com/presentation/d/16mqtv85KtG0NxHl0_RN7xojB5q6inaB3NnDdCEl3yKI/edit?usp=sharing

While results are current small when incorporating in-canopy photolysis attenuation only, we expect a more significant impact when later adding the combined effect of reduced vertical diffusivity of tracers (as shown for offline NACC-CMAQ full month tests in the presentation) in the CCPP physics side of Online-CMAQ. This work is also currently underway.

We would like to submit this new in-canopy photolysis feature as a PR to https://github.com/NOAA-EMC/AQM develop branch.

This effect needs to be further tested for the larger NA/793 domain, and would be grateful for collaboration with EMC on this.

@JianpingHuang-NOAA @chan-hoo @KaiWang-NOAA @bbakernoaa

[BrianCurtis-NOAA]

I've added this to be tracked as a part of AQM v8.