摘要
提出一种新的基于希尔伯特谱分析的降水发生器EHS.该模型首先对原始降雨场进行高斯隐变量转换,转换后的标准化降雨场随后进行经验正交函数分析(EOFA),提取出主要空间模态和对应的主成分时间序列.对主成分序列进行经验模态分解(EMD)和希尔伯特谱分析(HAS)可以得到不同特征周期的本征模态函数(IMF)及其对应的瞬时振幅和瞬时频率,利用随机相位法仿真各项IMF分量,对模拟得到的IMF分量进行EMD重构、EOF重构和高斯隐变量反操作,即可得到多站点降雨模拟场.本文以月降雨量均值、月降雨量标准差,空间相关系数、空间连接度、自相关系数为指标,利用湘江流域实测的降水数据,通过与现有多站点降水发生器MulGETS的比较,评估多站点降水发生器EHS的性能和优缺点.研究结果表明,多站点降雨发生器EHS能很好地模拟湘江流域的降雨,重现历史降雨场的统计特征.该工具可为水文水环境模型、生态模型等提供数据支撑.
Weather generators(WG)that create synthetic daily weather data statistically similar to observed data involves precipitation simulation as critical component.Preserving statistical properties(e.g.,spatial intermittence,low frequency variability)of precipitation is challenging.We propose a new framework for multisite precipitation generation consisting of three main components:a multi-site spatiotemporal field and corresponding temporal evolution based on empirical orthogonal function analysis(EOFA),principal component(PC)time series decomposed into intrinsic mode functions(IMFs)and subjected to Hilbert-Huang transform(HHT),and stochastic simulation(SS)achieved by assigning random phases for certain specific IMF.The proposed EOFA+HHT+SS model(EHS)is illustrated in a network of 12 stations in Xiang River Basin,China,with MulGETS,a typical multisite Richardson type WG,as reference.The synthetic precipitation series were compared to records and evaluated with respect to basic statistics(mean and standard deviation of monthly precipitation),spatial dependence(spatial correlation and continuity ratio)and temporal dependence statistic(autocorrelation).EHS precipitation generator was found to have superior capability to conserve historical statistical properties of the observation,especially with respect to autocorrelation at various time lags and low frequency variability.EHS is an effective model for generating multi-site precipitation field and can be expected to generate plausible scenarios for impact study of climate change and climate variability.
作者
周凌峰
孟耀斌
逯超
伍甘霖
张东妮
张朝
ZHOU Lingfeng;MENG Yaobin;LU Chao;Wu Ganlin;ZHANG Dongni;ZHANG Zhao(Key Laboratory of Environmental Change and Natural Disaster of Ministry of Education,Academy of Disaster Reduction and Emergency Management,Ministry of Emergency Management&Ministry of Education,Faculty of Geographical Science,Beijing Normal University,100875,Beijing,China;State Key Laboratory of Earth Surface Processes and Resource Ecology,Beijing Normal University,100875,Beijing,China)
出处
《北京师范大学学报（自然科学版）》
CAS
CSCD
北大核心
2019年第2期263-271,共9页
Journal of Beijing Normal University(Natural Science)
基金
北京师范大学地表过程与资源生态国家重点实验室方向性资助项目(2017-FX-07)
关键词
多站点降雨模拟
主成分分析
经验模态分解
时域法
频谱法
multi-site precipitation generator
principle component analysis
empirical mode decomposition
time domain analysis
spectral analysis
