By:Tahereh Ensafi Moghadam Aridity zoning of dry-land (Climatic Index of desertification) based on precipitation and temperature in central basin of Iran

1.Determine the geographical situation on the map 2.Select of meteorological stations 3.Extraction of climatic Data for 35 stations 4.Synthetic statistics generation 5.Statistical calculations 6.Research Conclusion 7.Dryness Climatic Index measurement method 8.Assessment the climatic dryness intensity and spreading by drawing of map Research Methods

Extraction of climatic Data *Monthly precipitation *Maximum daily precipitation *Monthly temperature minimum average *Monthly temperature maximum average *Absolute maximum temperature *Absolute minimum temperature

Statistical Calculations on the Climatic Data: 1) Calculation of Montly and Annual Climatic Data Average, variance and Standard deviation 2) Calculation of Mean Annual temprature about 35 stations in the career 3) Calculation of seasonal fluctuation about 35 stations in the career 4) Calculation of temprature range fluctuation about 35 stations in the career 5) Calculation of Annual and Montly Temprature and rain Coefficient of variability about 35 stations in the career 6) Calculation of Interannual relative Rainfall Variability about 35 stations in the career 7) Calculation of Montly and Annual Average, variance and Standard deviation about total of obtain results in the career 8) Calculation of Montly and Annual Z score about total of obtain results in the career 9) Collection 0f Montly and Annual Z score together and divide to columns number (Dryness Climatic Index constructing) 10)Drawing of ( Dryness Climatic Index ) maps and graphs about 35 stations in the career

:Synthetic statistics generation *Calculation of ‍Permissible limit of statistic prolongation with use: *correlation coefficient of Dipendant and indipendant stations *Number of statistical years and number of common years between Dipendant and indipendant stations and use follow formul: *With Extraction of a & b quantities and their replace in regrresion equation(Y=a+bx), reducted lack of data dipendant stations

Classifying of Climate: in order to climate classify, in this study the method of De MARTONNE has been used. De MARTONNE proposed a coefficient dryness as follows: The climate regions is divided in four climatic zones namely: Extra-Arid zone, Semi-Arid zone, Desert- Arid zone and Mediteranian zone. The regional climate average is Semi-Arid according to the method of De MARTONNE. P M = T + 10

Climatic dryness zones map in Central basin according to De MARTONNE Index

For calculate of z scores, first, has been obtain total of average and total of standard deviation of calculated results. Then according to formula, has been calculated precipitation and temprature z scores seprately and the answers insert to a column under title z scores column. After select of most important and most determining of z score, including of: 1) Annual Coefficient of Rainfall Variability 2) Annual Coefficient of Temprature Variability 3) Montly Coefficient of Rainfall Variability 4) Interannual relative Rainfall Variability 5) Temprature Annual and seasonal fluctuation Average of month warmest maximums (july)- Average of month coldest minimums (jan) 6Temprature Annual and seasonal Range: Temperature maximum average in every season - Temperature minimum averagein the same season Dryness Dryness Climatic Index (DCI) measurement method

Dryness Climatic Index (DCI) formula whole of Z scores has been gathered together and has been divided to columns number. Obtained results Which is changed among –2 untill +3, is a criteria under title: “Desertification Climatic Index” for determining the climatic dryness intensity and spreading.

Climate degrees intensity classification table on the basis of (DCI)

Assessment of Dryness Climate degrees intensity on the basis of (DCI) For indicate “DCI” variability during 40 years, the linear diagarms has been drawn for every station and In this program the Mean of all stations, merely interprete.

Maximum degrees intensity DCI:(1973)+0.72 Moderate Climatic Dryness Minimum degrees intensity DCI:(1957) - 0/73 : Desirable climate Trend:Positive

Climatic Dryness PROCESS IN CENTRAL BASIN OF IRAN (1957)

Climatic Dryness PROCESS IN CENTRAL BASIN OF IRAN (1958)

Climatic Dryness PROCESS IN CENTRAL BASIN OF IRAN (1959)

Climatic Dryness PROCESS IN CENTRAL BASIN OF IRAN (1968)

Climatic Dryness PROCESS IN CENTRAL BASIN OF IRAN (1969)

Climatic Dryness PROCESS IN CENTRAL BASIN OF IRAN (1980)

FORTY MAP & TABLE OF CLIMATIC DRYNESS PROCESS IN CENTRAL BASIN OF IRAN

10 YEARS MOVING AVERAGE GRAPH OF ARIDITY ZONES PERCENT IN CENTAL BASIN OF IRAN The positive gradient of trend line in this graph obviously explains, continuation of this movement in future years 10 YEARS MOVING AVERAGE GRAPH OF ARIDITY ZONES PERCENT IN CENTAL BASIN OF IRAN

*Conclusion: DCI Index suggest climatic effects on Dryness and it is one of most suitable criteria for determining the climatic dryness intensity and spreading As of result of this research, spreading and intensity degrees, during 17 years of the forty years career, has enjoyed of desirable and slightly desirable climatic and too, 23 years of this term, has allocated to low climatic dryness degrees with tendency to moderate climatic dryness. * Among 35 stations of one long term, Varamin station and interpolation areas of its around with sq km, has exposed climatic dryness, more than of other stations The Central basin of Iran, however, not so very, but with quiet and continuously movement, has been led toward climatic dryness.