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۱Retrieval of Total Perceptible Water (TPW) From NOAA –16 Satellite Data over Land
نویسنده(ها): ،
اطلاعات انتشار: پنجمین کنفرانس بین المللی پیشرفتهای علوم و تکنولوژی، سال
تعداد صفحات: ۹
Radiance measurements from satellites offer the opportunity to retrieve atmospheric variables at much higher spatial resolution than is presently afforded by in situ measurements (e.g., radiosondes). However, the accuracy of these retrievals is crucial to their usefulness, and the ill–posed nature of the problem precludes a straight forward solution. In this paper, an inversion neural network method has been investigated to retrieve Total Perceptible water (TPW), over Iran, from Advanced Microwave Sounding Unit–B (AMSU–B) measurements on NOAA–16 satellite. Because this satellite passes over Iran at approximately the radiosonde launch times, 0000 GMT, collocated radiosonde data were available for training and comparison with the satellite brightness temperature. The collocated radiosonde observations, at 00.00 GMT, and AMSU–B data during 2003 – 2007 are employed to build the neural network training and testing data sets. Overall 1250 days of collocated AMSU–B and radiosonde data were matched in this period. The Root Mean Square Error (RMSE) of TPW retrieved with neural network algorithm is about 3.45 mm and mean bias of 0.86 for entire sounding over Iran land. The RMS errors of the TPW retrieved with the trained neural network are compared with the errors from the multi–linear regression method. It is show that the neural network – based algorithm can provide much better results in the experimental region in all weather conditions<\div>

۲Study of long–term Trend in Dust Distribution over Persian Gulf: Satellite Imagery Application and Weather Charts interpretation
نویسنده(ها): ، ، ،
اطلاعات انتشار: هفتمین کنفرانس بین المللی پیشرفتهای علوم و تکنولوژی، سال
تعداد صفحات: ۶
Landuse change, loss of soil moisture and special dynamic and thermodynamic conditions can caused intense soil erosion and dust storms. Emission of dust on land surface is a function of wind shear and surface properties. According to marginal basin properties of Persian Gulf, this area suffers from high level mineral dust concentration during the year. As first step, annual mean aerosol concentrations were studied using satellite data from SeaWiFS sensor over Persian Gulf during 1997–2010. It was observed that in this area is experienced high level of concentrations in 2005. Then, the inter–annual variability of mineral dust concentration was studied and it has usually shown monthly peak of concentration in June–July, but in 2005 it was occurred in April with strong positive anomaly. Thereafter, in order to determine the weather conditions during April 2005, actual weather charts were interpreted in surface and standard synoptical levels. It is observed that five synoptical scale cyclones, originated from the east of Mediterranean Sea have crossed this region during April 2005. These systems were associated with significant dynamical baroclinicity in low level troposphere and perfect surface wind shear over known dust emission sources over marginal basin of Persian Gulf.<\div>
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