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1.
[目的]鼎湖山自然保护区地处我国热带与亚热带交汇处,在全球气候变化研究中占居独特而重要的地位。全球气候变化背景下,降水格局变化将影响区域森林生态系统内部小气候。降水是森林生态系统水循环过程中重要的输入因子,研究鼎湖山大气降水氢氧稳定同位素特征和水汽来源,对探讨该地区森林生态系统水循环过程、森林群落演替动态及区域水资源合理利用和管理等具有重要理论和实践意义。[方法]运用氢氧稳定同位素技术,研究和分析鼎湖山2013年8月~2014年8月13个月108个大气降水的氢氧同位素组成及与环境因子的关系,并运用HYSPLIT模型后向轨迹法模拟大气降水气团传输途径和过程,判定该地区水汽来源。[结果]鼎湖山大气降水线方程为:δD=7.863δ~(18)O+9.664(R~2=0.975,n=108);δD和δ~(18)O值范围分别为-118.26‰~-15.52‰,-16.05‰~2.25‰,均值分别为-34.44‰,-5.58‰;大气降水过量氘(d)显示出冬高夏低的季节变化;鼎湖山降水量效应显著,温度效应不显著。[结论]鼎湖山大气降水氢氧稳定同位素特征存在明显的季节性变化;干季的气团主要来自局地蒸发、中国华北地区及寒冷干燥的亚欧大陆,湿季的气团主要来自温暖湿润的西太平洋、南海和印度洋。 相似文献
2.
小五台山自然保护区气候特征初步分析 总被引：1，自引：1，他引：0
利用小五台山自然保护区山涧口沟山神庙滩自动气象站3a的观测资料,分析了该地区温度、湿度、雨量、大气压强和辐射等气象要素的季节变化特征。结果表明:该区具有气温日较差和年较差较大的气候特点,年均气温为7.87℃,气温季节变化中降温率高于升温率;年降水总量高,达728.48mm;平均相对湿度季节变化过程分布与年变化基本与气温的季节变化一致,与降水量分布一致;大气压强变化分布主要受季节变化过程影响,与相对湿度呈现反向关系;月均总辐射强度夏季明显高于冬季,5月出现最大值,与大气所含水汽、天空云量、下垫面性质等因素有关。 相似文献
3.
为了评估森林的生态服务,提高森林生态效益认识,指导天水市生态旅游建设与管理,实现关中—天水经济区发展规划和天水市森林资源资产的价值,通过分层随机抽样,对SO2、NOx、大气总悬浮微粒进行实地调查,利用地统计学技术得出天水市生态旅游区SO2、NOx、大气总悬浮微粒分布的一些定性、定量结论:①仙人崖、马跑泉公园空气质量处于一级;②净土寺NOx含量在三级,其余都为一级;③仙人崖日大气悬浮物含量最高,其次是马跑泉公园、玉泉观和南郭寺,净土寺和麦积山植物园大气悬浮物含量低,其含量都很高,超过三级标准。并得出SO2、NOx和总悬浮颗粒物在空间上不相关,其变化不是由森林覆盖率、林种类型、温度、时间、大气环境等结构性因素引起的,而是由人为因素引起的。 相似文献
4.
甲烷(CH_4)是重要的增温气体,在气候变化敏感的寒温带森林地区,土壤CH_4排放量的估算和排放机制存在很大的不确定性。本文以研究寒温带森林沼泽湿地CH_4浓度变化特征为主要目的进行研究。采用LGR快速甲烷分析仪(FMA)定位连续测定大兴安岭天然林沼泽湿地近地表CH_4浓度及其水汽浓度,分析了森林沼泽湿地CH_4浓度的变化特征及其与水汽浓度的关系。结果表明:测定期内,寒温带森林沼泽湿地近地表CH_4浓度日变化规律呈现明显的单峰日变化特征,日峰值出现时间12∶00左右;CH_4浓度月变化规律呈现先减少后增大再下降的趋势。水汽浓度日变化规律呈双峰的变化特征,峰值呈现时间段分别为6∶00-12∶00之间、16∶00-19∶00之间。水汽浓度的月变化规律,呈现先增大后减少的趋势。沼泽湿地CH_4浓度随着大气的水汽浓度升高而降低,呈现负相关关系,相关关系为:y=-0.00001x+2.0258(R~2=0.7257,P0.05)。 相似文献
5.
[目的]研究汤浦水库湿地森林区大气降水中的氢氧稳定同位素特征及水汽来源,为定量阐明降水在会稽山-汤浦水库过渡带湿地森林生态系统水文循环过程中的分配和转化规律及绍兴饮水源水质的保护和管理提供科学依据。[方法]采集2015年7月至2017年7月2个水文年166个大气降水样品,利用稳定同位素技术,分析降水氢氧同位素组成,并阐明其与环境因子(温度、降水量)的关系;采用HYSPLIT模型中的后向轨迹法模拟追踪该地区降水气团的运输过程,判断气团的运移轨迹和水汽来源。[结果]汤浦水库湿地森林区大气降水δD与δ18O关系式:δD=8.36δ18O+14.92(R2=0.966,n=166,P0.01);大气降水中的δD值变化范围-147.52‰~2.71‰,均值-38.13‰±27.61‰;δ18O值变化范围-19.05‰-1.17‰,均值-6.34‰±3.24‰,且不同季节的大气降水氢氧同位素值明显不同;过量氘(d值)(12.61‰)高于全球d值的均值(10‰),呈现干季高湿季低的现象;大气降水δD、δ18O温度效应不显著,但降水量效应显著。[结论]汤浦水库湿地森林区大气降水线与全球及我国大气降水线有差异,降水中的δD、δ18O值有明显的季节变化;根据大气降水中的δD、δ18O值、d值及后向轨迹法模拟结果得出,汤浦水库湿地森林区干季(10月—次年4月)大气降水的水汽主要来源于内陆地区,湿季(5月—9月)的水汽主要来源于西太平洋和印度洋。 相似文献
6.
森林生态系统是生物圈生态系统的主体,森林的破坏,必然使生态系统的能量交换和物质循环失调,在太阳辐射、大气环流的作用下,便发生气候灾害,即人们常说的自然灾害。由于地理位置、地形地貌及森林植物的影响,各地的自然灾害是不相同的,灾害发生的层次和严重程度也不一样。合浦处于北热带季风区,气温高、常风大、雨量分布不均,干湿季明显;又位于北部湾畔, 相似文献
7.
《林业科学》2017,(12)
【目的】研究安庆地区大气降水氢氧同位素特征、水汽来源和运移过程,为揭示安徽沿江地区森林生态系统水循环过程对气候变化的响应机制提供科学依据。【方法】运用氢氧稳定同位素技术测定安庆地区2015年6月至2017年6月(25个月)共155个大气降水样品的氢氧同位素组成,得出大气降水线方程;建立安庆地区大气降水中氢氧稳定同位素值与气温、日降水量相关关系,分析影响该地区降水中氢氧同位素组成变化的主要因素;计算大气降水过量氘值用以示踪水汽来源,并运用HYSPLIT气团轨迹模型进一步验证水汽来源结果的可靠性。【结果】安庆地区大气降水氢同位素(δD)与氧同位素(δ~(18)O)关系为δD=(8.08±0.06)δ~(18)O+(10.84±0.48)(R~2=0.99,n=154);降水δD和δ~(18)O均与气温显著负相关(P0.01),与日降水量无显著相关关系;大气降水过量氘值接近全球平均值(10‰),表明该地区水汽主要受海洋季风的影响;HYSPLIT气团轨迹模型结果进一步表明,安庆地区春季的水汽主要来源于我国华北、华南地区的大陆性气团及局地蒸发水汽,降雨量较大时也会受到太平洋东南季风的影响,而夏、秋、冬季的水汽主要受我国南海气团、印度洋西南季风及太平洋东南季风的影响。【结论】安庆地区大气降水由海洋水汽主导;不同于经典大气降水稳定同位素理论中的温度效应,安庆地区大气降水稳定同位素呈现显著的反温度效应,这可能与其所处纬度有关,表明不同地理位置会对大气降水的氢氧稳定同位素组成产生影响,今后研究中需加以区分。 相似文献
8.
在未来的数十年里,单环境变化或工业技术进步所引起的影响不可能比大气中二氧化碳含量的增加对森林的影响更为普遍。二氧化碳的增加对整个世界及各地气候的变化是一个关键性的因素,它将直接影响树木的生长发育。因为,二氧化碳含量的增加会影响森林的生态关系和林木的生长条件。本文为对二氧化碳增加效应的科学性与变异性作一评论,并对此而引起的林业七项挑战作一概述。 相似文献
9.
选择昆明市主城区及周边具有代表性的居民密集区域和森林植被分布区域作为监测对象,对同一天气环境、不同时段的空气负氧离子浓度进行测定,探讨不同区域环境下空气负氧离子浓度变化特征。结果表明,不同区域环境空气负氧离子含量差异显著,森林植被好的区域空气负氧离子浓度高,空气质量好;在不同时段,上午空气负氧离子浓度最高,中午和下午负氧离子浓度低;在同一天内,森林植被好的区域空气负氧离子浓度日变化大,居民密集区空气负氧离子浓度日变化较小;空气负氧离子浓度与森林植被呈正相关关系,森林植被越好,负氧离子浓度越高,空气越清新。 相似文献
10.
<正>气象条件与森林火灾的关系非常密切。我们生活在地球的大气圈内,大气垂直向上分成对流层、平流层、中间层(中层)、暖层(散逸层)。对流层是地球大气中最低的一层,其底界是地面,占整个大气厚度的1%,集中了整个大气3/4的质量和几乎全部的水汽。云、雾、雨等主要天气现象都出现在此层, 相似文献
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13.
Tanaka Kenzo Reiji Yoneda Mohamad Alias Azani Nik Muhamad Majid 《Journal of Forest Research》2008,13(2):137-142
Leaf hairs may assist in maintaining high leaf water use efficiency in tropical secondary forest tree species. We compared
leaf temperature, transpiration, photosynthesis and water use efficiency between hairy and depilated leaves in Mallotus macrostachyus (Euphorbiaceae), to determine the role of leaf hair in leaf water use efficiency (WUE) in tropical degraded secondary forest
in Malaysia. Measurements were made on five mature individuals growing in sun-exposed conditions and five in shaded conditions.
The hair dry weight per unit leaf area was significantly greater in sun leaves than in shade leaves. The transpiration rate
(Trmax) of depilated leaves in sun-exposed conditions was slightly higher than in hairy leaves in both morning and afternoon measurements.
In contrast, Trmax in the shade leaves was almost identical in hairy and depilated leaves. Leaf stomatal conductance (g
s) in the morning showed almost the same value among leaf types and light conditions. In the afternoon, g
s slightly decreased from the morning values in both sun and shade conditions. In the morning, the leaf water use efficiency
(A
max/Trmax) in both conditions did not differ significantly between hairy and depilated leaves. However, in the afternoon, WUE in the
depilated leaves was significantly lower than in hairy leaves in sun-exposed conditions. These observations suggest that leaf
hairs in M. macrostachyus contribute to the high leaf water use efficiency in drought conditions, such as high vapor pressure deficit experienced at
midday in degraded tropical secondary forests. 相似文献
14.
We compared leaf gas exchange and water potential among the dominant tree species and major size classes of trees in an upland, pine-oak forest in northern Arizona. The study included old-growth Gambel oak (Quercus gambelii Nutt.), and sapling, pole, and old-growth ponderosa pines (Pinus ponderosa var. scopulorum Dougl. ex Laws.). Old-growth oak had higher predawn leaf water potential (Psi(leaf)) than old-growth pine, indicating greater avoidance of soil water stress by oak. Old-growth oak had higher stomatal conductance (G(w)), net photosynthetic rate (P(n)), and leaf nitrogen concentration, and lower daytime Psi(leaf) than old-growth pine. Stomatal closure started at a daytime Psi(leaf) of about -1.9 MPa for pine, whereas old-growth oak showed no obvious reduction in G(w) at Psi(leaf) values greater than -2.5 MPa. In ponderosa pine, P(n) and G(w) were highly sensitive to seasonal and diurnal variations in vapor pressure deficit (VPD), with similar sensitivity for sapling, pole, and old-growth trees. In contrast, P(n) and G(w) were less sensitive to VPD in Gambel oak than in ponderosa pine, suggesting greater tolerance of oak to atmospheric water stress. Compared with sapling pine, old-growth pine had lower morning and afternoon P(n) and G(w), predawn Psi(leaf), daytime Psi(leaf), and soil-to-leaf hydraulic conductance (K(l)), and higher foliar nitrogen concentration. Pole pine values were intermediate between sapling and old-growth pine values for morning G(w) and daytime Psi(leaf), similar to sapling pine for predawn Psi(leaf), and similar to old-growth pine for morning and afternoon P(n), afternoon G(w), K(l), and foliar nitrogen concentration. For the pines, low predawn Psi(leaf), daytime Psi(leaf), and K(l) were associated with low P(n) and G(w). Our data suggest that hydraulic limitations are important in reducing P(n) in old-growth ponderosa pine in northern Arizona, and indicate greater avoidance of soil water stress and greater tolerance of atmospheric water stress by old-growth Gambel oak than by old-growth ponderosa pine. 相似文献
15.
Experimental investigations in an atmospheric boundary layer wind tunnel were carried out in order to study both the influence
of the windward edge structure and the stand density on the flow characteristics near the canopy top of forest edges. For
the edge structure investigation, two different types of forest edges were used. The taper angle was varied three times for
both edge types, and all tapered edges were combined with both dense and sparse forest stands. In addition, a configuration
was investigated where the airflow in the trunk space of the dense forest was blocked completely by an impermeable wall. In
order to study the influence of stand density, forest stands were varied three times by removing whole rows of the originally
dense model forest. The measurements show that a forest edge induces strong disturbances in the flow field at the near-edge
region leading to an increased momentum transfer and to an increased wind loading on trees. The region of significant disturbances
extends to a distance of about eight tree heights. Both edge density and taper angle determine the amount of volume influx
through the edge, which seems to be primarily responsible for the flow field properties near the canopy top. It was found
that for sparse forest stands, sloping tapered edges reduce the wind velocities nearest to the canopy. It could also be shown
that the positive skewness of the near-canopy longitudinal velocity distribution is diminished with decreasing taper angle
indicating that higher wind velocity fluctuations are reduced. 相似文献
16.
《Scandinavian Journal of Forest Research》2012,27(4):360-373
Abstract Forest carbon sinks significantly contribute to mitigation of atmospheric concentrations of carbon dioxide. Thus, estimating forest carbon is becoming important to develop policies for mitigating climate change and trading carbon credits. However, a great challenge is how to quantify uncertainties in estimation of forest carbon. This study investigated uncertainties of mapping aboveground forest carbon due to location errors of sample plots for Lin-An County of China. National forest inventory plot data and Landsat TM images were combined using co-simulation algorithm. The findings show that randomly perturbing plot locations within 10 distance intervals statistically did not result in biased population mean predictions of aboveground forest carbon at a significant level of 0.05, but increased root mean square errors of the maps. The perturbations weakened spatial autocorrelation of aboveground forest carbon and its correlation with spectral variables. The perturbed distances of 800 m or less did not obviously change the spatial distribution of predicted values. However, when the perturbed distances were 1600 m or larger, the correlation coefficients of the predicted values from the perturbed locations with those from the true plot locations statistically did not significantly differ from zero at a level of 0.05 and the spatial distributions became random. 相似文献
17.
森林与生态环境(上) 总被引：4，自引：0，他引：4
本文介绍了目前国际社会注目的10个生态环境问题:温室效应加剧、生物多样性锐减、大气臭氧层损耗、水资源危机、水土流失、沙漠化扩大、土壤退化、噪声污染、大气污染和酸沉降、海洋污染,简述了生态环境恶化带来的严重后果,并重点阐述了森林与温室效应、生物多样性保护、大气臭氧层损耗、水资源危机的关系。 相似文献
18.
福州旗山常绿阔叶混交林空气含氧量日变化特征 总被引：1，自引：0，他引：1
运用PTM400氧气分析仪和气象测定仪对福州旗山森林公园中常绿阔叶混交林和停车场进行24小时连续同步观测,据此分析出2类观测点内空气含氧量的日动态变化规律以及常绿阔叶混交林中空气含氧量与气象因子之间的关系。结果显示:1)2类观测点内空气含氧量一天24小时的变化规律相似,呈抛物线形曲线变化,峰值都出现在下午15∶00,呈现出"昼高夜低"的变化规律;但在常绿阔叶混交林中,其各时段空气含氧量都比停车场高,且差异显著。2)常绿阔叶混交林空气氧气含量与空气温度呈极显著正相关,与光照强度呈显著相关,与空气湿度呈及显著负相关,与平均风速的相关性不显著。空气含氧量与气象因子的相关系数排序为空气温度空气湿度光照强度风速。 相似文献
19.
Shuhua Liu Haoyu Jiang Yi Deng Mingmin Ma Ying Pan Haimei Jiang Hongtao Lin Fuming Liang Heping Liu Jianhua Wang 《Frontiers of Forestry in China》2006,1(1):1-11
Based on the basic principles of the micrometeorology of atmospheric boundary layers and vegetation canopy, a numerical model
of the interaction between forest ecosystems and atmospheric boundary layers was developed. The model is used to simulate
the diurnal variations of heat balance in forest ecosystems, canopy temperatures, ground surface temperatures, as well as
the profiles of temporal and spatial distributions of potential temperatures, wind speeds, specific humidity, and turbulence
exchange coefficients. Our study indicates that the model can be applied to study the interaction between land surface processes
and atmospheric boundary layers over various underlying surfaces and their regional climate effects. This paper will establish
a solid foundation to investigations on the coupling of climate models and the biosphere.
Translated from Chinese Journal of Applied Ecology, 2004, 15(11) (in Chinese) 相似文献
20.
Kenichi Daikoku Shigeaki Hattori Aiko Deguchi Yuji Fujita Hotaek Park Kazuho Matsumoto 《Journal of Forest Research》2007,12(6):452-466
We explored the relationship between directional variation (changes in direction from a reference point) in vegetation and
wind profiles, and propose an empirical wind profile model that may reproduce the wind profile within the canopy (such as
secondary wind maximum) and reduce calculation loads. Based on the results of our observations in secondary broad-leaved forest,
we clarified the variation in secondary wind maximum and aerodynamic parameters in wind direction, and assessed the influence
of forest structural heterogeneity on the wind profile. Wind blew from specific directions depending on the time of day and
season, and secondary wind maxima were observed in particular wind directions. Outlier estimations of aerodynamic parameters
were determined for wind directions of 45°, 120–210°, and 300°, and these did not show a logarithmic distribution. Our proposed
model reproduced the wind profile within and above the canopy, closely resembling K-theory and closure models, and reduced
the required number of calculations and observations. The influence of forest structural heterogeneity was greatest in the
upper part of the canopy (9.14 m), and reproducibility of the wind profile was improved by 0.05 m/s (3.4% on average) by changing
the forest structural parameters of the model according to the wind direction. It was clear that forest structural heterogeneity
did not cause critical errors in estimation of the wind profile, even at our study site, which had complex forest structure. 相似文献