abstract this research evaluates climate change effects on drought severity in the region of gharesou, iran. the standardized precipitation index (spi) has been used for estimation of drought severity. a geographical information system is applied for calculating the mean areal precipitation time series from 11 meteorological stations, in and out of the area for the hydrological period jan 1971-...

For estimation of monthly precipitation, considering the intricacy and lack of accurate knowledge about the physical relationships, black box models usually are used because they produce more accurate values. In this article, a hybrid black box model, namely ANN-RBF, is proposed to estimate spatiotemporal value of monthly precipitation. In the first step a Multi Layer Perceptron (MLP) network i...

The knowledge of tropical palaeoclimates is crucial for understanding global climate change, because it is a test bench for general circulation models that are ultimately used to predict future global warming. A longstanding issue concerning the last glacial maximum in the tropics is the discrepancy between the decrease in sea-surface temperatures reconstructed from marine proxies and the high-...

• Climate change (altered CO(2) , warming, and precipitation) may affect plant-microbial interactions, such as the Lolium arundinaceum-Neotyphodium coenophialum symbiosis, to alter future ecosystem structure and function. • To assess this possibility, tall fescue tillers were collected from an existing climate manipulation experiment in a constructed old-field community in Tennessee (USA). Endo...

prediction of annual average precipitation over a regin is one of important issues in watersherd management and natural resources planning. geostatistics is one of the useful methods for precipitation prediction which varies based on type of the variable. this study was conducted in karoon and dez basins located in southwertern of iran. the data set including 20 years of annual precipitation of...

this analysis was conducted on 31 synoptic stations in iran. initially, the mann-kendall test was administered in order to analyse the trend of alterations of these two components over time and the results suggest that 16% of the stations show significant relationship with annual precipitation (positive and negative). more stations showed significant relationships between sunspots and minimum a...

   The presented study investigates application of polyethylene glycol (PEG)-coated Fe3O4 nanoparticles as an magnetic nanoadsorbent for magnetic solid-phase extraction (SPE) and the selective removal of toxic heavy metals such as mercury (II) from aqueous solutions and their determination using graphite furnace atomic absorption spectrometry (GF-AAS)...

Ferric hydroxide supported Au prepared with co-precipitation without heat treatment could be a very effective catalyst for selective CO oxidation in the presence of H2 at lower temperatures.

The exploration of coarse-grained WC cemented carbide has become a research hotspot for its application in the fields rock cutting and mining; key issue is how to achieve uniform dispersion densification sintered phase, as well obtain better mechanical properties. In this paper, chemical co-precipitation, combined with hydrogen reduction, was adopted. CoCl2·6H2O CeCl3 were used precursors coat ...