Assessing the intensity of heatwaves in a warming climate at the urban
scale: A case study of the Metropolitan Area of Barcelona
Abstract
Given that more than half of the world’s population currently resides in
cities, further understanding of the potential impact of future climate
change on urban areas is needed. In this regard, we project recent
heatwave (HW) episodes in the Metropolitan Area of Barcelona (AMB) with
future climate conditions until 2100 using the pseudo global warming
(PGW) method. First, we determine all the HWs that occurred in the AMB
during the last climatological period of 30 years (1991-2020) and
simulate each individual event using the Weather and Research
Forecasting (WRF) model at high-resolution. Then, these historical HW
events are re-simulated with the modified atmospheric conditions of the
mid-century (2041-2070) and the end-of-the-century (2071-2100) according
to the scenario SSP370, in which CO2 emissions are projected to almost
double from current levels by 2100 following a low emission reduction
scenario. HW intensity is expected to increase by 2.5 °C and 4.2 °C in
the mid- and end-of-the-century periods, respectively. Higher
temperatures are related to stationary and stable synoptic patterns,
which are projected to experience the greatest intensification in the
future. The geopotential height at 500 hPa could increase up to 100
geopotential meters (gpm) by the end of the century, leading to values
up to 6050 gpm, which indicates changes in thermodynamic and dynamic
effects resulting in potentially warmer HW episodes. The results
obtained can aid in understanding the expected changes for this century,
which could facilitate the formulation of heat mitigation and adaptation
strategies, particularly for the most exposed areas.