The Dynamics and Predictability of Midlatitude Sub-monthly Retrograde Waves

GSTDTAP

项目编号	1724555
	The Dynamics and Predictability of Midlatitude Sub-monthly Retrograde Waves
	Huei-Ping Huang
主持机构	Arizona State University
项目开始年	2017
	2017-06-15
项目结束日期	2020-05-31
资助机构	US-NSF
项目类别	Continuing grant
项目经费	200545(USD)
国家	美国
语种	英语
英文摘要	Maps of the wintertime atmospheric circulation commonly show wavelike features in the middle latitudes of the Northern Hemisphere, with jet streams meandering northward around ridges and southward around troughs in the upper-level pressure pattern. Most of these waves either remain stationary or propagate from west to east, like the upper-level ridges and troughs associated with the fronts seen on surface weather charts. This project considers the unusual case of retrograde waves, which propagate from east to west and thus contrary to the strong westerly winds that prevail in the mid-latitude upper troposphere. The retrograde waves occur largely between 40N and 70N, moving along a path poleward of the jet stream. They are slow and long, with periods from eight to thirty days and only one or two undulations over a full latitude circle. Although they tend to have their largest amplitude over the North Pacific, they can influence weather and climate over the continental US, including precipitation over California. They were documented in the 1980s but have not received much attention from the research community and are still relatively unexplored. This project addresses several key questions regarding retrograde waves, including the mechanisms that generate them, their predictability, and their effect on the predictability of day-to-day surface weather. One possibility to be explored is that the waves are generated by tropical precipitation, as the Coriolis force acting on upper-level divergence above precipitating regions can generate waves at some distance from the source. Another possible origin is the shedding of potential vorticity on the poleward flank of the jet stream. These mechanisms are explored through diagnostic analysis of retrograde waves identified in meteorological (reanalysis) datasets. The predictability of the waves and their influence on the skill of weather forecasts is examined using retrospective forecasts prepared at the NOAA Earth System Research Laboratory. The work has societal broader impacts due to its potential value for long-range weather prediction. The slow movement of the waves suggests that they may be somewhat predictable, and it is possible that their effects on day-to-day weather may provide some basis for practical long-range forecasting. In addition, the project provides support and training to a graduate student, thereby providing for the future workforce in this research area.
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/71137
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Huei-Ping Huang.The Dynamics and Predictability of Midlatitude Sub-monthly Retrograde Waves.2017.