Sunset City: Surface Energy Balance, Stored Heat and the…

What Surface Energy Balance Is

Surface energy balance refers to the exchange of energy between a surface (such as a city block) and its surroundings. This includes incoming solar radiation, outgoing longwave radiation, sensible heat transfer due to temperature differences, and latent heat associated with phase changes like evaporation.

In urban environments, this balance is crucial for understanding local climate conditions, air quality, and energy consumption.

Why It Matters

Understanding surface energy balance helps in designing more sustainable cities that can mitigate the heat island effect. By managing how surfaces absorb and release heat, urban planners can reduce energy use for cooling and improve overall air quality.

This knowledge is also vital for predicting weather patterns and understanding climate change impacts on urban areas.

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The Night Heat Island

During the day, city surfaces absorb more solar radiation than rural areas due to their darker colors and materials. This leads to higher temperatures in cities compared to surrounding areas—a phenomenon known as the heat island effect.

At night, when there is no incoming solar radiation, urban surfaces release this stored heat slowly, often leading to warmer nighttime temperatures in city centers.

Real-World Examples

The concept of surface energy balance has been applied in various cities around the world. For example, Tokyo's urban planning includes reflective surfaces and green spaces to manage heat absorption and release.

In Paris, the 'City of Light' implemented a program to paint roofs white to reflect more sunlight, reducing the overall temperature of buildings.

Frequently asked questions

How does the heat island effect impact urban areas?

The heat island effect can lead to higher temperatures in cities compared to their rural surroundings, affecting air quality and energy consumption for cooling. It also impacts human health and local weather patterns.

Can surface energy balance be used to design cooler cities?

Yes, by using materials with high albedo (reflectivity) and incorporating green spaces, urban planners can reduce the amount of heat absorbed by city surfaces. This helps in managing the overall temperature and improving air quality.

What role does stored heat play during nighttime?

Stored heat from daytime activities continues to be released into the atmosphere at night, contributing to higher temperatures in urban areas compared to rural regions. This phenomenon is known as the night heat island effect.

How can wind affect surface energy balance?

Wind can carry warm air from city centers to surrounding areas, influencing local temperature patterns and affecting the overall surface energy balance of an urban environment.

Try it live

Everything above runs in your browser — open Sunset City: Surface Energy Balance, Stored Heat and the Night Heat Island and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.

▶ Open Sunset City: Surface Energy Balance, Stored Heat and the Night Heat Island simulation