Studies of the Early-1990s Climate Shift in the Pacific and Its Linkage to the Atlantic Multi-decadal Oscillation

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项目编号	1505145
	Studies of the Early-1990s Climate Shift in the Pacific and Its Linkage to the Atlantic Multi-decadal Oscillation
	Jin-Yi Yu
主持机构	University of California-Irvine
项目开始年	2015
	2015-09-01
项目结束日期	2018-08-31
资助机构	US-NSF
项目类别	Standard Grant
项目经费	849543(USD)
国家	美国
语种	英语
英文摘要	Changes in the climate of the Pacific Ocean and overlying atmosphere have worldwide consequences, and the causes and consequences of such changes are important topics in climate dynamics. One such change is the Pacific climate shift of the early 1990s, in which 1) the location of El Nino/Southern Oscillation (ENSO) events shifted from the eastern equatorial Pacific to the central equatorial Pacific; 2) the year-to-year variability of the Northern Hemisphere monsoons decreased dramatically; 3) sea level in the western tropical Pacific began rising at a faster rate; and 4) the north equatorial current and countercurrent migrated southward. This project tests the hypothesis that the 1990s climate shift is related to an intensification of the subtropical Pacific high, a quasi-stationary region of high sea level pressure which extends past the dateline from the California coast and covers much of the subtropical North Pacific. When the subtropical Pacific high intensifies the surface winds circulating around it speed up, and the higher speed has the effect of strengthening the coupling of the ocean and atmosphere in the region. Work under this award examines the extent to which the intensification of ocean-atmosphere coupling can lead to the four climate shift impacts listed above. The project further tests the hypothesis that the intensification of the Pacific high occurred in response to the reversal of the Atlantic Multi-decadal Oscillation (AMO) which occurred at the same time. The AMO is a slowly varying mode of sea surface temperature (SST) variation in which the Atlantic north of the equator is either warmer or colder than average, with a transition from colder to warmer SSTs around 1990. The research is conducted using a suite of simulations from a climate model configured in various ways to test the hypotheses. In one configuration SSTs are prescribed globally, with the AMO pattern imposed in the Atlantic so that the response of the Pacific high to the AMO can be assessed. Other configurations use a partially or fully interactive ocean model, allowing the changes in the Pacific high to affect SSTs and the subsurface ocean. These configurations allow the changes in ocean-atmosphere coupling and their hypothesized consequences to be examined. Aside from its scientific interest, the 1990s Pacific climate shift has societal importance due to its worldwide impacts. The variability of monsoon systems is consequential for water resources, while the shift from eastern to central Pacific ENSO events has implications for the impacts of these events on the weather and climate of the US. In addition, the project provides support and training for a postdoctoral associate and two graduate students, thereby providing for the next generation of researchers in this field.
来源学科分类	Geosciences - Atmospheric and Geospace Sciences
文献类型	项目
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/68757
专题	环境与发展全球科技态势
推荐引用方式 GB/T 7714	Jin-Yi Yu.Studies of the Early-1990s Climate Shift in the Pacific and Its Linkage to the Atlantic Multi-decadal Oscillation.2015.