Supporting Data for "Impact of the AMOC Weakening on Upper Troposphere/Lower Stratosphere Warming over the Extratropical North Pacific"

This repository contains the supporting data in the NetCDF format for the following paper:

Joshi, R. and Zhang, R. (2026). Impact of the AMOC Weakening on Upper Troposphere/Lower Stratosphere Warming over the Extratropical North Pacific, Geophysical Research Letters, 53, e2026GL122116. https://doi.org/10.1029/ 2026GL122116

In this study, we analyze an idealized water hosing ensemble in comparison with the control ensemble conducted with a high-resolution fully coupled climate (GFDL CM4C192) to understand how a substantially weakened AMOC induces the UTLS response over the extratropical North Pacific during boreal winter.

Descriptions of data files in this repository:

1. Long-term mean boreal winter response in precipitation, temperature at 200hPa, velocity potential at 200hPa, and omega at 200hPa, along with the two-sided student t-test for statistical testing for the response (Figure 1a-d). 

Precipitation_Response.nc, Temperature_Response_200hPa.nc, Velocity_Potential_Response_200hPa.nc, Omega_Response_200hPa.nc

2. Long-term mean boreal winter divergent wind response at 200hPa (Figure 1c).

Divergent_Wind_Response_200hPa.nc

3. Contribution from the response in omega to the vertical advection of mean potential temperature at 200hPa during boreal winter, along with the two-sided student t-test for statistical testing of the contribution term (Figure 1e).

Omega_Contribution_Term_200hPa.nc

4. Time series (11-year running mean) of the estimated vs. modeled boreal winter temperature response at 156°W and 200 hPa, shown in Figure 1f.

Time_Series_Temp_Response_156W.nc

5. Long-term mean boreal winter response in the zonal wind and air temperature averaged zonally over the extratropical North Pacific, along with the two-sided student t-test for statistical testing for the response (Figure 2a). 

Zonal_Wind_Response_NP.nc, Temperature_Response_NP.nc

6. Time series (11-year running mean) of the thermal wind balance terms at 200hPa during boreal winter shown in Figure 2b.

Thermal_Wind_Balance_Terms.nc

7. The leading Principal Component (PC1) of the smoothed (11-year running mean) 200 hPa streamfunction response with the zonal mean removed (Figure 3a). 

PC1.nc

8. Leading Empirical Orthogonal Function (EOF1) of the smoothed (11-year running mean) 200hPa streamfunction response with the zonal mean removed (Figure 3b).

EOF1.nc

8. Regression of the response in the relative vorticity at 200 hPa on the PC1 of the North Pacific of the smoothed 200hPa streamfunction response (Figure 3c).

Regression_Vorticity_200hPa.nc

9. The wave activity associated with the leading EOF1  of the smoothed (11-year running mean) 200hPa streamfunction response shown in Figure 3b. 

Wave_Activity_Flux_Associated_With_EOF1.nc

10. Regression of the response in the tropical North Pacific zonal mass overturning on the PC1 of the North Pacific of the smoothed 200hPa streamfunction response (Figure 4a).

Regression_TNP.nc

11. Regression of the response in the eastern Pacific meridional mass overturning streamfunction on the PC1 of the North Pacific of the smoothed 200hPa streamfunction response (Figure 4b).

Regression_ENP.nc

12. Regression of the response in the OLR on the PC1 of the North Pacific of the smoothed 200hPa streamfunction response (Figure 4c).

Regression_OLR.nc

Acknowledgments

We acknowledge the use of the following model code in this study:

The code of the Geophysical Fluid Dynamics Laboratory coupled climate model version 4 (GFDL-CM4) is publicly available at https://zenodo.org/records/3339397.