Warming is significantly affecting ecosystems in dry-warm areas,such as the Middle East[1],but long-term climatic records are often scarce in these regions.One important proxy source of climate data is tree rings,whic...Warming is significantly affecting ecosystems in dry-warm areas,such as the Middle East[1],but long-term climatic records are often scarce in these regions.One important proxy source of climate data is tree rings,which have contributed to understanding climate changes over the past millennium[1].Under the PAGES2K framework[2],a tree-ring network of the Eurasian continent展开更多
Long-term high resolution climate proxies are essential for understanding climate variability particularly,in regions such as the western Himalayas of northern Pakistan,where few long-term climate records are availabl...Long-term high resolution climate proxies are essential for understanding climate variability particularly,in regions such as the western Himalayas of northern Pakistan,where few long-term climate records are available.Using standard dendrochronological methods,an 1132-year(882 to 2013 C.E.)tree-ring chronology of Juniperus excelsa M.Bieb was established from the western Himalayas,northern Pakistan(WHNP).Tree growth was negatively and significantly(r=-0.65)correlated with the growing season(June-July)mean temperature,and positively and weakly(r=0.22)associated with precipitation.This inverse relationship of tree radial growth with temperature and positive association with precipitation demonstrated that forest growth is sensitive to high temperature related drought.Utilizing a reliable STD chronology and robust reconstruction model,a 928-year(1086 to 2013 C.E.)mean temperature reconstruction was developed for the WHNP using the substantial negative correlation between the summer temperature and standard tree ring-width chronology.According to statistical validation,the reconstruction accounted for 41.6% of the climatic variation for the period of 1956-2013 C.E.instrumental period.Individual extreme-warm periods occurred in 1093 C.E.(29.42℃)and extreme cold periods in 1088 C.E.(26.99℃)observed during the past 928 years.The reconstruction's multi-taper method(MTM)spectral analysis reveals significant(p<0.05)2-3-year and 63.8-year cycles.Since the 2-3-year cycle occurred within the range of ENSO variation,which indicates that ENSO had an impact on the regional temperature in our studied area.展开更多
基金supported by the International Partnership Program of Chinese Academy of Sciences(131C11KYSB20160061)the National Natural Science Foundation of China(41525001,41571201)+1 种基金Chinese Academy of Sciences President’s International Fellowship Initiative(2016VBC055)Karaj Branch Islamic Azad University for supporting Vilma Bayramzadeh’s sabbatical program in the Institute of Tibetan Plateau Research, Chinese Academy of Sciences
文摘Warming is significantly affecting ecosystems in dry-warm areas,such as the Middle East[1],but long-term climatic records are often scarce in these regions.One important proxy source of climate data is tree rings,which have contributed to understanding climate changes over the past millennium[1].Under the PAGES2K framework[2],a tree-ring network of the Eurasian continent
基金supported by the National Natural Science Foundation of China(Grant No.42007407)the Sino-German mobility program(M-0393)the China-Pakistan Joint Research Center on Earth Sciences(No.131551KYSB20200022).
文摘Long-term high resolution climate proxies are essential for understanding climate variability particularly,in regions such as the western Himalayas of northern Pakistan,where few long-term climate records are available.Using standard dendrochronological methods,an 1132-year(882 to 2013 C.E.)tree-ring chronology of Juniperus excelsa M.Bieb was established from the western Himalayas,northern Pakistan(WHNP).Tree growth was negatively and significantly(r=-0.65)correlated with the growing season(June-July)mean temperature,and positively and weakly(r=0.22)associated with precipitation.This inverse relationship of tree radial growth with temperature and positive association with precipitation demonstrated that forest growth is sensitive to high temperature related drought.Utilizing a reliable STD chronology and robust reconstruction model,a 928-year(1086 to 2013 C.E.)mean temperature reconstruction was developed for the WHNP using the substantial negative correlation between the summer temperature and standard tree ring-width chronology.According to statistical validation,the reconstruction accounted for 41.6% of the climatic variation for the period of 1956-2013 C.E.instrumental period.Individual extreme-warm periods occurred in 1093 C.E.(29.42℃)and extreme cold periods in 1088 C.E.(26.99℃)observed during the past 928 years.The reconstruction's multi-taper method(MTM)spectral analysis reveals significant(p<0.05)2-3-year and 63.8-year cycles.Since the 2-3-year cycle occurred within the range of ENSO variation,which indicates that ENSO had an impact on the regional temperature in our studied area.
