• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Seasonal hydrologic trends in Iowa watersheds over the last half of the 20th century.
【24h】

Seasonal hydrologic trends in Iowa watersheds over the last half of the 20th century.

机译：20世纪后半叶，爱荷华流域的季节性水文趋势。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Climate change is expected to cause significant changes in the global hydrologic cycle, yet the impact to regional hydrology is not well known for the Midwest U.S. As a first step in understanding the impact of climate change in Iowa watersheds, historical streamflow observations and model-derived time series of soil moisture, frozen ground and snow cover for ten Iowa watersheds were analyzed. The modeled data were generated using precipitation and temperature data spanning 1948 to 2003 as inputs to the conceptually-based hydrologic models of the National Weather Service river forecasting system. The models were calibrated for each watershed using observed discharge data. The time series were tested for trend significance using the Mann-Kendall test with the Trend-Free Pre-Whitening procedure at a p = 0.1 significance level. Results show an increasing trend in mean daily discharge, peak flow from rain, and low flows over the last 50 years. Monthly soil moisture content is also increasing, and is strongest during the warm seasons. Maximum daily flow from snow displays a decreasing trend and tendency to occur earlier in the year suggesting an earlier melt of the snowpack in the region. Results for frozen ground and snow cover show that the onset and conclusion has shifted to earlier in the year with more melt days occurring over the snow season. Although several of the hydrologic variables examined did not show statistical significance, trends in most hydrologic processes were observed. Different model calibration periods were tested and found to have minor influence on the average simulation accuracy, but did impact the simulated trends in streamflow. Model results from three calibrations indicate that the modeling system responds to changes in climate, but other factors that the model cannot account for (e.g. land-use change) may be reflected in the observed discharge from several basins.
机译：预计气候变化将导致全球水文循环发生重大变化，但是对于美国中西部地区的区域水文学影响并不为人所知。这是了解气候变化对爱荷华州流域的影响，历史流量观测和模型推导的第一步。分析了爱荷华州十个流域的土壤水分，冻土和积雪的时间序列。建模数据是使用1948年至2003年的降水和温度数据作为国家气象局河流预报系统基于概念的水文模型的输入而生成的。使用观察到的流量数据针对每个流域对模型进行校准。使用Mann-Kendall检验和无趋势的预增白程序，以p = 0.1的显着性水平测试了时间序列的趋势显着性。结果表明，在过去50年中，平均每日流量，雨水的高峰流量和低流量的趋势有所增加。每月土壤含水量也在增加，在温暖季节最强。积雪的最大日流量显示出下降的趋势，并倾向于在今年早些时候发生，表明该地区积雪的融化较早。冻结的地面和积雪的结果表明，开始和结论已经转移到一年中的早期，整个雪季的融化天数更多。尽管所检查的几个水文变量没有显示统计学意义，但在大多数水文过程中都观察到了趋势。测试了不同的模型校准周期，发现它们对平均模拟精度影响很小，但确实影响了流量模拟趋势。来自三个标定的模型结果表明，建模系统对气候变化做出了响应，但是模型无法解释的其他因素（例如土地利用变化）可能会反映在几个流域观测到的流量中。

著录项

  • 作者

    Conrad, Kayla J.;

  • 作者单位

    Iowa State University.;

  • 授予单位 Iowa State University.;
  • 学科 Hydrology.
  • 学位 M.S.
  • 年度 2010
  • 页码 82 p.
  • 总页数 82
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号