Several ANN models were developed to prediction of monthly precipitation data in Mashhad synoptic station. From the total 636 monthly precipitation data (from 1958 to 2008), 580 data has been used for training networks and the rest selected randomly has been used for validation of the models. To extract the precipitation dynamic of this station by ANN, a new approach of three-layer feed-forward...

abstract obligatory modelling of precipitations in various periods, have a lot of problems and weakness because of their casual nature in time and space. moreover, their uncertainty in predictions, reduce credibility of estimations which have done via these models. wavelet is one of the novel and very effective methods in analyzing of time series and signals considered in the hydrology in recen...

during february of 2005 the north of iran witnessed the development and activity of a variety of severe meteorological systems accompanied with unusual heavy precipitation, mostly snow and hail. the rate and amount of snow in the northern coastal region was so heavy that it made a new record for that region with a report of more than 3m of snow in rasht, a city located in that area. also the da...

because of the role of climate parameters in climate change and improve the efficiency of climate and rainfall prediction models, the study of these parameters are very important in the world. the study of clouds have special important, because the clouds make connection between the synoptic patters and surface climate conditions and any change in its properties, can start a chain reaction in o...

Quantitative Precipitation Nowcasting (QPN) is one of the main applications of radar observations. On one hand, one of the most used nowcasting algorithms is Lagrangian extrapolation. It shows skill in specifying the timing and location of precipitation over short time periods, but shows low skill when using past precipitation trends to predict changes in precipitation intensity. On the other h...

Commentary: Prediction and Predictability 2 Concepts and GEWEX Recent News of Relevance to GEWEX 3 Ensemble Weather and Climate Prediction 4 Global Climate Predictability at Seasonal 6 to Interannual Time Scales NCEP Implements Major Upgrade to its 8 Medium-Range Global Forecast System The Hydrologic Ensemble Prediction 10 Experiment (HEPEX) Contributions of GAME and CEOP to 11 Operational Pred...

Precipitation, in meteorology, is defined as any product, liquid or solid, of atmospheric water vapor that is accumulated onto the earth’s surface. Water, and thus precipitation, has a major impact on our daily livelihood. As such, the uncertainty of both the future occurrence and amount of precipitation can have a negative impact on many sectors of our economy, especially agriculture. There is...