| 摘要: |
| 利用采自湖南慈利的马尾松树轮样本，建立研究区的标准树轮宽度年表。树轮气候响应分析发现：马尾松径向生长与月最大日降水量在生长季之前部分月份显著负相关（p＜0.05），在生长季之内部分月份显著正相关（p＜0.05），与月平均温度、月平均最低温度、月极端最低温度在生长季之前和之内大多月份均显著正相关（p＜0.05），其中与上一年11月到当年2月（冬季）的平均极端最低温度相关最好（r=0.62，p＜0.01）。重建了湖南慈利地区1854年以来冬季极端最低温度，重建气温在十年尺度上表现出明显的反“S”型，1854—1916年和1981—2015年处于暖冬时期，1917—1980年处于寒冬时期。此外，共发现29个寒冬年，其中包括3个寒冬时段，分别为1922—1925年、1927—1930年和1953—1960年，其中1953—1960年是自1854年以来最冷的时段。空间相关性分析表明重建序列可以指示我国中东部的冬季低温变化，而冬季低温可能与热带印度洋、西太平洋海温变化异常有关。 |
| 关键词: 亚热带 马尾松 树轮宽度 气候响应 冬季极端低温重建 寒冬年及寒冬时段 |
| DOI：10.7515/JEE182088 |
| CSTR： |
| 分类号: |
| 基金项目:国家自然科学基金项目（41671212，41630531）；中国科学院“西部之光”项目；黄土与第四纪地质国家重点实验室开放基金项目 |
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| Response of tree-ring width of Pinus massoniana to climate change and winter extreme minimum temperature reconstruction since 1854 in Cili, Hunan Province of subtropical China |
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QIAN Hengjun, CAI Qiufang, LIU Yu
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1. State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061, China
2. CAS Center for Excellence in Quaternary Science and Global Change, Xi’an 710061, China
3. Open Studio for Oceanic-Continental Climate and Environment Changes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266061, China
4. University of Chinese Academy of Science, Beijing 100049, China
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| Abstract: |
| Background, aim, and scope Because of the advantages of high resolution, accurate dating, strong continuity and easy access to samples, tree rings have become an important proxy for the reconstruction of climate in different space-time scales of the past 2000 years. However, the development of dendroclimatological researches in China is very uneven. Before the early twenty-first Century, the research areas were mainly concentrated on arid to semi-arid areas and the Qinghai-Tibet Plateau. In the last ten years, some researches have been carried out gradually in the subtropical China, but it is relatively less in Hunan Province. Our study aimed to supply tree-ring research data in Hunan Province and provide evidence for understanding the history of extreme winter and preventing future snowstorms. Materials and methods In our study, 37 tree-ring cores from 17 healthy Pinus massoniana were collected from Cili (111°17′24″E, 29°23′24″N, 281 m a.s.l.) of Hunan Province in August, 2016. All the tree-ring cores were measured using the LINTAB measurement machine with 0.01 mm resolution, then cross-dated by the COFECHA program and finally 35 series that successfully passed the COFECHA program were used to develop the standardized tree-ring width chronology via the ARSTAN program. Because the sampling site is located inside the village, where the growth environment is similar to that of the urban weather station, so climatic records from Yueyang weather station (113°03′00″E, 29°13′48″N, 53 m) in Yueyang City was selected, instead of that from the nearest Shimen weather station located in the mountain area. MATLAB was used to calculate the correlation coefficients between tree-ring width STD chronology and climate factors and then determine which climate factor limited tree growth most. LRM (linear regression model) was used to establish the conversion equation between tree-ring width index and the most relevant climate factor. Spatial correlation patterns between tree-ring width chronology and the gridded data including land temperatures and sea surface temperature (SST) were calculated via the website http://climexp.knmi.nl. Results As growth-climate response analyses show, the growth of Pinus massonian positively correlates with the mean temperature, minimum temperature and extreme minimum temperature in several months before and during the growing season (p＜0.05). Among these temperature factors, the extreme minimum temperature of previous winter (from previous November to current February) is the most relevant (r=0.62, p＜0.01). The 162 yeas’ winter extreme minimum temperature since 1854 has been reconstructed, which is significantly related to the winter temperatures for the large areas of eastern central China, and the SSTs in the tropical India ocean and the western Pacific Ocean during the observed period (1952—2015). Discussion The reconstruction shows a reversed S-shaped structure on the ten-year scale, that is the winters during 1854—1916 and 1981—2015 are comparatively warm, while winters during 1917—1980 are comparatively cold. In addition, 29 extreme winters are found, including 3 extreme winter periods: 1922—1925, 1927—1930 and 1953—1960. 1953—1960 is the coldest period since 1854. The reasons why the reconstructed extreme winters are not the same as the ice records of rivers and lakes in the south of the Yangtze River, in addition to the different icing mechanism of trees and rivers (Ⅰ, Ⅱ), are the Heat-island Effect of the village that weakened the severity and the duration of extreme winter such as 2007 when it just began to cool down in January. Conclusions Previous winter extreme minimum temperature is the main limiting climate factor that affects tree-ring width in Cili, and variance of the reconstruction equation was 37.9%. The reconstruction is in good agreement with winter temperature reconstructions by tree-ring width in the surrounding areas. The spatial correlation patterns show that the reconstruction can indicate the variation of winter minimum temperature in eastern central China and is mainly affected by SSTs in the tropical Indian and western Pacific Oceans. Recommendations and perspectives Although it is difficult to study the internal mechanism of tree-ring width and SST, it’s hoped that there will be progress through further researches. |
| Key words: subtropical area Pinus massoniana tree-ring width climate response winter extreme minimum
temperature reconstruction extreme winter and extreme winter period |
