oa 2015, A Year of Climate and Air Quality Anomalies

We report on a number of climate and air quality anomalies during 2015 and their potential impacts on human health, solar power generation and water security in Qatar and the wider region. The anomalies include a strong cut-off low pressure system and accompanying sand-storm in early April, elevated Sea Surface Temperatures (SST) from early summer through October in the Arabian Gulf, substantially higher year-on-year particulate matter concentrations (PM10 and PM2.5) in Qatar, and the development of two late season record strength cyclones in the Arabian Sea.

The impacts of climate change and air quality on sustainable development and human health are important considerations for all countries. The manifestations of climate change may differ from region to region, but the effects of a warming anomaly in the world's oceans, known as El Niño, has global reach. We present an analysis of surface observations, upper air and satellite data over Qatar and the GCC that relate the occurrence of these anomalies to the development of El Niño within the context of a changing climate.

The summer of 2015 saw increased ambient temperatures, dew point temperatures (a measure of relative humidity) and SST, compared to climatological averages, throughout much of the region. The July heat wave [Schär, 2015] resulted in temperatures in excess of 45C and SST exceeding 34C on July 31st. We report a substantial increase in particulate matter concentrations in the Doha urban area, as high as 20%-50% higher than the same period in 2014, during the summer months and into late October and early November. The higher concentrations of particulates are linked to increased evaporation and flux of sea salt particles during the warmer summer and their growth by interaction with emissions from the urban environment.

Tropical cyclones Chapala and Megh, developed one week apart in late October and early November, and were unprecedented in the historical record. Tropical cyclone Chapala developed over the warmest ever-recorded sea surface temperatures in the Arabian Sea and intensified to a Category 4 storm, causing severe damage.

The Southwest Monsoon keeps tropical cyclones from forming in the Arabian Sea for much of the year, allowing only a short season from May to early June before the monsoon arrives, and another short season in late October through November after the monsoon has departed. Arabian Sea tropical cyclones during the pre-monsoon period in May and June have become stronger over the past thirty years owing to a reduction in vertical wind shear brought about by dimming of sunlight from air pollution particles primarily emitted in India [Evan et al., 2011].

[Evan et al., 2011] also speculated that continued growth in air pollution emissions might also reduce wind shear in the post-monsoon October-November period, thus increasing the likelihood of development of intense tropical cyclones during that time. This is corroborated by evidence of the substantially higher year-on-year particulate matter concentrations in Doha presented earlier and the development of the two tropical cyclones in October and November.

Finally, we correlate the observed anomalies with projected climate trends to predict the contributions from climate change and air quality to human health impacts as well as those related to solar power generation and water security in Qatar and the region.