نتایج جستجو برای: arid land
تعداد نتایج: 134159 فیلتر نتایج به سال:
One of the characters in Iranian Model of Desertification Potential Assessment (IMDPA) is soil. Since soil is very important in the degradation of land, so some indices were determined for this character in order to evaluate desertification potential of arid, semi-arid and dry sub humid areas of Iran. The indices included soil texture, deep gravel percentage, soil depth, and EC. To calibrate th...
a r t i c l e i n f o Land degradation in drylands is one of the major environmental issues of the 21st century particularly due to its impact on world food security and environmental quality. Climate change, shifts in vegetation composition, accelerated soil erosion processes, and disturbances have rendered these landscapes susceptible to rapid degradation that has important feedbacks on regio...
Classifying remote sensing imageries to obtain reliable and accurate LandUse/Cover (LUC) information still remains a challenge that depends on many factors suchas complexity of landscape especially in arid region. The aim of this paper is to extractreliable LUC information from Land sat imageries of the Pishkouh watershed of centralarid region, Iran. The classical Maximum Likelihood Classifier ...
A refined land cover classification for the arid Phoenix (Arizona, USA) metropolitan area and some simple modifications to the surface energetics were introduced in the fifth-generation PSU/NCAR mesoscale meteorological model MM5. The single urban category in the existing 24-category United States Geological Survey (USGS) land cover classification used in MM5 was divided into three classes to a...
100-150 words) Remote sensing methods for locating and monitoring temporary ponds over large areas in arid lands were tested on a study site in Northern Senegal. Three main results are presented, validated with field data and intended to highlight different spectral, spatial and temporal characteristics of the methods: 1) Among several water indices tested, two Middle InfraRed-based indices (MN...
Assessing optical earth observation systems for mapping and monitoring temporary ponds in arid areas
100-150 words) Remote sensing methods for locating and monitoring temporary ponds over large areas in arid lands were tested on a study site in Northern Senegal. Three main results are presented, validated with field data and intended to highlight different spectral, spatial and temporal characteristics of the methods: 1) Among several water indices tested, two Middle InfraRed-based indices (MN...
Monitoring of net primary productivity (NPP) is especially important for the fragile ecosystems in arid and semi-arid regions. Great interest exists in observing large-scale vegetation dynamics and understanding spatial and temporal patterns of NPP in these areas. In this study we present results of NPP obtained with the model BETHY/DLR for Kazakhstan for 2003-2011 and its spatial and temporal ...
Understanding of hydrological processes, including consideration of interactions between vegetation growth and water transfer in the root zone, underpins efficient use of water resources in arid-zone agriculture. Water transfers take place in the soil-plant-atmosphere continuum, and include groundwater dynamics, unsaturated zone flow, evaporation/transpiration from vegetated/ bare soil and surf...
This paper examines the effects of urbanization on the flood hazard in semi-arid/arid southern California using traditional hydrograph, frequency-magnitude and statistical analysis augmented with GIS-based variable parameterizations and visualizations. It was found that the peak flood discharges were significantly increased in urban watersheds in conjunction with increasing mean baseflow in the...
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