Large-scale Meteorological Organization of Extreme Weather Events: Final Technical Report

• Main Authors: Black, Robert X., Deng, Yi, Zhao, Siyu, Xie, Zuowei
• Language: unknown
• Published: 2019
• Subjects: 58 GEOSCIENCES; 54 ENVIRONMENTAL SCIENCES; Pacific; North Atlantic; North Atlantic oscillation
• Online Access: http://www.osti.gov/servlets/purl/1481773; https://www.osti.gov/biblio/1481773; https://doi.org/10.2172/1481773

Although the occurrence of regional extreme weather events (EWEs) such as cold air outbreaks, heat waves, droughts and floods are known to be related to planetary climate modes (PCMs) such as the El-Nino Southern Oscillation or North Atlantic Oscillation, intermediate meteorological patterns (IMPs) such as jet stream blocking, cyclones, and high pressure systems are required to connect PCMs to EWEs. Our project has revealed a physical pathway for the interplay among EWEs, IMPs and PCMs. Under support of this award, we have characterized the behavior of IMPs that cause winter cold air outbreaks, extreme floods and warm season dry spells in the US. This includes formulating meteorological “fingerprints” for easily identifying IMPs. The research performed includes a parallel analysis of how well modern climate models are able to simulate IMP behavior. We have also developed a novel approach for characterizing PCM structures and identifying EWE-LMP-PCM linkages. We discovered that dry spells occurring during spring and summer over the US are affected by changes in the North Pacific Ocean temperature. We further revealed the physical origin of a critical jet stream pattern occurring over the North Pacific Ocean that provides a “bridge” between the water cycles of East Asia and North America, respectively. We developed an advanced diagnostic technique (called piecewise tendency diagnosis or PTD) to understand the physical causes for the IMP formation and EWE-LMP-PCM linkages.