Interaction between decadal-to-multidecadal oceanic variability and sudden stratospheric warmings

Area of Science:

• Atmospheric Science
• Climate Dynamics
• Stratospheric Physics

Background:

• Major sudden stratospheric warmings (SSWs) are key drivers of wintertime stratospheric variability.
• SSWs cause polar temperature increases and stratospheric easterlies, impacting surface circulation.
• SSW occurrence varies multidecadally, potentially linked to sea surface temperatures.

Purpose of the Study:

• Investigate the influence of Pacific decadal variability (PDV) and Atlantic multidecadal variability (AMV) on SSWs.
• Examine how PDV and AMV modulate SSW frequency, precursors, and impacts.
• Utilize a large ensemble of historical experiments for comprehensive analysis.

Main Methods:

• Analysis of a large ensemble of historical climate simulations.
• Examination of the relationship between PDV, AMV, and SSW characteristics.
• Investigation of interference between oceanic variability and tropospheric stationary waves.

Main Results:

• PDV significantly impacts SSW occurrence, increasing frequency during its positive phase.
• PDV's influence is mediated by constructive interference with tropospheric stationary waves.
• AMV primarily modulates the tropospheric response to SSWs.

Conclusions:

• PDV is a significant factor in controlling SSW frequency.
• AMV affects the predictability of the tropospheric impacts of SSWs.
• Findings aid in understanding and predicting stratospheric variability and its teleconnections.