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1.
中国近50年太阳直接辐射和散射辐射变化趋势特征   总被引:7,自引:0,他引:7       下载免费PDF全文
马金玉  梁宏  罗勇  李世奎 《物理学报》2011,60(6):69601-069601
利用近50年(1961—2009年)14个站以及31年(1961—1991年)49个气象站点的地面直接辐射和散射辐射观测资料,采用线性倾向估计、小波分析和Mann-Kendall(M-K)统计检验等方法,分析了太阳直接辐射和散射辐射年际、季节的长期变化趋势特征、年代际距平、周期和突变点.研究表明:1)采用归一化的气候倾向系数方法,有更好的比较性,能较好地揭示辐射气候趋势的时空分布特征;2)全国太阳直接辐射和散射辐射总体呈下降趋势,但地区、年代际和季节有升降的差异;3)基于观测站点地理分布的特点,按气候带划 关键词: 直接辐射 散射辐射 变化趋势 小波分析  相似文献   

2.
This paper describes an objective traffic noise survey of Turin, an industrial town in north Italy. The main objects of the investigation were to determine the nature and level of outdoor traffic noise in an actual urban situation and to verify the relationships between level of traffic noise, traffic volume and traffic composition.Noise measurements were performed at 70 locations uniformly distributed over the town, in the autumn of 1974. A ten-minute record was made at each site every hour for 23 hours.The results are presented and compared with published data from previous surveys carried out in other European and North American towns.  相似文献   

3.
我国地域辽阔,各地光气候有很大区别,为了扩大和提高太阳能与天然光的利用范围及利用效率,采用一种便携式的光谱扫描仪,对我国不同光气候分区的7个代表性城市(昆明、西宁、北京、深圳、南京、南昌和重庆)一天中不同太阳高度角对应时刻的地面直射日光光谱在380~780 nm可见光谱段进行了跟踪观测,分析了不同光气候分区城市一天中不同太阳高度角对应时刻的日光光谱变化规律,比较了不同光气候分区城市的日光光谱曲线,总结了日光光谱辐射强度的影响因素。分析表明:不同光气候分区城市一天中不同太阳高度角对应时刻的日光光谱辐射强度不同,但日光光谱功率的分布和走向基本一致,总体呈先上升后下降的趋势,最大峰值出现在475 nm附近,380~475 nm之间光谱功率分布曲线出现陡升,475~700 nm之间曲线有下降趋势但基本平稳,>700 nm曲线出现了反复的较大起伏;不同光气候分区城市的日光光谱功率分布曲线的分布和走向也基本一致,没有明显的与不同光气候分区直接相关的日光光谱功率分布差异性规律;日光光谱辐射强度与太阳高度角和日面状况密切相关。  相似文献   

4.
Summary Daily global solar-radiation sequences are studied for Italy. We show that the experimental data can be described as a first-order autoregressive stochastic process independent of locality or season: the only climatic information needed is the monthly average of the clearness index. We also show that the clearness index sequences can be transformed in sequences with normal distribution but with the same autocorrelation properties; it is then easy to construct synthetic sequences of radiation data with the same statistical properties as the real data, useful for performance prediction of solar systems.
Riassunto Si analizzano le serie temporali dei valori giornalieriK T (rapporto tra la radiazione solare globale su superficie orizzontale e la radiazione extra-atmosferica) per il territorio italiano. Si dimostra che i dati possono essere descritti con processi stocastici autoregressivi del primo ordine indipendentemente dalla località o stagione: la sola informazione necessaria è il valore medio mensile dei rapportiK T . Si dimostra inoltre che le successioni dei valoriK T possono essere trasformate in successioni con funzione di distribuzione normale e con le stesse caratteristiche statistiche di autocorrelazione dei dati originari; in tal modo è poi possibile costruire successioni di dati di radiazione, di lunghezza pari al numero di giorni in un mese e con le stesse proprietà statistiche dei dati sperimentali, utili per il calcolo delle prestazioni di sistemi solari.

  相似文献   

5.
齐月  房世波  周文佐 《物理学报》2015,64(8):89201-089201
利用1961-2011年中国东、西部地区地面太阳辐射和长期气象数据观测资料, 综合分析了东、西部地区地面太阳总辐射的变化特征, 并结合云量、日照百分率、风速、相对湿度等分析了影响东、西部地面太阳总辐射的变化原因. 结果表明: 近50年来东、西部地区地面太阳总辐射整体呈下降趋势, 下降幅度有所不同; 20世纪90年代之前大部分地区地面太阳总辐射呈下降趋势, 之后呈缓慢增加; 东西部各地区地面太阳总辐射与日照时数间存在显著相关性; 分析影响地面太阳总辐射减少的因素, 东部地区地面太阳总辐射与日照百分率呈显著正相关, 日照百分率是影响地面太阳总辐射减少的主要因素, 总云量与低云量已不是东部地区影响太阳辐射的主要因素; 西部地区地面太阳辐射与云量相关性较低, 主要受大气污染和日照百分率的影响. 风速成为影响地面大气辐射的一个重要因子, 并且风是驱逐大气对流层雾霾等大气污染的主要因子, 这进一步证实了大气污染已经成为影响地面太阳辐射的重要因素, 尤其在中国东部地区.  相似文献   

6.
微波消解/ICP-MS法检测八种梨果实中主要矿质元素含量   总被引:3,自引:0,他引:3  
采用ICP-MS法测定了八种梨果实中的钠、钾、钙、镁、锌、铜、铁、锰、硼等元素的含量。不同品种梨果实中主要元素组成基本相同, 但各种元素的含量存在一定的差异。其中,钾的含量最高, 其次是镁、钙、钠等元素。采用欧盟果蔬汁工业协会(AIJN)提供的果汁质量评价参考范围作参照标准,梨果实中钾、镁和钙元素含量高于该标准,钠元素含量低于该标准,其余元素含量均接近于该标准的规定。  相似文献   

7.
8.
Using artificial neural networks (ANN), we study the possibility for long-term forecasting of the annual mean Wolf numbers and the monthly average solar radiation flux at 2800 MHz. A feedback ANN with error backpropagation was designed and implemented for this purpose. The software allows one to vary the number of input parameters and neurons and the values of the training parameters. The forecast error is calculated and the actual data are graphically compared to the predicted ones. The annual Wolf number was forecasted directly one year ahead using an auxiliary training (warming-up) of the ANN by the previous 18 values of the annual Wolf number entering the training sequence. The prediction efficiency was 92%. Adding the coronal index and the annual solar-radiation flux (i.e., the SF index) to the input parameters leads to some improvement of the forecast. The iterative long-term forecast of the annual Wolf number for 1986-2000 yielded an efficiency of 71%. Using the direct and iterative techniques, the annual Wolf number was forecasted for the rest of the 23rd and the beginning of the 24th cycles (2000-2010).  相似文献   

9.
We review recent progress towards increasing solar cell efficiencies beyond the Shockley‐Queisser efficiency limit. Four main approaches are highlighted: multi‐junction cells, intermediate‐band cells, hot carrier cells and spectrum conversion. Multi‐junction cells use multiple solar cells that selectively absorb different regions of the solar spectrum. Intermediate‐band cells use one junction with multiple bandgaps to increase efficiencies. Hot‐carrier cells convert the excess energy of above‐bandgap photons into electrical energy. Spectrum conversion solar cells convert the incoming polychromatic sunlight into a narrower distribution of photons suited to the bandgap of the solar cell.  相似文献   

10.
The long-period variations in the climatic position of the Arctic front in the North Atlantic have been investigated. It is found that oscillations of the Arctic front latitude near Greenland occur with main periods of ~80, ~44, and ~22 years; this finding indicates possible relationship of these oscillations with the solar activity and variations in galactic cosmic rays. It is shown that the secular oscillations of the Arctic front latitude can be responsible for the amplitude modulation of the 11-year harmonic in sea-level pressure variations in the North Atlantic.  相似文献   

11.
刘磊  陈铮  王永欣 《物理学报》2015,64(1):16401-016401
对合金沉淀颗粒劈裂过程的模拟发现晶核长大过程中由结构和温度变化引起的体积变化的同时也发生弹性能坍塌现象. 弹性能坍塌方式可以是瞬间坍塌方式也可以是渐进坍塌方式, 计算结果表明: 沉淀是否发生劈裂与弹性能坍塌时刻有关, 而沉淀发生何种劈裂与弹性能坍塌的速率有关. 对弹性能坍塌速率较快的瞬间坍塌, 沉淀是否发生劈裂只决定于弹性能坍塌的时刻, 在沉淀晶核长大到直径为80l到90l之间大小时引入瞬间弹性能坍塌, 则沉淀发生4块型劈裂. 对弹性能坍塌速率较慢的渐进坍塌, 在引入时刻大于τ= 7.5× 103 s的情况下, 沉淀发生且只发生两块型劈裂.  相似文献   

12.
Manifestation of the 200-year solar cycle (de Vries cycle) in climatic changes (summer temperatures) has been investigated by analyzing the radial growth of long-lived (800–1200 yr) Juniperus turkestanica trees in Central Asia. Quasi-two-hundred-year variations in the radial growth of trees have been revealed, which correlate well (correlation coefficient reaches 0.94) with similar solar activity variations (Δ14C).  相似文献   

13.
冬小麦冠层光谱的方向性特征分析   总被引:6,自引:0,他引:6  
二向性反射因入射和观测的角度变化而变化,合理选择遥感观测角度、太阳天顶角等为提高遥感应用精度提供可能。通过采用各向异性因子和各向异性指数定量分析了冬小麦冠层窄波段二向性反射率及NDVI的方向性特征。分析结果表明:主平面内二向性反射率的各向异性最强,垂直主平面最弱,其他平面介于前两者之间;可见光波段反射率随观测天顶角的敏感性大于近红外波段;反射率对太阳天顶角的敏感性随着观测天顶角的增大而增大。前向NDVI整体上大于后向,且NDVI随着太阳天顶角的增大呈增大趋势。为了减少观测方式所带来的不确定性,应尽量选择近红外波段和小太阳天顶角,估算结构参数时应尽量选择主平面进行遥感观测,在利用NDVI估算生物物理参数时尽量远离“热点”区域。  相似文献   

14.
The study is devoted to the development of the technique for searching for neutrons of solar origin during solar flares using the neutron detector of the PAMELA magnetic spectrometer onboard the RESURS-DK1 satellite. The study of the neutron detector counting rates showed that it operates properly and background conditions are stable in the geomagnetic equator region. 27 solar events from December 2006 to September 2014 were analyzed. Some events contain indications of solar neutron detection. The final conclusion on the nature of these neutrons requires an increase in statistics; to this end, background conditions in polar regions should be analyzed to increase the observation interval.  相似文献   

15.
Shielding is arguably the main countermeasure for the exposure to cosmic radiation during interplanetary exploratory missions. However, shielding of cosmic rays, both of galactic or solar origin, is problematic, because of the high energy of the charged particles involved and the nuclear fragmentation occurring in shielding materials. Although computer codes can predict the shield performance in space, there is a lack of biological and physical measurements to benchmark the codes. An attractive alternative to passive, bulk material shielding is the use of electromagnetic fields to deflect the charged particles from the spacecraft target. Active shielding concepts based on electrostatic fields, plasma, or magnetic fields have been proposed in the past years, and should be revised based on recent technological improvements. To address these issues, the European Space Agency (ESA) established a Topical Team (TT) in 2002 including European experts in the field of space radiation shielding and superconducting magnets. The TT identified a number of open research questions to be addressed, including development and testing of novel shielding materials, studies on the angular distributions of energetic solar particles, and cooling systems for magnetic lenses in space. A detailed report to the ESA will be published within a few months. A summary of the TT conclusions and recommendations will be discussed in this paper, with emphasis on active shielding using superconducting magnets.  相似文献   

16.
Summary The influence of hills, valleys and other obstacles on the atmospheric boundary layer is such that in their lee the mean wind velocity is reduced. Intermittent or fully separated flow conditions can arise, including regions of negligible mean wind. In these conditions dispersion is driven mainly by turbulent fluctuations, which prevail over the mean motion. In this work we review the general features of mean flow and turbulence intensity in the lee of a 2D obstacle. Using published wind tunnel data, we examine a case study of dispersion from a source placed in the lee and compare the measured concentrations with those of a random walk model simulation. Paper presented at the GNFAO/EURASAP Meeting, Turin, September 1989. To speed up publication, proofs were not sent to the authors and were supervised by the Scientific Committee.  相似文献   

17.
A so-called extended elliptical-complex (EEC) function method is proposed and used to further study the Einstein–Maxwell-dilaton-axion theory with p vector fields (EMDA-p theory, for brevity) for . An Ernst-like matrix EEC potential is introduced and the motion equations of the stationary axisymmetric EMDA-p theory are written as a so-called Hauser–Ernst-like self-dual relation for the EEC matrix potential. In particular, for the EMDA-2 theory, two Hauser–Ernst-type EEC linear systems are established and based on their solutions some new parametrized symmetry transformations are explicitly constructed. These hidden symmetries are verified to constitute an infinite-dimensional Lie algebra, which is the semidirect product of the Kac–Moody algebra and Virasoro algebra (without centre charges). These results show that the studied EMDA-p theories possess very rich symmetry structures and the EEC function method is necessary and effective.  相似文献   

18.
本文基于丝网印刷和丝网印刷后光诱导电镀太阳电池,分析了太阳电池前表面金属电极引起的光学损失的各种情况.考虑到空气-玻璃界面和金属电极两侧边缘区域的反射,通过将金属电极截面近似为半椭圆形模拟了电极的光学损失,计算得到的有效宽度比约为金属电极几何宽度的40%.通过对不同类型样品反射谱的测量计算,同时在理论模拟和实验测量上得到了太阳电池前表面金属电极的光学损失,相应的理论与实验结果相符合. 关键词: 光学损失 有效宽度比 光诱导电镀 反射谱  相似文献   

19.
Research has been done on solar-terrestrial correlations on the basis of the organism model for the Earth, which suggests that the Earth affects the Sun by means of a natural energy and information flow and as a result of man-made factors. Changes in the Earth pattern affect regular processes in the solar system and cause new formations in solar activity. Solar-terrestrial correlations represent an energy and information flux and provide regulation mechanisms for the biosphere and the climatic engine on an evolutionary basis in strict agreement with the evolution of the solar system.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 105–110, March, 1992.  相似文献   

20.
Summary The hourly solar-radiation values, global and diffuse, recorded during nine years in the town of Genua and at Monte Capellino and during seven years in the town of Macerata, in Italy, have been used to find simple expressions which give the hourly and daily solar irradiations in average sky conditions. It is then shown how the long-term average hourly, direct and diffuse, irradiation can be deduced with good accuracy by using, solely, the knowledge of the long-term average daily, direct and diffuse, irradiations, respectively. The long-term averages have been calculated, with an original method, on a time basis of six days instead of the monthly time basis, as is usual in the literature. Finally, the correlation between long-term averages of diffuse and global solar radiation is analysed and discussed.
Riassunto L'analisi dei valori orari della radiazione solare, globale e diffusa, registrati per nove anni nella città di Genova e sul Monte Capellino e per sette anni nella città di Macerata, in Italia, ha permesso di trovare semplici espressioni che danno i valori degl'irraggiamenti solari, orari e giornalieri, in condizioni di cielo medie. è quindi mostrato come il valore orario della radiazione diretta e diffusa, mediato su tempi lunghi, possa essere dedotto, con buona approssimazione, dalla sola conoscenza del valore giornaliero della radiazione, rispettivamente diretta e diffusa, mediato su tempi lunghi. Le medie su tempi lunghi sono state calcolate applicando una metodologia originale, sulla base di periodi di sei giorni invece che su quelle, abituale nella letteratura, di periodi di un mese. Infine è stata analizzata e discussa la correlazione fra i valori giornalieri di radiazione diffusa, mediati su tempi lunghi, e i valori orari di radiazione globale, pure mediati su tempi lunghi.

Work supported by CNR-Progetto Finalizzato Energetica, S.P. RERE, Tema N, under contract 80.00936.92.  相似文献   

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