MERRA2 diagnosed number concentrations of ice friendly (NIFA) and liquid friendly aerosols (NWFA).

[AnningCheng-NOAA]

Description

Provide a clear and concise description of what the problem is. Ex. I'm always frustrated when [...] number concentrations of ice friendly (NIFA) and liquid friendly aerosols (NWFA) are forecasted in Thompson microphysics. It is taken about 10% more computation time and becomes unrealistically large with long integration

Solution

Add a clear and concise description of what solution you provide. MERRA2 climatological aerosols are used to calculate number concentrations of ice friendly (NIFA) and liquid friendly aerosols (NWFA). So IN and CCN can be activated using aerosol. This approach is about 10% less expensive than the forecast approach. The indirect interaction of aerosol and clouds is expected to happen.

Alternatives

If applicable, add a description of any alternative solutions or features you've considered.

Testing:

1. Have you tested the code changes? On what platforms? Hera
2. Have you run regression test in ufs-weather-model or ufs-s2s-model with code changes? Yes

• Will the baseline results change? Yes
• If yes, please give brief explanation of your code updates on the regression test.

Dependent PRs:

Directly reference any issues or PRs in this or other repositories that this is related to, and describe how they are related. Example:

• required to support noaa-emc/GFDL_atmos_cubed_sphere/issues/<issue_number>
• ncar/ccpp-physics/pull/<720>
• associated ufs-weather-model/pull/<951>