Atlanta’s heatwave where the heat islands are and what it means

Areas in a “concrete jungle” with buildings and asphalt absorb and re-radiate heat, keeping those areas warmer throughout the day and night.

ATLANTA — The Atlanta metro area is in the throes of a major heat wave, highlighting the fact that some areas of the city are disproportionately hotter than others.

This phenomenon is known as the heat island effect. Why do heat islands exist?

Because our growing city has a wide variety of land uses and surfaces.

For instance: Atlanta’s lush canopy helps keep many of its single-family residential areas cool. But in contrast, areas of a “concrete jungle” with buildings, asphalt and concrete absorb and re-radiate heat, keeping those areas warm during the day and night.

Last September, Spelman College and other local institutions teamed up to put a number on the extreme heat.

See the full study here, or embedded at the bottom of this story

The researchers had 60 volunteers go around the city three times by bike or by car on the day of the study. They found that the hottest parts of the city were on average 14.5 degrees warmer than the coldest.

“The central part of downtown Atlanta…these large communities are actually warmer than where the trees are, the vegetation is,” said Dr. Guanyu Huang, who helped administer the study. “So we’re seeing a pretty big, strong temperature hotspot over downtown.”

Volunteers recorded more than 48,000 temperature measurements, showing which neighborhoods are most at risk from extreme heat.

So what exactly does the data look like? The scientists first took temperature data along the paths the volunteers took in the city at each collection time:

Morning – 6 a.m. to 7 a.m.

Afternoon – 3 p.m. to 4 p.m.

Evening – 7 p.m. to 8 p.m.

Then they combined the collected temperatures and land cover knowledge into a computer model, which was able to plot a predictive picture of what the temperature profile of the entire city of Atlanta looked like at those three times.

They not only produced maps that show estimated temperatures, but also with colors that clearly show anomalies, areas that deviate from the average temperature

In the map below, the dark red colors are the hottest areas of the city in each period.

Neighborhoods located mostly in or south of the city center recorded the hottest temperatures. Many of these areas are historically black neighborhoods.

According to Dr. Huang, historically underserved communities are most affected by the extreme heat.

“PPeople of color and, you know, communities of color… actually suffer more heat than… surrounding areas,” he said.

The city of Atlanta has decided to become a partner in the study. Dr Huang said the city is aiming use the data to highlight neighborhoods that need improvements to limit the impacts of oppressive heat.

While “green roofs” are a recent trend among the city’s newest high-rise developers, planting trees and adding small parks in the hottest parts of town may be among the most cost-effective and easily obtainable means of relief for most Atlanta residents. in need.

“Trees and vegetation are actually very helpful in cooling the area,” Dr Huang said. “So based on our study, we just noticed that above the parks, even as a very small park, a block-sized park, actually helped a lot in reducing the temperature or change the microclimate in a neighborhood.”

The next goal, Dr Huang said, is to work on a proposal to further study temperature distributions and generate community engagement, to increase awareness of climate change and environmental justice issues. .

“This project that we’re working on, definitely, the goal is always to make Atlanta a better place for everyone,” he said.

The complete study

Wiley C. Thompson