the survey of temporal-spatial changing trend of nightly temperature in isfahan province

in this research the temporal-spatial changing trend of nightly temperatures in isfahan province has been studied with the purpose of manifesting temperature changes, recognition of temperature abnormality and comparison for the two methods of pixel and station. on this basis, the data of the minimum temperature average of 21 synoptic and climatology stations were processed in the said province and out of it during the statistical period 1961-2010. after assuring from abnormality of the data by the software ncss and minitab, and also homogeneity of the data using the tests of succession, kolmogorov-simonov and chi-square, by programming in software surfer, the station data were changed to the pixel data with the dimension of 5 x 5 km. then it was used in a matrix with the dimensions of 4260 x 600 and the trend of each pixel was calculated in matlab software, using the statistical- graphic test of mann – kendall in a significant level 95% in monthly and annual scale. in the station method, the missing data were restored by the interpolation method by surfer software. then the data trend was studied by the test of mann – kendal, data changes were recognized and their type and time were determined. the obtained results express that during the all months of the year, the positive trend dominated on the negative trend in a manner that in the pixel method it covers more than 41%of the area of the province per month and in the station method more then 12.5 % per month. concerning the place expansion also the positive trend dominated in low height areas located at east of the province. considering the drawn graph and equation for befitting line, nightly temperatures of this province is rising and it increased 0.052 per year and 2.6 centigrade degree during the recent half century.