نتایج جستجو برای: storms
تعداد نتایج: 8428 فیلتر نتایج به سال:
BACKGROUND Since the U.S. National Lightning Detection Network (NLDN) became fully operational in 1989, meteorologists have spent considerable time trying to identify cloud-to-ground (CG) lightning characteristics that are uniquely associated with severe weather. Many studies focused on the dominant CG lightning polarity as a potential indicator of severe weather. Knapp (1994) found that 39% of...
Shelf-to-basin sediment transport during storms was studied at the southwestern end of the Gulf of Lions from November 2003 to March 2004. Waves, near-bottom currents, temperature and sediment fluxes were measured on the inner shelf at 28-m depth, in the Cap de Creus submarine canyon head at 300-m depth and in the northwestern Mediterranean basin at 2350-m depth. This paper is a synthesis of re...
BACKGROUND AND PURPOSE Although the research linking cardiovascular disorders to geomagnetic activity is accumulating, robust evidence for the impact of geomagnetic activity on stroke occurrence is limited and controversial. METHODS We used a time-stratified case-crossover study design to analyze individual participant and daily geomagnetic activity (as measured by Ap Index) data from several...
Study of physical and chemical characteristics of dust storms in Iran is necessary. In this regard, 10 samples from Khozestan dust storms in 1387 and 1388 were collected for XRD and SEM studies. XRD result show that mineralogical composition of these dust particles can be divided into three groups: (1) Carbonate group (calcite mineral), (2) Silicate group (quartz mineral) and (3) Clay group (Ka...
Although migration is a widespread and taxonomically diverse behaviour, the ecological factors shaping migratory behaviour are poorly understood. Like other montane taxa, many birds migrate along elevational gradients in the tropics. Forty years ago, Alexander Skutch postulated that severe storms could drive birds to migrate downhill. Here, we articulate a novel mechanism that could link storms...
We investigate the relationship between magnetic structures of CME source regions and geomagnetic storms, in particular the super storms when the Dst index decreases below -200nT. By examining all full halo CMEs that erupted between 1996 and 2004, we selected 73 events associated with M and X-class solar flares, which have a clearly identifiable source region. By analyzing daily full disk MDI m...
Multi-annual dust transport simulations have been performed using a Mars general circulation model containing a dust transport scheme which responds to changes in the atmospheric state. If the dust transport is ‘radiatively active’ the atmospheric state also responds to changes in the dust distribution. This paper examines the suspended dust distribution obtained using different lifting paramet...
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