Several statistic indexes including pelt weight, pelt area, skin thickness, length of hair, fineness of hair and hair density, were adopted in the evaluation of winter pelt quality of blue frost fox and their parents....Several statistic indexes including pelt weight, pelt area, skin thickness, length of hair, fineness of hair and hair density, were adopted in the evaluation of winter pelt quality of blue frost fox and their parents.Results showed that some indexes of qualitative characters of blue frost fox were the medium between blue fox and silver fox, and some were superior to them.展开更多
全球气候变化情景下干旱事件频率和强度持续增加,识别和理解干旱胁迫下植被光合过程的突变是生态监测与气候适应管理的关键,当前对植被光合变化点的识别方法多样,但缺乏对不同方法性能差异及其干旱响应解析能力的系统评估。该文聚焦中...全球气候变化情景下干旱事件频率和强度持续增加,识别和理解干旱胁迫下植被光合过程的突变是生态监测与气候适应管理的关键,当前对植被光合变化点的识别方法多样,但缺乏对不同方法性能差异及其干旱响应解析能力的系统评估。该文聚焦中国亚热带地区,基于太阳诱导叶绿素荧光(SIF)数据、标准化降水蒸散指数(SPEI)数据,综合运用BFAST(Breaks For Additive Season and Trend)、DBEST(Detecting Breakpoints and Estimating Segments in Trend)、PELT(Pruned Exact Linear Time)和Pettitt 4种变化点检测方法,从多维度协同解析区域植被光合动态的变化点特性,并刻画SIF与干旱指数SPEI的时空关系。结果表明:(1)2003—2022年中国亚热带地区SIF整体呈上升态势,区域植被光合作用总体增强。(2)不同方法在变化点识别上各具优势:BFAST适用于识别长期趋势性变化(单调递增类占比达82.25%);DBEST能捕捉云贵高原等复杂地形的渐进式变化;PELT对多断点和频繁扰动敏感;Pettitt主要识别突发性变化引起的结构性转折。(3)SIF与SPEI相关关系呈现显著空间异质性,四川盆地、闽粤沿海等水热条件较优区域以正相关为主,滇南及藏东则以负相关为主。(4)多方法协同分析显示,变化点后SIF与SPEI相关性整体增幅达112.07%,而PELT方法增幅仅为62.94%,反映该方法易受噪声干扰;BFAST与PELT的变化点解析具有互补性,二者组合可有效提升变化点识别的空间完整性与结果可靠性。研究结果可为亚热带地区生态系统韧性评估与气候适应性管理提供理论支撑。展开更多
文摘Several statistic indexes including pelt weight, pelt area, skin thickness, length of hair, fineness of hair and hair density, were adopted in the evaluation of winter pelt quality of blue frost fox and their parents.Results showed that some indexes of qualitative characters of blue frost fox were the medium between blue fox and silver fox, and some were superior to them.
文摘全球气候变化情景下干旱事件频率和强度持续增加,识别和理解干旱胁迫下植被光合过程的突变是生态监测与气候适应管理的关键,当前对植被光合变化点的识别方法多样,但缺乏对不同方法性能差异及其干旱响应解析能力的系统评估。该文聚焦中国亚热带地区,基于太阳诱导叶绿素荧光(SIF)数据、标准化降水蒸散指数(SPEI)数据,综合运用BFAST(Breaks For Additive Season and Trend)、DBEST(Detecting Breakpoints and Estimating Segments in Trend)、PELT(Pruned Exact Linear Time)和Pettitt 4种变化点检测方法,从多维度协同解析区域植被光合动态的变化点特性,并刻画SIF与干旱指数SPEI的时空关系。结果表明:(1)2003—2022年中国亚热带地区SIF整体呈上升态势,区域植被光合作用总体增强。(2)不同方法在变化点识别上各具优势:BFAST适用于识别长期趋势性变化(单调递增类占比达82.25%);DBEST能捕捉云贵高原等复杂地形的渐进式变化;PELT对多断点和频繁扰动敏感;Pettitt主要识别突发性变化引起的结构性转折。(3)SIF与SPEI相关关系呈现显著空间异质性,四川盆地、闽粤沿海等水热条件较优区域以正相关为主,滇南及藏东则以负相关为主。(4)多方法协同分析显示,变化点后SIF与SPEI相关性整体增幅达112.07%,而PELT方法增幅仅为62.94%,反映该方法易受噪声干扰;BFAST与PELT的变化点解析具有互补性,二者组合可有效提升变化点识别的空间完整性与结果可靠性。研究结果可为亚热带地区生态系统韧性评估与气候适应性管理提供理论支撑。
