introduction the city population, in particular at the industrialized cities and centers of provinces, has increased dramatically in iran during recent decades. arak city as center of markazi province is among those industrialized cities which has experienced a fast increase in population. these changes in population numbers tend to increase consuming water resources as well as increasing in en...

Ahvaz can be regarded as one of the most polluted cities in the world in terms of air pollution. Successive years of drought and weather conditions in recent years have resulted in particulate matter (PM10) concentration in Ahvaz. In this study, using probability distribution techniques, an appropriate threshold to identify the PM10 maximum extreme concentrations (MEC) has been detected. Based ...

Hanstrum et al. (2002) show from proximity soundings that cool-season tornadoes in southern Australia occur in environments characterised by relatively weak, but still positive, buoyancy in the lower troposphere, and strong wind shear from the surface to 1 – 1.5 km. Threshold criteria based on these proximity soundings (hereafter termed ‘proximity thresholds’) showed that a surface to 700 hPa l...

A simple model using once-daily upper-air values in the NCEP–NCAR reanalysis database estimates seasonal mass balance at two glaciers in southern Alaska, one in western Canada, and one in Washington substantially better than any of several seasonally averaged, large-scale climate indices commonly used. Whereas sea level pressure and sea surface temperature in the Pacific exert a strong influenc...

the climate and weather patterns of buffalo (new york, u.s.a.) are strongly influenced by thecity’s proximity to lake erie. total monthly snowfall in buffalo is forecasted using neural network techniques(multi-layer perceptron = mlp) and a multiple linear regression (lr) model. the period of analysis comprises 28 years from january 1982 to december 2009. input data include: zonal wind speed (u-...

1. introduction the position of iran in the subtropical region that has made its arid and semiarid climate and the topographic diversity changes this trend of climate. therefore, climate hazards such as frost, flood, dust storm, drought, temperature anomalies, heavy rainfall, avalanches, snow, sleet, etc occur in iran. the northwest of iran experiences the above conditions following the arrival...

The Amazon Basin is dominated by convective rainfall with significant spatial and diurnal variability. Diurnal seasonal distributions of events were determined from Cloud Top Temperature (CTT) between January 2008 December 2010 in city Belém-PA. decis technique was used to select the most intense (rainfall rate ≥ 15 mm h–1), which subsequently, subclassified into deep convection (DCE) shallow (...

Extraordinary floods are linked with heavy rainstorm systems. Among various systems, their synoptic features can be quite different. The understanding of extreme rainstorms by causative processes may assist in flood frequency analysis and support the evaluation any changes occurrence magnitudes. This paper aims to identify most dominant meteorological factors for rainstorms, using ERA5 hourly r...

introduction  the most notable convective systems are mesoscale convective systems (mcss). these systems are developed when clouds occurring in response to convective instability organize upscale into a single cloud system with a very large cirriform cloud structure and rainfall covering large contiguous areas (houz, 2004). detection and monitoring of mcss is very important in southwest iran be...

The temperature distributions of heated turbulent jets of air were determined using two dimensional (planar) laser induced phosphorescence. The jets were heated to specific temperature increments, ranging from 300 - 850 K and several Reynolds numbers were investigated at each temperature. The spectral ratio technique was used in conjunction with thermographic phosphors BAM and YAG:Dy, individua...