Dissertation Research: Paleoecology and Testing of Paleoclimate Hypotheses in Southern California During the Holocene

9801449 戴维斯 这一建议将为南加州山区建立一个完整的全新世古环境记录。 这些记录将被用来推断这些地区过去的气候，而这些气候反过来又将被用来测试从数学全球气候模型中得出的过去区域气候的模拟。 这些测试对于验证这些模型及其在预测未来气候方面的用途是必要的。 保存在山地草甸沉积物中的化石花粉将是过去气候条件的主要指示器。 此外，花粉数据将与木炭、其他植物化石和沉积物的物理特征相结合，以推断过去的条件。 化石花粉组合与典型植被的花粉组合的比较将是分析的主要方法。 类似的化石和现代花粉数据将被用来推断过去和现在植被的相似性，从而推断一个地点的气候。 最初的花粉计数表明，早全新世在S.Calif。山脉与现在的情况没有太大的不同。 这与内华达州和太平洋西北部相对干燥的条件形成对比，并与气候模式模拟的增强季风流进入西南部相一致。 分析结果将提高西南地区古环境记录的空间分辨率。

9801449 Davis This proposal will establish a full-Holocene paleoenvironment record for the Southern California Mountain region. This record will be used to infer past climates for the regions and these, in turn, will be used to test simulations of past regional climates derived from mathematical global climate models. These tests are necessary to validate such models and their use in forecasting future climates. Fossil pollen preserved in mountain meadow sediments will be the primary indicator of past climate conditions. In addition, pollen data will be combined with charcoal, other plant fossils, and the physical characteristics of sediments to infer past conditions. Comparison of fossil pollen assemblages to those representative of model vegetation will be a primary method for analysis. Similar fossil and modern pollen data will be used to infer similarity in past and present vegetation, and therefore climate at a site. Initial pollen counts suggest that the early Holocene in S.Calif. Mountains was not much different than present-day conditions. This contrasts with the relatively dry conditions that have been inferred for the Sierra Nevada and Pacific Northwest and is consistent with climate-model simulation of enhanced monsoonal flow into the Southwest. The results of our analyses will improve the spatial resolution of the paleoenvironmental record in the Southwest.