introduction jet stream is strong narrow current concentrated by strong vertical and lateral wind shears (vasantha et al, 2002). according to world meteorological organization nomenclature, jet stream formed when the speed of wind greater than 60 knots or 30 m/s. the major characteristics of the troposphere and lower stratosphere in the vicinity of jet streams were pointed out by a group of met...

In this study, wet-chemical process was performed to prepare nano-size hydroxyapatite (HA) powders (≈10 nm) by varying concentration (low, medium and high) of the starting solutions in order to increase the amount of as-dried HA powders with different process conditions. Particle sizes and density were analyzed and differential thermal analysis was used to determine the glass transition (Tg) an...

atmospheric circulation patterns are responsible for drought and flood occurrences around the globe specifically in moderate mid latitude climates. while some circulation patterns are responsible for wet spells and floods as well, the drought events can be attributed to some other circulation patterns. therefore, identification and distinction of dry/wet producing patterns and the geographical ...

In this paper an attempt is made to investigate the possible temporal correlation between heavy precipitation episodes and cosmic rays’ activity, on various time scales. Cosmic rays measurements are sparse and cover less extended periods than those of precipitation. Precipitation is largely influenced by local climatic and even physiographic conditions, while cosmic rays’ distribution is far mo...

Daily rainfall data for the winter season October–December for the long period of 102 years 1901–2002 over southeast peninsular India have been used to study the characteristics of daily precipitation extremes. The frequency and intensity of extreme precipitation events do not show statistically significant long-term trend. The relationship of El Nino-southern oscillation index with these extre...

dry and wet atmospheric depositions as well as urban surface soil samples were collected in eight different land use zones (during 2010) of the most important and largest industrial city, southwest iran for determining cadmium, chromium, lead and zinc. the average of cd, cr, pb and zn concentrations in the study area for wet precipitation were 17.8 μg/l, 49.97 μg/l, 2.31 μg/l, and 0.53 μg/l, re...

Two ice cores, covering 1500 years of climatic information, from the summit (5670 meters) of the tropical Quelccaya ice cap, in the Andes of southern Peru, provide information on general environmental conditions including droughts, volcanic activity, moisture sources, temperature, and glacier net balance. The net balance record reconstructed from these cores reflects major precipitation trends ...

Hydroxyapatite Ca10(PO4)6(OH)2 nanoparticles have been successfully synthesized by the wet chemical precipitation method at 60 °C in the presence of biocompatible natural surfactant-lecithin. The composition and morphology of nanoparticles of hydroxyapatite synthesized with lecithin (nHAp-PC) was studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning el...

Alterations in global and regional precipitation patterns are expected to affect plant and ecosystem productivity, especially in water-limited ecosystems. This study examined the effects of natural and supplemental (25% increase) seasonal precipitation on a sotol grassland ecosystem in Big Bend National Park in the Chihuahuan Desert. Physiological responses – leaf photosynthesis at saturating l...

To assess the sources, transport and deposition of atmospheric mercury (Hg) in Michigan, a multi-site network was implemented in which Hg concentrations in event precipitation and ambient samples (vapor aod particulate phases) were determined. Results from the analysis of 2 years of event precipitation samples for Hg are reported here. The volume-weighted average Hg concentration in precipitati...