Ziping Zuoa, Jimmy C.H. Funga,b,
Zhenning Lia,*, Yiyi Huangd, Mau
Fung, Wonga, Alexis K.H. Laua,c,
Xingcheng Lue
a Division of Environment and Sustainability,
The Hong Kong University of Science and Technology, Clear Water Bay,
Hong Kong, China
b Department of Mathematics, The Hong Kong
University of Science and Technology, Clear Water Bay, Hong Kong, China
c Department of Civil and Environmental
Engineering, The Hong Kong University of Science and Technology, Clear
Water Bay, Hong Kong, China
d Department of Hydrology and Atmospheric
Sciences, University of Arizona, Tucson, AZ, USA
e Department of Geography and Resource
Management, The Chinese University of Hong Kong, Shatin, Hong Kong,
China
Corresponding author: Zhenning Li,lzhenn@ust.hk
ABSTRACT
Recent worldwide heatwaves have shattered temperature records in many
regions. In this study, we applied a dynamical downscaling method on the
high-resolution version of the Max Planck Institute Earth System Model
(MPI-ESM-1-2-HR) to obtain projections of the summer thermal
environments and heatwaves in the Pearl River Delta (PRD) considering
three shared socioeconomic pathways (SSP1-2.6, SSP2-4.5, and SSP5-8.5)
in the middle and late 21st century. Results indicated that relative to
the temperatures in the 2010s, the mean increases in the summer
(June–September) daytime and nighttime temperatures in the 2040s will
be 0.7–0.8 °C and 0.9–1.1 °C, respectively. In the 2090s, the mean
difference will be 0.5–3.1 °C and 0.7–3.4 °C, respectively. SSP1-2.6
is the only scenario in which the temperatures in the 2090s are expected
to be lower than those in the 2040s. Compared with those in the 2010s,
hot extremes are expected to be more frequent, intense, extensive, and
longer-lasting in the future in the SSP2-4.5 and SSP5-8.5 scenarios. In
the 2010s, a heatwave occurred in the PRD lasted for 6 days on average,
with a mean daily maximum temperature of 34.4 °C. In the 2040s, the
heatwave duration and intensity are expected to increase by 2–3 days
and 0.2–0.4 °C in all three scenarios. In the 2090s, the increase in
these values will be 23 days and 36.0 °C in SSP5-8.5. Moreover, a
10-year extreme high temperature in the 2010s is expected to occur at a
monthly frequency from June to September in the 2090s.
SIGNIFICANCE STATEMENT
Pearl River Delta (PRD) has been experiencing record-shattering
heatwaves in recent years. This study aims to investigate the future
trends of summer heatwaves in the PRD by modeling three future scenarios
including a sustainable scenario, an intermediate scenario, and a
worst-case scenario. Except the sustainable scenario, summer
temperatures in the intermediate and worst-case scenarios will keep
increasing, and heatwaves will become more frequent, intense, extensive,
and longer-lasting. In the worst-case scenario, extreme heat events that
occurred once in 10 years in the 2010s will shorten to once a month in
the 2090s. A better understanding of heatwave trends will benefit
implementing climate mitigation methods, urban planning, and improving
social infrastructure.