نتایج جستجو برای: storms

تعداد نتایج: 8428  

2008
E. A. MacDonald M. H. Denton M. F. Thomsen

accelerating relativistic outer-belt electrons in the aftermath of geomagnetic storms. Using measurements from the Los Alamos Magnetospheric Plasma Analyzers in geosynchronous orbit, we perform a superposed-epoch study of the storm-time behavior of the inferred plasma-sheet whistler growth parameter. Separate analyses are done for storms that result in strong relativistic electron enhancements ...

Journal: :Nature 1870

Journal: :پژوهش های جغرافیای طبیعی 0
سمیه ناصرپور کارشناس ارشد اقلیم شناسی دانشگاه خوارزمی تهران بهلول علیجانی استاد دانشکدۀ علوم جغرافیایی دانشگاه خوارزمی تهران و مدیر قطب علمی تحلیل فضایی مخاطرات محیطی پرویز ضیائیان دانشیار دانشکدۀ علوم جغرافیایی دانشگاه خوارزمی تهران

introduction the dust storms are one of the climatic hazards in the dry climates of the world. they cause many damages to the environment and humans. one of the aspects of a study to understand the origin of this phenomenon is the formation of foci in the recent years in the areas of research. it has been done in the central regions. the dust storms have gained global scale. this has demonstrat...

2008
N. M. Pedatella J. M. Forbes J. Lei J. P. Thayer K. M. Larson

[1] In this brief report, the interplay between meteorological and geomagnetic activity influences on the low-latitude ionosphere is studied. Specifically, the disruption of the dominant wave-4 longitudinal structure of the equatorial ionization anomaly (EIA) by geomagnetic storms is investigated in connection with a sequence of three coronal mass ejections in July 2004. Observations of in situ...

2014
Abdulwaheed Musa Saad O. Bashir Aisha H. Abdalla

Suspended particles in the atmosphere during sand and dust storms have numerous consequences on electromagnetic wave propagation in arid regions. The electromagnetic wave signal may suffer attenuation and cross polarization upon encounter with the suspended particles. However, meager information has hitherto been reported about effect of storms on the telecommunication systems operating in such...

2005
N. Srivastava

A comparative study of five super-storms (Dst<−300 nT) of the current solar cycle after the launch of SoHO, to identify solar and interplanetary variables that influence the magnitude of resulting geomagnetic storms, is described. Amongst solar variables, the initial speed of a CME is considered the most reliable predictor of the strength of the associated geomagnetic storm because fast mass ej...

Journal: :Environmental research 2004
Yong-Shing Chen Pai-Ching Sheen Eng-Rin Chen Yi-Kuen Liu Trong-Neng Wu Chun-Yuh Yang

In spring, windblown dust storms originating in the deserts of Mongolia and China make their way to Taipei City. These occurrences are known as Asian dust storm events. The objective of this study was to assess the possible effects of Asian dust storms on the mortality of residents in Taipei, Taiwan, during the period from 1995 to 2000. We identified 39 dust storm episodes, which were classifie...

2015
Huidong Hu Rui Wang Zhongwei Yang Bei Zhu Yi A. Liu Janet G. Luhmann John D. Richardson Ying D. Liu

The largest geomagnetic storms of solar cycle 24 so far occurred on 2015 March 17 and June 22 with Dst minima of 223 and 195 nT, respectively. Both of the geomagnetic storms show a multi-step development. We examine the plasma and magnetic field characteristics of the driving coronal mass ejections (CMEs) in connection with the development of the geomagnetic storms. A particular effort is to re...

2001
James P. Smith D. N. Baker

We present a new paradigm for the driving of storms and substorms. Using a model that tracks the major energy components of the magnetosphere-ionosphere system, we demonstrate that both storms and substorms can be obtained from the same dynamical system for di erent levels of forcing. To say that storms are made up of substorms would be incorrect. Instead we see that periodic substorms result f...

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