Seeking Assistance with GEOS-Chem Sea Salt Mode Implementation Issue

[ChenBHXMU]

Your name

Baihua Chen

Your affiliation

Xiamen University

Please provide a clear and concise description of your question or discussion topic.

Dear @yantosca ,

I hope this letter finds you well.

Currently, sea salt only includes SALC and SALA. I am researching how to add two mode for sea salt. However, I have encountered the following problem. While working in GCClassic/src/GEOS-Chem/GeosCore/convection_mod.F90, I encountered an issue where I traced it back to QC being NaN. I have modified the parameter TINYNUM to 1e-4_fp, but the problem persists. The version of GEOS-Chem is 14.4.3.

I understand that code modification is not your responsibility, but since I am unable to quickly grasp the architecture of this project, I am struggling to resolve this issue. I hope my work can contribute to the advancement of GEOS-Chem. Thank you for your assistance.

Best regards,
Baihua Chen

[yantosca]

Thanks for writnig @ChenBHXMU. TINYNUM should not be set to a value as high as 1e-4. It is meant to prevent underflow when very small values are encountered.

One suggestion: If you have introduced new variables into convection_mod.F90 (or anywhere, really), make sure to initialize them to zero before they are used. When you build GEOS-Chem with -DCMAKE_RELEASE_TYPE=Debug it will set uninitialized values to NaN to make it easier to find them. I wonder if this is what is happening here.