During January to February in 2008,severe ice-snows occurred on 2.09×10^6 km^2 of south China and caused tremendous damage to the forests.Stem damage and crown debris input from the ice-snow in a Cunninghamia lan...During January to February in 2008,severe ice-snows occurred on 2.09×10^6 km^2 of south China and caused tremendous damage to the forests.Stem damage and crown debris input from the ice-snow in a Cunninghamia lanceolata stand in northern Guangdong Province,China,were investigated to determine the extent of ice-snow damage to trees and the nutrient distribution characteristics on woodland.Icicles were produced on branches and leaves of the C.lanceolata trees by sleets,resulting in all live trees were damaged by stem breakage.A strong positive correlation was found between the broken position of trees and diameter at breast height(DBH).Nutrient concentrations varied according to components of crown debris.Total nutrient concentration graded in the following order:leaves 〉stembark 〉branches 〉stemwood.Crown debris input from ice-snows was 19.11 t·ha^-2,and branches,stemwood,leaves and stembark accounted for 37%,28%,27% and 8%,respectively.Nutrient distributions between components of crown debris differed drastically in 2008.The contribution of leaves to total nutrient accumulation of crown debris was 70%,whereas branches,stemwood and stembark contributed 13%,7% and 10%,respectively.Accumulations of N,P and K by the woodland were 105 067.9 t·ha^-2 in 2008,and the nutrients of crown debris,litter and the stand soil accounted for 0.18%,0.03% and 99.79%,respectively.The order of nutrient accumulation in leaves,branches,stembark,stemwood of crown debris and litter was N〉K〉P,but the nutrients stored in the soil were in the order of K 〉N 〉P.The N and P concentrations of litter in 2009 were greater than those in 2008,whereas its K concentration was smaller than that of the latter.N and P concentrations of stemwood and stembark in 2009 were slightly greater than those in 2009,whereas their K concentration was smaller than the latter.The N and P accumulations of stemwood and stembark of crown debris in 2009 were close to those in 2008,whereas their K accumulation was slightly smaller than the latter.The N,P and K accumulations of litter in 2009 was greater than those in 2008.展开更多
An engineering approach for the calculation of the specific heat energy needed for melting of the ice, which is created from the freezing of hygroscopically bounded water in the wood, qbw, has been suggested. The appr...An engineering approach for the calculation of the specific heat energy needed for melting of the ice, which is created from the freezing of hygroscopically bounded water in the wood, qbw, has been suggested. The approach, together with the equation that presents it, includes mathematical descriptions of the density of frozen wood in the hygroscopic diapason, Pw, and of the specific heat capacity of the ice formed from the bounded water in the wood, cbw for the calculation of Pw, cbw and qbw according to the suggested approach a software program has been prepared in the calculation environment of Visual Fortran. Using the program computations have been carried out for the determination ofpw, cbw and qbw, of oak, pine, beech and poplar frozen wood with initial temperature in the range from -20℃ to -2℃, at which the thawing of the ice from the bounded water is completed, and with moisture content in the hygroscopic range during wood defrosting. Based on the obtained results, a very simple and easy for use equation for the calculation of qbw depending only on the wood moisture content and on the content of non-frozen water in the wood at given initial wood temperature has been suggested.展开更多
A 350-cm-long sediment core sequence from Dahu Swamp situated in the eastern Nanling Mountains was selected for high-resolution paleoclimatic reconstruction since the Late Glacial period. The multi-proxy records of th...A 350-cm-long sediment core sequence from Dahu Swamp situated in the eastern Nanling Mountains was selected for high-resolution paleoclimatic reconstruction since the Late Glacial period. The multi-proxy records of this paper reveal several evidently dry and cold events that may coincide with the Oldest Dryas, the Older Dryas, the Younger Dryas in the late deglacial period. Two relatively wetter and warmer phases occurred in ca. 15,000-14,400 cal yr B.P. and 13,500-12,800 cal yr B.P. respectively may correspond to the Boiling and Allerod warming events. The Younger Dryas event (ca. 12,800-11,500 cal yr B.P.) revealed by multi-proxies was characterized by relatively colder and drier climate. A warmer and wetter climate, occurred in ca. 10,000~5000 cal yr B.P., was consistent with the Holoeene Optimum, which coincided with the maximum Northern Hemisphere insolation. The "8.2kyr cool event" and even the "8.8kyr cool event" were indicated as well from our sediment core. A dry mid-Holocene period (ca. 60000 3000 cal yr B.P.) indicated by multi-proxies does not follow the traditional concept of the wet mid-Holocene conditions observed in other regions in China.展开更多
A modern research approach and working techniques in hitherto unexamined areas, produced the following results: 1). The tongues of deca- kilometre long Karakorum glaciers belong to temperate ice-streams with an an...A modern research approach and working techniques in hitherto unexamined areas, produced the following results: 1). The tongues of deca- kilometre long Karakorum glaciers belong to temperate ice-streams with an annual meltwater output. The short Aghil glaciers on the contrary are continental, arid and cold. 2). The present-day oscillations of the Karakorum glaciers are related to their own mass, and are contrary to and independent of the actual climate. Only the short glaciers, with steep tongue fronts, show a present-day positive balance. 3). C- dated Late Glacial moraines indicate14 a 400~800 m thick valley glacier at the former confluence point of the K2-, Sarpo Laggo- and Skamri glaciers. 4). From the evidence of transfluence passes with roches moutonnées, striae and the limits of glacial polishing, as well as moraines and erratics, a High Glacial at least 1200 m thick ice-stream network between the Karakorums and the Kuen Lun north slopes was reconstructed. The Shaksgam and Yarkand valleys were occupied by glaciers coming from west Tibet. The lowest-lying moraines are to be found in the foreland down to 2000 m, indicating a depression of the High Glacial (LGM) snowline (ELA) by 1300 m. 5). The approximately 10,000 measurements of the radiation balance at up to heights of 5500 m on K2 indicate that with incoming energy near the solar constant the reflection from snow- covered ice is up to 70% greater than from rock and rock waste surfaces. 6).These results confirm for the very dry western margins of Tibet an almost complete ice sheet cover in an area with subtropical energy balance, conforming with the Ice Age hypothesis of the author which is based upon the presence of a 2.4 million km2 Tibetan inland ice sheet. This inland ice developed for the first time when Tibet was uplifted over the snowline during the early Pleistocene. As the measured subtropical radiation balance shows, it was able to trigger the Quaternary Ice Ages.展开更多
This study focuses on the characters of public perceptions on climate and cryosphere change,which are based on a questionnaire survey in the(U|¨)r(u|¨)mqi River Basin.In comparison with scientific observatio...This study focuses on the characters of public perceptions on climate and cryosphere change,which are based on a questionnaire survey in the(U|¨)r(u|¨)mqi River Basin.In comparison with scientific observation results of climate and cryosphere change,this paper analyzes the possible impact of the change on water resources and agriculture production in the area.Perceptions of most respondents on climate and cryosphere changes confirm the main objective facts.For the selection of adaptation measures addressing the shortage of water resource,the results are as follows:most people preferred to choose the measures like "policy change" and "basic facility construction" which are mostly implemented by the government and the policy-making department;some people showed more preference to the measures of avoiding unfavorable natural environment,such as finding job in or migrating to other places.The urgency of personal participation in the adaptation measures is still inadequate.Some adaptation measures should be implemented in line with local conditions and require the organic combination of "resource-development" with "water-saving".展开更多
Hydrochemical characteristics and solute dynamics of bulk meltwater draining from Urumqi Glacier No.1 were investigated in years 2006 and 2007. The glacial meltwater was slightly alkaline with the mean pH of 7.64 and ...Hydrochemical characteristics and solute dynamics of bulk meltwater draining from Urumqi Glacier No.1 were investigated in years 2006 and 2007. The glacial meltwater was slightly alkaline with the mean pH of 7.64 and 7.61 in 2006 and 2007, respectively. In the meltwater, the dominant anions were the bicarbonate and sulphate, and the dominant cation was calcium. The concentration of major cations were varied as c(Ca2+) 〉 c(Mg2+) 〉 c(K+) 〉 c(Na+), while the order for the cations was c(HCO3-) 〉 c(SO42-) 〉 c(NQ-) 〉 c(C1-). The total dissolved solids (TDS) in meltwater had inverse relationships with the diurnal discharge. The major ion composition of meltwater was mainly controlled by rock weathering as inferred from the Gibbs model. Furthermore, the ion ratios and Piper diagram indicated that the main processes controlling the meltwater chemistry were carbonate weathering, pyrite weathering and feldspar weathering in rocks, and Ca2+ and HCQ- were the dominant ions during the carbonate weathering process. Solute flux calculation at Glacier No.1 station suggested that chemical denudation rates were 11.46 and 13.90 tonkm-2.yr-1 in 2006 and 2007, respectively.展开更多
Fluctuation history of Midui glacier in the southeastern Tibet since the Little Ice Age(LIA) was reconstructed by the dating of lateral and terminal moraines using tree rings.Four conversions of glacier advance/stabil...Fluctuation history of Midui glacier in the southeastern Tibet since the Little Ice Age(LIA) was reconstructed by the dating of lateral and terminal moraines using tree rings.Four conversions of glacier advance/stabilization to retreat were identified at around 1767,1875,1924 and 1964.The glacier reached its LIA maximum position at 1767.The fluctuations are consistent with those of other glaciers from the Tibetan Plateau,the Rockies and the Alps,suggesting high spatial coherency of glacier fluctuations in the Northern Hemisphere.Comparison with the summer temperature reconstruction in the southeastern Tibetan Plateau indicated that the Midui glacier fluctuation may be related to temperature variation on the centennial timescale.On the decadal scale,the fluctuation could correspond to cold/warm variation with an 8-year lag on average.展开更多
文摘During January to February in 2008,severe ice-snows occurred on 2.09×10^6 km^2 of south China and caused tremendous damage to the forests.Stem damage and crown debris input from the ice-snow in a Cunninghamia lanceolata stand in northern Guangdong Province,China,were investigated to determine the extent of ice-snow damage to trees and the nutrient distribution characteristics on woodland.Icicles were produced on branches and leaves of the C.lanceolata trees by sleets,resulting in all live trees were damaged by stem breakage.A strong positive correlation was found between the broken position of trees and diameter at breast height(DBH).Nutrient concentrations varied according to components of crown debris.Total nutrient concentration graded in the following order:leaves 〉stembark 〉branches 〉stemwood.Crown debris input from ice-snows was 19.11 t·ha^-2,and branches,stemwood,leaves and stembark accounted for 37%,28%,27% and 8%,respectively.Nutrient distributions between components of crown debris differed drastically in 2008.The contribution of leaves to total nutrient accumulation of crown debris was 70%,whereas branches,stemwood and stembark contributed 13%,7% and 10%,respectively.Accumulations of N,P and K by the woodland were 105 067.9 t·ha^-2 in 2008,and the nutrients of crown debris,litter and the stand soil accounted for 0.18%,0.03% and 99.79%,respectively.The order of nutrient accumulation in leaves,branches,stembark,stemwood of crown debris and litter was N〉K〉P,but the nutrients stored in the soil were in the order of K 〉N 〉P.The N and P concentrations of litter in 2009 were greater than those in 2008,whereas its K concentration was smaller than that of the latter.N and P concentrations of stemwood and stembark in 2009 were slightly greater than those in 2009,whereas their K concentration was smaller than the latter.The N and P accumulations of stemwood and stembark of crown debris in 2009 were close to those in 2008,whereas their K accumulation was slightly smaller than the latter.The N,P and K accumulations of litter in 2009 was greater than those in 2008.
文摘An engineering approach for the calculation of the specific heat energy needed for melting of the ice, which is created from the freezing of hygroscopically bounded water in the wood, qbw, has been suggested. The approach, together with the equation that presents it, includes mathematical descriptions of the density of frozen wood in the hygroscopic diapason, Pw, and of the specific heat capacity of the ice formed from the bounded water in the wood, cbw for the calculation of Pw, cbw and qbw according to the suggested approach a software program has been prepared in the calculation environment of Visual Fortran. Using the program computations have been carried out for the determination ofpw, cbw and qbw, of oak, pine, beech and poplar frozen wood with initial temperature in the range from -20℃ to -2℃, at which the thawing of the ice from the bounded water is completed, and with moisture content in the hygroscopic range during wood defrosting. Based on the obtained results, a very simple and easy for use equation for the calculation of qbw depending only on the wood moisture content and on the content of non-frozen water in the wood at given initial wood temperature has been suggested.
基金Under the auspices of National Natural Science Foundation of China (No. 40671189)Natural Science Foundation of Guangdong Province (No. 8151063101000044, 06025042)the Fok Ying Tung Education Foundation (No. 91021)
文摘A 350-cm-long sediment core sequence from Dahu Swamp situated in the eastern Nanling Mountains was selected for high-resolution paleoclimatic reconstruction since the Late Glacial period. The multi-proxy records of this paper reveal several evidently dry and cold events that may coincide with the Oldest Dryas, the Older Dryas, the Younger Dryas in the late deglacial period. Two relatively wetter and warmer phases occurred in ca. 15,000-14,400 cal yr B.P. and 13,500-12,800 cal yr B.P. respectively may correspond to the Boiling and Allerod warming events. The Younger Dryas event (ca. 12,800-11,500 cal yr B.P.) revealed by multi-proxies was characterized by relatively colder and drier climate. A warmer and wetter climate, occurred in ca. 10,000~5000 cal yr B.P., was consistent with the Holoeene Optimum, which coincided with the maximum Northern Hemisphere insolation. The "8.2kyr cool event" and even the "8.8kyr cool event" were indicated as well from our sediment core. A dry mid-Holocene period (ca. 60000 3000 cal yr B.P.) indicated by multi-proxies does not follow the traditional concept of the wet mid-Holocene conditions observed in other regions in China.
文摘A modern research approach and working techniques in hitherto unexamined areas, produced the following results: 1). The tongues of deca- kilometre long Karakorum glaciers belong to temperate ice-streams with an annual meltwater output. The short Aghil glaciers on the contrary are continental, arid and cold. 2). The present-day oscillations of the Karakorum glaciers are related to their own mass, and are contrary to and independent of the actual climate. Only the short glaciers, with steep tongue fronts, show a present-day positive balance. 3). C- dated Late Glacial moraines indicate14 a 400~800 m thick valley glacier at the former confluence point of the K2-, Sarpo Laggo- and Skamri glaciers. 4). From the evidence of transfluence passes with roches moutonnées, striae and the limits of glacial polishing, as well as moraines and erratics, a High Glacial at least 1200 m thick ice-stream network between the Karakorums and the Kuen Lun north slopes was reconstructed. The Shaksgam and Yarkand valleys were occupied by glaciers coming from west Tibet. The lowest-lying moraines are to be found in the foreland down to 2000 m, indicating a depression of the High Glacial (LGM) snowline (ELA) by 1300 m. 5). The approximately 10,000 measurements of the radiation balance at up to heights of 5500 m on K2 indicate that with incoming energy near the solar constant the reflection from snow- covered ice is up to 70% greater than from rock and rock waste surfaces. 6).These results confirm for the very dry western margins of Tibet an almost complete ice sheet cover in an area with subtropical energy balance, conforming with the Ice Age hypothesis of the author which is based upon the presence of a 2.4 million km2 Tibetan inland ice sheet. This inland ice developed for the first time when Tibet was uplifted over the snowline during the early Pleistocene. As the measured subtropical radiation balance shows, it was able to trigger the Quaternary Ice Ages.
基金funded by the "973" National Social Development Research Program "Dynamic process of cryosphere,the mechanism of cryospheric impacts on climate, hydrology and ecologyadaptation measures" (Grant No.2007CB411507)Science of state key laboratory open fund of "The research of typical basin of cryosphere change and its threshold level,adaptation and strategy"(SKLCS08-04)
文摘This study focuses on the characters of public perceptions on climate and cryosphere change,which are based on a questionnaire survey in the(U|¨)r(u|¨)mqi River Basin.In comparison with scientific observation results of climate and cryosphere change,this paper analyzes the possible impact of the change on water resources and agriculture production in the area.Perceptions of most respondents on climate and cryosphere changes confirm the main objective facts.For the selection of adaptation measures addressing the shortage of water resource,the results are as follows:most people preferred to choose the measures like "policy change" and "basic facility construction" which are mostly implemented by the government and the policy-making department;some people showed more preference to the measures of avoiding unfavorable natural environment,such as finding job in or migrating to other places.The urgency of personal participation in the adaptation measures is still inadequate.Some adaptation measures should be implemented in line with local conditions and require the organic combination of "resource-development" with "water-saving".
基金supported by the Knowledge Innovation Project of the Chinese Academy of Sciences(KZCX2-EW-311)the National Natural Science Foundation of China(Nos. 91025012,40701034,J0630966/J0109, 40701035)+1 种基金the SKLCS founding(SKLCS-ZZ-201004,SKLCS-ZZ-2012-01-01)the Foundation for Excellent Youth Scholars of CAREERI,Chinese Academy of Sciences(Y184C81001)
文摘Hydrochemical characteristics and solute dynamics of bulk meltwater draining from Urumqi Glacier No.1 were investigated in years 2006 and 2007. The glacial meltwater was slightly alkaline with the mean pH of 7.64 and 7.61 in 2006 and 2007, respectively. In the meltwater, the dominant anions were the bicarbonate and sulphate, and the dominant cation was calcium. The concentration of major cations were varied as c(Ca2+) 〉 c(Mg2+) 〉 c(K+) 〉 c(Na+), while the order for the cations was c(HCO3-) 〉 c(SO42-) 〉 c(NQ-) 〉 c(C1-). The total dissolved solids (TDS) in meltwater had inverse relationships with the diurnal discharge. The major ion composition of meltwater was mainly controlled by rock weathering as inferred from the Gibbs model. Furthermore, the ion ratios and Piper diagram indicated that the main processes controlling the meltwater chemistry were carbonate weathering, pyrite weathering and feldspar weathering in rocks, and Ca2+ and HCQ- were the dominant ions during the carbonate weathering process. Solute flux calculation at Glacier No.1 station suggested that chemical denudation rates were 11.46 and 13.90 tonkm-2.yr-1 in 2006 and 2007, respectively.
基金supported by National Natural Science Foundation of China (Grant Nos.40801033 and 41130529)DFG,German Research Foundation (Grant No.BR1895/21-1)
文摘Fluctuation history of Midui glacier in the southeastern Tibet since the Little Ice Age(LIA) was reconstructed by the dating of lateral and terminal moraines using tree rings.Four conversions of glacier advance/stabilization to retreat were identified at around 1767,1875,1924 and 1964.The glacier reached its LIA maximum position at 1767.The fluctuations are consistent with those of other glaciers from the Tibetan Plateau,the Rockies and the Alps,suggesting high spatial coherency of glacier fluctuations in the Northern Hemisphere.Comparison with the summer temperature reconstruction in the southeastern Tibetan Plateau indicated that the Midui glacier fluctuation may be related to temperature variation on the centennial timescale.On the decadal scale,the fluctuation could correspond to cold/warm variation with an 8-year lag on average.