LCZ 1 consists of a dense mix of tall buildings (10+ stories), creating "urban canyons" with paved surfaces and minimal green space. The building form itself provides some inherent "Urban Canyon Shading" at street level.
Heat Problem: Very High. Tall buildings trap heat and block wind, while dense materials absorb significant solar radiation.
Example Locations:
Temperate: Manhattan (USA), Tokyo (Japan), London (UK)
Tropical: Singapore, Hong Kong, Bangkok (Thailand)
Arid: Dubai (UAE), Doha (Qatar), Riyadh (Saudi Arabia)
Continental: Chicago (USA), Moscow (Russia), Toronto (Canada)
Mitigation Measures for LCZ 1
1. Green Roofs & Walls
Evaluation & Reasoning: Cools surfaces and ambient air through evapotranspiration (plants releasing water vapor, a cooling process) and provides shade. The soil and vegetation also act as an excellent insulating layer, reducing heat flow into the building in summer and heat loss in winter, thus saving energy year-round.
Climate Suitability:
All Climates: Highly effective due to the dual benefits of cooling and insulation.
Arid/Continental: The primary challenge is plant survival. This requires careful selection of drought-tolerant (succulents) or cold-hardy (sedums, grasses) plant species and potentially irrigation systems, which can impact viability in water-scarce regions.
2. Cool Roofs & Pavements
Evaluation & Reasoning: Utilizes materials with high solar reflectivity (albedo). By reflecting a large portion of incoming sunlight instead of absorbing it as heat, these surfaces stay significantly cooler, reducing heat transfer to the building below and the surrounding air.
Climate Suitability:
Arid/Tropical: Extremely effective and highly recommended due to intense, year-round sun exposure.
Temperate/Continental: Very effective in summer. However, in winter, the reflectivity can become a slight disadvantage (a "winter penalty") by reflecting away desirable solar heat. This is typically outweighed by the significant summer energy savings.
3. Natural Ventilation
Evaluation & Reasoning: Crucial for flushing trapped, hot air and pollution out of deep urban canyons. Stagnant air allows heat to build up, but creating wind corridors allows cooler, fresher air to move through the city.
Climate Suitability:
Universal: Effective in all climates. It's a design principle best implemented in new developments by varying building heights, creating gaps between buildings, and aligning structures with prevailing wind directions. Retrofitting is much more difficult.
4. Shading Structures
Evaluation & Reasoning: Provides direct shade for pedestrians and building facades, preventing solar radiation from hitting and heating surfaces. This is one of the most effective ways to improve outdoor thermal comfort.
Climate Suitability:
Arid/Tropical: Essential for creating comfortable public spaces. Awnings, canopies, and covered walkways are key strategies.
Temperate/Continental: Very useful during summer heatwaves. Retractable designs are ideal as they can be deployed in summer but removed in winter to allow for welcome passive solar heating.