Various experiments have been carried out recently in Middle East desert regions for prediction of aerosol particle concentration and size distribution. The differences between urban and non-urban desert coastal environments, and urban and non-urban desert continental environments, are of interest. During these experiments aerosol particle concentrations for similar weather but different environmental conditions were measured and analyzed. The well-known MODTRAN urban, desert, maritime, and continental aerosol models were tested for aerosol particle distribution prediction. Unfortunately, many of those models did not predict correctly the aerosol distributions in different types of arid environments. Comparison of results leads to the following interesting conclusions: the aerosol distribution for each of our environments, such as urban-coastal-desert, non-urban-coastal-desert, urban-continental-desert, and non-urban-continental-desert, can be predicted by multiplying the Mediterranean coastal aerosol model parameters with semi-empirical correction functions or factors. The functions are different for coastal and continental environments, and for urban and non-urban environments. The models proposed in this work better describe effects of different atmospheric conditions for Middle East desert aerosol modeling.
Various experiments have been carried out recently in the Middle East urban (Beer Sheva, Israel) environment for prediction of aerosol particle concentration and size distribution. During these experiments aerosol particle concentrations for different weather conditions were measured and analyzed. New aerosol size distributions are described in this work, based on an extensive series of measurements. This measurement data show the processes of absorption and scattering by aerosol particles in urban inhomogeneous areas for rainy atmospheric conditions. Several parts of the results are compared with those obtained through measurements in different geographic and climatic environments, as well as with different aerosol distribution models. Effects of different atmospheric conditions during rain on aerosol modeling are better described in this work.
Various experiments have been carried out recently in the Middle East urban (Beer Sheva, Israel) environment for prediction of aerosol particle concentration and size distribution. During these experiments aerosol particle concentrations for different weather conditions were measured and analyzed. This work proposes a new model for urban aerosol size distribution prediction based on an extensive series of measurements. The model introduces coefficients and characteristics of processes of absorption and scattering by aerosol particles in the urban inhomogeneous region for semi-arid and rainy atmospheric conditions. Several parts of the results are compared with those obtained through measurements in different geographic and climatic environments, as well as with different aerosol distribution models. It is shown that, in Middle East urban regions, larger differences in aerosol particle concentration are observed. Effects of different atmospheric conditions for urban aerosol modeling are better described by the model proposed in this work using parameters obtained empirically.
Recently, an extension of the Navy Aerosol Model (NAM) was proposed based on analysis of an extensive series of measurements at the Irish Atlantic Coast and at the French Mediterranean Coast. We confirm the relevance of that work for the distant eastern Meditteranean and extend several coefficients of that coastal model, proposed by Piazzola et al. for the Meditteranean Coast (a form of the Navy Aerosol Model), to midland Middle East coastal environments. This analysis is based on data collected at three different Middle East coastal areas: the Negev Desert (Eilat) Red Sea Coast, the Sea of Galilee (Tiberias) Coast, and the Mediterranean (Haifa) Coast. Aerosol size distributions are compared with those obtained through measurements carried out over the Atlantic, Pacific, and Indian Ocean Coasts, and Mediterranean, and Baltic Seas Coasts. An analysis of these different results allows better understanding of the similarities and differences between different coastal lake, sea, and open ocean zones. It is shown that in the coastal regions in Israel, compared to open ocean and other sea zones, larger differences in aerosol particle concentration are observed. The aerosol particle concentrations and their dependences on wind speed for these coastal zones are analyzed and discussed. We propose to classify the aerosol distribution models to either: 1. a coastal model with marine aerosol domination; 2. a coastal model with continental aerosol domination (referred to as midland coast in this work); or 3. a coastal model with balanced marine and continental conditions.
Various experiments have been carried out recently in Middle East (Israel) environments for prediction of aerosol particle concentration and size distribution versus sea-breeze wind speeds and overland ranges. During these experiments aerosol particle concentrations for different overland distances were measured and analyzed. This work proposes a new model for aerosol size distribution prediction up to 50-km distance away from the Mediterranean coast based on an extensive series of measurements. The model introduces coefficients and characteristics of processes of absorption and scattering by aerosol particles in the northern Negev desert areas. Effects of sea breeze wind over different ranges are described by the model proposed in this work using parameters obtained empirically.
Refractive index structure parameter, C2n, which characterizes turbulence caused by local gradients of microscale
meteorological parameters and by variations of macrometeorological features of the atmosphere such as air temperature, wind speed and direction, relative humidity, etc., is examined theoretically and experimentally for near ground Middle East environments. In our theoretical analysis, we present several known models for over-land atmospheric optical communication or imaging channels to predict the turbulence intensity (represented by C2n). Via comparison with our two-year continuous experiments carried out in Israel we show their limitations for both day- and nighttime turbulent atmospheres under different meteorological conditions. An extension of an existing "practical" model, applicable for two summer and winter seasons, is presented in this work which, as is shown experimentally, can be a good predictor of C2n for optical atmospheric paths in Middle East climates.
Line-of-sight bending, called "beam bending", is an effect caused by strong atmospheric turbulence, where during daytime targets are seen lower and during nighttime higher than their real locations. This effect takes place in conditions of very low or absence of wind speed and relatively high turbulence, which characterize non-uniform atmospheres. During past three years high-resolution experiments in different desert and low vegetation areas of the Middle East (Israel) were performed. A model for predicting line-of-sight bending based on effects of turbulence and atmospheric conditions, described by pressure, temperature, relative humidity, etc., was developed and investigated. This paper describes investigations made to parameterize this model based on high-percentage prediction of results for different areas, day/night time, and heights above the ground surface.
Recently several investigators proposed an extension of the Navy Aerosol Model (NAM) based on analysis of an extensive series of measurements at the Irish Atlantic Coast and at the French Mediterranean Coast. This work extends NAM by use of a similar analysis using data collected at three different Middle East Coastal areas: the Negev Desert (Eilat) Red Sea Coast, the Sea of Galilee (Tiberias) Coast, and the Mediterranean (Haifa) Coast. Results of the aerosol size distribution are compared with those obtained through measurements carried out over the Atlantic Ocean and Mediterranean Coasts. An analysis of these different results allows a better understanding of the similarities and differences between different coastal and open ocean zones. Parameterization is introduced. The aerosol particle concentrations and their dependences on wind speed for these coastal zones are analyzed and discussed.
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