首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
中国北方云量的四季分布与降水   总被引:3,自引:1,他引:2  
利用中国35°N以北地区1960-2005年333个站逐日地面观测总云量、低云量、降水量资料,并依据相关文献进行区划,系统研究了中国北方地区46年云和降水的时空分布特征,讨论了总云量、低云量、降水的相互关系.结果表明:中国35°N以北地区总云量、低云量分布形势与地形吻合较好,沿北方高大山脉有明显的云量高值区.总云量、低云量的季节分布特点显著:春夏两季东西部呈反相分布,秋冬季全区总云量、低云量分布稀少,但冬季在新疆天山以北有明显云量大值区.中国北方地区总云量、低云量与降水呈正相关关系,春季相关性最好,秋冬季次之,夏季最弱,但平原地区夏季的总云量、低云量与降水相关性尤为显著,山区则相反.逐区统计分析各区雨日数及各雨量级的总云量、低云量,发现北方各区在相同量级的降雨日,总云量、低云量差异不大.  相似文献   

2.
甘南高原低云量的变化趋势分析   总被引:1,自引:0,他引:1  
利用甘南地区8个气象观测站1974年到2013年的低云观测资料,对其40年低云的时空变化特征进行了分析。结果表明:甘南地区低云分布呈南多北少和东多西少的特征;月际变化表现为1-9月呈上升趋势,10-12月下降趋势;年际变化表现为甘南各地分布均呈上升趋势,原本云量较多的地区云量增加也更明显;低云量的变化与气温、降水、水汽压、人类活动等都有密切关系,相关分析表明低云量的变化与气温、水汽压呈正相关,与降水量呈弱的负相关。  相似文献   

3.
利用环渤海地区69个观测站点2001年6月-2016年12月8次/d的云观测资料,欧洲中期数值天气预报中心ERA-Interim的垂直速度和比湿数据,初步分析了该地区云量的时空分布特征及成因.结果表明,环渤海地区总云量年平均和秋冬季呈南多北少、西多东少的分布特征,春季分布相对均匀,夏季从东南向西北递减;低云量年平均和各季节的空间分布大体相同,其中对流云量北部山区多于南部平原地区,非对流云量从东南沿海向西北内陆递减,北部低云以对流云为主,南部以非对流云为主.总云量的空间分布与上升运动和水汽的空间分布呈正相关;对流云量的空间分布与大尺度下沉运动呈正相关,与水汽呈负相关;非对流云量的空间分布在秋冬季只与水汽呈正相关,在春夏季只与大范围上升运动呈正相关.两个代表站围场站和莒县站的总云量、围场站的对流云量以及莒县站的非对流云量年变化均比较显著,夏季最多,春秋季次之,冬季最少,主要是由垂直上升运动和水汽的年变化引起的.两站总云量全年各季日变化均不明显,对流云量和非对流云量在夏季表现出明显的日变化特征,对流云量在08:00最少,午后对流活动发展,云量增加,至14:00达到峰值;非对流云量夏季峰值出现在05:00,在14:00达到谷值.  相似文献   

4.
通过对T639数值预报产品的释用,结合地面气象观测站资料,以环渤海地区兴城站为例,建立了云量的精细化预报模型.从云形成的基本条件出发,选取4类天气学意义明确的预报因子:水汽类、大气不稳定度类、大气上升运动类和天气系统强度类,以总云量、低云量为预报对象,通过逐步回归法建立兴城站逐月、逐时次的云量预报方程.结果表明,云量主要受水汽、大气上升运动和大气不稳定度影响.回代检验结果表明,总云量平均绝对误差为20%,低云量平均绝对误差为16%,低云量的预报方程预报效果更好;总云量夏半年预报准确率更高,低云量冬半年预报准确率更高,可为云量精细化预报提供参考.  相似文献   

5.
我国总云量时空特征及其影响因素分析   总被引:1,自引:0,他引:1  
目的分析中国总云量的时空分布特征、变化趋势及影响原因。方法利用全国360个地面站1951~2009年地面月总云量观测资料,采用线性倾向估计和相关分析方法。结果总云量最多区域位于西南和华南地区,最少位于北部干旱少雨地区。约35°N以北总云量从南到北随纬度增加带状分布减少,此纬度以南同纬度东部云量多于西部云量。20世纪90年代以及21世纪前10年总云量减少最明显。总云量减少最明显的区域位于东北、西藏西南部以及山东、安徽北部地区。大部分地区总云量与太阳黑子相对数、降水量、相对湿度、最大积雪深度之间存在显著正相关关系,蒸发量与总云量存在显著负相关关系。结论我国总云量总体上呈减少趋势,气候因素对总云量变化有重要影响。  相似文献   

6.
利用气象信息综合分析处理系统地面实况报文和欧洲中期天气预报中心再分析(ERA Interim)的4次/d总低云量资料,对比分析了再分析资料对太原和五寨总低云量的代表性.结果表明,太原和五寨不同观测时次总云量和低云量多年平均(2002年2月1日-2013年12月31日)观测值与ERA Interim再分析云量变化趋势较为一致,除02:00外, 08:00、14:00、20:00的ERA Interim再分析资料均偏低, ERA Interim低云量均低于观测值.总云量月平均值ERA Interim资料高于站点观测值,14:00偏差较大.太原和五寨不同观测时次总云量累积分布趋势整体较一致.太原和五寨总云量的相关系数在0.6以上, 08:00和14:00相关系数在0.7以上.低云量相关系数明显低于同时次的总云量相关系数,低云量不同月份不同时次的相关系数差异较大,总云量平均绝对误差相差不大;低云量平均绝对误差部分时次较大.  相似文献   

7.
基于云水资源积分推导公式,选取50年的气象站资料研究三江源地区(the Three River Headwaters Region,TRHR)云量与降水时空演变规律及其统计关系,并对降水效率(Precipitation Efficiency,PE)时空特征深入分析,挖掘人工增雨试验潜力.结果表明:①总、低云量分别以长江源区的治多、清水河为高值中心向西呈"经向型"分布,向东呈"纬向型"分布.低云量与降水量呈增加趋势且通过了α=0. 005显著性检验,总云量呈减少趋势并通过了α=0. 01显著性检验;②各源区总、低云量与降水的突变年份不同步.降水年际波动较云量变化大且低云与降水相关性较好.低云量随总云量增加而增加,当总云量增加1. 7%时,低云量将增加1%,同期降水增加10mm,年降雨频率最高出现在400mm;③TRHR多年PE空间分布与降水、云量一致,整体表现出自东南向西北方向递减空间分布,PE高、低值区分布在34°N以南和34°N以北.④TRHR多年平均PE为40. 3%且增幅变化不大,长江源区西部和黄河源区东北部增雨潜力(Precipitation Enhancement Potential,PEP)最大,最佳开发时间在3~4月和10~11月.  相似文献   

8.
基于2008-2013年全球天气预报系统(GFS)预报场资料,构造了30个云预报因子,分析了其与低云量的相关关系,采用多元逐步回归预报方法建立了黄河河套周边地区低云量0~168 h逐小时精细化区域预报,评估了预报模型的预报效果.结果表明,低云量与水汽类因子整层湿度和整层相对湿度具有较强的正相关性;与大气可降水量、低层温度露点差和总温度具有较强的负相关性;与GFS云类预报因子有较强的正相关性.在预报方程中水汽类预报因子和GFS云量因子具有较高的引用频数.多元逐步回归方法低云量预报值与实况的差值明显低于直接使用GFS低云量的预报结果,在夏季逐步回归方法对低云量有较大改进,上半年对低云量的订正效果强于下半年.逐步回归方法对西北部低云量的订正能力高于东南部地区,部分地区的订正能力在20%以上.  相似文献   

9.
因三清山位于玉山境内,用玉山气象站2005-2015年的地面气象要素资料,分析了近11 a三清山云海的气候特征及其与气温、降水、相对湿度、风速的相关关系,并通过逐步回归算法得出了云量与日平均气温、前一日降水、相对湿度的等式关系。结果表明,三清山年平均云海日数为169 d,云海日数的月变化呈现多波动的形势,且1-6月云海日数明显多于7-12月。三清山平均低云量与平均相对湿度、前一日降水量显著正相关,与平均温度、最高气温、最低气温呈负相关关系。  相似文献   

10.
本论述使用地面气象观测日照资料,运用气候趋势法,对日照时数年变化、季变化和月变化时间序列进行了分析,并对与日照时数变化相关的降水量、气温、水汽压、相对湿度、总云量等气象因子进行了逐月平均特征的相关性分析,结果表明:(1)过去50年,三明市逐年日照时数呈现减少趋势,平均每10 a减少68.85 h.(2)三明市四季日照时数的季节变化趋势与年际变化趋势一致,也呈现出减少趋势,减速2.5~37.8 h/10 a,夏季减速最大,秋季减速最小.(3)逐月日照时数呈现"单峰型"分布,7月达到峰值,2月最少.(4)逐月平均日照时数与平均气温、平均水汽压呈现出显著的正相关性,与平均相对湿度、平均总云量、平均降水量呈现出负相关性,  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

15.
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   

16.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

17.
以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.  相似文献   

18.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

19.
Quality traits in wheat (Triticum aestirum L.) were studied by quantitative trait locus (QTL) analysis in a recombinant inbred line (RIL) population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross (ChSh). Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.  相似文献   

20.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号