Long Range Streamflow and Drought Prediction

本研究的三个主要目标如下：1)开发一种远程工具，一种可以提前6到12个月预测河流流量和干旱的工具。2)研究气候变化与区域水文过程之间的联系，并以此为依据，确定对ENSO事件有特殊响应的区域。3)在国际合作伙伴的协助下，编制环太平洋流域的流量和干旱指数数据集。研究计划和方法可总结如下：1)与几位环太平洋地区的研究人员合作，编制一套河流和干旱指数数据集，作为本研究工作的基础，并将向公众提供。2)利用调和分析和空间互相关分析的统计方法识别ENSO相干响应区域。3)通过评估拉尼娜、非ENSO和厄尔尼诺事件概率分布的变化来量化ENSO的影响。箱形图表示每个分布的第10、第30、第50、第70和第90个百分位数。4)建立基于模糊概念的径流和干旱预测模型，一个模型基于模糊规则，另一个模型基于模糊回归。基于模糊规则的模型可以看作是一个水文变量条件对大气环流型的预测。5)将预测模型应用于美国西部。1948-1988年期间将用于模型的校准和验证，然后将这些模型应用于环太平洋地区的其他相关地区。将作出修改以反映区域大气条件。本研究的重要意义在于对河流和干旱的长期预测作出重大贡献。目前的流量预测技术依赖于已知的降水量，并且仅限于提前三到六个月的预测。这项拟议的研究依赖于发生在河流或干旱之前6到8个月的大规模环流模式。它们的使用可能会提前一年做出预测。第二，将汇编和提供一个独特的数据库，以支持远远超出本建议所列范围的未来研究。最后，国际合作的工作不仅将建立新的国际研究联系，因为大量的数据缺口正在填补，而且仍然有可能利用这一国际合作者群体作为基础进行进一步的研究。

9421030 Dracup The three primary objectives of this research are as follows: 1) To develop a long range tool, one that will predict streamflow and drought six to twelve months in advance. 2) To investigate the connection between climatic variations and regional hydrologic processes and, in support of this, to identify regions that respond specifically to ENSO events. 3) To assemble, with the assistance of international collaborators, a Pacific Rim streamflow and drought indice data set. The research plan and methods can be summarized as follows: 1) With the cooperation of several Pacific Rim researchers, to compile a streamflow and drought indice data set that is the basis of this research effort and which will be made available to the public. 2) To use the statistical methods of harmonic analysis and spatial cross correlation analysis in identifying regions of coherent response to ENSO. 3) To quantify the ENSO impact by evaluating the shift in the probability distributions of of La Nina, Non-Enso, and El Nino events. Boxplots will represent the 10th, 30th, 50th, 70th, and 90th percentile values of each distribution. 4) To develop streamflow and drought prediction models based on fuzzy concepts, one model to be based on fuzzy rules, the other on fuzzy regression. The fuzzy ruled- based model can be viewed as the prediction of a hydrologic variable condition upon atmospheric circulation patterns. 5) To apply the prediction models to the western U.S. The time period of 1948-1988 will be used for calibration and verification of the models, and these models will then be applied to the other relevant regions of the Pacific Rim. Modifications will be made to reflect the regional atmospheric conditions. The significance of this research will be its major contribution to long range prediction of streamflow and drought. Current streamf low forecasting techniques rely on known precipitation quantities and are limited to forecasts of three to six months in advance. This proposed research relies on large scale circulation patterns that occur six to eight months in advance of a streamflow or drought. Their use may make possible predictions that could be given as much as a year in advance. Secondly, a unique data base that will support future research, far beyond that included within this proposal, will be assembled and available. Finally, the work of international collaboration will not only forge new international research links, as large data gaps are being filled in, but the possibility remains of conducting further research using this group of international collaborators as a base.