近500年来亚洲干旱变化的树轮记录研究
发布时间：2019-02-14 23:27
【摘要】：区域干旱化已成为全球变化研究中的一项重要内容。近半个世纪以来,在全球变暖的背景下,全球极端干旱区域的面积扩大了两倍以上,严重的影响了地区社会经济发展。理解亚洲地区干旱变化的时空特征及其与大尺度海-气-陆相互作用的联系对该地区气候变化研究具有重要意义。本文利用树轮指标单点重建了泰和山地区和区域集成了亚洲地区的干旱变化历史,探讨其与大尺度气候变化的可能的联系。1.在甘肃省泰和山地区采集了一组油松宽度样本,经过前处理、交叉定年、测量、标准化等步骤生成了标准化年表(STD)。气候响应分析结果表明STD年表与降水呈正相关,显著相关的月份有上年的8月和9月和当年的4月。STD年表与温度呈负相关,显著相关的月份有上年的9月和当年的1月、2月、3月和5月。季节组合之后,STD年表与降水相关性最高的月份组合为上年8月到当年5月,与温度相关性最高的月份组合为当年1月到5月。与标准化降水蒸发指数(SPEI)在1 24个月时间尺度上都有着显著的相关,最高的相关发生在10 13个月时间尺度上,而相关性最高的月份组合为10个月尺度的4 6月平均SPEI,说明油松生长可能具有适应短期的干旱的机制,而只有长期暴露在干旱的环境下才能够被显著影响。2.根据气候响应分析的结果,建立转换方程并重建了泰和山283年以来干旱指数的变化。交叉验证结果表明转换方程具有很高的可靠性和稳定性。重建结果方差解释量为51%,在高频和低频上与观测数据都有着很好的对应。重建结果展现出了干旱的长期变化情况,发现了1763 1766、1831 1833、1882 1884和1928 1930共4个持续时间超过3年的干旱时段以及1730 1733、1784 1787、1702 1704、1919 1922、1943 1946和1948 1952共6个持续时间超过3年的湿润时段。重建与周围很大范围的干旱指数都有很高的相关性,并与附近的旱涝指数和基于树轮的降水重建都有很好的可比性,表明该地区干旱可能主要受到降水的控制。3.多锥度方法(MTM)、小波分析方法和集合经验模态分解(EEMD)方法都显示出了泰和山干旱变化具有显著的高频和低频周期。2 7年准周期可能是受到了ENSO变化和QBO的影响,而25年左右准周期可能是受到太阳活动以及太平洋十年涛动(PDO)变化的影响,百年准周期则可能反应的是太阳活动的变化。重建与印度洋、赤道中东太平洋和北太平洋的海平面温度都有着显著的相关关系,并与PDO序列存在显著的反相位的关系,表明地区的干旱与大尺度的海-气-陆相互作用有很大关联。4.利用CRUST程序将在亚洲收集到的389组树轮记录生成零信号年表。所有的代用资料和器测数据在重建之前都经过了白噪化处理,并在重建后将移除的器测数据的自相关加回到重建结果中。将研究区域分成了41个子区域,并采用6中代用资料筛选办法。利用采用最小二乘法(TTLS)进行表转化的气候场重建方法—RegEM方法对每个子区域进行重建,最后再将所有子区域的重建组合到一起形成最终的过去500年的夏季帕尔默干旱指数(PDSI)重建。合适的代用资料筛选办法能够在一定程度上提高验证的结果,但是更严格的筛选条件并不一定能够产生更好的验证。在验证时段,65.73%格点的误差缩减(RE)是正值,42.51%格点的相关系数的平方(R2)通过了90%的置信度,31.46%格点的有效系数(CE)值为正值。5.亚洲干旱重建结果与历史上许多著名的干旱时段(如1586 1589、1638 1641,1876 1878和1928 1931)都有着良好的对应,也与利用点对点回归(PPR)方法的重建的PDSI有着良好的相关。主成分分析方法得到的公元1500年 2014年的PDSI变化的前4个主模态的空间型和时间变化序列与器测数据(公元1951年 2014年)的EOF分析结果对应良好。而四个模态的时间序列与SST空间相关表明,亚洲干旱受到了赤道印度洋和赤道太平洋SST变化的显著影响,表明研究地区干旱与亚洲夏季风强度以及ENSO等都有着密切的关系。
[Abstract]:Regional drought has become an important part of global change research. For nearly half a century, in the context of global warming, the area of the global extreme arid region has increased by more than two times, which has seriously affected the socio-economic development of the region. It is of great significance to understand the spatial and temporal characteristics of the drought in the region and its relationship with the large-scale sea-gas-land interaction. The paper makes use of the tree-wheel index to reconstruct the history of drought change in the region and the region, and to explore its possible relationship with the large-scale climate change. A set of Chinese tabulaeformis's width samples were collected in Taihe mountain area of Gansu province, and the standardized annual table (STD) was generated by the steps of pretreatment, cross-setting, measurement and standardization. The results of the climatic analysis show that the annual scale of the STD is positively related to the precipitation, and the related month is August and September of last year and April of the same year. The STD chronology was negatively correlated with the temperature, and the related month was the last year of September and January, February, March and May of the same year. After the season combination, the monthly combination of the STD annual table and the precipitation correlation was from August to May, and the combination of the month with the highest temperature correlation was from January to May of the same year. 涓庢爣鍑嗗寲闄嶆按钂稿彂鎸囨暟(SPEI)鍦，
本文编号：2422716
[Abstract]:Regional drought has become an important part of global change research. For nearly half a century, in the context of global warming, the area of the global extreme arid region has increased by more than two times, which has seriously affected the socio-economic development of the region. It is of great significance to understand the spatial and temporal characteristics of the drought in the region and its relationship with the large-scale sea-gas-land interaction. The paper makes use of the tree-wheel index to reconstruct the history of drought change in the region and the region, and to explore its possible relationship with the large-scale climate change. A set of Chinese tabulaeformis's width samples were collected in Taihe mountain area of Gansu province, and the standardized annual table (STD) was generated by the steps of pretreatment, cross-setting, measurement and standardization. The results of the climatic analysis show that the annual scale of the STD is positively related to the precipitation, and the related month is August and September of last year and April of the same year. The STD chronology was negatively correlated with the temperature, and the related month was the last year of September and January, February, March and May of the same year. After the season combination, the monthly combination of the STD annual table and the precipitation correlation was from August to May, and the combination of the month with the highest temperature correlation was from January to May of the same year. 涓庢爣鍑嗗寲闄嶆按钂稿彂鎸囨暟(SPEI)鍦，
本文编号：2422716
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