一次热浪事件对祁连山海晏草甸草原CO_(2)通量的影响过程  

Effects of a heat wave event on CO_(2)fluxes in Haiyan meadow grassland in Qilian Mountains

作　　者：马文婧 李英年[3] 张法伟[3] 韩琳[1] MA Wenjing;LI Yinnian;ZHANG Fawei;HAN Lin(College of Atmospheric Sciences,Chengdu University of Information Technology,Chengdu 610200,China;Haibei Tibetan Autonomous Prefecture Meteorological Bureau,Xihai 810200,China;Northwest Institute of Plateau Biology,Chinese Academy of Sciences,Xining 810001,China)

机构地区：[1]成都信息工程大学大气科学学院,成都610200 [2]海北藏族自治州气象台,西海810200 [3]中国科学院西北高原生物研究所,西宁810001

出　　处：《生态科学》2023年第6期33-43,共11页Ecological Science

基　　金：国家自然科学基金项目(41877547);国家重点研发计划项目(2016YFC0501802);科技部基础资源调查专项(2019FY101300)。

摘　　要：全球气候变化引发的“热浪”事件对高寒草地碳循环有显著影响。热浪作为一种典型的极端气候事件,直接影响植物生长呼吸的同时也间接影响土壤呼吸,进而导致生态系统呼吸及其“常通量”层的CO_(2)通量发生变化。热浪对青藏高原草地生态系统CO_(2)通量的影响如何?以青藏高原东北隅高寒草甸草原为研究对象,以涡度相关系统为观测手段,结合连续观测的CO_(2)通量及微气象数据,研究2010—2019年10年间发生的一次“热天”维持时间较长的热浪事件(2015年7月25日至8月2日的热浪事件)对净生态系统碳交换量(NEE)、生态系统呼吸(Re)与总初级生产力(GPP)的影响过程。结果表明热浪的发生会带来短暂的高温和干旱,热浪期(7月25日至8月2日)相比于热浪前期(7月17日至7月24日),气候因子日最高气温(Ta_(max))、日平均气温(Ta)、日最低气温(Ta_(min))、日较差(ADT)、5 cm土壤温度(Ts)、饱和水汽亏(VPD)分别提高了42%、64%、146%、23%、46%、35%;热浪后期(8月3日至8月10日)比热浪前期降水量(PPT)降低77%。热浪结束后,气温及土壤温度不会马上降回热浪前的状态,热浪后期比热浪前期Ta_(max)、Ta、Ta_(min)、Ts分别提高5%、22%、142%、12%。此次热浪事件中热浪前期和热浪后期较热浪期逐时及逐日CO_(2)通量均显著降低,热浪前期、热浪后期相比热浪期逐时CO_(2)净吸收分别降低20.3%、37.6%;逐时Re分别降低16.8%,13.8%;逐时GPP分别降低17.6%、21.7%。热浪前期和热浪后期逐日CO_(2)净吸收比热浪期分别下降20.5%、37.8%,逐日Re分别下降16.7%、13.6%,逐日GPP较热浪期分别下降17.4%、21.7%。The"heat wave"events caused by global climate change have a significant impact on the carbon cycle of alpine grassland.Heat wave,as a typical extreme climate event,directly affects plant growth and respiration,but also indirectly affects soil respiration,and then leads to changes in ecosystem respiration and CO_(2)flux in the"constant flux"layer.What is the effect of heat wave on CO_(2)flux in grassland ecosystem of Qinghai-Tibet Plateau?Taking the alpine meadow grassland in the northeast corner of the Qinghai-Tibet Plateau as the research object and the vorticity correlation system as the observation method,combined with continuously observed CO_(2)flux and micrometeorological data,in this study,we studied the effects of a long"hot day"heat wave event(from July 25 to August 2,2015)on net ecosystem carbon exchange(NEE),ecosystem respiratory(Re)and total primary productivity of the ecosystem(GPP)during 2010-2019.It turned out that heat wave can bring brief periods of heat and drought,the heat wave period(25 July to 2 August)compared to the pre-heat wave period(17 July to 24 July),the daily maximum temperature(Ta_(max)),daily mean temperature(Ta),daily minimum temperature(Ta_(min)),daily range(ADT),5 cm soil temperature(Ts)and vapor press deficit(VPD)increased by 42%,64%,146%,23%,46%and 35%,respectively.The precipitation(PPT)in the late phase of the heat wave(from August 3 to 10)was 77%lower than that in the pre-heat wave period.When the heat wave was over,air and soil temperatures won't immediately return to their pre-heat state,Tamax,Ta,Tamin and Ts were increased by 5%,22%,142%and 12%in the late phase of heat wave,respectively.In this heat wave event,hourly and daily CO_(2)flux in the early and late stage of the heat wave decreased significantly compared with the heat wave period,and hourly net CO_(2)absorption in the early and late stage of the heat wave decreased by 20.3%and 37.6%,respectively,compared with the heat wave period;hourly Re decreased by 16.8%and 13.8%,respectively;the hourly GPP decreased by 17.6

关 键 词：草甸草原 热浪 CO_(2)通量 涡度相关系统 

分 类 号：P467[天文地球—大气科学及气象学]