西双版纳热带季雨林林冠层CO_2浓度特征及其影响因素  

Characteristic of CO_2 Concentration of Canopy and Its Influencing Factors in Tropical Seasonal Rainforest in Xishuangbanna,China

作　　者：张娜 巩在武 ZHANG Na1,2,GONG Zaiwu1(1. School of Low ＆ Public AFFairs, Nanjing University of Information Science ＆ Technology, Nanjing 210044, China; 2. Meteorological Bureau of Yangquan City, Shanxi Province, Yangquan, Shanxi 045000, Chin)

机构地区：[1]南京信息工程大学法政学院,南京210044 [2]山西省阳泉市气象局,山西阳泉045000

出　　处：《水土保持研究》2018年第4期181-188,共8页Research of Soil and Water Conservation

基　　金：国家自然科学基金资助项目:群体共识快速收敛:建模;实验及仿真分析研究(71571104)

摘　　要：根据2015年西双版纳热带季节雨林群落冠层植物表面温度以及林冠上、林冠下的气温资料,对热带季节雨林林冠层CO_2浓度特征及其影响因素进行了分析。结果表明:(1)近地层地温呈现正弦变化趋势;深层地温相对稳定,随深度增加地温日变幅减小;地温峰值出现时刻随深度增加而呈现滞后现象;地温季节差异明显,平均地温在雨季较高,雾凉季较低,干热季居中。(2)西双版纳热带季节雨林CO_2浓度表现出明显的日变化、季节变化和林冠上下差异。在日尺度上,林冠上方的CO_2浓度时间变化曲线为"单峰型",林内近地层CO_2浓度时间变化曲线为"双峰型";在季节尺度上,林冠上方和林内近地层CO_2浓度均呈现雨季低、干季高的特点,并且林冠上方CO_2浓度低于林内近地层CO_2浓度。(3)热带季节雨林土壤呼吸存在明显的日变化规律,随时间变化表现为单峰型,且峰值出现的时间在14:00左右,对于季节变化规律,在7—8月份达到峰值,8月份以后,土壤呼吸急剧下降,在12月份最低。(4)不同季节热带季节雨林土壤呼吸、CO_2浓度均与林冠温度的指数关系达到了极显著水平(p<0.01),且指数模型的决定系数最大,故指数模型的拟合效果最好。(5)林冠上方CO_2浓度与光合有效辐射之间皆表现出正相关,随着光合有效辐射的增强,CO_2浓度相应地升高;林内近地层CO_2浓度与光合有效辐射之间的正相关关系较林冠上方强,地温与林冠上方CO_2浓度和林内近地层CO_2浓度均没有显著的相关性(p>0.05)。林内近地层CO_2浓度与土壤温度以及土壤呼吸的相关系数为正,土壤呼吸可以认为是影响和控制近地层CO_2浓度的主要因子。Based on the observation data in 2015,we analyzed the influencing factors of CO2 concentration of canopy in tropical seasonal rainforest in Xishuangbanna,China.The results showed that：（1）the diurnal variation of soil temperature in near-surface soil layer demonstrated a sine trend,while it was relatively stable in the deeper soil layers;diurnal change rate of soil temperature decreased with the increase of soil depth,the occurrence time of the peak of soil temperature presented the hysteresis with the increase of soil depth,seasonal difference of soil temperature was significant,the mean soil temperature was higher in the rain season,it was lower in the cold season,it was the medium in the dry and hot season;（2）daily and seasonal CO_2 concentrations in tropical seasonal rainforest showed the significant difference in canopy,on the daily scale,CO2 concentration above the canopy showed the unimodal type,and CO2 concentration beneath the canopy showed the bimodal pattern;on seasonal scale,CO2 concentration above canopy was higher than that beneath the canopy;（3）the daily soil respiration showed the unimodal type,and the peak occurred at 14：00;the soil respiration reached to the peak in July,it sharply declined after July,and it was lowest in December;（4）the exponential model can be used to describe the relationship between soil respiration,CO_2 concentration and canopy temperature（p0.01）;（5）CO2 concentrations above and beneath the canopy were positively related to photosyntheticallyactive radiation,and the related coefficients beneath the canopy were higher than those above canopy.There was a positive correction between CO2 concentration and soil respiration,thus,soil respiration can be regarded as the mainly influencing factor on CO2 concentration in Xishuangbanna,China.

关 键 词：热带季雨林 林冠层 CO2浓度 影响因素 

分 类 号：S718[农业科学—林学]