Flash droughts developing faster in southeast China amid climate change
A new PolyU study published in Nature Communications has found that southeast China – the region spanning from the Yangtze River Delta to Hainan province – is at a higher risk of experiencing more rapid drying, with an increase in the proportion of flash droughts developed within five days by as much as 18.67 per cent during 2000 - 2020.
The finding by Dr Wang Shuo, Assistant Professor of PolyU’s Department of Land Surveying and Geo-Informatics, showed that contrary to the common understanding that the region is vulnerable to typhoons, rainstorms and floods, rapidly developing flash droughts are actually emerging at a faster rate in the region and many parts of the world amid climate change.
Ordinary droughts usually take five to six months or an even longer time to develop to full strength. But for flash droughts, their rapid onset in less than a month and the fast depletion of water availability means there are less early warning indicators for impact preparation, according to Dr Wang.
“Flash drought occurrence is often accompanied by above-average temperatures and a precipitation deficit, which may trigger compound extreme events such as the concurrence of a flash drought and heat wave. Thus, flash droughts can pose even more serious threats to urbanised areas like Hong Kong due to the urban heat island effect,” he said.
Compared with traditional, slowly developing droughts, flash droughts evolve with a relatively fast depletion of soil moisture that may cause an imbalance of ecosystems and agricultural systems.
Based on different data sets that use satellite soil moisture measurements, the study found that although flash droughts are not becoming more frequent in most parts of the world, they are developing at a faster rate (i.e. in a shorter period of time). Out of all flash droughts that occurred in the past two decades, these data sets showed that there was about 33.64 - 46.18 per cent of flash droughts that developed within five days, representing an increase of 3.23 - 19.03 per cent during the period.
“Governments and the public should realise the increasing flash drought risk in addition to commonly known extreme weather events, and adapt to such emerging climate-induced natural disasters. It is crucial to improve traditional drought monitoring systems and indicators for capturing rapidly evolving flash droughts,” Dr Wang said.
You Might Also Like
“Art and Culture Series” back in May to celebrate PolyU 85th Anniversary
Art and culture enrich our lives in many ways, inspiring our creativity and nurturing our appreciation of beauty. At PolyU, art an...
Transforming research excellence into societal impact
With the concerted efforts of scientists and researchers from different academic backgrounds, PolyU brings together knowledge, experience and intelligence to solve pressing problems of our time, working towards a more sustainable future for all. The Faculty of Applied Science and Textiles (FAST) has recently produced the new “FAST Research Impact 2022” video series, illustrating how FAST researchers translate their research into real-world applications and contribute to society and the world. Check out the teaser video to learn more!
Nine PolyU disciplines rank top 10 nationally by Research.com
PolyU is thrilled to announce that the University has attained remarkable results in the recently announced 2022 Top Universities Rankings conducted by the international academic website Research.com, based on the assessment of h-index performance...