河南省栾川县近50a降水特征及其对氧同位素的影响

Characteristics of Precipitation and Their Influence on Oxygen Isotope for the Past 50 Years in Luanchuan County,Henan Province,China

通过对近631个大气降水量和平均气温数据的分析发现,河南省栾川县近50 a来年降水量呈下降趋势,20世纪60年代降水量偏高,90年代降水量偏低,而年平均气温整体呈现上升趋势,与近20 a全球变暖的规律一致。另外,研究区大气降水氧同位素值和日降水量及日平均气温呈现负相关的关系,结合栾川县近50 a器测资料与相邻地区洞穴石笋δ(18O)记录的对比分析表明,亚洲季风系统在20世纪60年代中期和70年代中期发生的两次减弱事件在栾川县降水量和石笋δ(18O)记录中都有响应,由此说明该地区大气降水的氧同位素组成固然有降水量效应,但大气环流效应更为显著。

The author focuses on the comparative study between the instrumental data for the past 50 years in Luanchuan County,Henan Province,China,based on the background of global changes and the δ18O values from the nearby cave stalagmites in the monsoonal areas.The significance of comparative study is to find the inherent relationship between the precipitation and temperature data from 1957 to 2010 and δ18O values of paleoclimatic records based on the oxygen isotope of precipitation monitoring,and to get the characteristic of evolvement in precipitation in Luanchuan County.Based on nearly 631 atmospheric precipitation and average temperature data analysis,it shows the precipitation of Luanchuan downward trend in the past 50 years,high precipitation in 60＇s and low rainfall in 90＇s of the 20th century,while the average annual temperature of the overall kept upward trend and consistent with global warming law about 20 years ago.The oxygen isotope values of precipitation and daily precipitation are negatively correlated and the oxygen isotope values with daily temperature also keep a negative correlation in the study areas.Based on comparing the instrumental data of the past 50 years in Luanchuan County with stalagmites δ18O records of adjacent areas caves,the author found that the two weakening of the Asian Monsoon circulation after the middle of 1960s and 1970s are responded by precipitation of Luanchuan and stalagmites δ18O records.Therefore,the author suggests that the changes in the precipitation oxygen isotope of Luanchuan County are due to amount effect certainly there,but more significant by the Chinese monsoon circulation effect.