3 years ago

On the formation mechanism for wintertime extreme precipitation events over the southeastern Tibetan Plateau

Wenyu Huang, Tianpei Qiu, Zifan Yang, Daiyu Lin, Jonathon S. Wright, Bin Wang, Xinsheng He

Abstract

The formation mechanism for wintertime extreme precipitation events over the southeastern Tibetan Plateau (SETP) are explored. The crucial step in the development of these events was the emergence of a cyclonic anomaly above the Tibetan Plateau (TP). Wave activity fluxes (WAFs) along a Rossby wave train embedded in the subtropical jet stream (i.e., the circumglobal teleconnection) played the dominant role in producing this cyclonic anomaly, supported by weaker WAFs along a second Rossby wave train originating over Scandinavia. The cyclonic anomaly then moved over the SETP, favored strong updrafts, large‐scale moisture convergence, and intense precipitation. Extreme precipitation was more likely to ensue when the arrival of the cyclonic anomaly was preceded by persistent warm anomalies over the SETP, which favored moisture accumulation there. Temperatures above the SETP dropped sharply around the onset of the extreme precipitation. A heat budget analysis indicates that adiabatic cooling associated with convective ascent along the downstream edge of the cyclone played a leading role in this temperature drop, while a cold air intrusion associated with an anticyclonic anomaly over western Siberia (one center of action along the second wave train) played a complementary role. An Eulerian moisture budget analysis shows that variations in precipitable water delayed the onset and enhanced the intensity of these events, with moisture for precipitation delivered to the SETP mainly through the western and southern boundaries. A companion Lagrangian moisture source analysis reveals that the land areas south of the TP typically contributed 78.7% of the moisture supply for these events.

Publisher URL: https://onlinelibrary.wiley.com/doi/abs/10.1029/2018JD028921

DOI: 10.1029/2018JD028921

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.