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21.
本文用云南天文台在第22周太阳活动峰年期间拍摄到的大太阳黑子群照相资料,太阳黑子目视描述资料,以及Nimbus—7卫星上辐射计测量的太阳总辐照度,分别计算了太阳总辐射照度与大黑子群的本影视面积,大黑子群全群视面积和日面上全部黑子的总视面积的相关系数。结果表明,太阳总辐射照度与这三种视面积均存在强的负相关。其中与大黑子群本影视面积的相关最强,其次是与全群视面积的相关,最后是与日面上全部黑子的总视面积的相关。并对以上结果和其它有关结果进行了分析和讨论。  相似文献   
22.
We study the periodicity of twisting motions in sunspot penumbral filaments, which were recently discovered from space (Hinode) and ground-based (SST) observations. A sunspot was well observed for 97 minutes by Hinode/SOT in the G-band (4305 Å) on 12 November 2006. By the use of the time?–?space gradient applied to intensity space?–?time plots, twisting structures can be identified in the penumbral filaments. Consistent with previous findings, we find that the twisting is oriented from the solar limb to disk center. Some of them show a periodicity. The typical period is about ≈?four minutes, and the twisting velocity is roughly 6 km s?1. However, the penumbral filaments do not always show periodic twisting motions during the time interval of the observations. Such behavior seems to start and stop randomly with various penumbral filaments displaying periodic twisting during different intervals. The maximum number of periodic twists is 20 in our observations. Studying this periodicity can help us to understand the physical nature of the twisting motions. The present results enable us to determine observational constraints on the twisting mechanism.  相似文献   
23.
We present a study of magnetic fields in umbral dots (UDs) and its consequences on the Joule heating of the UDs. Hamedivafa (Astron. Astrophys. 407, 761, 2003) studied the Joule heating using the vertical component of the magnetic field. In this paper the magnetic field profile in the UDs is investigated by including a new azimuthal component of the magnetic field that might explain a relatively large enhancement of Joule heating causing higher brightness near the circumference of the UDs.  相似文献   
24.
区域短波通信台网选频的研究   总被引:2,自引:0,他引:2  
河南省地震局短波通信台网的工作频率被限制在短波的低频段,受干扰严重,中心台又位于市中心,环境噪声电平很高,加之,局网内可用的电台大部分发射功率小、抗干扰性能差。这些因素给通信台网的工作频率选择带来困难。为提高区域通信的质量,在对短波电离层信道传播特性进行分析的基础上,结合本地大气噪声和环境噪声的实际情况,对河南省地震局通信网的选频问题进行了研究,给出了选频的原则和方法,介绍了选频试验的结果和体会。  相似文献   
25.
Using the characteristic values of sunspot number variations during the descent and ascent of solar cycles,a neural network is designed to make long-term predications of the ascending period and the maximum smoothed monthly mean sunspot number for the Solar Cycle 23. Moreover,the factor of geomagnetic disturbance is also added as an input. The trained and tested results from Solar Cycle 12 to 22 have been obtained. Finally,the predictions of the ascending period and the maximum smoothed monthly mean sunspot number are given for Solar Cycle 23.  相似文献   
26.
利用1957~1998年安阳区域夏季降水资料,确定安阳区域性夏季大旱的标准,分析了大旱成因:东亚沿海低槽较常年异常深厚和偏东以及西太平洋副高异常偏东、偏南和偏弱;当年6~8月太阳黑子相对平均数处于谷点或从谷点开始上升时期;当年春季出现厄尔尼诺或存在厄尔尼诺现象,绝大部分安阳降水偏少或特少,出现干旱或大旱;6~8月西风急流轴异常偏北,也是造成安阳区域性夏季大旱的原因之一。  相似文献   
27.
太阳活动百年尺度的跃变与气候跃变的相关分析   总被引:10,自引:5,他引:5  
冯松  汤懋苍 《高原气象》1998,17(3):266-270
讨论了2500多年来太阳黑子周期长度(SCL)的跃变特征,发现有在年尺度上SCL基本在平均值附近变化,而其变率则存在明显的跃变现象,当SCL的变率增大时,气候随之发生冷跃变,反之,则发生暖跃变。小冰期内,太阳活动弱且不稳定,与地球气候冷且不稳定具有同时性。  相似文献   
28.
Since the discovery of a striking correlation between 1-2-2-2-1 filtered solar cycle lengths and the 11-year running average of northern hemisphere land air temperatures, there have been widespread speculations as to whether these findings would rule out any significant contributions to global warming from the enhanced concentrations of greenhouse gases. The solar hypothesis (as we shall term this assumption) claims that solar activity causes a significant component of the global mean temperature to vary in phase opposite to the filtered solar cycle lengths. In an earlier article we have demonstrated that for data covering the period 1860–1980 the solar hypothesis does not rule out any significant contribution from man-made greenhouse gases and sulphate aerosols. The present analysis goes a step further. We analyse the period 1579–1987 and find that the solar hypothesis—instead of contradicting—appears to support the assumption of a significant warming due to human activities. We have tentatively corrected the historical northern hemisphere land air temperature anomalies by removing the assumed effects of human activities. These are represented by northern hemisphere land air temperature anomalies calculated as the contributions from man-made greenhouse gases and sulphate aerosols by using an upwelling diffusion-energy balance model similar to the model of Wigley and Raper, 1993 employed in the Second Assessment Report of The Intergovernmental Panel on Climate Change (IPCC). It turns out that the agreement of the filtered solar cycle lengths with the corrected temperature anomalies is substantially better than with the historical anomalies, with the mean square deviation reduced by 36% for a climate sensitivity of 2.5°C, the central value of the IPCC assessment, and by 43% for the best-fit value of 1.7°C. Therefore our findings support a total reversal of the common assumption that a verification of the solar hypothesis would challenge the IPCC assessment of man-made global warming.  相似文献   
29.
用太阳活动拟合近2000年的温度变化   总被引:5,自引:4,他引:5  
利用两个反映太阳活动的指标-太阳黑子相对数及太阳黑子周期长度-来拟合近2000年我国的温度变化,其结果与近2000年,特别是近700年来温度变化的总趋势基本一致。同时拟合了120年来北半球温度的演变,结果表明:太阳活动是引起10^1年以上气温变化的基本因素,近十多年来温室气体的作用似乎不可忽略。  相似文献   
30.
This is a study of an extremely good outcrop of 1745 varves inthe Villarroya Pliocene Basin (Spain). The thicknesses of the light and darklayers, which were obtained from enlarged photograph negatives, are dealt withseparately, and three time series, of light, dark, and the sum of both layers,are performed. Periodicities of about 12, 6–7 and 2–3 years havebeen obtained. The origin of the recurrent behaviour of the sediments withthese periods could be related to natural phenomena like sunspot cycles, ElNiño-Southern Oscillation (ENSO), North Atlantic Oscillation (NAO) andQuasi-biennial Oscillation (QBO), as these phenomena are capable of modulatingthe climate in this frequency band. From our point of view, there could be aclose relationship between sedimentation in the Villarroya Basin and thesenatural phenomena, which is moved through climate. The light layers record therun-off of gastropods, ostracods and charophytes from a seasonal productivitycycle, and are generated during late summer and autumn. It seems clear that theclimatic information provided by these cycles corresponds mainly to summertime, which would be translated into a variation of the light layer thicknessdue to a more or less intense development of the flora and fauna, being thickerin years of higher temperatures and thinner in years of lower temperatures.Considering the results, we would suggest that the sedimentation of thesematerials in the Pliocene was driven by solar activity or/and ENSO, NAO, andQBO phenomena. Nowadays these phenomena produce rainfall and temperaturechanges with the cyclicities shown in this study and we think they could haveoperated in the same way in Pliocene times.  相似文献   
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