2025JD045810 - How does explicit tropospheric VOC chemistry affect radiative forcing? Investigation of preindustrial climate using the Community Earth System Model version 2

This repository contains the netCDF4 output from the Community Earth System Model version 2 configured with the Whole Atmosphere Community Climate Model version 6 (CESM2-WACCM6) from six piControl (1850 C.E.) simulations (WF.f19_g17, MF.f19_g17, WC.f19_g17, MC.f19_g17, W23.f19_g17, and M23.f19_g17). The atmospheric grid in these simulations is a 1.9° × 2.5° finite-volume grid. The simulations are configured as follows: (1) WF.f19_g17 is the whole-atmosphere chemistry configuration using fixed sea surface temperatures (fSSTs); (2) MF.f19_g17 is the middle-atmosphere chemistry-only configuration using fSSTs; (3) WC.f19_g17 is the whole-atmosphere chemistry configuration in a fully coupled setup; (4) MC.f19_g17 is the middle-atmosphere chemistry-only configuration in a fully coupled setup; (5) W23.f19_g17 is identical to WC.f19_g17 but uses the initialization scheme described in Stanton and Tandon (2023) [DOI: 10.5194/acp-23-9191-2023]; and (6) M23.f19_g17 is identical to MC.f19_g17 but also uses the initialization scheme described in Stanton and Tandon (2023). Aerosol data are categorized as dry aerosol (a) or in-cloud aerosol (c), and further grouped into four modal bins: (1) accumulation (a1/c1), (2) Aitken (a2/c2), (3) coarse (a3/c3), and (4) primary carbon (a4/c4). For the WF.f19_g17 and MF.f19_g17 simulations, the output variables from simulation years 1–150 include AODVISdn (aerosol optical depth at 550 nm, day–night average), bc (black carbon aerosol: a1, a4, c1, c4), pom (primary organic matter aerosol: a1, a4, c1, c4), ncl (sea-salt aerosol: a1, a2, a3, c1, c2, c3), dst (dust aerosol: a1, a2, a3, c1, c2, c3), so4 (sulfate aerosol: a1, a2, a3, c1, c2, c3), soa (secondary organic aerosol; WF: soa1_a1–soa5_a2 and soa1_c1–soa5_c2, MF: soa_a1, soa_a2, soa_c1, soa_c2), FLNT (net longwave flux at top of model), FSNT (net shortwave flux at top of model), LWCF (longwave cloud forcing), SWCF (shortwave cloud forcing), OH (hydroxyl, mole mixing ratio), PRECC (convective precipitation rate, liquid + ice), PRECL (large-scale precipitation rate, liquid + ice), and U10 (10 m wind speed). For the WC.f19_g17 and MC.f19_g17 simulations, the output variables from years 1–250 include CLDTOT (total cloud fraction), FLNT, FSNT, LWCF, SWCF, OH (mole mixing ratio), PRECC, PRECL, PSL (sea-level pressure), T (atmospheric temperature), TS (surface temperature), U (zonal wind), V (meridional wind), aice (sea-ice concentration), and MOC (meridional overturning circulation). WC.f19_g17 also includes TAREA (grid-cell area) to aid in sea-ice area calculations. For the W23.f19_g17 and M23.f19_g17 simulations, the available output variables are MOC, aice, and TS. The data for each simulation are contained in a folder named after its case (e.g., WF.f19_g17, MF.f19_g17, etc.). In addition to the model output, a “Matlab Scripts” folder includes all MATLAB scripts used to generate the figures, tables, and spatial correlation analyses presented in the main manuscript and supporting information.