No abstract

The Urban Heat Island (UHI) results in significant and sometimes dramatic increases in air temperature differences between the urban environment and its surrounding areas. The heat island structure may extend from the ground to the top of roofs and canopy levels above ground. The Urban Heat Island effect is a leading factor in a long list of human health problems which are expected to increase with the rapid growth of urban populations and projected future climate change. Urban heat island studies can be conducted through either direct measurements of air temperature using automobile transects and weather station networks or through measuring surface temperature using airborne or satellite remote sensing. In this study, UHI was investigated over the Greater Cairo during both summer and winter seasons over two different dates. Landsat 7 ETM + data were used and the mono-window algorithm was applied in the study. Results emphasis that both types of heat islands exist in the study area i.e. the surface and the atmospheric heat islands. Temperature differences ranged between 0.5˚C to 3.5˚C and these are much related to the existing land use/covers. It could be concluded that expansion of urban areas in Greater Cairo has led to increased thermal radiation of land surface on the highly populated areas.

Crop yield estimation is a very important aspect in food production as it provides information

Abstract-Population increase within urban environments especially in the developing countries, has posed a need to understand the urban climates. While the importance of urban climates cannot be overemphasized, acquiring knowledge about contributing factors to urban climates can be challenging.Measuring land surface temperatures is one of the ways to acquire such knowledge which could be an uphill task if done manually. However, satellite remote sensing data could be applied to spatially estimate such factors. Land surface temperatures (LST) were estimated from the thermal bands of the Landsat Enhanced Thermal Mapper Plus (ETM+) using remote sensing and geographic information system (GIS) techniques. In addition, meteorological data which included air temperature and relative humidity for the same satellite image dates were used in the analysis. Results showed that Durban metropolitan area is experiencing a major heat island over the city centre with some micro ones around the metro. Comparing the LST results to the landuse/cover of the city showed the UHI phenomenon is a reality with a 3°C and 4°C LST increase over the city centre of Durban for winter and summer seasons respectively in 2012 and being attributed greatly to the human activities within the area that has led to increase thermal radiation from land surface over highly dense and paved areas.

The Rietspruit is located in Gauteng Province, South Africa, within the Witwatersrand Basin. The basin is noted for its vast gold deposit. The river extends for about 60 km before joining the Vaal River. The aim of this study was to determine the concentration of uranium in the Rietspruit and the factors that influenced the concentration of U at each of the sites. The source of uranium in the river is the discharge from the gold mine and the mine wastes. Inductively coupled plasma mass spectrometry was used for water and sediment analysis in order to determine the concentration of U. High concentration of U was found in the river water and sediment, which is above the permissible limit of U. The water is used for irrigation of farmlands, cattle watering and for human consumption despite the high concentration of uranium in it. Ingestion of uranium is dangerous to human health. Due to the toxic nature of uranium, consumption of the water for domestic use and agriculture purpose must be discouraged.