Collaborative Research: Holocene Drought Cycles and Impacts on the Northern Great Plains

这项研究将利用高分辨率分析的核心从封闭盆地湖泊在北方大平原，以确定频率，强度，持续时间，周期性和同步性的干旱在全新世，并研究如何植被和火灾响应干旱。 由于北方大平原的植被和湖泊对干旱高度敏感，该地区提供了一个记录美国中部大陆十年至世纪尺度气候周期的绝佳机会。工作假设是，来自单一地点的干旱信号是区域性的，整个区域的干旱是同步的。 为了验证这一假设，这项研究将利用湖泊沉积物矿物学，化石花粉，碳同位素的木炭，木炭丰度开发详细的重建干旱周期从北方大平原在十年尺度。 这将有助于评估大陆中部气候与北大西洋区域之间的遥相关，最近的调查已将世纪至千年尺度的气候振荡与太阳辐照度的变化联系起来。这项研究有可能在物理和社会科学领域产生广泛的影响。通过大气模式对北方大平原的干旱影响预测进行评估需要了解自然干旱的变化。来自古科学的证据表明，20世纪世纪的干旱（例如，沙尘暴）并没有提供对即使是最近发生的严重干旱范围的看法。 历史证据是不完整的，古科学数据尚未在适当的时间和空间尺度上进行组装，以评估过去干旱的强度，周期性和影响。

This study will utilize high-resolution analysis of cores from closed-basin lakes in the northern Great Plains to determine the frequency, intensity, duration, periodicity, and synchrony of droughts during the Holocene and to examine how vegetation and fire responded to drought. Since vegetation and lakes in the Northern Great Plains are highly sensitive to drought, this region offers an extraordinary opportunity to document decadal- to-century scale climate cycles in the mid-continental United States. The working hypothesis is that the signal of drought from a single site is regional and that droughts were synchronous across the region. To test this hypothesis, the study will utilize lake-sediment mineralogy, fossil pollen, carbon isotopes of charcoal, and charcoal abundance to develop detailed reconstruction of drought cycles from the Northern Great Plains at a decadal scale. This will facilitate evaluation of the teleconnections between mid-continental climate and the North Atlantic region, where recent investigations have linked century to millennial scale climate oscillations to variations in solar irradiance. This research has the potential for broad impact in range of physical and social sciences. Assessment of drought impacts forecast by atmospheric models for the Northern Great Plains requires understanding of natural drought variability. Evidence from paleoscience suggests that 20th century droughts (e.g., the Dust Bowl) do not provide perspective on the range of severe droughts that have occurred in even the recent past. Historical evidence is incomplete and paleoscience data have not yet been assembled at appropriate temporal and spatial scales to assess the intensity, periodicity, and impacts of past droughts.