近400年来新疆策勒地区红柳沙包稳定氧同位素特征与环境变化

发布时间：2018-11-27 11:01

【摘要】：策勒县位于新疆南疆塔克拉玛干沙漠南缘中段(35°17′~39°30′N,80°03′~82°10′E),平均海拔1380 m,气候类型为典型的暖温带荒漠气候,干旱少雨,蒸发量大;日照时间长,光照充足,昼夜温差大;春夏多干热天气,风沙活动频繁;相应的典型地带性土壤主要为棕漠土、风沙土以及盐土;植物种类极其贫乏,且植被群落简单、结构单一。策勒县的荒漠区是塔克拉玛干沙漠南缘的代表区域,对策勒地区气候环境变化的分析探讨,对整个干旱荒漠区的气候环境变化研究具有重要意义。红柳沙包沉积纹层是由红柳风沙层和枯枝落叶层交替堆积而成,是一种有效的高分辨率的计年手段,且纹层中的红柳有机质和沙物质蕴藏了大量具有研究价值的古气候环境信息,是研究干旱区气候环境变化的理想信息载体。因此,可以利用红柳沙包沉积纹层来探讨和恢复百年尺度上荒漠区的气候环境变化。本文以新疆策勒地区红柳沙包为主要研究对象,采用移动平均法对红柳纤维素中δ~(18)O进行预处理,得到δ~(18)O_(ma)序列,在分析红柳沙包稳定氧同位素特征与气候环境变化关系的基础上,定量恢复重建了百年尺度上策勒地区气候要素序列。取得的主要结论有:(1)红柳落叶δ~(18)O_(ma)序列对平均气温的响应性不明显。由此推测,本研究区温度的变化可能对红柳落叶δ~(18)O的影响不起主要作用。但这与非干旱区树轮的δ~(18)O值与温度的相关性结果保持一致,当高于或低于某个临界温度时,δ~(18)O值呈现出不同的变化趋势。(2)红柳落叶δ~(18)O_(ma)序列对各月平均最低气温变化情况指示性较差,这可能是由于该研究区其他气候要素对δ~(18)O_(ma)产生的作用更为显著,导致对平均最低气温的敏感性极低。(3)红柳落叶δ~(18)O_(ma)序列与4~10月和12月空气相对湿度呈显著正相关。δ~(18)O_(ma)对空气相对湿度的指示性较好,由此推测,在红柳生长季,空气相对湿度对红柳落叶δ~(18)O_(ma)的影响十分显著。(4)红柳落叶δ~(18)O_(ma)序列与2~3月、8~9月份降水量相关性显著。但是在年平均降水量仅为38.64 mm,而蒸发量可达2595.3 mm的策勒地区,降水量的多少对红柳的生长不起决定性作用,它的生长更依赖于地下水、河流水和土壤水等其他水分来源。(5)红柳落叶δ~(18)O_(ma)序列与日照时数存在一定的相关性,且在日照时数较长的秋季,氧同位素与日照时数呈显著负相关关系。(6)通过对策勒地区4月平均气温的重建,得到两个偏冷期1724~1790年、1900~2009年;两个偏暖期1670~1723年、1791~1899年。通过对策勒地区8月降水量的重建,得到两个偏干期1635~1723年、1792~1899年;两个偏湿期1724~1791年、1900~2009年。
[Abstract]:Cele County is located in the middle section of the southern margin of Taklimakan Desert in southern Xinjiang (35 掳17) (39 掳30 掳N), with an average elevation of 1380 m. The climate type is a typical warm temperate desert climate, with less drought and less rain, and large evaporation. The sunshine time is long, the light is sufficient, the temperature difference between day and night is big; the dry and hot weather in spring and summer, the wind and sand activity are frequent, the corresponding typical zonal soil is mainly brown desert soil, windy sand soil and salt soil; The plant species are extremely poor, and the vegetation community is simple and the structure is simple. The desert area of Cele County is the representative area of the southern edge of Taklimakan Desert. The analysis and discussion of climate and environment change in the area of countermeasures is of great significance to the study of climate and environment change in the whole arid desert area. The sedimentary grain layer of Hongliu sandbag is formed by alternating accumulation of wind-sand layer and litter layer, which is an effective and high-resolution dating method. The organic matter and sand in the laminae contain a large amount of paleoclimate and environmental information, which is an ideal information carrier for the study of climate and environmental change in arid areas. Therefore, it is possible to study and restore the climatic and environmental changes of desert area on a century-scale by using the Sedimentary grain layer of Salix mandshurica. In this paper, the 未 ~ (18) O in red willow cellulose was pretreated by moving average method, and the 未 ~ (18) O _ (ma) sequence was obtained. Based on the analysis of the relationship between the stable oxygen isotopic characteristics and climate and environmental changes of Salix mandshurica, the climatic element sequence of Cele area on the scale of 100 years was reconstructed quantitatively. The main conclusions are as follows: (1) the response of 未 ~ (18) O _ (ma) sequence to mean temperature is not obvious. It is inferred that the change of temperature in this study area may not have a major effect on the 未 ~ (18) O of red willow leaves. But this is consistent with the correlation between 未 ~ (18) O value of tree ring and temperature in non-arid region, when it is above or below a critical temperature, The 未 ~ (18) O values showed different trends. (2) the 未 ~ (18) O _ (ma) sequence of red willow leaves had a poor indication to the mean minimum temperature of each month. This may be due to the more significant effect of other climatic factors on 未 ~ (18) O _ (ma) production in the study area. The sensitivity to mean minimum temperature was very low. (3) the 未 ~ (18) O _ (ma) sequence was positively correlated with air relative humidity from April to October and December. 未 ~ (18) O _ (ma) had a good indication to air relative humidity. It is inferred that the effect of air relative humidity on 未 ~ (18) O _ (ma) of red willow leaves is significant in the growing season. (4) there is a significant correlation between 未 ~ (18) O _ (ma) sequence and precipitation from February to March and from August to September. However, in Cele, where the average annual precipitation is only 38.64 mm, and evaporation is up to 2595.3 mm, the amount of precipitation does not play a decisive role in the growth of Salix willow, and its growth depends more on groundwater. Other water sources, such as river water and soil water. (5) the 未 ~ (18) O _ (ma) sequence of red willow leaves was correlated with the sunshine hours, and in the autumn when the sunshine hours were longer, There is a significant negative correlation between oxygen isotopes and sunshine duration. (6) through the reconstruction of the average temperature in April in Cele, two cold periods were obtained: 1724 ~ 1790 and 1900 ~ 2009; The two warm periods were 1670 ~ 1723 and 1791 ~ 1899. Through the reconstruction of precipitation in August in Cele area, two partial dry periods were obtained: 1635 ~ 1723, 1792 ~ 1899, and 1724 ~ 1791, 1900 ~ 2009.
【学位授予单位】：河北师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q948

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