the two main approaches for estimating pmp are the synoptic and statistical techniques that their results are often different and selection of the appropriate option is difficult. in the most previous researches the frequency factor in the statistical method has been considered equal to 15 which this is the ultimate limit of frequency factor and the corresponding pmp is became too large. in the...

climatic parameters in time and space scales of change are for many reasons of changes and how they should be based on observations using a statistical method to be determined. analysis of the most widely used statistical methods that assess potential climate change on hydrological time series, such series of precipitation, temperature and flow rate used. this study of 11 synoptic,rain gage and...

The long-standing mainstay of support for C. T. R. Wilson’s global circuit hypothesis is the similarity between the diurnal variation of thunderstorm days in universal time and the Carnegie curve of electrical potential gradient. This rough agreement has sustained the widespread view that thunderstorms are the ‘‘batteries’’ for the global electrical circuit. This study utilizes 10 years of Trop...

An archive of land-based, surface-observed cloud reports has been updated and now spans 39 years from 1971 through 2009. Cloud-type information at weather stations is available in individual reports or in long-term, seasonal, and monthly averages. A shift to a new data source and the automation of cloud reporting in some countries has reduced the number of available stations; however this datas...