Rocky Mountain hydroclimate: Holocene variability and the role of insolation, ENSO, and the North American Monsoon
Rocky Mountain hydroclimate: Holocene variability and the role of insolation, ENSO, and the North American Monsoon
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落基山水文气候：全新世变化和日照、ENSO 和北美季风的作用
DOI：
10.1016/j.gloplacha.2012.05.012
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发表时间：
2012
影响因子：
2.2
通讯作者：
L. Anderson
中科院分区：
文献类型：
--
作者：
L. Anderson
在仪器记录期间，科罗拉多落基山脉源头的最大降水量主要是冬季降雪，并且有很大程度的年际变化与太平洋-大气动力学有关。高海拔积雪是重要的储水区域，需要仔细观察，以满足大半干旱地区日益增长的用水需求。这里的目的是考虑全新世期间落基山的水趋势，当时地球能量平衡的已知变化是由进动驱动的日照变化引起的。太阳辐射的变化被认为影响了厄尔尼诺南方涛动（ENSO）、太平洋年代际涛动（PDO）和北美季风的变化和强度，以及高海拔地区雨雪之间的季节性降水平衡。全新世记录来自位于科罗拉多州西北部的两个高海拔湖泊，记录了过去约 7000 年十年到一个世纪规模的降水季节性。与 ENSO 副热带记录的比较表明，以降雪为主的降水最大值出现于约 3000 和 4000 年前，这与 ENSO/PDO 动态增强的证据一致。在全新世早中期，记录表明季风对降水的影响更大，积雪减少，降雨量增加，净水分亏缺比最近的干旱更为严重。全新世对降水的看法表明，变化范围比上个世纪要广泛得多，并强调了美国西部水文气候的非线性特征。
Over the period of instrumental records, precipitation maximum in the headwaters of the Colorado Rocky Mountains has been dominated by winter snow, with a substantial degree of interannual variability linked to Pacific ocean–atmosphere dynamics. High-elevation snowpack is an important water storage that is carefully observed in order to meet increasing water demands in the greater semi-arid region. The purpose here is to consider Rocky Mountain water trends during the Holocene when known changes in earth's energy balance were caused by precession-driven insolation variability. Changes in solar insolation are thought to have influenced the variability and intensity of the El Niño Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and North American Monsoon and the seasonal precipitation balance between rain and snow at upper elevations. Holocene records are presented from two high elevation lakes located in northwest Colorado that document decade-to-century scale precipitation seasonality for the past ~7000years. Comparisons with sub-tropical records of ENSO indicate that the snowfall-dominated precipitation maxima developed ~3000 and 4000years ago, coincident with evidence for enhanced ENSO/PDO dynamics. During the early-to-mid Holocene the records suggest a more monsoon affected precipitation regime with reduced snowpack, more rainfall, and net moisture deficits that were more severe than recent droughts. The Holocene perspective of precipitation indicates a far broader range of variability than that of the past century and highlights the non-linear character of hydroclimate in the U.S. west.