江苏省农作物最大光能利用率时空特征及影响因子  

The spatial and temporal variations of maximum light use efficiency and possible driving factors of Croplands in Jiangsu Province

作　　者：康婷婷[1] 高苹 居为民[1] 黄金龙[1] 

机构地区：[1]南京大学国际地球系统科学研究所,南京210023 [2]江苏省气象服务中心,南京210008

出　　处：《生态学报》2014年第2期410-420,共11页Acta Ecologica Sinica

基　　金：全球变化重大科学研究计划资助项目(2010CB950702)

摘　　要：基于遥感数据的光能利用率模型被广泛应用于计算陆地生态系统的生产力,但其结果对最大光能利用率(εmax)参数非常敏感。由于该参数存在明显的时空变异性,在区域尺度上难以确定。利用MODIS遥感数据、分县产量统计数据和VPM模型推算了2001—2010年江苏省各县逐年的农田εmax,分析了其时空变化特征及其可能原因。结果表明,在2001—2010年期间,江苏省61个县区农田εmax平均值的变化范围为0.757—3.435 g C/MJ,呈现北高南低、中间高四周较低的空间分布特征;各县区农田的εmax都呈现出上升趋势,但在2001—2006年期间存在明显的年际波动,2002年、2004年和2006年的εmax相对较低,2007年后全省农田εmax稳定上升;εmax的年际波动呈现由北向南递减的趋势;全省大部分地区εmax的年际变化与单位耕地面积农用化肥施用量呈正相关性,苏北北部尤为明显;同时也与C4作物产量所占比例相关。研究表明在利用光能利用率模型计算农田生产力时,需要发展能考虑εmax时空变化的参数化方案。The productivity is a critical component of the terrestrial carbon cycle. Remote sensing driven light use efficiency models have been widely utilized to calculate the productivity of terrestrial ecosystems. They calculate the productivity as a linear product of maximum light use efficiency e scaling factors of environmental stress, and absorbed photosynthetically active radiation （APAR）. The outputs of these models are very sensitive to t maximum light use efficiency （ εmax ） , which represents the utilization rate of photosynthetically active radiation under ideal conditions without restrictions. However, it is difficult to determine this parameter properly since it is affected by numerous factors, including canopy nitrogen content, atmospheric concentration of CO2, plant types and species, and exhibit significant spatial and temporal variations. In currently used light use efficiency models, this parameter only changes with plant types. Such simplified parameterization might induce large uncertainties in calculated productivity of terrestrial ecosystems at regional and global scales. In this study, MODIS reflectance data, county／level yield census data, locally observed meteorological data, and the vegetation photosynthesis model （VPM） were employed to derive annual mean county／level cropland e in Jiangsu province for the period from 2001 to 2010. The county／level yield census data was converted into total net primary productivity of each county for estimating the parameter in the VPM model. Then, the spatial and temporal variations of and possibledriving factors were analyzed were analyzed. The results show that the county／level means of cropland in 61 counties of Jiangsu province varied between 0.757--3.435 g C/MJ during the period from 2001 to 2010, with an overall gradient decreasing from the north to the south. It is higher in the central areas than in the surrounding areas. Annual mean cropland εmax increased during the period from 2001 to 2010 in all 61 counties, but showed obvio

关 键 词：光能利用率 VPM模型 农田 时空变化 影响因子 

分 类 号：S31[农业科学—作物栽培与耕作技术]