Projected Changes in Annual Temperature and

Precipitation in Semi Arid Region

          (North East of Algeria)

 

 

Tarek Bouregaa (1)   and Mohamed Fenni (2)

  (1), (2) Laboratory of Valorization of Biological and Natural Resources, Faculty of Natural and Life Sciences, University Setif 1, Algeria

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Abstract- Known for its arid and semi-arid climate, Algeria is highly vulnerable to climate change. There is now a strong consensus that climate change presents a fundamental challenge to the well being of all countries, with potential of being the harshest on countries already suffering from water scarcity.  In this communication we present the projected temperature and precipitation changes in semi arid region of Algeria (Setif high plains) between three time slices: 2011- 2040 (centered on 2025), 2036-2065 (centered on 2050) and 2061-2090 (centered on 2075). MAGICC – SCENGEN5.3 (version 2) was used as a tool for downscaling the 4 chosen general circulation models (GCMs) output data. The projections are based on the SRES A2 and B2 scenarios. Under A2 scenario, The average model prediction of warming is 0.97, 1.75 and 2.88 °C across the three time slices, while the annual precipitation total is expected to reduce from -9% to -25.6%. Under B2 scenario, the four models estimate an increase in global temperature, but less than the first scenario. The average model prediction for the decrease in precipitation is -5.8%, -9.8% and -14.1% across the three periods.

 

Keywords- Temperature, precipitation, Semi arid, MAGICC -SCENGEN, GCMs.

                                                                                                                                                                       

Introduction

      For many parts of the arid and semi arid regions there is an expected precipitation decrease over the next century of 20% or more. The trend of increasing annual mean temperature that has been observed for the second half of the 20th century in North Africa is likely to continue and to cause warmer and drier conditions. Temperatures are likely to rise between 2 and 3 °C while precipitation is likely to decrease between 10% and 20% until the year 2050 under SRES A1B scenario conditions [1]. Precipitation of North Africa is characterized by a wet season in winter and dry conditions in summer. The rainy season, which starts in October and lasts until April, has its maximum in the months from December to February [2]. Over the last 50 years, an increase in extreme weather events has been observed in Algeria. Experts from the ‘Hydro-meteorological Institute for Training and Research’ foresee a reduction in the rainy season and a rise in temperatures of around 1°C to 1.5°C by 2020, which would have fatal consequences for 30 percent of animal species. They also estimate that temperatures will rise a further 3°C by 2050 due to global warming [3].

   The main objective of this study is to show the impact of global warming on annual temperature and precipitation changes during three periods of the 21st century in Setif high plains region by using four GCMs under two emission scenarios.

 

 

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