Global Distribution and Density of Constructed Impervious Surfaces

Area of Science:

• Environmental Science
• Remote Sensing
• Urban Planning

Background:

• Impervious surface area (ISA) is a key indicator of human development and environmental impact.
• Previous global ISA inventories lacked high spatial resolution and comprehensive data.
• Understanding ISA distribution is vital for ecological and hydrological studies.

Purpose of the Study:

• To create the first global inventory of impervious surface area (ISA) distribution and density.
• To develop a novel method for estimating ISA using coarse-resolution satellite data.
• To provide a foundational dataset for global environmental and urban research.

Main Methods:

• Utilized satellite-observed nighttime lights and population counts as indicators for ISA.
• Calibrated the model using high-resolution ISA data from the U.S. Geological Survey for the USA.
• Generated a global ISA density map on a one-km² grid.

Main Results:

• Estimated 0.43% of the world's land surface (579,703 km²) as constructed impervious surface.
• Found China has the largest total ISA (87,182 km²), while the USA has higher per capita ISA (297 m²).
• Identified concentrated ISA impacts in drainage basins across the USA, Europe, Japan, China, and India.

Conclusions:

• The developed method provides a valuable global estimate of impervious surface area.
• Future work should incorporate more diverse reference ISA data to refine the global product.
• This inventory is essential for assessing human impact on global ecosystems and water resources.