申双和 ,孙照渤,陈镜明. 2005. 北方黑云杉林冠内空气CO2浓度及其上方通量模拟[J]. 气象学报, 63(6):969-979, doi:10.11676/qxxb2005.092
北方黑云杉林冠内空气CO2浓度及其上方通量模拟
MODELLING OF AIR CO 2 CONCENTRATION AND FLUX IN/ABOVEA BOREAL BLACK SPRUCE STAND
投稿时间:2004-06-30  修订日期:2005-01-12
DOI:10.11676/qxxb2005.092
中文关键词:  黑云杉,CO2通量,完全多层模式,二叶模型,叶片丛聚
英文关键词:CO2 flux, Complete multiplayer model, Two-leaf submodel, Leaf clumping, Black spruce.
基金项目:国家自然科学基金项目(B29200)
作者单位
申双和 南京信息工程大学气象灾害实验室, 南京,210044 
孙照渤 南京信息工程大学气象灾害实验室, 南京,210044 
陈镜明 多伦多大学地理规划系,多伦多, M5S 3G3 
摘要点击次数: 2457
全文下载次数: 2578
中文摘要:
      考虑植物阴叶和阳叶对环境的反应、植物叶片丛聚特性以及叶片氮素水平的垂直差异,建立了黑云杉林与大气之间物质输送和能量交换的一维完全多层模式。模式中对阳叶和阴叶的叶面积指数借用Chen J M 等提出的方法,并经过修改以适用于多层模拟。叶水平的光合作用c运用Farq uhar方程并与CO 2传导方程联列获得。模式验证的资料取自BOREAS(Boreal Ecosystem fAtmosphere Study)研究计划中加拿大Saskatchewan的南试验区,属于温带气候。通过对冠o层上方的显热、感热和CO2通量、以及植物光合作用、蒸腾作用和气孔传导等生理作用t过程的实测值进行了计算结果的验证,结果表明:计算的显热通量比实测值偏低,潜热通量则略高于实测值,而CO2通量只有在较高水平时偏高,3个通量的计算值与实测值比较接近,R2分别为0.71,0.78和0.65,取得了较好的效果。气孔导度、光合作用和蒸腾作用的模拟结果表明,三者的实测与模拟值之间的R 2分别达到0.57,0.69和0.66,均通过0.01显著度检验,且无显著的系统偏差。因此,可以认为在多层模拟中充分考虑叶片不同受光状况,不同氮素水平以及叶片丛聚特性的影响有助于更好地研究植被与大气的交换过程。
英文摘要:
      A complete multilayer model of vegetation-atmosphere exc hange has been developed for a boreal black spruce stand, taking into account re sponse of sunlit and shaded leaves to ambient conditions respectively, leaf clumping and nitrogen level in the leaves at different layers. The established model consists of one dimensional air diffuse meteorological equation for transfer of water, heat, CO 2 within and above the forest canopy, a two leaf submodel for leaf air exchange, and an exponential function for distribution of nitrogen level in leaves with height of canopy. Estimation of sunlit and shaded leaf area index was borrowed from Chen′s method, modified for layer-by -layer by the authors of this paper. Photosynthesis at leaf level was computed by combining Farquhar' s equations and CO 2 conductance equation. Soil temperature, moisture, and thermal and water fluxes between adjacent soil layers, obtained from ESES, were used for calculating exchanges of radiation, latent and sensible heat between soil surface and its immediately overlying canopy air. Data for model validation came from a southern study area (53°59′N, 105°07′W) of BOREAS (Boreal Ecosy stem -Atmosphere Study) located in Saskatchewan, Canada and beloging to temperate cl imatic zone. The involved data, just covering main growing season in 1994, were sensible heat flux, latent heat flux, CO2 flux which were all measured by eddy correlation method, and soil heat flux measured by thermal flow plate, CO 2 concen tration profile by LI 6262 IRGA, net radiation and other regular meteorological elements such as air temperature, humidity, wind speed, and air pressure. Measur ements of leaf photosynthesis, transpiration and stomata conductivity to CO2 were made by LI6200 portable photosynthesis system. The validation for physiological progresses of the leaf stomata conductance, photosynthesis and transpiration shows that there were good agreements and no marked systematic discrepancies bet ween the measurements and the estimates. The flux modeling indicates that sensible heat fluxes were slightly overestimated in comparison with observed ones, and between them a squared correlation coefficient (R 2) amounted to 0.71 bu t the difference fluctuated from time to time. In contrast to the sensible heat flux,estimates of latent thermal flux were a little lower than observed ones and R 2 r eached 0.78. CO2 flux simulation had the lowest R 2 of 0.65 and slightly underest imated when it goes over 7 μmol/(m 2?s). CO 2 concentration was of the biggest R2 of 0.90 although there were larger errors in the canopy air close to the forest floor, rising from omitting moss respiration. Analysis of these flux simulations leads to conclude that the complete multilayer model of vegetation-atmosphere resented achieves good results and is helpful to better investigat ion into vegetation-atmosphere exchange process because of its well dealing wit h the leaf radiance absorption, nitrogen level and clumping.
HTML   查看全文   查看/发表评论  下载PDF阅读器
分享按钮