introduction frost as a harmful climatologic phenomenon affects various human activities and biological processes. due to mountainous nature of kurdistan province as the study area of this research in one hand and type and diversity of effective air masses on the other, the frequency, severity and duration of this phenomenon in the province are outstanding. confronting frost could be one of the...

Remote sensing has changed modern oceanography by proving synoptic periodic data which can be processed. Since the satellite data are usually too much and nonlinear, in most cases, it is difficult to distinguish the patterns from these images. In fact, SOM (Self-Organizing Maps) model is a type of ANN (Artificial Neural Network) that has the ability to distinguish the efficient patterns from th...

Remote sensing has changed modern oceanography by proving synoptic periodic data which can be processed. Since the satellite data are usually too much and nonlinear, in most cases, it is difficult to distinguish the patterns from these images. In fact, SOM (Self-Organizing Maps) model is a type of ANN (Artificial Neural Network) that has the ability to distinguish the efficient patterns from th...

Drought is a major environmental disaster in many parts of the world. Knowledge about the timing, severity and extentof drought can aid planning and decision-making. Drought indices derived from in-situ meteorological data have coarsespatial and temporal resolutions, thus, obtaining a real-time drought condition over a large area is difficult. This studyused advanced very high resolution radiom...

—This paper investigated the normalized difference vegetation index (NDVI) stability in the NOAA/NESDIS Global Vegetation Index (GVI) data during 1982-2003, which was collected from five NOAA series satellites. An empirical distribution function (EDF) was developed to eliminate the long-term inaccuracy of the NDVI data derived from the AVHRR sensor on NOAA polar orbiting satellite. The instabi...

Snow cover area is one of the most important criteria to calculate snow melt runoff. This can have an effect on the biology of the plant and the environment of a region. Using the catchment basin physical characteristic to calculate snow cover area is a conventional method, though its accuracy is not good enough. Most of the useful methods in calculating snow cover area are based on satellite i...

Snow cover area is one of the most important criteria to calculate snow melt runoff. This can have an effect on the biology of the plant and the environment of a region. Using the catchment basin physical characteristic to calculate snow cover area is a conventional method, though its accuracy is not good enough. Most of the useful methods in calculating snow cover area are based on satellite i...

snow cover area is one of the most important criteria to calculate snow melt runoff. this can have an effect on the biology of the plant and the environment of a region. using the catchment basin physical characteristic to calculate snow cover area is a conventional method, though its accuracy is not good enough. most of the useful methods in calculating snow cover area are based on satellite i...