Introduction: Sand dunes in Earth’s large deserts are similar in size and relationship to substrate and topography to the tens of thousands of dunes seen on the surface of Titan by Cassini. Field studies of large dunes can thus inform our understanding of the evolution of similar dunes on Titan. A recent field study to the Namib Sand Sea yielded valuable results concerning the morphology, inter...

Distinctive, eolian-dominated sandy deposits 35 m thick exposed along the SW margin of the Plio-Pleistocene Valdarno Basin in the Northern Apennines, Italy, reflect an unusually arid period in the region. Paleomagnetic investigation and Ar/Ar dating of a tephra layer, 10 m above the eolian sand, suggest that the sand was deposited between about 2.7 and 2.4 Ma. This age is coeval with the global...

Drought is one of the most important weather-induced phenomena which may have severe impacts on different areas such as agriculture, economy, energy production, and society. A number of drought indices have been introduced and used in various countries to date. In the current study, four meteorological drought indices including Percent of Normal Precipitation Index (PNPI), Standard Index of Ann...

1. Dept. of Social Medicine, School of Medicine, Dezful University of Medical Sciences, Dezful, Iran 2. Dept. of Epidemiology and Biostatistics, School of Public Health, Iran University of Medical Sciences, Tehran, Iran 3. Dept. of Public Health, Faculty of Health, Zabol University of Medical Sciences, Zabol, Iran 4. Dept. of Epidemiology and Biostatistics, School of Public Health, Tehran Unive...

The presented paper compares forecast of drought indices based on two different models of artificial neural networks. The first model is based on feedforward multilayer perceptron, sANN, and the second one is the integrated neural network model, hANN. The analyzed drought indices are the standardized precipitation index (SPI) and the standardized precipitation evaporation index (SPEI) and were ...

Mexico City lies in a high altitude basin where air quality and pollutant fate is strongly influenced by local winds. The combination of high terrain with weak synoptic forcing leads to weak and variable winds with complex circulation patterns. A gap wind entering the basin in the afternoon leads to very different wind convergence lines over the city depending on the meteorological conditions. ...