Adaptive Smoothing Method For Computer Derivation of K-Indices     

Krzysztof Nowo&#;y&#;ski  Tomasz Ernst  Jerzy Jankowski 《Geophysical Journal International》1991,104(1):85-93

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1991年3月5日的喷泉状爆发日珥及视向速度分布     

钟树华 《天文研究与技术》1995,(3)

本文介绍了１９９１年３月５日一个与３Ｎ级光学耀斑伴生的喷泉状爆发日珥。用Ｈα线观测从开始到结束整个过程共持续约５０分钟时间，日珥的最大投影高度１５．９万公里，视向速度分布表明，日珥主要以较大的速度向着观测者的运动，最大速度每秒１２０公里。  相似文献   

The evaluation of eco-environmental susceptibility to human activity in Yulin region   总被引：1，自引：0，他引：1  

Liding Chen  Bojie Fu 《中国地理科学(英文版)》1995,6(1):57-65

The eco-environmental susceptibility is to demonstrate the reaction of a ecosystem under the same influences of the human activity. It comprise many influencing factors which have a complicated relation to the eco-environmental susceptibility. In this paper, the Analysis of Hierarchy Process (AHP) is used to determine the weight of each factor to the eco-environmental susceptibility through analyzing the relationship between human activity and environmental deterioration. And the weighted summation method is used to calculate the eco-environmental susceptibility of different divisions in Yulin region. The result shows that the loess hilly and gully area is more subjective to deteriorating eco-environment than the desert area because of the strong human activity and severe soil erosion. The project is supported by the National Natural Science Foundation of China  相似文献   

The early Cretaceous marine transgression and its significance for landscape interpretation     

《The Australian geographer》1991,22(2):178-184

Significant elements of the Australian landscape date from Mesozoic or earlier times. Australia did not separate completely from other Gondwanan components until Early Tertiary times and these Mesozoic and older elements can therefore be regarded as Gondwanan. During the separation and northern drift of the continent and particularly in Late Jurassic and earlier Cretaceous times the sea invaded and spread across much of the erstwhile landmass. The associated sediments not only covered and preserved much of the pre‐existing land surface, but they also augmented the effects of thalassostatic loading of the basins, causing further subsidence. Hinge lines developed near the coastal zones of the times, so that subsidence of the basins caused adjacent land masses to rise. Many old land surfaces have been re‐exposed at the former oceanic margins, but epigene forms are preserved high in the relief on the uplifted blocks. They survive partly because, as Crickmay (1976) suggested, rivers effectively erode at and near their channels; the divides remain untouched. A reinforcement effect also operates because the valleys are wet sites, the interfluves dry. Hence weathering and erosion proceed apace in the former while the latter are stable, allowing palaeoforms to survive.  相似文献   

The time-dependent transport of cosmic rays in the heliosphere     

Marius S. Potgieter 《Astrophysics and Space Science》1995,230(1-2):393-403

The modulation of cosmic rays (CRs) in the heliosphere is a dynamic and therefore a highly time-dependent process. Numerical models with only a time-dependent neutral sheet prove to be successful when moderate to low solar activity occurs but fail to describe large and discrete steps in modulated CRs when solar activity is high. To explain this feature of heliospheric modulation, the concept of global merged interaction regions (GMIRs) is required. The combination of gradient, curvature and neutral sheet drifts with these GMIRs has so far been the most successful approach in explaining the 11-year and 22-year cycles in the long-term modulation of CRs.  相似文献   

Study on respiratory electron transport system （ETS） of phytoplankton in Taiwan Strait and Xiamen Harbour   总被引：1，自引：0，他引：1  

黄邦钦洪华生  徐宪忠刘媛 《中国海洋湖沼学报》2005,23(2):176-182

Phytoplankton respiratory electron transport system (P-ETS) activities were studied in two cruises in Taiwan Strait (Aug. 1997 and Feb. -Mar.1998) and two cruises in Xiamen Harbour (Oct., 1997 and Apr.,1998). Results showed that P-ETS activity in the surface water of southern Yaiwan Strait in summer was homogeneous [mean value of 0.106 μ102/(L.h)], inhomogeneous in northern Yaiwan Strait in winter. Variation of P-ETS activity in middle part of the Strait was not obvious between summer and winter. Mean P-ETS activity of Xiamen Harbour in autumn was 0.255 μ102/(L.h) with a little higher value in Jiulong River estuary areas. In spring, P-ETS activity was more homogeneously distributed and the mean value was 1.076 μ102/(L.h). P-ETS activity in spring was obviously higher than in autumn in Xiamen Harbour. Vertical distribution of P-ETS in Taiwan Strait was homogeneous at some stations in winter and in summer. An obvious daily variation of P-ETS activity was recorded at Stn 9837, high at midnight and low in the early morning. Significant correlation between P-ETS activity and Chl-a was observed. Results also showed that the ratio of estimated respiratory rate to photosynthetic rate varied seasonally, high in winter (0.41) and low in summer (0.12).  相似文献   

Magnetic fields at the surfaces of stars     

J. D. Landstreet 《Astronomy and Astrophysics Review》1992,4(1):35-77

Summary Magnetic fields have now been detected in stars in several parts of the Hertzsprung-Russell diagram. Roughly dipolar fields ranging in strength between 3× 10² and 3×10⁴ G are found in many chemically peculiar A and B main sequence stars. Dipolar fields are also found in some 2–3% of white dwarfs, but with strengths between 1×10⁶ and 5×10⁸ G. In both these types of stars, the observed fields vary as the underlying star turns, but do not change in a secular manner. In solartype stars, structurally complex fields of a few kG are found with filling factors of the order of 0.1 to 0.8. Further indirect evidence of fields in cool main sequence stars is provided by detection of visible and ultraviolet line emission (chromospheric activity), x radiation (coronal matter), and giant starspots. In this review, we survey the observations of stellar magnetism in all these types of stars, as well as efforts to model the observed magnetic fields and associated photospheric peculiarities and activity.This article was processed by the author using the Springer-Verlag T_EX AAR macro package 1991.  相似文献   

Does sunspot activity originate in slow global oscillations of the sun?     

M. H. Gokhale 《Journal of Astrophysics and Astronomy》1986,7(4):241-257

We present preliminary results of a spherical-harmonic-Fourier analysis of sunspot activity during the twenty-two years 1933–1954. The results indicate that the sunspot activity might be originating in global solar oscillations with periods of years and decades. However, except for the axisymmetric mode of degree 6, the set of other axisymmetric modes showing ∼ 11 yr periodicities are different from one sunspot cycle to another. A more detailed analysis, preferably with larger data series, will be needed to arrive at a more definite conclusion.  相似文献   

水库地震地质判别标志的研究     

虞永林 《浙江国土资源》1996,(2)

本文研究了中国水库诱发地震的地质构造总体环境，从中提取出诱发水库地震的八项地质判别标志。同时进一步将它们划分为一般性和特征性两类地质判别标志，前者在水库地震和天然地震中均可出现，后者一般是水库地震中所特有的标志，是判断发生水库地震的王要地质判据，故在水库选址、最低限度在大坝选址时，要避开具有明显诱发水库地震的地质标志地段。  相似文献   

低纬高原大气不稳定参数与雷电活动相关性     

杨宗凯  殷娴  胡颖  周清倩 《气象科技》2018,46(5):1020-1025

应用云南省2014—2017年闪电资料和探空资料,分析了低纬高原地区大气不稳定参数与雷电活动的相关性,从9个参数中选取了相关性较强的5个参数,运用数理统计方法确定各参数可预测雷电发生的阈值,再运用复相关系数法计算各参数权重,建立雷电潜势预报方程。最后通过预报检验法及个例分析法对方程进行验证,结果显示低纬高原地区大气不稳定参数对雷电活动较为敏感,响应阈值普遍低于平原区域。该预报方程对未来12h雷电活动的发生预报效果显著,具有良好的推广运用价值。  相似文献