摘要
青藏高原被誉为"中华水塔",在全球气候变化的大背景下,青藏高原的水热平衡发生了一系列变化,研究青藏高原蒸散与气候变化关系,对于揭示气候变化对高原水文过程影响具有重要意义。基于2011-2016年6年自动观测连续数据,选取净辐射总量、气温、饱和水汽压差、降水、风速、相对湿度、日照时数7个主要气象因子,采用随机森林分析方法,分析了参考蒸散的季节及年际变化趋势,评估各气象因子对青藏高原参考蒸散的贡献。结果表明:1)在季节尺度上,参考蒸散总体表现为单峰曲线,即1-7月呈增加趋势,7月份达到最大值(132.48mm),7-12月开始逐渐下降;在年际尺度上,参考蒸散总体呈现递增的趋势,平均为1 023.03mm,且每年以29.61mm增加趋势上升。2)净辐射是影响参考蒸散年内变异最重要的气象因子,其他气象因子对其影响强弱排序为饱和水汽压差>最高气温>日照时数>平均气温;对于生长季参考蒸散,气象因子对其影响强弱依次排序为净辐射>日照时数>饱和水汽压差>最高气温。而降水、风速、最低气温和平均气温对年内参考蒸散和生长季参考蒸散影响较小。对非生长季参考蒸散,其所受气象因子强弱排序为净辐射>饱和水汽压差>风速>最高气温>平均气温,而相对湿度、日照时数、降水和最低气温对非生长季参考蒸散贡献较小。本研究表明,青藏高原矮嵩草(Kobresia humilis)草甸参考蒸散主要受净辐射驱动,且相比于平均温和最低气温,最高气温对其参考蒸散影响更大,这对于明晰高寒草甸水循环过程具有重要意义。
The Qinghai-Tibet Plateau,also known as“China’s water tower”,has undergone a series of changes in the water-heat balance in its alpine meadows,which are attributed to global climate change.Therefore,it is vital to examine the effects of climate change on the hydrological processes on the plateau by analyzing the relationship between evapotranspiration and meteorological factors.In the present study,based on automatically observed meteorological data from 2011-2016,random forest analysis was applied to quantitatively evaluate the relative importance of seven major meteorological factors(e.g.,net radiation,temperature,apor pressure deficit,rainfall,wind speed,relative humidity,and sunshine hours)on the reference evapotranspiration(ET 0)to explore the key meteorological factors affecting variation in ET 0.In addition,the seasonal and interannual variation in ET 0 from 2011-2016 were also analyzed.The results show that 1)at the seasonal scale,ET 0 could be characterized by a unimodal relationship that increases from January to July,with the maximum value occurring in July(132.48 mm),then decreases from July to December.At the interannual scale,the ET 0 increased significantly from 2011-2016 with an average of 1 023.03 m 2)The net radiation was the most important factor affecting the annual variation in ET 0,followed by vapor pressure deficit,maximum air temperature,sunshine hours,and mean air temperature.The impact of meteorological factors on the growing season ET 0 was ranked in the following order:net radiation>sunshine hours>vapor pressure deficit>maximum air temperature;rainfall,wind speed,minimum air temperature,and mean air temperature had little impact.The impact of meteorological factors on the non-growing season ET 0 was ranked in the following order:net radiation>vapor pressure deficit>wind speed>maximum air temperature>mean air temperature;relative humidity,sunshine hours,rainfall,and the minimum air temperature had little impact.Our results indicated that the ET 0 of an alpine Kobresia meadow in the northern Qinghai-Tibet Plateau was dominated by net radiation.Moreover,the maximum air temperature had stronger effects on the ET 0 than did mean air temperature or minimum air temperature,which could provide a new insight for the appropriate management of plateau water resources.
作者
戴黎聪
曹莹芳
柯浔
张法伟
杜岩功
郭小伟
曹广民
DAI Licong;CAO Yingfang;KE Xun;ZHANG Fawei;DU Yangong;GUO Xiaowei;CAO Guangmin(Northwest Institute of Plateau Biology,Chinese Academy of Sciences,Xining 810001,Qinghai,China;University of Chinese Academy of Sciences,Beijing 100039,China)
出处
《草业科学》
CAS
CSCD
2018年第9期2137-2147,共11页
Pratacultural Science
基金
国家自然科学基金项目(41730752
31770530)
青海省基础研究计划自然科学基金青年项目(2016-J-923Q)
关键词
中华水塔
水热平衡
全球气候变化
水文过程
随机森林
季节和年际变化
China’s water tower
water-heat balance
global climate change
random forest
hydrologic process
seasonal and interannual variation
作者简介
戴黎聪(1993-),男,江西余干人,在读硕士生,主要从事水文生态学研究。E-mail:18270821151@163.com;通信作者:曹广民(1963-),男,陕西渭南人,研究员,博士,主要从事生物地球化学循环研究。E-mail:caogm@nwipb.cas.cn。
