Supporting Data for "Non-Uniform Reduction of the North Atlantic Tropical Cyclones in Response to the AMOC Weakening under External Freshwater Forcing"

This repository contains the supporting data in the NetCDF format for the following paper: Joshi, R. and Zhang, R. (2026). Non-Uniform Reduction of the North Atlantic Tropical Cyclones in Response to the AMOC Weakening under External Freshwater Forcing, submitted to Geophysical Research Letters In this study, we investigate the evolution of the North Atlantic Tropical Cylone (TC) activity in response to the Atlantic Meridional Overturning Circulation (AMOC) weakening under external freshwater forcing. Our results are derived by analyzing an idealized water hosing ensemble and a control ensemble conducted with the high-resolution fully coupled climate model (GFDL CM4C192). In this work, tropical cyclones (TCs) are objectively detected and tracked using a TC tracker, allowing a direct evaluation of changes in TC activity rather than inferring indirectly from large-scale environmental variables such as sea surface temperature and vertical wind shear. Descriptions of data files in this repository: 1. Time series (11-yr running mean) of the annual mean maximum AMOC streamfunction at 26.5 °N for the control and water hosing ensembles, as shown in Figure 1a. Maximum_AMOC_26_5N.nc 2. Long-term mean response in surface temperature and latent heat flux, along with the two-sided student t-test for statistical testing for the response, as shown in Figure 1b–c. The response is computed as the ensemble mean difference (hosing—control), averaged over boreal hurricane season (JJASON) of the last 40 years of the ensembles. Long_Term_Mean_Surface_Temperature_Response.nc Long_Term_Mean_Latent_Heat_Flux_Response.nc 3. Time series (11-yr running mean) of the ensemble mean North Atlantic Tropical Cyclone counts in the control and water hosing ensembles during boreal hurricane season (JJASON), as shown in Figure 1d. North_Atlantic_TCs_JJASON.nc 4. Annual tropical cyclone genesis locations for each ensemble member of the control and water hosing experiments during the last 40 years of the ensembles, as shown in Figure 2c-h. TC_Control_Ensemble1.csv; TC_Control_Ensemble2.csv; TC_Control_Ensemble3.csv TC_Hosing_Ensemble1.csv; TC_Hosing_Ensemble2.csv; TC_Hosing_Ensemble3.csv 5. Climatological seasonal cycle of the North Atlantic tropical cyclone counts for the ensemble mean over the last 40 years of the control and water hosing ensembles, as shown in Figure 2b. Seasonal_Cycle_TCs.nc 6. Transient evolution of the aggregated (i.e., all ensemble members) North Atlantic Tropical cyclone genesis locations and tracks during JJASON for the control and water hosing ensembles, as shown in Figure 3a-h TCs_Genesis_and_Tracks_Control_Year01to10.csv; TCs_Genesis_and_Tracks_Control_Year11to20.csv; TCs_Genesis_and_Tracks_Control_Year21to30.csv; TCs_Genesis_and_Tracks_Control_Year31to40.csv TCs_Genesis_and_Tracks_Hosing_Year01to10.csv; TCs_Genesis_and_Tracks_Hosing_Year11to20.csv; TCs_Genesis_and_Tracks_Hosing_Year21to30.csv; TCs_Genesis_and_Tracks_Hosing_Year31to40.csv 7. Transient response in relative SST and 1000hPa specific humidity, as shown in Figure 3i-p. The response is computed as the ensemble mean difference (hosing—control) during JJASON. Transient_Relative_SST_Response.nc Transient_Specific_Humidity_1000hPa_Response.nc 8. Transient response of the Atlantic basin averaged zonal wind and temperature during JJASON, as shown in Figure 4a-d. The response is computed as the ensemble mean difference (hosing—control) during JJASON. Transient_Atlantic_Avg_Zonal_Wind_Response.nc Transient_Atlantic_Avg_Temp_Response.nc 9. Transient response in vertical wind shear, as shown in Figure 4e-h. The response is computed as the ensemble mean difference (hosing—control) during JJASON. Transient_Vertical_Wind_Shear.nc Acknowledgments We acknowledge the Geophysical Fluid Dynamics Laboratory (GFDL) Coupled Model, version 4 (CM4), whose source code was used in this study. The code is publicly available at: https://doi.org/10.5281/zenodo.3339397. We also acknowledge the GFDL Tropical Storm Detection and Tracking code used in this study. The code is publicly available at: https://github.com/NOAA-GFDL/TCtracker.