期刊文献+
共找到2篇文章
< 1 >
每页显示 20 50 100
基于集对分析的不同分类方法对汛期分期的影响 被引量:4
1
作者 虞慧 刘星根 +3 位作者 王姣 王永文 彭圣军 胡强 《人民长江》 北大核心 2021年第3期9-15,共7页
为揭示集对分析不同分类方法对汛期分期的影响程度和原因,以江西省信江七一水库为例,采用集对分析及合理性检验等方法,探讨了均值标准差法、距平百分率法等分类方法对集对分析联系度的影响。同时,对均值标准差法、距平百分率法中k阈值与... 为揭示集对分析不同分类方法对汛期分期的影响程度和原因,以江西省信江七一水库为例,采用集对分析及合理性检验等方法,探讨了均值标准差法、距平百分率法等分类方法对集对分析联系度的影响。同时,对均值标准差法、距平百分率法中k阈值与p阈值的最优取值进行了探究。结果表明:①均值标准差法的最优k阈值为0.56~0.58,距平百分率法的最优p阈值为0.42~0.44;阈值大小通过影响分类区间范围进而影响符号量化和汛期分期结果。②经合理性检验,均值标准差法的最优分期结果与合理性检验的最优分期结果最为接近,而距平百分率法的最优分期结果与合理性检验的最优分期结果存在一定差异。因此,2种方法相比,均值标准差法更适用于集对分析。同时,建议今后在将集对分析应用于汛期分期时,应进行最优分类区间筛选和分期结果比较分析。 展开更多
关键词 汛期分期 集对分析 均值标准差 距平百分率法 联系度 分类标准 阈值
下载PDF
Research on the Summer Drought in Chongqing Using MODIS-EVI Time Series Data
2
作者 易佳 高阳华 +1 位作者 杨世琦 田永中 《Agricultural Science & Technology》 CAS 2010年第7期124-127,167,共5页
MODIS-EVI time series data from 2000 to 2009 in Chongqing were selected for this study.By the use of best index slope extraction (BISE) method for cloud elimination,analysis on the change vector of EVI time series d... MODIS-EVI time series data from 2000 to 2009 in Chongqing were selected for this study.By the use of best index slope extraction (BISE) method for cloud elimination,analysis on the change vector of EVI time series data were conducted to investigate the EVI response on drought; then,four typical regions were selected to study the relationship between precipitation,temperature and EVI when the sever drought occurred in 2006; finally,based on the time series of vegetation condition index (VCI) and precipitation abnormity percentage,the temporal and spatial distributions of drought were studied.The results showed that,the EVI value of the summer in 2006 was significantly lower than the average EVI at the corresponding period of the other years in Chongqing.In addition,summer drought occurred mainly during the hot and dry weather.Except the southeast area,most of the other regions in Chongqing were all under severe drought. 展开更多
关键词 Time series of vegetation condition index Precipitation abnormity percentage Best index slope extraction CHONGQING
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部