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UP: Fachverband Umweltphysik

UP 5: Modelling and Prediction Across Scales

UP 5.3: Vortrag

Dienstag, 10. März 2026, 14:45–15:00, MER/0002

An optimization-based approach to track the Asian summer monsoon anticyclone across daily and interannual variability — •Oleh Kachula, Bärbel Vogel, Gebhard Günther, and Rolf Müller — Forschungszentrum Jülich, 52428 Jülich, Germany

The Asian summer monsoon anticyclone (ASMA) is an upper troposphere-lower stratosphere (UTLS) meteorological circulation system that develops over Asia during summer months in the Northern Hemisphere. It strongly influences regional weather, particularly monsoon rainfall, and shapes the climate of densely populated regions such as India and Southeast Asia. The ASMA also plays a major role in transporting near-surface anthropogenic pollutants to the UTLS, with important implications for air quality and stratospheric chemistry. Improving our understanding of this complex system is essential for enhancing weather prediction capabilities and for better assessing climate and environmental impacts.

We present a novel method based on the absolute vortex moments that defines the ASMA boundary by solving an optimization problem. Here, we address the ASMA's climatology (1980-2023), interannual variability, the variability of the start and end dates and the duration of the anticyclone peak phase calculated with help of the defined novel method by using the ERA5 reanalysis provided by ECMWF. Our findings show that the ASMA area decreases at 370, 390 and 410 K over the period 1980-2023 in contrast to previous studies. Further, we provide evidence of possible bimodality of the ASMA.

Keywords: Optimization; Atmosphere; Anticyclones; Monsoons; Interannual variability