呼和浩特市近61年气温年际变化特征分析

利用呼和浩特市近61年平均气温序列资料,通过描述统计、趋势分析、Mann-Kemdall突变检验方法对呼和浩特市气温变化特征进行分析。结果表明,1954年以来,呼和浩特市年平均气温总体呈上升趋势,变化速度约为0.5℃/10 a,尤其进入20世纪90年代增温趋势明显加快;冬季升温对全年升温贡献最大;20世纪80年代中期气温发生了由冷向暖的突变。     

河北省武邑县35年来气温变化特征分析

利用武邑县1972～2006年气温资料,分析了武邑县近35年气温变化特征,结果表明:近35年来武邑县平均气温显著上升,其中冬季增暖幅度最大,夏季变化不明显,而且20世纪70年代最冷,80年代开始升温,90年代至今最暖.     

我国东北地区冬季气温时空变化特征分布的研究

以东北地区(包括黑龙江省、吉林省、辽宁省、内蒙古地区)为研究区域,1960年~2015年138个气象站点的月平均气温数据为数据源,采用网格面积加权法,获得这四个省、地区冬季平均温度时间序列,运用反距离加权法、样条法和克里金法插值并进行验证,获得东北地区冬季气温空间分布图。将1960~2015年数据按照年际、年代际进行划分,分析随时间变化东北地区气温的趋势图计算方差。研究结果表明:56年来,东北地区的平均气温大致以0.0481℃/年的幅度呈上升趋势,东北暖指数明显增加,暖夜日平均增加趋势为1.4d/10a,北区达到1.9d/10a,南区相对较小为1.2d/10a,故北部相对南部升温快、幅度大。根据气温的时间变化折线图可知,1980~1984年为气温最低年际,2004~2008为气温最高年际,60~70年代是增温过程,70~80年代是降温过程,80年代之后为增温过程,且增温现象明显。根据增温情况,大致以1991年为界,60年代至90年代为偏冷期,90年代之后是偏暖期。     

内蒙古西中东部代表站近50年气温变化特征对比分析

选取代表内蒙古西、中、东部的阿拉善左旗、呼和浩特、海拉尔3个站1961-2010年气温资料,用线性回归、方差分析、对比分析等统计方法分析年平均气温、年平均最高气温、年平均最低气温的年代际变化特征以及季节性变化规律,总结代表站温度变化的异同点,并得出近50年来各代表站的平均气温均以每10年0.57℃的幅度增加的结论。     

河北雄安新区近50a气温变化特征

为科学掌握雄安新区气候特征,为雄安新区建设提供基础数据保障,基于雄安新区区域内3个国家气象观测站的多年气象观测资料,采用线性回归分析、Mann-Kendall突变检验和小波分析等统计分析方法,系统分析了雄安新区近50 a气温的时间序列变化、突变现象、周期变化特征。结果表明:(1)雄安新区年平均气温呈显著波动升高趋势,气候倾向率为0.265℃/10 a,略高于全国平均气温变化速率;不同季节平均气温升温对年平均气温的贡献为春季冬季夏季秋季。(2)平均最高、最低气温均呈波动升高趋势,气候倾向率分别为0.238℃/10 a、0.422℃/10 a,平均最低气温升温趋势显著;平均最高气温不同季节的升温幅度为春季夏季冬季秋季,平均最低气温的升温幅度为春季冬季夏季秋季。(3)年、冬季、春季和夏季平均气温增暖趋势均存在突变现象,年平均最高气温自90年代开始呈现持续增暖趋势,突变点为1990年。年平均最低气温及各季节的平均最高气温、平均最低气温的增温趋势不存在突变现象。(4)年平均气温存在8 a、13 a、19 a周期变化,年平均最高气温存在8 a、11 a、19 a周期震荡,年平均最低气温存在13 a、19～20 a周期震荡。雄安新区气温研究结果对全面认识该区域气候特征及变化趋势系具有一定的现实意义。     

气候变化对昆明园林环境的影响

通过对昆明1951～2007年气候资料的分析得知,近60年来,昆明平均气温变暖,最为突出的是近十余年增温幅度高达0.4℃/10a,同时年较差缩小,体现在最低气温的显著升高,昆明的冬天正在变暖;伴随气温变暖,降水量却显著减少,过去14年中降水量减少幅度约为18.05mm/a;相对湿度与降水量呈正相关,这导致昆明将更加缺水和干燥;日照时数的下降率约107h/10a,主要原因之一就是昆明快速城市化过程。昆明城市的四个重要气候指标近60年来的变化呈现一高三低态势,应对其年平均气温的升高、降水量减少以及城市整体气候变化提出园林建设对策。     

大兴安岭地区降水量和气温变化趋势分析

以大兴安岭地区为研究区域,利用大兴安岭地区5个气象站点1961-2014年的月气温和月降水量的资料,使用R软件与Excel软件对所得数据进行探索与处理,获得1961-2014年大兴安岭地区的降水量及气温的变化情况,并对其进行验证,研究该地区1961-2014年降水量及气温的变化趋势。研究结果表明,1961-2014年大兴安岭地区平均气温在-22.27~9.67℃,年平均气温波动上升,气温倾向率为0.88℃/10 a,明显高于全国平均增温速率0.22℃/10 a。其中冬季增温速率最大,为0.605 7℃/10 a。1961-2014年大兴安岭地区平均降水量在17.52~44.82mm,年平均降水量波动上升,降水量倾向率为1.00 mm/10 a,与全国年均降水量略微下降的趋势相反。夏季降水增长速率最大,为2.51 mm/10 a。     

阿城区近50年旱涝、霜冻变化特征分析

分析了哈尔滨市阿城区近50年旱涝气象灾害的基本特征,变化情况,霜冻的初、终霜日数变化及无霜期的变化,从而得出了近50年该地区极端天气现象的变化规律:(1)上世纪80年代末期以来春旱频率升高;春季异常多水年份主要发生在上世纪60年代末到七十年代末,特别是七十年代的10年间发生了3次;夏季异常少水年以20世纪末期以来最多,出现了6次。(2)自1961年以来,阿城的霜冻初日以0.478/10年的趋势增长,随着气候增暖的趋势变化缓慢后延,主要受秋季平均气温、秋季平均最高和平均最低气温上升变化的影响;霜冻终日以0.829/10年的趋势增长;该区的年平均无霜期为143天,无霜期呈现缓慢减少的趋势,变率为-0.1007。     

鸡东气象台站新旧址气象观测资料差异对比分析

鸡东县旧的气象观测场由于受到周边环境变化的影响与新址的气象要素有一定的差异,为了检验新旧址的气象观测资料是否有明显的差异,对鸡东气象站新旧址的气象观测数据差异进行对比分析。利用2011-2012年新旧址平行观测数据的平均气温、最高气温、最低气温、降水量、相对湿度、风速等数据的对比,进行差值的平均值和标准差的计算,以及降水量累计相对差值和风向相符率的计算,并对新旧址观测数据差异进行显著性检验。结果发现:新旧址的气温年值差异很小,但各月差值正负相间;新址的风速大于旧址,年平均风速相差0.4m/s,4月、5月相差明显;旧址的相对湿度略小于新址3%;5~9月降水总体相差不大。新旧址的平均气温和相对湿度一致性较好,观测数据较稳定,最低气温和风速一致性最差,风向相符率仅为29%左右。显著性检验结果表明,新旧址的气温和相对湿度平均值差异不显著,7、8月降水量和1、4、12月平均风速差异较显著。     

1990～2000年昆明市景观格局变化研究

利用昆明市1990年和2000年2期遥感影像解译数据,结合GIS和统计软件,对昆明市10年间景观格局变化特征进行分析.结果表明:1990~2000年昆明市各景观要素之间变化显著,景观要素面积增加的有建设用地、城镇居住用地、草地和旱地,增加最大的是城镇居住用地,增加了10.92 km2,比1990年增加了5.5%;面积减少的有水田、林地和湿地;各景观要素之间相互转化,其主要特征:①城区外水田、旱地等生产用地向城市居住用地和建设用地转移,其中水田在10年间向城镇居住用地转化了1 134.25 hm2,占1990年水田的5.81%;②林地、旱地和草地之间相互转化,林地向草地转化的面积最大,为1 694.19 hm2.对昆明市景观格局分析结果为,随着城市化的快速发展,城市居住用地景观破碎度减少,斑块形状趋于规则化;林地、草地和旱地景观破碎度增大、斑块形状复杂化;景观总体格局趋向于多样化、复杂化.     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.