In the heart of China, two cities are playing a real-life game of hot and cold, and the results could shape how we tackle urban heat in coastal and inland cities worldwide. Yaru Meng, a researcher from the National Engineering Laboratory for Satellite Remote Sensing Applications, part of the Chinese Academy of Sciences, has been crunching numbers and analyzing data to understand how Beijing and Dalian stack up when it comes to surface urban heat islands (SUHI). The study, published in the journal ‘Remote Sensing’ (translated from Chinese), sheds light on the spatiotemporal evolution of land surface temperature and SUHI intensity in these two cities from 2003 to 2023.
So, what’s the deal with these heat islands? Imagine a city as a giant frying pan, with buildings and pavement soaking up the sun’s heat during the day and releasing it at night. This is what’s known as the urban heat island effect, and it’s a big deal for city dwellers and maritime professionals alike.
Meng and her team found that Beijing, the inland city, has a higher SUHI intensity than Dalian during summer days, with a difference of 0.45°C. But here’s where it gets interesting: Dalian, the coastal city, has a stronger SUHI intensity during winter nights, with a difference of 0.24°C. Why? Well, Dalian’s maritime climate raises nighttime land surface temperatures, intensifying the winter SUHI. As Meng puts it, “Dalian’s maritime climate, which raises nighttime LSTs and intensifies the winter SUHI.”
Both cities show similar trends in land surface temperature and SUHI intensity, with fluctuations until 2010, an increase after 2011, and a peak in 2023. But here’s where things get really interesting for maritime professionals: the expansion of heat island areas is occurring mainly in suburban regions, which could have significant impacts on port operations and coastal infrastructure.
So, what’s driving these changes? Meng and her team found that temperature (TEMP) is the primary factor promoting SUHI intensity, followed by evapotranspiration (ET) and population (POP). But here’s where things get tricky: the enhanced vegetation index (EVI) is the main mitigating factor. In Beijing, precipitation (PREP) weakens the SUHI, while in Dalian, PREP promotes it. This means that coastal cities should focus on water bodies and wetland planning to mitigate heat islands, especially in areas like Dalian which are affected by PREP.
For maritime professionals, this research opens up a world of opportunities. From designing heat-resistant port infrastructure to developing coastal wetland management strategies, the findings of this study could help shape the future of coastal cities and their ports. And with the global push towards sustainable urban development, the time to act is now. So, let’s take a page from Meng’s book and start thinking about how we can mitigate the urban heat island effect in our own cities and ports. After all, the future of our coastal communities depends on it.