欢迎访问《应用生态学报》官方网站,今天是 分享到:

应用生态学报 ›› 2020, Vol. 31 ›› Issue (11): 3814-3822.doi: 10.13287/j.1001-9332.202011.013

• • 上一篇    下一篇

陕甘宁地区降水同位素云下二次蒸发效应

肖涵余, 张明军*, 王圣杰, 车存伟, 杜勤勤, 张宇, 韩婷婷, 苏鹏燕   

  1. 西北师范大学地理与环境科学学院, 兰州 730070
  • 收稿日期:2020-07-01 接受日期:2020-08-23 出版日期:2020-11-15 发布日期:2021-06-10
  • 通讯作者: * E-mail: mjzhang2004@163.com
  • 作者简介:肖涵余, 女, 1996年生, 硕士研究生。主要从事寒旱区生态水文过程研究。E-mail: hyxiao1996@163.com
  • 基金资助:
    甘肃省高等学校科研项目(2018C-02)资助

Sub-cloud secondary evaporation effect of precipitation isotope in Shaanxi-Gansu-Ningxia region, China

XIAO Han-yu, ZHANG Ming-jun*, WANG Sheng-jie, CHE Cun-wei, DU Qin-qin, ZHANG Yu, HAN Ting-ting, SU Peng-yan   

  1. College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China
  • Received:2020-07-01 Accepted:2020-08-23 Online:2020-11-15 Published:2021-06-10
  • Contact: * E-mail: mjzhang2004@163.com
  • Supported by:
    the Scientific Research Program of Higher Education Institutions of Gansu Province (2018C-02).

摘要: 大气降水过程中,雨滴由云层底部降落至地面经过不饱和空气时发生的蒸发现象,即为云下二次蒸发,这会使得降水同位素组成发生改变。利用氢氧稳定同位素方法研究云下二次蒸发效应的时空变化及其成因,对探讨区域水循环过程具有重要意义。本研究基于陕甘宁地区2018年3月—2019年2月187个气象站逐小时气象数据,采用改进后的Stewart模型,分析了该区域蒸发剩余比(f)与降水过量氘变化量(Δd)的时空变化,并探讨了f以及气象要素与Δd的关系。结果表明: 从小时尺度来看,该区域各省f与Δd最小值均出现在白天,最大值出现在夜晚,即白天云下二次蒸发效应更明显。从月尺度来看,各省f、Δd月变化趋势较为一致,最小值多出现在夏半年,最大值多出现在冬半年,即夏半年云下二次蒸发效应更显著。研究区f、Δd值在季节尺度上的空间变化一致:春季,东、西部地区较大,中部较小;夏季,西北部地区偏小,其他地区偏大;秋季,由南向北减小;冬季,中部、南部较小,西部及东北部较大,研究区不同季节云下二次蒸发效应的空间差异显著。陕甘宁三省(区)f与Δd的线性关系的斜率均小于1‰·%-1,这可能与该地区干旱半干旱气候具有较大关系。当气温较高,相对湿度、水汽压、降水量和雨滴直径较小时,Δd值较小,云下二次蒸发效应较明显。

关键词: 陕甘宁地区, 降水, 稳定同位素, 云下二次蒸发, Stewart 模型

Abstract: During atmospheric precipitation, the evaporation of raindrops falling from the bottom of cloud layer to the ground and passing through unsaturated air, a process was called sub-cloud secondary evaporation, which will change the isotopic composition of precipitation. Using the hydrogen and oxygen stable isotope method to understand the temporal and spatial variation of secondary evaporation effect under clouds and its causes is important to understand regional water cycle process. Based on hourly meteorological data of 187 meteorological stations in Shaanxi-Gansu-Ningxia region from March 2018 to February 2019, the spatial and temporal variations of evaporation surplus ratio (f) and precipitation excess deuterium variation (Δd) were analyzed using the improved Ste-wart model, and the relationships between f and meteorological elements and Δd were examined. The results showed that, at the hourly scale, the minimum values of f and Δd in all provinces of the region appeared in the daytime, and the maximum values appeared in the night, indicating that the secondary evaporation effect under the cloud was more obvious in the daytime. At the monthly scale, the monthly variation trend of f and Δd in each province was relatively consistent, with the minimum value appearing in the summer half year, and the maximum value appearing in the winter half year, indicating that the second evaporation effect under cloud was more significant in the summer half year. From the spatial perspective, the spatial variation of f and Δd values in the region was consistent with that at the seasonal scale. In spring, the eastern and western regions were larger while the central part was smaller. In summer, the northwest region was smaller, and other regions were larger. In autumn, it decreased from south to north. In winter, the central and southern regions were smaller, and the western and northeast regions were larger. The spatial differences of secondary evaporation effects under clouds in different seasons was significant. The slopes of the linear relationship between f and Δd in Shaanxi, Gansu and Ningxia provinces were all less than 1‰·%-1, which may be caused by the arid and semi-arid climate in this area. When air temperature was higher and the relative humidity, vapor pressure, precipitation and raindrop diameter were smaller, the value of Δd was smaller, and the secondary evaporation effect under the cloud was more obvious.

Key words: Shaanxi-Gansu-Ningxia region, precipitation, stable isotopes, sub-cloud secondary evaporation, Stewart model