International Journal of Students Research in Technology & Management Vol 2 (03), May 2014, ISSN 2321-2543, pg. 109-112 http://www.giapjournals.org/ijsrtm.html 109 An Assessment of Temperature and Precipitation Change Projections in Muscat, Oman from Recent Global Climate Model Simulations Abdulaziz Al-Ghafri #1 , Luminda Gunawardhana #2 , Ghazi Al-Rawas #3 # Department of Civil and Architectural Engineering, Sultan Qaboos University P.O. Box 33, Postal code 123, Al-Khoud, Sultanate of Oman 1 u088532@student.squ.edu.om 2 luminda@squ.edu.om 3 ghazi@squ.edu.om Abstract — Oman is vulnerable to the impacts of climate change, the most significant of which are increased temperature, less and more erratic precipitation, see level rise (SLR) and desertification. The objective of this research is to investigate the potential variation of precipitation and temperature in Muscat, the capital city of Sultanate of Oman in future. We used the MIROC general circulation model (GCM) output (maximum and minimum temperatures and precipitation) from the Representative Concentration Pathways (RCPs) 2.6, 4.5, 6.0 and 8.5 scenarios of the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) for assessing changes in climate in the period of 2080-2099 compared to the baseline period of 1986-2005. The spatial mismatch between GCM grid scale and local scale was resolved by applying the LARS stochastic Weather Generator (WG) model. The results obtained for 4 scenarios indicate a significant warming in future, which ranges from 0.93 ᴼ C (minimum temperature by 1.1 ᴼ C and maximum temperature by 0.86 ᴼ C) for the lowest scenario, RCP 2.6, to 3.1 ᴼ C (minimum temperature by 3.2 ᴼ C and maximum temperature by 3.0 ᴼ C) for the highest one, RCP 8.5, relative to baseline level. The differences in the precipitation projections between the scenarios are much greater compared to consistent warming depicted in temperatures. The results reveal -36.4% and -36.0% decreases in precipitation for the RCP 2.6 and RCP 4.5 scenarios, respectively, while, RCP 6.0 and RCP 8.5 scenarios predict increase in precipitation in a range from 9.6% to 12.5%, respectively during 2080-2099 compared to 1986-2005 period. These results need to be further improved by adopting more GCMs, which will provide potential changes in a consistent range. I. INTRODUCTION Observed and projected increases in temperature and precipitation variability are perhaps the most influential climate driven changes to impact water systems (Parry et al., 2007). Located in an arid region, the climate of Oman is vulnerable to the potential impacts of climate change, the most significant of which are increased average temperatures, less and more erratic precipitation, sea level rise (SLR) and desertification. Oman is primarily concerned due to its chronic water stress and lack of resilience (institutional, infrastructure and social) against climate change. Groundwater represents about 78% of the water supply in Oman. Owing to a lack of data and the very slow reaction of groundwater systems to changing recharge conditions, impacts of climate change on groundwater are poorly understood. Groundwater resources are related to climate change through hydrologic processes, such as precipitation and evapotranspiration, and through interaction with surface water. With increased evapotranspiration as a result of higher air temperature and decreased precipitation, the impact of climate change will result in declining groundwater recharge (Eckhardt and Ulbrich, 2003; Brouyere et al., 2004) and alter the associate temperature distribution in the subsurface. For example, in the Ogallala Aquifer region, projected natural groundwater recharge decreases more than 20% in all simulations with warming of 2.5°C or greater (Rosenberg et al., 1999). Integrating climate change mitigation and adaptation in development strategies and policies is a must for Oman which is at the early stage of economic and industrial development. Thus far in Oman, the scientific knowledge about the climate change and its impacts on the hydro-meteorological extremes has not been fully studied thereby making it difficult to assess future risks. Therefore, the main objective of this research is to investigate the potential variation of precipitation and temperature in Muscat, the capital city of Sultanate of Oman in future. II. STUDY AREA Oman located in south-Eastern corner of the Arabian Peninsula, encompasses a diverse range of topography, including mountain ranges, low land, coastal areas and arid deserts. The coastal line of Oman extends over 3165 km and experiences very severe tropical cyclones. The supper cyclonic storm, hurricane Gonu in 2007 led to the worst natural disaster on record in Oman, with total rainfall reached 610 mm near the cost. The cyclone and flash flood caused about $4 billion in damage (2007 USD) and 49 deaths (Rafy and Hafez, 2008). The climate of the country is mainly arid or semiarid, which receives less than 100 mm in annual rainfall on average compared to annual global average of 1123 mm.