background: air pollution and concerns about health impacts have been raised in metropolitan cities like tehran. trend and prediction of air pollutants can show the effectiveness of strategies for the management and control of air pollution. artificial neural network (ann) technique is widely used as a reliable method for modeling of air pollutants in urban areas. therefore, the aim of current ...

abstract recent global warming has led to a change in the global hydrological cycle and an increase in extreme events such as flood and drought at the global and continental scales. however, at the regional scale, the magnitude of warming and the resulting changes in water resources are different from one region to another. unlike air temperature whose increase is evident throughout the world, ...

1. introduction glaciers and snow covers in the mountains play an important role in the water budget of many areas of the world (ramage and isacks, 2003). in high altitudes and mountainous regions, snowmelt is a great contributor to the yearly runoff. the snow melt supplies 1/6 of people's needed water but due to global warming these glaciers may be at risk (barnett, et al. 2005). for the regio...

in recent years, extraction of atmospheric temperature and humidity profiles from thermal bands of satellite images is a common practice. the most deployed images for this task have been acquired by moderate resolution imaging spectroradiometer (modis). this sensor which is onboard of terra and aqua platforms consists of a spectroradiometer with 36 bands in visible (vis), near infra-red (nir) u...

Streamflow is an important factor in the study of water resource management, floods, and droughts. Dramatic climate change has created extreme rainfall distributions, making the study of streamflow trends and variability even more crucial. In this study, the long-term streamflow data and trends recorded at gauging stations in Northern Taiwan are analyzed using the Mann-Kendall test. The data us...

introductionclimate change has played an important role in all aspects of human life. therefore, climatepredictions in atmospheric general circulation models (gcm) will have particular importance.in this study, downscaling by a1b scenarios, ipcm4 and bcm2 of atmosphere generalcirculation models in lars-wg model are used for analysis of climate change impacts onmaximum and minimum temperature, s...

evapotranspiration is one of the most important components of the hydrological cycle which is directly influenced by atmospheric conditions. this study investigated annual and seasonal trends in reference evapotranspiration (et0) and its key influencing climatic variables during 1966-2005 at 10 stations in southern iran (with centrality of fars province). first, multivariate regression analysis...