青藏高原及其毗邻地区降水中稳定同位素成分的经向变化

doi:10.7522/j.issn.1000-0240.2002.0047

摘要/Abstract

摘要： 分析了从南亚经青藏高原到毗邻的我国西北地区一个经向剖面上降水中稳定同位素成分的时空分布以及与温度、降水量、水汽来源的关系.在青藏高原南部和南亚,温度效应均不存在.在所统计的站点中,大约一半的取样站具有降水量效应,但降水中稳定同位素比率的季节变化并不与降水量强度的变化相一致.在季节变化中,δ¹⁸O的最大值往往出现在雨季到来之前的春季,最小值则出现在雨季后期或雨季结束的秋季.在青藏高原中、北部和毗邻的我国西北地区,各取样站均具有显著的温度效应,且降水中δ¹⁸O的季节变化与温度的季节变化几乎一致.说明在这些地区,温度是制约降水中稳定同位素变化的主要影响因子.由于来自源区水汽的直接凝结,南亚地区降水中平均稳定同位素成分相对较重.稳定同位素比率的季节差异较小;从青藏高原南坡的坚景到唐古拉山,由于翻越喜马拉雅山时水汽受强烈的洗涤作用,降水中稳定同位素比率急剧减小,达经向分布中δ¹⁸O的最低值段;从31°N到青藏高原北部,降水中稳定同位素比率随纬度而增大,并最终过渡到与我国西北地区降水中稳定同位素比率的变化型相类似.

关键词: 青藏高原及其毗邻地区, 降水, 稳定同位素, 变化

Abstract: The temporal and spatial variations of stable isotopic compositions in precipitation and their relationship with temperature, precipitation and vapor sources are analyzed in a meridianal section of the Tibetan Plateau and its adjacent regions. There is no temperature effect in the southern Tibetan Plateau and South Asia. Amount effect has been observed at New Delhi, Katmandu, Kyangjin and Lhasa that account for about a half of the statistical stations. However, the seasonal variations of stable isotopic compositions in precipitation at those stations are inconsistent with that of precipitation intensity: the maximum δ¹⁸O in precipitation usually appears in spring before the rainy season, and the minimum δ¹⁸O in precipitation is in fall during the late rainy season or after the rainy season. This distribution shows that the variations of stable isotopic compositions in precipitation are not mainly controlled by precipitation intensity in the southern Tibetan Plateau and South Asia. There is notable temperature effect in the middle northern Tibetan Plateau and its adjacent Northwest China. It has been observed that the seasonal variations of δ¹⁸O in precipitation are almost consistent with those of air temperature in these regions, which shows that temperature is a main factor controlling the stable isotopic variations in precipitation. The relationship between the weighted mean δ¹⁸O and the mean temperature on the Tibetan Plateau and its adjacent regions is not distinctly different from the global scale pattern. Comparatively speaking, during the cold season, there is a closer correlation between the weighted mean δ¹⁸O and the mean temperature on the Tibetan Plateau and its adjacent regions, with a nonlinear correlation coefficient reaching 0.9414. This probably arises because all of Asia is under the control of the strong cold high pressure over Mongolia during the winter season. The situation during the warm season is different. Although the general trend of the weighted mean δ¹⁸O with the mean temperature has not been changed, the spatial variation clearly displays that the weighted mean δ¹⁸O for the stations from Kyangjin on the southern slope of the Himalayas to the Tanggula Mountains in the middle Tibetan Plateau are all lower than the typical ones of the globe for the same temperature. As for the other stations on the middle and northern Tibetan Plateau in the north of the Tanggula Mountains and Northwest China, their weighted mean δ¹⁸O, all greater than -10.0‰, are distributed around the global regression line. Because vapor is directly originated from low latitude oceans, the relative heavy δ¹⁸O with small variation characterizes the rainfall in South Asia. A sharp depletion of stable isotopic compositions in precipitation takes place from Kyangjin on the southern slop of the Himalayas to the Tanggula Mountains in the middle Plateau. δ¹⁸O reaches its minimum due to very strong rainout of the vapor from oceans as the vapor rises over the Himalayas. From the Tanggula Mountains to the northern Tibetan Plateau, δ¹⁸O in precipitation increases with increasing latitude. Isotopes in the northern Plateau transfer into the Northwest China with little disruption.

Key words: Tibetan Plateau and its adjacent regions, precipitation, stable isotopes, variation

中图分类号:

P426.61⁺²

章新平, 姚檀栋, 中尾正义, 韩健康, 谢自楚. 青藏高原及其毗邻地区降水中稳定同位素成分的经向变化[J]. 冰川冻土, 2002, 24(3): 245-253.

ZHANG Xin-ping, YAO Tan-dong, Masayoshi NAKAWO, HAN Jian-kang, XIE Zi-chu . Meridianal Variation of Stable Isotopic Compositions in Precipitation of the Tibetan Plateau and Its Adjacent Regions[J]. JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY, 2002, 24(3): 245-253.

参考文献

[1] Dansgaard W. The abundance of δ¹⁸O in atmospheric water and water vapor [J]. Tellus, 1953, 5(4): 461-469.
[2] Dansgaard W. Stable isotopes in precipitation [J]. Tellus, 1964, 16(4): 436-468.
[3] Jouzel J. Isotopes in cloud: multiphase and multistage condensation process [A]. Handbook of Environmental Isotope Geochemistry (2) [C]. Amsterdam: Elsevier Scientific Publishing Company, 1986. 61-112.
[4] Yao Tandong, Sun Weizhen, Pu Jianchen, et al. Characteristics of stable isotope in precipitation in the inland area-a case study of the relation between δ¹⁸O in precipitation and temperature in rümqi River, China [J]. Journal of Glaciology and Geocryology, 2000, 22(1): 15-22. [姚檀栋, 孙维贞, 蒲健辰, 等. 内陆河流域系统降水中的稳定同位素-乌鲁木齐河流域降水中δ¹⁸O 与温度关系研究[J]. 冰川冻土, 2000, 22(1): 15-22.]
[5] Zhang Xinping, Shi Yafeng, Yao Tandong. Variational features of precipitation δ¹⁸O in Northeast Qinghai-Tibet Plateau [J]. Science in China (B), 1995, 38(7): 854-864.
[6] Zhang Xinping. Variation of d δ¹⁸O/dT in precipitation in the Qinghai-Xizang Plateau [J]. Chinese Geographical Science, 1997, 7(4): 339-346.
[7] Thompson L G, Thompson E M, Davis M E, et al. A 1000 year climatic ice-core record from the Guliya ice cap, China: its relationship to global climate variability [J]. Annals of Glaciology, 1995, 21: 175-181.
[8] Yao Tandong. Abrupt climatic changes on the Tibetan Plateau during the Last Ice Age [J]. Science in China (D), 1999, 42(4): 358-368.
[9] Yao Tandong, Thompson L G, Qin Dahe, et al. Variations in temperature and precipitation in the past 2000 a on the Xizang (Tibet) Plateau Guliya ice core records [J]. Science in China (B), 1996, 39(4): 425-433.
[10] Stewart M K. Stable isotope fractionation due to evaporation and isotopic exchange of falling water drops: application to atmospheric processes and evaporation of lakes [J]. Journal of Geophysical Research, 1975, 80: 1 133-1 146.
[11] Zhang Xinping, Xie Zichu, Yao Tandong. Mathematical modeling of variations on stable isotopic ratios in falling raindrops [J]. Acta Meteorologica Sinica, 1998, 12(2): 213-220.
[12] Zhang Xinping, Masayoshi Nakawo, Koji Fujita, et al. The variation of precipitation δ¹⁸O in Langtang Valley, Himalayas [J]. Science in China (D), 2001, 31(3): 206-213. [章新平, 中尾正义, 藤田耕史, 等. 喜马拉雅山朗塘流域降水中δ¹⁸O 的变化[J]. 中国科学(D辑), 2001, 31(3): 206-213.]
[13] He Yuanqing, Yao Tandong, Yang Meixue, et al. Contemporary significance of snow and ice indicated by the record in a shallow ice core from a temperate glacier in southwestern monsoon region [J]. Journal of Glaciology and Geocryology, 2000, 22(3): 235-242. [何元庆, 姚檀栋, 杨梅学, 等. 玉龙山温冰川浅冰芯记录现代指示意义[J]. 冰川冻土, 2000, 22(3): 235-242.]
[14] He Yuanqing, Yao Tandong, Yang Meixue, et al. The new results of δ¹⁸O studies on the system of precipitation, snow-ice and glacier runoff at the Glacier Baishui No. 1 region in Mt. Yulong, China [J]. Journal of Glaciology and Geocryology, 2000, 22(4): 391-393. [何元庆, 姚檀栋, 杨梅学, 等. 玉龙山白水1号冰川区大气降水冰雪水文系统内δ¹⁸O 研究的新结果[J]. 冰川冻土, 2000, 22(4): 391-393.]
[15] Ye Duzheng, Gao Youxi. Meteorology of the Tibetan Plateau [M]. Beijing: Science Press, 1979. 202-212. [叶笃正, 高由禧. 青藏高原气象学[M]. 北京: 科学出版社, 1979. 202-212.]
[16] Dai Jiaxi. Climate of the Tibetan Plateau [M]. Beijing: Meteorological Press, 1990. 63-74. [戴加洗. 青藏高原气候[M]. 北京: 气象出版社, 1990. 63-74.]
[17] Tian Lide, Yao Tandong, Sun Weizhen, et al. The relationship between (δD and δ¹⁸O in precipitation, and vapor cycle from the southern to the northern Tibetan Plateau [J]. Science in China (D), 2001, 31(3): 214-220. [田立德, 姚檀栋, 孙维贞, 等. 青藏高原南北降水中δD和δ¹⁸O 关系及水汽循环[J]. 中国科学(D辑), 2001, 31(3): 214-220.]
[18] Datta P S, Tyagi S K, Chandrasekharan H. Factors controlling stable isotope composition of rainfall in New Delhi, India [J]. Journal of Hydrology, 1991, 12: 223-236.
[19] Aragu s-Aragu s L, Froehlich K, Rozanski K. Stable isotope composition of precipitation over southeast Asia [J]. Journal of Geophysical Research, 1998, 103: 28 721-28 742.
[20] Saxena R K, Eriksson E. Hydrometeorological interpretation of isotopic data on atmospheric moisture and precipitation [J]. Annals of Glaciology, 1985, 7: 181-184.
[21] Fricke H C, O'Neil J R. The correlation between δ¹⁸O/16O ratios of meteoric water and surface temperature: its use in investigating terrestrial climate change over geologic time [J]. Earth and Planetary Science Letters, 1999,170: 181-196.