植被双向反射分布函数的模型及其发展

介绍了双向反射分布函数(BRDF)的概念和反映植被特性的归一化植被指数(NDVI)、增强植被指数(EVI)、差值植被指数(DVI)等一些重要指数参数。评述了近年发展起来的植被BRDF模型的构建方法,例如统计反演方法,MODIS植被指数合成法和集合卡曼滤波法(EnKF)。分析了目标表面BRDF数据的获取方法和改进的驱动核算法。对BRDF模型的发展趋势进行了展望。     

作物覆盖条件下土壤中水热分布的稳态数值比较

本文应用非饱和多孔介质中传热传质的数学模型,考虑到作物根系和冠层的影响,对稳态情况下圆柱形士壤床中的水热分布进行了数值计算模拟。在不同环境条件下对土壤中的水热分布也进行了模拟计算。同时,在相同环境条件下对有作物覆盖的土壤床和无作物覆盖的土壤床中的水热分布也进行了模拟比较。文中数值模拟的结果较好地反映了实际情况。     

Global vegetation change analysis based on MODIS data in recent twelve years①

Vegetation cover change is critical for understanding impacts and responses of vegetation to climate change. A study found that vegetation in the regions between 45°N-70°N was increasing using normalized difference vegetation index( NDVI) from 1981 to 1991 ten years ago. The global vegetation growth has changed because of climate change in recent twelve years( 2001- 2012). After thorough analysis based on satellite data,it is found that it is evident that the global vegetation changed( NDVI) little,and it is increasing slightly in Northern hemisphere while it is decreasing slightly in Southern Hemisphere. For different latitudes,vegetation is increasing 0.17% every year from 60°N to 70 °N( R~2= 0.47,P 0.013),while the vegetation is decreasing 0.11% every year from 10°N to 10° S( R~2= 0.54,P 0.004). For different continents,the vegetation in South America is decreasing 0.16% every year( R~2= 0.78,P 0.0001) and it is increasing 0.05% every year in Asia( R~2= 0.28,P 0.072) and 0.25% every year in Oceania( R~2= 0.24,P 0.1). The analysis of global vegetation in different seasons indicates that spatial distribution of global temperature and water vapor will affect the spatial distribution of vegetation,in turn,the spatial distribution of vegetation will also regulate the global temperature and water vapor spatial distribution at large scale. The growth and distribution of vegetation are mainly caused by the orbit of the celestial bodies,and a big data model based on gravitational-magmatic change with the solar or the galactic system as its center is proposed to be built for analyzing how the earth's orbit position in the solar and galaxy system affects spatial-temporal variations of global vegetation and temperature at large scale. These findings promise a holistic understanding of the global climate change and potential underlying mechanisms.     

The epipharyngeal sensilla of the damselfly Ischnura elegans (Odonata,Coenagrionidae)

The knowledge on Odonata adult mouthparts sensilla is scanty and, notwithstanding the epipharynx in the labrum is considered an organ of taste, no ultrastructural investigation has been performed so far on this structure in Odonata. The labrum of the adult of the damselfly Ischnura elegans (Odonata, Coenagrionidae) shows on its ventral side the epipharynx with sensilla represented by articulated hairs and by small pegs located at the apex of slightly raised domes. Under scanning and transmission electron microscope, the articulated hairs, with a well developed socket and tubular body, have the typical structure of bristles, the most common type of insect mechanoreceptors, usually responding to direct touch; the pegs, showing an apical pore together with a variable number of sensory neurons (from two to five), the outer dendritic segments of which show a dendrite sheath stopping along their length, have features typical of contact chemoreceptors.     

Vegetation effects on mean daily maximum and minimum surface air temperatures over China

Changes in the daily maximum (Tmax) and minimum (Tmin) surface air temperatures and the associated temperature extremes have severe consequences on human society and the natural environment. In this study, we assess vegetation effects on mean Tmax and Tmin over China by computing a vegetation feedback parameter using the satellite-sensed Normalized Difference Vegetation Index (NDVI) and observed temperatures for the period 1982–2002. In all seasons, vegetation exerts a much stronger forcing on Tmax than on Tmin, and thus has a substantial effect on the diurnal temperature range (DTR) over China. Significant positive feedbacks on Tmax and the DTR occupy many areas of China with the feedback parameters exceeding 1°C (0.1 NDVI)–1, while significant negative effects only appear over the summertime climatic and ecological transition zone of northern China and some other isolated areas. Also, the vegetation feedbacks are found to vary with season. In areas where significant feedbacks occur, vegetation contributes to typically 10%–30% of the total variances in Tmax, Tmin, and the DTR. These findings suggest that vegetation memory offers the potential for improving monthly-to-seasonal forecasting of Tmax and Tmin, and the associated temperature extremes over China. Meanwhile, the limitations and uncertainties of the study should be recognized.     

九寨沟自然保护区种子植物区系组成分析

九寨沟种子植物(按恩格勒系统)已鉴定的植物有88科299属744种,其中裸子植物4科10属27种,被子植物84科289属717种.从生长型来看,乔木81种,灌木141种,藤木37种,草本485种.属的系数41.7.区系分区属泛北极植物区,中国-喜马拉雅森林植物亚区,横断山脉地区.属分布区类型温带215属,占83.65%;热带分布27属,占10.51%.地中海成分8属,占3.12%;全世界分布42属.国家重点保护的珍稀濒危植物7种.植被组成中以冷杉、云杉、松等属的植物为优势种,阔叶树的优势种是杨柳科、桦木科、椴树科等.主要灌木有茶藨子、蔷薇、枸子、悬钧子、花揪、忍冬、杜鹃等植物.草本以菊科、禾本科、莎草科、毛茛科等植物为主.     

大别—桐柏山区植被分类初探

本文提出大别—桐柏山区自然植被分类的依据、原则和分类系统的单位及命名方法。根据野外考察资料分析,初步拟定了大别—桐柏山区自然植被分类系统方案,将其分为针叶林、阔叶林、竹林、灌丛植被、草丛植被、沼泽植被和水生植被7个植被型,在植被型下再分17个群系组和124个群系。     

历史时期华北平原的植被变迁

全新世中期由于全球处于冰后期的气候温暖期，所以我国华北平原北部分布着含有亚热带植物种属的暖温带落叶阔叶林，而该平原中南部则分布着北亚热带落叶阔叶与常绿阔叶混交林．到全新世晚期，即我国自西周以来的近三千年时期中，由于全球气候变得较前干冷，整个华北平原均变为暖温带落叶阔叶林区；随着人为活动的不断增强，人工栽培植被分布范围几经扩缩后，终于成为这一平原植被的主体，自然植被则几近消失．     

安徽省鹞落坪自然保护区的植被类型及其分布

鹞落坪自然保护区地处大别山腹地主峰分水岭的主段，植物种类丰富，计有野生种子植物１２９８种，５７２属、１４１科。植物区系起源古老、特有现象明显。区系成分以温带为主，兼为温带和热带，亚热带的双重性质。植被类型多样，该区自然植被主要有５个植被型。８个植被亚型，２４个群系。     

洞庭湖区水生药用动物资源调查初报

报道洞庭湖区水生药用动物４５科８３属１０５种，并对其特点进行了分析，探讨了当前存在的若干利用问题，同时针对其现状提出了有关的开发对策。