P2C2: Synoptic Dendroclimatology--Using Tree Rings to Reconstruct the Driving Forces of Hydroclimatic Variability in the Western United States

研究人员将使用天气树状气候学研究美国西部的水文气候变异性及其与厄尔尼诺/南方涛动(ENSO)的关系。天气树状气候学将天气气候学和树状年代学结合在一起，采用一种基于过程的方法，将大规模环流模式与局部树木生长异常联系起来。研究人员认为，由于影响模式的不稳定性和其他大气控制对美国西部气候模式的影响，应用现有的ENSO重建来评估热带外地区的ENSO影响一直是困难的。这项研究的主要目的有三个：1)利用现有的树轮年表和网格化再分析数据建立大气压力模式的长期记录；2)利用有针对性的现场采样和天气分析来确定对持续的经向和纬向大气流型的控制；3)通过将前两个目标的数据与现有的干旱和ENSO重建数据联系在一起，描绘出过去ENSO事件的空间足迹。更广泛的影响包括支持一名职业生涯早期的新女性调查员，对一名研究生的教育和培训，以及将一些本科生纳入实地和实验室研究。这项工作将与水资源管理人员和其他对美国西部水气候感兴趣的人相关，而网格化压力重建将对其他气候研究人员具有价值。

The researcher will examine western U.S. hydroclimatic variability and its relationship to El Nino/Southern Oscillation (ENSO) using synoptic dendroclimatology. Synoptic dendroclimatology integrates synoptic climatology and dendrochronology in a process-based approach linking large-scale circulation patterns to local tree-growth anomalies. The researcher contends that it has been difficult to apply existing ENSO reconstructions to assess ENSO impacts in extratropical regions due to the instability of the impact pattern and the influence of other atmospheric controls on climate patterns in the U.S. west.There are three main objectives of the research: 1) develop a long-term record of atmospheric pressure patterns using existing tree-ring chronologies and gridded reanalysis data; 2) determine controls on persistent meridional and zonal atmospheric flow regimes using targeted field sampling and synoptic analysis; and 3) delineate the spatial footprint of past ENSO events by tying together data from the first two objectives with existing reconstructions of drought and ENSO.The broader impacts include supporting a new female investigator early in her career, the education and training of a graduate student, and the inclusion of a number of undergraduates in field and lab research. The work would be relevant for water managers and others interested in the hydroclimate of the Western U.S. while the gridded pressure reconstruction would be of value to other climate researchers.