UAE temperatures likely to increase, but so will summer rainfall, say researchers

The Arabian heat low has intensified over the past 41 years, a trend thought to be caused by climate change

Temperatures in the Gulf have been rising for 40 years.

Climate researchers have predicted summer temperatures in the UAE will increase after they identified a strengthening of a key weather system associated with hotter air.

Scientists at Khalifa University of Science and Technology found the Arabian heat low has intensified and grown over the past four decades, a trend thought to be caused by climate change.

This low-pressure system is linked to the extremely high temperatures the Gulf region experiences each summer.

“This means that the region witnessed an increase in summer temperature extremes and this impacted larger areas,” said Dr Diana Francis of Khalifa University, one of the authors of a paper that details the research.

Heat lows, also called thermal lows, are caused when land areas in the subtropics are heated strongly during warmer parts of the year.

Over the past 41 years, the Arabian heat low “exhibits a clear positive trend”, according to the paper, with the weather system intensifying and growing larger.

Related to this were what Dr Francis described as “positive trends” in maximum temperatures during the summer, which are "likely linked to global warming”.

“The UAE lies in the centre of the summer Arabian heat low and therefore the extreme summer temperatures recorded over the UAE are directly linked to the heat low,” she said.

Previous studies have shown the Gulf region has some of the most severe hot and humid weather on the planet.

As reported in The National last year, the Arabian peninsula has been the site of more than half of the extreme temperature and humidity readings recorded on Earth.

Scientists in the UK and US analysed readings from weather stations and found that, of the 14 most extreme readings ever recorded on land, all of which happened in the past two decades, eight took place in the Gulf region.

Dr Francis, who heads Khalifa University’s Environmental and Geophysical Sciences laboratory, said the new study indicated that warming would continue.

“Based on our analysis of the past four decades, we expect a continuity in the observed trends, which will translate to an increase in temperatures during summer over the region as well as an intensification of the AHL [Arabian heat low] both in magnitude and size,” she said.

As well as analysing the Arabian heat low, which is associated with the weather system that causes the summer monsoon in South Asia, the research looked at the intertropical discontinuity, which is the boundary between hot and dry desert air and moister air from the Arabian Sea.

While this boundary has an annual cycle in which it moves north each summer, its average location has also been migrating north.

The intertropical discontinuity (ITD) helps to form clouds over the UAE in the summer, and there is likely to be more rain as a result.

“The arrival of the ITD over the UAE in summer announces the arrival of summertime convection and rain over the country,” Dr Francis said.

“The ITD showed slight progress northward … which could be related to the expansion of the tropics associated with the climate change, where a warmer atmosphere can hold more water vapour.

“We project an increase in convection and rain during summer due to the projected expansion of the tropics.”

The potential link between climate change and the changes happening to weather systems in the region will be a focus of the Environmental and Geophysical Sciences laboratory's future work.

The new study is co-authored by two postdoctoral fellows at Khalifa University, Dr Ricardo Fonseca and Dr Narendra Nelli, and Dr Mohan Thota of the National Centre for Medium Range Weather Forecasting in Noida, India.