Getting a better idea of the UAE’s rainfall

September 21, 2018

By Dr. Taha B.M.J. Ouarda
February 15, 2014

Desalination may be the major source of the water we use in our daily lives, but rainfall still plays an important role in the UAE. It is critical for replenishing natural water supplies, refilling dams, wells and reservoirs. It also helps keep the air clean and provides the moisture that keeps our desert ecosystems thriving.

But how much rain can we expect in the future? Previous studies have indicated that the whole region faces a general decline in its overall rainfall, but we need to know more – and so a team of Masdar Institute researchers, working with researchers from the Massachusetts Institute of Technology, is studying climate variability and change in the region, and the impact they have on water resources.

We have analyzed the rainfall over time at stations across the UAE, to try to spot trends and predict potential change. We looked into the total annual, seasonal and monthly rainfall; annual, seasonal and monthly maximum rainfall; and the number of rainy days per year, season and month.

And we have found that while some data does give evidence of a decrease in rainfall, the data is not always statistically significant. There does seem to be less rain in February and March – the two rainiest months of the year.

But there is more to the data than this. More sophisticated analysis found that, for all of our rain measurement stations, the general trend is actually for an increase in the amount of rainfall, although the year 1999 corresponds to a drop in rainfall amounts.

We have also been trying to understand the underlying climate mechanisms, in order to better model the long-term variability in rainfall in the UAE and the Arabian Peninsula. In this research, we found a strong correlation between rainfall in the UAE and climate oscillations such as the El Niño-Southern Oscillation (ENSO).

It also seems that, over the past 15 years, rain has been falling on the UAE earlier in the winter, with most important rains falling between December and February, rather than in February and March.

While this research has allayed some concerns that the UAE and the region overall are becoming more dry, more work is needed to fully understand the dynamics of climate variability in the UAE and to detect any long-term changes.

The better we understand the UAE’s precipitation trends, the better we can manage agriculture, flood protection, drought emergency response, water resources planning and management, and urban planning.

Good planning in these areas will provide the UAE with reduced losses from extreme events, and safeguard a brighter future for the country.
Dr Taha B.M.J. Ouarda is a professor at Masdar Institute of Science and Technology and head of the Institute Centre for Water and Environment (iWater).