روندهای تغییر اقلیم طی دو دوره در همدان و تبریز

نوع مقاله: مقاله پژوهشی

نویسندگان

دانشگاه بوعلی سینا

چکیده

در این پژوهش، تغییرات اقلیمی همدان (ایستگاه نوژه) و تبریز در دو دورة 41 و 55 سالة منتهی به سال 2005 میلادی با آزمون­های من-کندال و رگرسیون خطی بررسی شد. نتایج دورة 55 ساله برای همدان نشان دهندة روند کاهش بارندگی بهاره و افزایش سرعت باد در مقادیر سالانه، بهار و تابستان و همچنین روند افزایش بیشینة دما در میانگین سالانه و اواخر زمستان تا اوایل پاییز بود. همزمان، روند کاهش کمینة دما در دورة 55 ساله به روند افزایشی در دورة 41 ساله تغییر یافت. در دورة 41 ساله، میانگین سالانه و تابستانة دمای متوسط و میانگین سالانه، زمستان، اواخر تابستان و اوایل پاییز ساعات آفتابی افزایش یافت. تغییرات 55 ساله در تبریز شامل کاهش بارش سالانه و زمستان، رطوبت نسبی در طول سال و سرعت باد در تابستان و از طرفی افزایش کمینه، بیشینه و متوسط دمای سالانه و تابستان بود. در دورة 41 ساله، تبخیر- تعرق گیاه مرجع در زمستان، اوایل بهار و اوایل پاییز روند افزایشی داشت که همزمان با روند کاهشی رطوبت نسبی و روند افزایشی ساعات آفتابی و دماهای کمینه، بیشینه و متوسط بود. در مجموع با کاهش بارندگی و افزایش تبخیر- تعرق، شاخص خشکی در تبریز روند کاهشی داشته و اقلیم آن خشک­تر شده است. 

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Climate Change Trends During Two Periods in Hamedan and Tabriz

نویسندگان [English]

  • M Karimi Kakhki
  • A Sepehri
چکیده [English]

This study was carried out to investigate climate change at Hamedan-nozheh and Tabriz meteorological stations during two periods of 55 and 41 years ending to 2005, using nonparametric Mann-Kendall and parametric linear regression tests. Results indicated the upward trend of maximum temperature in Hamedan at annual scale and at late winter to early autumn in 55 years period. Increasing wind speed at annual scale, spring and summer and decreasing of the spring precipitation were occurred in this period. The minimum temperature had synchronous downward trend. In 41 years period, the maximum temperature was stable and decreasing minimum temperature trend was changed to upward trend. Also, the mean temperature at annual scale and summer and the sunshine hours at annual, winter, late summer and early autumn were increased. Noticeable changes in Tabriz climate were decreasing of precipitation at annual scale and winter, decreasing of the relative humidity throughout the year, decreasing of the wind speed at summer and increasing of the minimum, maximum and mean temperatures at annual scale and summer in 55 years period. In 41 years period, reference evapotranspiration had upward trend at winter, early spring and early autumn. The relative humidity and sunshine hours had synchronous downward and upward trends, respectively. Also, the minimum, maximum and mean temperatures had upward trends in some cases. Altogether, aridity index had downward trend in consequence of precipitation decrease and reference evapotranspiration increase in Tabriz that led to rise of climate aridity.  

کلیدواژه‌ها [English]

  • Aridity Index
  • Precipitation
  • Reference evapotranspiration
  • Trend
Allen RG, Pereira LS, Raes D and Smith M, 1998. Crop Evapotranspiration: Guidelines for Computing Crop Water Requirements. FAO Irrigation and Drainage Paper No 56. FAO, Rome.
Anonymous, 2009. ETo Calculator, Land and Water Digital Media Service, No. 36. FAO, Rome.
Anonymous, 2007. Climate Change Adaptation and Mitigation in Developing Countries. Summary for Policymakers. Intergovernmental Panel on Climate Change (IPCC), Geneva, Switzerland.
Anonymous, 2007. Confronting Climate Change. Report prepared for the United Nations Commission on Sustainable Development. Sigma Xi, Research Triangle Park, NC, and the United Nations Foundation, Scientific Expert Group on Climate Change (SEG), Washington DC.
Anonymous, 1979. Aridity definition (UN documents), United Nations Educational, Scientific and Cultural Organization, UNESCO, New York.
Chen S, Liu Y and Axel T, 2006. Climatic change on the Tibetan plateau: potential evapotranspiration trends from 1961–2000. Climatic Change 76: 291–319.
da Silva VPR, 2004. On climate variability in Northeast of Brazil. J Arid Environ 58: 575–596.
Hu ZZ, Yang S and Wu R, 2003. Long-term climate variations in China and global warming signals. J Geophys Res 108: 34–46.
Jhajharia D, ShrivastavaSK, Sarkar D and Sarkar S, 2009. Temporal characteristics of pan evaporation trends under the humid conditions of northeast India. Agric For Meteorol 149: 763–770.
Jung HS, Choi Y, Oh JH and Lim GH, 2002. Recent trends in temperature and precipitation over South Korea. Int J Climatol 22: 1327–1337.
Loaiciga HA, Valdes JB, Vogel R, Garvey J and Schwartz H, 1996. Global warming and the hydrological cycle. J Hydrol 174: 83–127.
Manton MJ, Della-Marta PM, Haylock MR, Hennessy KJ, Nicholls N, Chambers LE, Collins DA and Daw G, 2001. Trends in extreme daily rainfall and temperature in Southeast Asia and the South Pacific; 1961–1998. Int J Climatol 21: 269–284.
Modarres R and da Silva VPR, 2007. Rainfall trends in arid and semi-arid regions of Iran. J Arid Environ 70: 344–355.
Pal I and Al-Tabbaa A, 2009. Trends in seasonal precipitation extremes – An indicator of ‘climate change’ in Kerala, India. J Hydrol 367: 62–69.
Palle E and Butler CJ, 2001. Sunshine records from Ireland: Cloud factors and possible link to solar activity and cosmic rays. Int J Climatol 21: 709–729.
Roderick ML and Farquhar GD, 2002. The cause of decreased pan evaporation over the past 50 years. Science 298: 1410–1411.
Seneviratne SI, Lüthi D, Litschi M and Schär C, 2006. Land–atmosphere coupling and climate change in Europe. Nature 443: 205–209.
Todisco F and Vergni L, 2008. Climatic changes in central Italy and their potential effects on corn water consumption. Agric For Meteorol 148: 1–11.
Vinnikov KY, Grody NC, Robock A, Stouffer RJ, Jones PD and Goldberg MD, 2006. Temperature trends at the surface and in the troposphere. J Geophys Res 111: 103-116.
Zhai P and Pan X, 2003. Trends in temperature extremes during 1951-1999 in China. Geophys Res Lett 30: 13–19.