Thermal Islands

Topic(s):

Atmosphere, Biosphere, Climate, Energy, Weather

Scenario:

A heat wave in Chicago, increased thunderstorm activity in Quincy Illinois, and fogless London days and nights – is it possible these are all related to thermal islands? What is the role of cities in our climate – and more specifically, how does the urban heat island affect climate – not only in cities but in the surrounding countryside?

Numerous studies have shown how the concrete pavements and buildings retain heat in cities, making cities several degrees warmer than the surrounding countryside. The research of Tim Oke from the University of British Columbia has shown that cities of a million people can be 1 to 3 degrees Celsius warmer than the surrounding countryside during the day and as much as 12 degrees Celsius warmer at night.

Increased morbidity and mortality rates in cities during heat waves (sometimes referred to as Excessive Heat Events or EHEs) are exacerbated by the urban heat island effect. For this and other reasons, many believe mitigation of urban heat islands should be pursued. Some strategies being recommended include increasing trees and vegetation, and developing roofs that are green and/or cool.

As cities have grown, they have warmed. One result has been a decrease in fog. London, for example, used to be known for its "pea soup" fogs, but today, dense fog is rare in the city. New York, Tokyo and Los Angeles show similar trends. According to a November, 2005 article in Nature, changes in land cover in both cities and the countryside is responsible for part of the warming the United States has experienced in the past century.

In a 2003 paper in the Journal of Applied Meteorology , Rozoff, Cotton and Adegoke demonstrated how the urban heat island of St. Louis enhanced convective activity (thunderstorms) downstream of the city.

Not all the consequences of an urban heat island are negative. For example, savings in winter heating costs, less ice and snow, and longer growing seasons in urban areas are all positive results.

Task:

Your team has been approached by the congressional science committee interested in the impact of thermal islands on climate. Your ESS analysis of this possible connection will become an important part of their deliberations.

Basic: According to the National Resources Defense Council, heat waves contributed to the deaths of at least 225 people in the United States during July, 2006 NRDC Web Site . Assuming no mitigation strategies are initiated, determine how urban development will impact health, heat and climate during the next 50 years.

Comprehensive: The percentage of the world's population living in cities is increasing. Today, about 50% of the world's people live in cities. Some projections indicate this number will rise to 70% (of an overall population that is 50% larger than today) by 2050. There is a concern among policy makers that these trends in urban poulation and development, as well as local trends in climate change may enhance the thermal island effect of cities, resulting in increasing morbidity and mortality during heat waves. Because of a possible increasing magnitude of urban heat islands over the next 50 years, your team has been tasked to develop possible mitigation strategies.

Date: 1/22/2010

Scenario Images:

This image shows how both nocturnal and daylight temperatures vary in the vicinity of an urban heat island, and the fact that they have a different magnitude, especially in the daytime. More... Image: Courtesy: EPA (modified after Voogt, J.A., 2002: Urban heat island, in Vol. 3, Encyclopedia of Global Environmental Change, Ed. Ted Munn, John Wiley & Sons, Ltd, Chichester, 660-666)

Buildings, asphalt, concrete, and industry all contribute to the Urban Heat Island by their uptake and subsequent release of heat, and, in the case of industry, by adding heat to the atmosphere. More... Image: Courtesy NASA Earth Observatory

Resources:

3D Atlanta Heat Island (Cycle A)
Very interesting animations of of Atlanta's heat island and the development of convective clouds in the heat island.

Atlanta Heat Island: Landsat Land Use Classification and Thermal IR Data (Cycle A)
Compares land use and thermal IR imagery of Atlanta.

Beating the Heat in the World's Big Cities (Cycle A)
Provides an overview of the urban heat island phenomenon and describes prior heat waves.

Excessive heat events guide (Cycle A)
This EPA guide summarizes risks of excessive heat events. It also outlines procedures for notification and response.

Health Benefits of Urban Heat Island Mitigation (Cycle A)
This power point explores how urban heat islands exacerbate the effects of Excessive Heat Events (EHE) on morbidity and mortality.

Heat Island Effect (Cycle A)
Describes an urban heat island with links to mitigation and impacts.

NASA's Earth Observatory (Cycle A)
The Earth Observatory's mission is to share with the public the images, stories, and discoveries about climate and the environment that emerge from NASA research, including its satellite missions, in-the-field research, and climate models.

Zoom and Spin Around Atlanta: Daytime Thermal View of the Heat Island (Cycle A)
Contains daytime views of Atlanta's thermal islands.

Zoom and Spin Around Atlanta: Nighttime Thermal View of the Heat Island (Cycle A)
Uses thermal (infrared) imagery to show the Atlanta Heat Island at night.

Air Pollution Prevention Through Urban Heat Island Mitigation: (Cycle B)
Describes the relation between air polution and heat island in the urban environment. Also looks at mitigation and remote sensing of the urban environment.

Heat Island Group (Cycle B)
Describes the urban heat island including effects on air quality and energy use. Includes links to mitigation strategies including vegetation , cool roofs, and cool pavements.

LAUNCH (Cycle B)
LAUNCH is a joint NASA, USAID and Nike program looking toward sustainable agriculture. Vertical hydroponic farming is among the projects described.

Mitigating New York City's heat island with urban forestry, living roofs, and light surfaces (Cycle B)
This conference paper outlines a strategy for New York City and estimates the various mitigation effects.

NASA Satellite Confirms Urban Heat Islands Increase Rainfall Around Cities (Cycle B)
Describes how urban heat islands enhace precipitation (especially summer precipitation) downwind of a city.

Reducing the Urban Heat Island: Compendium of strategies (Cycle B)
Contains an overall review of urban heat islands and some suggested mitigation strategies.

Urban climatology and air quality (Cycle B)
Although this site has not been updated in a while, it contains good basic information and links.

Urban heat islands make cities greener. (Cycle B)
Shows how urban heat islands prolong the growing season and make cities greener.

Digital Library for Earth System Science (Cycle C)
The ultimate resource for Earth Science lesson plans, investigations and publications.

MetEd (Cycle C)
Meterology, weather forecasting and related geoscience topics training and teaching resources. Registration is required to access modules and courses.

MY NASA DATA (Cycle C)
Lesson plans, activities, resources and more using NASA data.

NASA's Climate Kids (Cycle C)
News, information, games, teacher resources and more.

NASA's Global Climate Change (Cycle C)
Climate key indicators, evidence, effects, interactives, images and more. Educator tips and tricks for use in your classroom are provided.

Sample Investigations:

Feeling the heat (Cycle A)
Students learn about the urban heat island effect by investigating which areas of their schoolyard have higher temperatures. Then they analyze data about how the number of heat waves in an urban area has increased over time with population.
Difficulty: beginner

Measuring Temperature Islands (Cycle A)
Goal is to identify both natural and urban heat islands and learn to use an infrared thermometer.
Difficulty: beginner

The Urban Heat Island effect (Cycle A)
Students investigate microclimate by taking measurements around their School's grounds.
Difficulty: beginner

Trees and air quality (Cycle A)
Students investigate the ways in which trees benefit air quality and determine how to landscape a home with trees to decrease energy use.
Difficulty: beginner

Weather and health (Cycle A)
A COMET learning module that describes weather and health. The section on everyday weather includes heat waves. There is also a game on weather and health. Registration is required (free registration) on UCAR's meted website.
Difficulty: beginner

What's hot at the mall? (Cycle B)
Shows how shopping malls change the natural environment trough deforeststion and contribution to the urban heat island
Difficulty: beginner

Why is the city hot? (Cycle B)
Examines the formation of urban heat islands with Atlanta as an example using NASA data.
Difficulty: beginner

Mapping Local Data in GIS (Cycle C)
From the Earth Exploration Toolbook. Explores the relation between land cover and surface air temperature.
Difficulty: advanced

Weather and the Built Environment (Cycle C)
A COMET learning module that describes weather and built environment. Includes a section on the urban heat island. Registration is required (free registration) on the Univerity Corporation for Atmospheric Research's (UCAR) meted website.
Difficulty: advanced

Standards:

• Science
  National Science Education Standards - Science Content Standards http://www.nap.edu/readingroom/books/nses/html/overview.html#content The science content standards outline what students should know, understand, and be able to do in the natural sciences over the course of K-12 education.
  • K-12 UNIFYING CONCEPTS AND PROCESSES
    The understandings and abilities associated with the following concepts and processes need to be developed throughout a student's educational experiences:
    • Evidence, models, and explanation
  • GRADES K-4 CONTENT STANDARDS
    • Science as Inquiry (Std A)
      • Abilities necessary to do scientific inquiry
      • Understanding about scientific inquiry
    • Physical Science (Std B)
      • Properties of objects and materials
    • Earth and Space Science (Std D)
      • Properties of earth materials
      • Changes in earth and sky
    • Science in Personal and Social Perspectives (Std F)
      • Personal health
      • Changes in environments
  • GRADES 5-8 CONTENT STANDARDS
    • Science as Inquiry (Std A)
      • Abilities necessary to do scientific inquiry
      • Understanding about scientific inquiry
    • Physical Science (Std B)
      • Properties and changes of properties in matter
      • Transfer of energy
    • Life Science (Std C)
      • Regulation and behavior
    • Science and Technology (Std E)
      • Understanding about science and technology
    • Science in Personal and Social Perspectives (Std F)
      • Personal health
      • Populations, resources, and environments
      • Natural hazards
      • Risks and benefits
  • GRADES 9-12 CONTENT STANDARDS
    • Science as Inquiry (Std A)
      • Abilities necessary to do scientific inquiry
    • Physical Science (Std B)
      • Interactions of energy and matter
    • Earth and Space Science (Std D)
      • Energy in the earth system
      • Geochemical cycles
    • Science in Personal and Social Perspectives (Std F)
      • Personal health
      • Personal and community health
      • Environmental quality
      • Natural and human-induced hazards
• Mathematics
  Principles and Standards for School Mathematics, National Council of Teachers of Mathematics (NCTM), 2000 http://standards.nctm.org/document/prepost/cover.htm This set of Standards proposes the mathematics concepts that all students should have the opportunity to learn. Each of these ten Standards applies across all grades, prekindergarten through grade 12. Even though each of these ten Standards applies to all grades, emphases and expectations will vary both within and between the grade bands (K-2, 3-5, 6-8, 9-12). For instance, the emphasis on number is greatest in prekindergarten through grade 2, and by grades 9-12, number receives less instructional attention. Also the total time for mathematical instruction will be divided differently according to particular needs in each grade band - for example, in the middle grades, the majority of instructional time would address algebra and geometry.
  • STANDARD 2: PATTERNS, FUNCTIONS, AND ALGEBRA
    Mathematics instructional programs should include attention to patterns, functions, symbols, and models so that all students—
    • use symbolic forms to represent and analyze mathematical situations and structures;
  • STANDARD 5: DATA ANALYSIS, STATISTICS, AND PROBABILITY
    Mathematics instructional programs should include attention to data analysis, statistics, and probability so that all students—
    • pose questions and collect, organize, and represent data to answer those questions;
    • interpret data using methods of exploratory data analysis;
    • develop and evaluate inferences, predictions, and arguments that are based on data;
  • STANDARD 6: PROBLEM SOLVING
    Mathematics instructional programs should focus on solving problems as part of understanding mathematics so that all students—
    • build new mathematical knowledge through their work with problems;
    • develop a disposition to formulate, represent, abstract, and generalize in situations within and outside mathematics;
    • apply a wide variety of strategies to solve problems and adapt the strategies to new situations;
    • monitor and reflect on their mathematical thinking in solving problems.
  • STANDARD 8: COMMUNICATION
    Mathematics instructional programs should use communication to foster understanding of mathematics so that all students—
    • organize and consolidate their mathematical thinking to communicate with others;
    • express mathematical ideas coherently and clearly to peers, teachers, and others;
    • extend their mathematical knowledge by considering the thinking and strategies of others;
    • use the language of mathematics as a precise means of mathematical expression.
  • STANDARD 9: CONNECTIONS
    Mathematics instructional programs should emphasize connections to foster understanding of mathematics so that all students—
    • recognize, use, and learn about mathematics in contexts outside of mathematics.
  • STANDARD 10: REPRESENTATION
    Mathematics instructional programs should emphasize mathematical representations to foster understanding of mathematics so that all students—
    • create and use representations to organize, record, and communicate mathematical ideas;
    • use representations to model and interpret physical, social, and mathematical phenomena.
• Geography
  Geography for Life: National Geography Standards, 1994
  • THE WORLD IN SPATIAL TERMS
    Geography studies the relationships between people, places, and environments by mapping information about them into a spatial context. The geographically informed person knows and understands:
    • How to use maps and other geographic representations, tools and technologies to acquire, process, and report information from a spatial perspective
  • PLACES AND REGIONS
    The identities and lives of individuals and people are rooted in particular places and in those human constructs called regions. The geographically informed person knows and understands:
    • The physical and human characteristics of places
  • PHYSICAL SYSTEMS
    Physical processes shape Earth’s surface and interact with plant and animal life to create, sustain, and modify ecosystems. The geographically informed person knows and understands:
    • The characteristics and spatial distribution of ecosystems on Earth’s surface
  • ENVIRONMENT AND SOCIETY
    The physical environment is modified by human activities, largely as a consequence of the ways in which human societies value and use Earth’s natural resources, and human activities are also influenced by Earth’s physical features and processes. The geographically informed person knows and understands:
    • How human actions modify the physical environment
    • How physical systems affect human systems
• Technology
  The International Society for Technology Education From http://www.iste.org and http://www.edtech.sandi.net/index.php?option=com_docman&task=doc_download&gid=349&Itemid=229
  • SOCIAL, ETHICAL AND HUMAN ISSUES
    • Students develop positive attitudes toward technology uses that support lifelong learning, collaboration, personal pursuits, and productivity.
  • TECHNOLOGY PRODUCTIVITY TOOLS
    • Students use technology tools to enhance learning, increase productivity, and promote creativity.
  • TECHNOLOGY COMMUNICATION TOOLS
    • Students use a variety of media and formats to communicate information and ideas effectively to multiple audiences.
  • TECHNOLOGY RESEARCH TOOLS
    • Students use technology to locate, evaluate, and collect information from a variety of sources.
    • Students use technology tools to process data and report results.
  • TECHNOLOGY PROBLEM- SOLVING AND DECISION-MAKING TOOLS
    • Students use technology resources for solving problems and making informed decisions.
    • Students employ technology in the development of strategies for solving problems in the real world.