Sensitivity of Dynamically Downscaled Hydroclimate Projections Over Puerto Rico to the Parameterization of Dust Emissions and Transport in WRF-Chem

Hydroclimate variables were downscaled over Puerto Rico using the Weather Research and Forecasting (WRF) model (Skamarock & Klemp, 2008), version 3.8. Data were downscaled for three time periods: a historical period between 1 January 2013 to 31 December 2018, a mid-21st century period between 1 January 2044 and 31 December 2049, and an end-21st century period between 1 January 2084 and 31 December 2089. The mid- and end-21st century simulations were forced with output from the CMIP5 Community Earth System Model version 1 (CESM1) RCP8.5 scenario (Monaghan et al., 2014). The historical simulation was forced with initial and boundary conditions from the ERA5 reanalysis (Hersbach et al., 2020) to maintain parallelism with the pre-processed CESM output, which was bias-corrected against the now-deprecated ERA-Interim (Monaghan et al., 2014). Fore each simulation period, two sets of simulations were conducted: one scenario in which dust is allowed to perturb the large-scale circulations over the tropical North Atlantic (these files include the "_dust" tag in the respective file name) and a second scenario with all atmospheric chemistry, including dust effects, turned off. For the dust-on simulations, dust emissions were parameterized using the GOCART model (Ginoux et al., 2001) with Air Force Weather Agency modifications (GOCART-AFWA) (LeGrand et al., 2019). Ginoux, P., Chin, M., Tegen, I., Prospero, J. M., Holben, B., Dubovik, O., & Lin, S.-J. (2001). Sources and distributions of dust aerosols simulated with the GOCART model. Journal of Geophysical Research: Atmospheres, 106(D17), 20255–20273. https://doi.org/10.1029/2000JD000053 Hersbach, H., Bell, B., Berrisford, P., Hirahara, S., Horányi, A., Muñoz‐Sabater, J., et al. (2020). The ERA5 global reanalysis. Quarterly Journal of the Royal Meteorological Society, 146(730), 1999–2049. https://doi.org/10.1002/qj.3803 LeGrand, S. L., Polashenski, C., Letcher, T. W., Creighton, G. A., Peckham, S. E., & Cetola, J. D. (2019). The AFWA dust emission scheme for the GOCART aerosol model in WRF-Chem v3.8.1. Geoscientific Model Development, 12(1), 131–166. https://doi.org/10.5194/gmd-12-131-2019 Monaghan, A., Steinhoff, D., Bruyere, C., & Yates, D. (2014). NCAR CESM Global Bias-Corrected CMIP5 Output to Support WRF/MPAS Research [Data set]. UCAR/NCAR - Research Data Archive. https://doi.org/10.5065/D6DJ5CN4 Skamarock, W. C., & Klemp, J. B. (2008). A time-split nonhydrostatic atmospheric model for weather research and forecasting applications. Journal of Computational Physics, 227(7), 3465–3485.