بررسی روند تغییرات دما، بارندگی و رطوبت نسبی در ایران

نوع مقاله : مقاله پژوهشی

نویسندگان

1 کارشناس ارشد مهندسی منابع آب، دانشگاه شهید چمران اهواز.

2 استاد دانشکده مهندسی علوم آب، دانشگاه شهید چمران اهواز

3 دانشیار دانشکده علوم و مهندسی آب، دانشگاه شهید چمران اهواز .

4 دانشیار دانشکده علوم و مهندسی آب، دانشگاه شهید چمران اهواز.

چکیده

اولین گام در راستای آشکارسازی و چگونگی تغییر اقلیم بررسی ناهنجاری و نوسانات ایجاد شده در پارامترهای اقلیمی میباشد. در این تحقیق به بررسی روند تغییرات پارامترهای اقلیمی دما، بارندگی و رطوبت نسبی در مقیاس‌ زمانی سالانه در 37 ایستگاه سینوپتیک کشور (2010-1961) با استفاده از آزمون‌های آماری ناپارامتریک من-کندال و تخمین‌گر شیب سن پرداخته شده است. به‌طور کلی نتایج حاکی از روند افزایشی دما و روند کاهشی بارندگی و درصد رطوبت نسبی در اکثریت نقاط کشور می‌باشد. در کل کشور به غیر از ایستگاه‌های مرتفع و کوهستانی شهرکرد، خرم‌آباد و سقز روند افزایشی دما مشاهده شد که بیشترین افزایش معنی‌دار دما (سطح اطمینان 95درصد) در ایستگاه‌های مشهد، زاهدان، زابل، بم، یزد، بابلسر، کرمانشاه، آبادان، خوی و تبریز به میزان 1.5 درجه‌ی سانتی‌گراد در طی 50 سال می‌باشد. روند کاهش بارندگی خصوصاً در نیمه‌ی شرقی، غرب و شمال غرب کشور مشاهده گردید که بیشترین کاهش بارندگی معنی‌دار (سطح اطمینان 95 درصد) در  شمال غرب کشور و در حدود 3.2 میلی متر در سال می‌باشد. روند کاهش رطوبت نسبی در اغلب نواحی به غیر از قسمتی در ناحیه‌ی شمال غرب و جنوب دریای خزر مشاهده شد که بیشترین کاهش معنی‌دار در سطح اطمینان 95 درصد در ایستگاه‌های آبادان، زاهدان و کرمانشاه در حدود 4.1 درصد در 50 سال گذشته می‌باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Trend Analysis of Temperature, Precipitation, and Relative Humidity Changes in Iran

نویسندگان [English]

  • Anahita Eblaghian 1
  • Ali mohammad Akhondali 2
  • Fereydon Radmanesh 3
  • Heidar Zarei 4
1 M.Sc. of Hydrology and Water Resource Engineering Department of Shahid Chamran University of Ahvaz, Iran.
2 professor, faculty member of Hydrology and Water Resource Engineering Department of Shahid Chamran University of Ahvaz, Iran
3 Associate professor, faculty member of Hydrology and Water Resource Engineering Department of Shahid Chamran University of Ahvaz, Iran.
4 Associate professor, faculty member of Hydrology and Water Resource Engineering Department of Shahid Chamran University of Ahvaz, Iran.
چکیده [English]

Introduction
In the pursuit of detecting the trend and the shift in trend in hydro-meteorological variables, various statistical methods have been developed and used over the years. Of the two methods commonly used (parametric and non-parametric), the non-parametric method has been favored over parametric methods. Long term trend analysis can reveal the beginning of the trend year, trend changes over time, and abrupt trend detection in a time-series. It is expected that the findings of this study will bring about more insights on understanding the regional hydrologic behavior over the last several decades in Iran.
 
Methodology
This paper analyzes the behavior of annual and seasonal temperatures, precipitation, and relative humidity. Datasets of 37 stations in Iran were analyzed from 1961 to 2010. The
 pre-whitening technique was used to eliminate the effect of the autocorrelation of data series. The Mann–Kendall (MK) test and the Sen's slope estimator were applied to quantify the significance of the trend and the magnitude of the trend at a 95% confidence level, respectively. The surface interpolation technique was used to prepare a spatial temperature, precipitation, and relative humidity data map over Iran from the point data measuring stations within the ArcGIS framework. For spatial distribution of trends in maps, contours are generated using an inverse-distance-weighted (IDW) algorithm.

کلیدواژه‌ها [English]

  • Trend
  • Nonparametric Tests
  • Mann-Kendall Test
  • Sen's Slope Estimator
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