The decade mean temperature anomaly series was reconstructed on the basis of histori-cal documents recorded in substantive local gazetteers. Firstly, the severity of the cold weath-er events such as snowing and severe...The decade mean temperature anomaly series was reconstructed on the basis of histori-cal documents recorded in substantive local gazetteers. Firstly, the severity of the cold weath-er events such as snowing and severe frost, which were frequently described in gazetteers,was estimated by using modern instrumental temperature observations. Secondly, the assort-ed cold events were classified into three classes according to the severity. the severity indexof them being --0.5, -- 1.0 and --2.0 respectively. The severity index was found fot eachseason since 1380 AD while there were somc descriptions of cold events. Finally, the re-gression coefficients between the decade sum of severity index and decade mean seasonal tem-perature anomalies was calculated. It shows that the severity index of--1 is equal to --0.2℃of the temperature anomaly. Then the decade mean seasonal temperature anomaly serieswas reconstructed from the 1380s (1380--1389 AD) to the 1980s. The series shows that therewere two cold periods; one between the 1550s and 1690s, another during the 1800s--1860s. Thelowest decade mean temperature anomaly reacked -- 1.8℃ in winter and varicd from 1--1.1to --1.4℃ for other seasons. In spring and summer series, the first cold period was mani-fested well. In autumn tbe second cold period was prominent. But in winter both the firstand the second cold periods were clearly observed. The timing of the cold periods found inthe present paper was earlier by 70 and 40 years respectively than that found by Chu Kochen(1973), which was mainly based on winter temperature documents in South China. It sug-gests that the timing of the cold period in the Litt1e Ice Age varied from place to placeeven within the Chinese territory.展开更多
Based on cross-dating tree rings from the Tianmu Mountain, Zhejiang Province, the tree rings α-cellulose δ13C time series was measured. By spectrum analysis, the variation of tree-ring δ13C sequence shows a quasi p...Based on cross-dating tree rings from the Tianmu Mountain, Zhejiang Province, the tree rings α-cellulose δ13C time series was measured. By spectrum analysis, the variation of tree-ring δ13C sequence shows a quasi periodicity of 4.4 years, which is coincident with the standard cycle of El Nino. After removing the long-term decrease trend of the δ13C variation related to atmospheric CO2 concentration, the response of the δ13C to climate elements was analyzed using meteorology data from a nearby weather station. The results suggest that there is a distinct relativity between high-frequency variation of tree ring δ13C series and seasonal climate parameters, e.g. temperature and precipitation, with a significant time-lag effect. In addition, the high frequency also reflects the strength change of the East Asian Monsoon. The multiple regression method was employed to reconstruct the historical climate, and to analyze the climate change and trend in the last 160 years in the northern Zhejiang Province.展开更多
文摘The decade mean temperature anomaly series was reconstructed on the basis of histori-cal documents recorded in substantive local gazetteers. Firstly, the severity of the cold weath-er events such as snowing and severe frost, which were frequently described in gazetteers,was estimated by using modern instrumental temperature observations. Secondly, the assort-ed cold events were classified into three classes according to the severity. the severity indexof them being --0.5, -- 1.0 and --2.0 respectively. The severity index was found fot eachseason since 1380 AD while there were somc descriptions of cold events. Finally, the re-gression coefficients between the decade sum of severity index and decade mean seasonal tem-perature anomalies was calculated. It shows that the severity index of--1 is equal to --0.2℃of the temperature anomaly. Then the decade mean seasonal temperature anomaly serieswas reconstructed from the 1380s (1380--1389 AD) to the 1980s. The series shows that therewere two cold periods; one between the 1550s and 1690s, another during the 1800s--1860s. Thelowest decade mean temperature anomaly reacked -- 1.8℃ in winter and varicd from 1--1.1to --1.4℃ for other seasons. In spring and summer series, the first cold period was mani-fested well. In autumn tbe second cold period was prominent. But in winter both the firstand the second cold periods were clearly observed. The timing of the cold periods found inthe present paper was earlier by 70 and 40 years respectively than that found by Chu Kochen(1973), which was mainly based on winter temperature documents in South China. It sug-gests that the timing of the cold period in the Litt1e Ice Age varied from place to placeeven within the Chinese territory.
基金This work was supported by the National Natural Science Foundation of China (Grant No.49771001)
文摘Based on cross-dating tree rings from the Tianmu Mountain, Zhejiang Province, the tree rings α-cellulose δ13C time series was measured. By spectrum analysis, the variation of tree-ring δ13C sequence shows a quasi periodicity of 4.4 years, which is coincident with the standard cycle of El Nino. After removing the long-term decrease trend of the δ13C variation related to atmospheric CO2 concentration, the response of the δ13C to climate elements was analyzed using meteorology data from a nearby weather station. The results suggest that there is a distinct relativity between high-frequency variation of tree ring δ13C series and seasonal climate parameters, e.g. temperature and precipitation, with a significant time-lag effect. In addition, the high frequency also reflects the strength change of the East Asian Monsoon. The multiple regression method was employed to reconstruct the historical climate, and to analyze the climate change and trend in the last 160 years in the northern Zhejiang Province.
