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1.
利用热扩散式液流探针,连续观测天目山古柳杉生长季树干液流速率,同步测定环境因子,测定柳杉液流昼夜变化、晴雨天气液流通量及不同月份的日均液流量变化特征,分析树干液流与环境因子的响应关系。结果表明:(1)柳杉树干液流量日变化幅度显著,日最大值和最小值分别为194.0 kg/d和5.4 kg/d;(2)晴天树干液流变化幅度比雨天要大,不同月份日均液流量最高为6月(66.85 kg),最低为8月(46.12 kg);(3)柳杉树干液流与空气温度、辐射强度呈极显著正相关,与空气湿度呈负相关。  相似文献   

2.
目的 探讨不同径级急尖长苞冷杉个体蒸腾耗水规律,并分析其与主要气象因子的相关性,为明确西藏亚高山区林木生长规律提供重要参考。方法 应用树干液流测定系统在西藏色季拉山天然急尖长苞冷杉林内对8株不同径级急尖长苞冷杉个体进行蒸腾耗水的连续测定,并同步监测5个气象因子。结果 急尖长苞冷杉树干液流速率日变化为单峰曲线,7月、8月和9月8株样木平均液流速率分别为137.09、142.71和184.43 g/h,日活动时间为10:00—22:00,其峰值出现在16:00左右。急尖长苞冷杉树干蒸腾耗水速率与大气温度和光合有效辐射呈极显著正相关关系,与饱和水汽压差显著正相关,与大气湿度极显著负相关,与风速无关;蒸腾耗水与各因子相关系数绝对值排序为大气湿度>大气温度>光合有效辐射>饱和水汽压差。急尖长苞冷杉边材面积和日蒸腾耗水量均与胸径呈极显著的二次曲线关系,决定系数分别为0.999和0.937。结论 急尖长苞冷杉蒸腾耗水日变化呈“N”形变化,受大气温湿度和光合有效辐射等环境因子影响显著;随胸径增加,单株日蒸腾耗水量迅速升高。  相似文献   

3.
影响丝栗栲树干液流速度的环境因子分析   总被引:2,自引:0,他引:2  
利用热技术对江西大岗山国家级生态站区常绿阔叶林优势树种之一的丝栗栲树干液流进行了研究,并用梯度自动气象站对气象和土壤等环境因子开展了同步监测。结果表明:丝栗栲树干液流速度表现为双峰曲线;影响丝栗栲树干液流的主要环境因子为风速、10cm土壤温度、20m大气温度、20m空气相对湿度和100cm土壤水势;其次是太阳辐射强度、光合有效辐射和饱和水汽压。即土壤温度和大气温度是影响树干液流速度的主导因子。  相似文献   

4.
研究不同方位间树干液流速率的差异及树干液流速率变化对环境因子的响应,有利于对桉树蒸腾耗水、水分利用效率的定量估算.以海南儋州林场尾叶桉人工林为研究对象,运用热扩散探针对尾叶桉树干东、南、西、北不同方位的液流进行连续监测研究.结果表明:(1)不同天气条件下的尾叶桉树干液流速率变化趋势不同,晴天液流变化呈单峰型曲线,阴天和雨天呈多峰型或无峰型曲线;尾叶桉树干不同方位之间的液流速率日变化趋势相似,但液流启动与到达峰值的时间存在时滞,其中东、南方位液流启动与到达峰值时间分别较西、北方位要早20 min左右.(2)不同天气条件下,尾叶桉树干不同方位之间的液流速率均呈极显著正相关(p0.01),且存在显著(p0.05)或极显著(p0.01)差异,晴天、阴天和雨天的东、南、西、北4个方位的树干液流速率最低值较最高值分别低13.7%、34.4%和9.4%.(3)晴天、阴天、雨天的光合有效辐射、大气温度、相对湿度和土壤水分等环境因子对树干液流速率变化的贡献不同;晴天和阴天是光合有效辐射对树干液流速率影响最大,其次是相对湿度;雨天是相对湿度对树干液流速率影响最大,其次是光合有效辐射;气温与土壤水分对树干液流速率影响相对较小.该研究为海南桉树林分尺度蒸腾耗水准确测算和人工林生态效应评估提供了基础数据,为进行更大时空尺度的树干液流监测提供了方法参考.  相似文献   

5.
2012年2月—2013年1月,利用热扩散技术和ECH2O系统对南京东善桥林场的杉木(Cunninghamia lanceolata)树干液流速率及相关环境因子进行连续观测,研究分析了杉木液流速率的变化特征。结果显示:不同季节不同天气的杉木液流速率日变化表现出明显的昼夜变化规律,变化曲线表现为单峰曲线。夏季的液流速率最高,峰值为1.45~3.49 kg/h,其次是秋季(0.55~1.91 kg/h),春季的液流速率峰值为0.71~1.44 kg/h,冬季液流速率最低,峰值为0.30~0.85 kg/h。降雨雨量越大,雨后液流速率开始的时间越早,峰值越高,影响持续的时间越长。冬季,降雨开始后液流速率会迅速升高,雨后就会很快降低,而夏季,液流速率会在雨后的白天表现出明显升高,在次日之后会再次降低到原来水平。影响杉木液流速率的主导环境因子存在季节性差异,各相关性系数分别为:春季饱和水气压差(0.884),夏季空气相对湿度(-0.882),秋季饱和水气压差(0.798),冬季林外太阳辐射(0.621),土壤温度是影响杉木日均液流速率的重要环境因子。  相似文献   

6.
 应用Granier热扩散技术对内蒙古浑善达克沙地榆(Ulmus pumila var. sabulosa)疏林林分进行树干液流通量研究.选择该区占林分80%以上林木的3种胸径级(小径级,15—25cm;中等径级,25—35cm;大径级,>35cm)榆树,使用Granier探针进行每隔15min的树干液流测定,同步测定各林分环境因子.林分中不同胸径级榆树树干液流通量特征表现为:树干液流密度峰值大径级树>中等径级树>小径级树,且差异明显;大径级树由于林龄较大,液流密度曲线变化平缓,没有明显的峰值,呈弧形曲线;液流密度随季节推移在生长季中液流密度均值逐渐减小,在生长季末期(10月)基本处于微弱波动状态.液流通量最大月平均值一般出现在6—8月,不同径级树月液流通量变化差异较大.对样木的日液流通量比较发现,胸径对液流有显著影响.对不同胸径树木各树种影响较大的环境因子为饱和水汽压差(VPD),光合有效辐射(PAR),气温(Ta);在不同生长季节,对不同胸径类型树木起主要作用的环境因子也不尽相同,但是PAR和VPD是其中起主要作用的两个因子.  相似文献   

7.
【目的】揭示乌兰布和沙漠1979年人工种植梭梭水分利用过程,以期为当地梭梭林的经营管理提供理论参考。【方法】利用PS-TDP8树木茎流监测系统和自动气象站对乌兰布和沙漠梭梭的液流变化及其周围的气象因子进行观测。【结果】梭梭晴天茎干液流日变化呈“单峰型”。春、夏、秋季梭梭茎干液流连日变化趋势一致,白天液流速率高于夜间,且夜间液流速率变化幅度小。5、7、9月时茎干直径12.5 cm的梭梭液流启动时间均早于直径8.95 cm的梭梭,平均液流速率也较高。茎干直径12.5 cm的梭梭在5、7、9月的液流峰值分别为2.90、4.18、3.15 cm/h,液流日累积量分别为12.29、14.23、9.44 L;茎干直径8.95 cm的梭梭同时期液流峰值分别为1.06、1.20、1.07 cm/h,液流日累积量分别为2.84、3.68、3.10 L;同一茎干直径梭梭在7月的液流日累积量最大。梭梭液流日变化中,晴天为“单峰型”,雨天呈“双峰型”;雨天液流峰值及夜间液流均低于晴天。夏季茎干液流启动时间最早,峰值出现时间最早,峰值最大;春季液流启动时间最晚,峰值出现时间最晚,峰值最小。春、夏、秋季梭梭夜间均存在微弱液流。【结论】影响梭梭液流速率的气象因子中,春季主要为太阳总辐射、空气温度、风速,夏季主要为太阳总辐射、空气相对湿度、风速,秋季主要为太阳总辐射、空气温度。  相似文献   

8.
用热扩散式树干径流计(TDP)和环境自动检测系统对黄河三角洲滨海盐碱地刺槐(Robinia pseudoacacia)-绒毛白蜡(Fraxinus velutina)混交林、刺槐纯林中刺槐单株的树干液流速率和环境因子进行了连续观测,结果表明:混交林中的刺槐单株树干液流日变化呈窄峰型曲线,纯林中的呈宽峰型曲线,二者峰值均出现在10:30左右,无明显启动时间,也没有明显的停止界限;混交林中刺槐单株的液流峰值高于纯林;混交林中刺槐单株的日平均液流速率为纯林中的145%。混交林土壤表层(0~60cm)含水量大于纯林,含盐量小于纯林。多元逐步回归分析表明,影响混交林刺槐树干液流速率的主要因子是太阳辐射强度、大气相对湿度,影响纯林刺槐液流速率的因子依次为大气温度、太阳辐射强度。  相似文献   

9.
林木耗水的准确评价对于低耗水树种的选择及林分结构优化配置具有重要意义。利用热扩散式边材液流探针和自动气象站,对油松和侧柏的边材液流速率和空气温度等环境因子进行了为期一年的同步测定,分析了空气温度与边材液流间的滞后效应。研究结果表明:林冠上层空气温度与液流速率的相关性最为显著。液流启动要滞后于空气温度2h以上,液流峰值出现的时间一般要比空气温度早1~2 h,液流趋于停止的时间和空气温度相差不大。液流速率和空气温度之间存在明显的滞后效应,春、夏、秋季油松树干边材液流与空气温度变化的滞后时间分别为170 min、-60 min和0 min,侧柏边材液流相对于空气温度分别提前40 min、30 min和10 min。考虑液流相对于空气温度的"滞后效应"可提高液流速率的拟合精度,油松提高了42.9%~122.0%,侧柏提高了6.4%~14.6%。  相似文献   

10.
茂兰喀斯特原生林细叶青冈树干液流环境响应特征   总被引:1,自引:0,他引:1  
【目的】研究喀斯特森林细叶青冈树干流特征及其与环境因子的关系。【方法】基于热扩散技术的液流探针和Campbell自动气象站,测定了贵州茂兰地区2012年3月至2014年2月喀斯特原生细叶青冈林(Cyclobalanopsis gracilis)的树干液流和气温、降水等环境因子。分析液流速率在不同天气(晴天、阴天和雨天)、不同季节条件下的变化过程及特征,及其对环境因子的响应。【结果】整个观测期内,青冈日平均液流速率(5.78±0.19)g/(m2·s),不同天气日平均液流速率(g/(m2·s))依次为:晴天(10.35)>阴天(3.28)>雨天(3.16)。青冈日平均液流通量(3.37±0.11)kg/d,阴天和雨天日液流通量分别仅为晴天(6.03 kg/d)的31.7%和30.6%。各季节的日平均液流速率(g/(m2·s))表现为:夏季(8.28±0.38)>秋季(6.75±0.38)>春季(6.11±0.34)>冬季(1.91±0.15)。空气相对湿度(RH)与液流速率呈负相关,光照、饱和水汽压差(VPD)、气温(Ta)、土壤含水量等与液流速率呈正相关。【结论】在不同天气条件或季节,各环境因子对液流速率的影响程度不同。光照、VPD、RH、Ta是影响细叶青冈液流速率最主要的因子,土壤轻度干旱对细叶青冈液流速率没有影响。  相似文献   

11.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

12.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

15.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

16.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

17.
18.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

19.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

20.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

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