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QBO’s Modulation of the Global Atmospheric River Activities

Presentation Date
Wednesday, January 31, 2024 at 5:45pm - Wednesday, January 31, 2024 at 6:00pm
The Baltimore Convention Center - 350



Impact of the Quasi-Biennial Oscillation (QBO) on Atmospheric River (AR) activity are found in various regions around the globe in ERA5 and MERRA-2 reanalysis. The AR frequencies and intensities are measured by multiple AR detection algorithms from the Atmospheric River Tracking Method Intercomparison Project (ARTMIP). The QBO phase is defined by the equatorial zonal wind at 50hPa in the December-January-February (DJF) season of each year from 1980 to 2017. The dominant AR regions over the North Pacific exhibit a systematic poleward shift in the QBO-Easterly (QBOE) years than in the QBO-Westerly (QBOW) years. This leads to less frequent AR landings with weaker intensities over the west coast of the North America continent in the late winter to late spring (January to May) season of the QBOE years, and vice versa. Less frequent AR activities in the QBOE years are also observed over northeastern Japan in the November-December-January (NDJ) season and over the Bering strait in the DJF season. In contrast, the AR frequencies increase in the July-August-September (JAS) season of the QBOE years over the Bering strait. Similar mid-to-high-latitude QBO-AR connections are found in the southern hemisphere as well. The mid-latitude AR responses are possibly the results of QBO’s modulations of the subtropical jet, the east Asian monsoon vapor, and the extratropical MJO teleconnections. The high-latitude AR responses may be related to the QBO’s influences on polar regions through the Holton-Tan effect, which needs further investigation. Some preliminary diagnostics regarding the QBO-AR connection in climate models are also carried out for comparison.

Funding Program Area(s)