CPIJ News LetterNo. 33, Mar 2010

Special Issue:

Sustainable Cities and Regions
Preface
Makoto Yokohari / Graduate School of Frontier Sciences,
The University of Tokyo

Published by the City Planning
Institute of Japan (CPIJ)
Edited by Makoto Yokohari & Akinobu
Murakami (International Affairs Committeeof CPIJ)

Akinobu Murakami / Graduate School of Systems and Information
Engineering, University of Tsukuba

Important changes in the quality of the urban environment have occurred in the last few decades. Despite
the progress achieved in controlling local air and water pollution, urban areas show increasing signs ofenvironmental stress. Major concerns for cities are the quality of air and water quality, heat island conditions and traffic congestion. Open spaces and green areas are under continuous threat due to more competitive uses for limited land resources. The quality of life in cities is also affected by the deterioration ofbuildings and infrastructure and the degradation of the urban landscape. Beyond their immediate environment, cities also absorb increasing amounts of resources and produce increasing amounts of emissions
and waste, causing significant burdens on the regional and global environment. These problems are warning signs of a more deep-seated crisis, and call for a rethinking of current models of organization and urban
development.
Urban environmental problems are often viewed as local problems, since the high concentration ofpeople and activities in cities is the cause of heavy pressures on the local environment. However, urban
environmental problems are closely linked with regional and global problems by their common causes andinterdependent effects. As cities deplete local resources and increase their dependence on imported global
resources, they become more vulnerable to the effects of global environmental change. Yet at the sametime, the disproportionately strong influence that urban areas have on the global environment also ensurethat implementation of measures to improve these areas can have significantly beneficial effects on theregional and global environment. This means that urban planning must deal simultaneously with both local
and global environmental problems, such as global climate change.
This century is projected to be the century of the environment. The future of human beings is dependent
on the actions we take on behalf of the environment. An adequate response to these environmental concerns requires a new concept of how cities can become more symbiotic with the local and global environment in the future. In order to develop such a concept, four authors report on their research in the areas ofurban planning and global/local environmental problems in this special issue.

Global Warming Countermeasures and City PlanningShuichi Kamata / Senior Deputy Director
City Planning Division, City and Regional Development Bureau, Ministry of Land, Infrastructure,
Transportation and Tourism

1. Global warming countermeasure trends in JapanIn December 1997, COP3 (3rd Session of the Conference of the Parties to the United Nations Framework
Convention on Climate Change) adopted the Kyoto Protocol, in which Japan pledged to reduce its greenhouse gas emissions 6% compared to 1990 levels by 2012. In October 1998, Japan enacted the Act on
Promotion of Global Warming Countermeasures and legally established the Kyoto Protocol Target Achievement Plan as the necessary plan to realize its pledge in the Kyoto Protocol. The actual plan was created in
April 2005, and was completely revised in March 2008.
In June 2008, the Act on Promotion of Global Warming Countermeasures was revised to promote cuts ingreenhouse gas emissions and the preservation and strengthening of absorption of these gases by local
governments. The revisions required that prefectures and cities of a certain size or larger (referred to below
as specially designated cities) to create plans to limit greenhouse gas emissions in their area (referred to
below as an implementation plan), and to tie these plans to the city plan.
Furthermore, in July 2008, the Cabinet Secretariat’s Urban Renaissance Headquarters designated certain cities as “eco model cities” and started to promote the spread of more-environmentally-suited cities
throughout Japan.
In this paper, I look at the relationship between efforts concerning global warming countermeasures andcity planning and the state of creating Low-Carbon City Development Guidelines that are expected to becompleted in March (2010) and will act as guidelines for concrete effects to create low-carbon cities.
2. Global warning countermeasure trends in the field of city planning(1) Kyoto Protocol Target Achievement Plan
In order to realize dramatic reductions in greenhouse gas emissions, both individual measures for eachsector (such as hybrid cars, energy efficient home electric appliances, and well-insulated houses) and arevolution in not only the structure of cities and local communities, but also social and economic systems
are necessary. Looking at the population density of Japanese cities and per capita CO2 emissions in thetransportation sector reveals that there is a strong correlation between a compact urban structure with highpopulation density and a decline in CO2 emissions in the transportation sector (figure 1). In addition, it isimportant to use the opportunity provided by development efforts throughout a city to increase the efficiency of energy use, which includes efforts such as introducing new types of energy. In the Kyoto Protocol
Target Achievement Plan, which was fully revised in March 2008, the following measures were considered
methods to create “(a) a low-carbon urban/regional structure and a social and economic system”
Creation of a low-carbon urban/regional structure and a social and economic system(excerpt from the Kyoto Protocol Target Achievement Plan)• Promote comprehensive urban and regional transportation systems in order to realize a compact city
structure• Intensively introduce facilities that employ multiple types of new energies into regions, cities, andbuildings• Use opportunities such as urban development to promote leading measures that can be expected todramatically reduce CO2 emissions throughout the area at the city and regional level through publicprivate cooperation• Promote the area use of energy through partnerships between various buildings at the city andregional level and operate and manage energy for the whole area• Using Maebashi-shi and Kochi-shi, which have about the same area and population, as examples, Maebashi-shi withextensive low-density urban areas is highly dependent on cars. Comparing per-capita CO2 emissions for the passenger
transportation sector, the figure for Maebashi-shi is 1.21 tons, around 40% greater than the 0.87 tons for Kochi-shi•

Maebashi-shy

䊶 Percentage of habitable land = 85%•

Kochi-shy

per-capita CO2 emissions = 1.21 tons

䊶 Percentage of habitable land = 39%
per-capita CO2 emissions = 0.87 tons

Source: 2004 White Paper On the Environment

Transformation of the city structure has a major impact on the form of transportation, causinga shift to transportation modes centered on public transportation that have low CO2 emissions
per distanced travel and promoting walking and the use of bicycles.
z Shift to a compact city structure also creates the conditions conductive to transforming thecity’s energy system into a low-carbon one that is more efficient.
z

Reference: Mamoru Taniguchi, Time Series Analysis of Car Co2 Emissions From A City Structure Perspective,
Toshi-Keikakau-Ronbunshu No. 43-3, October 2008

Per-capita Car CO2 emissions (g-CO2/person-day)* Per-capita CO2 emissions for the passenger transportation sector
Gifu
Yasug
i
JoetsuKanazawaCore cities in major
metropolitan areas
Peripheral cities in major
metropolitan areas
Provincial cities

KasugaiUji
FukuokaMatsudoTokoro Central wards
zawa of Tokyo
Kyoto

Osaka

Population density in urban areas (people/ha)

Figure 1(2) Revision to the Act on Promotion of Global Warming Countermeasures and city plans
Revisions were made to the Act on Promotion of Global Warming Countermeasures in June 2008, which
included requiring prefectures, ordinance-designated cities, core cities, and specially designated cities tocreate a new implementation plan that “establishes measures with various objectives including reducing
emissions of greenhouse gases according to the natural and social conditions of that area”. Revisions also
mandated that the following items be examined in the new implementation plan; in June 2009, the Ministryof the Environment created a manual for local governments that indicated the ministry’s thoughts on creating this plan.
Mandatory items to be examined in the new implementation plan
• Promotion of the use of natural energy such as solar power and wind power• Promotion of activities by businesses and residents to limit greenhouse gases emissions• Increase in the use and convenience of public transportation, preservation of existing green areasand introduction of greenery in cities, and the development of and improvements to the local environment that would contribute to various efforts including cutting greenhouse gas emissions• Promotion of reductions in the production of waste material and other measures to create a recyclingbased society
The revisions also required that consideration be given to tying the implementation plan to the city plan.
Act on Promotion of Global Warming Countermeasures, Article 20.3.4
In order to promote global warming countermeasures, prefectures, designated cities, etc. shall take
into consideration efforts aimed at reducing greenhouse gas emissions through coordination with thelocal government’s implementation plan by harmonizing these goals with those of the city plan, agricultural promotion zone plan, and other measures related to efforts to limit the emission of greenhousegases.

(3) Eco model cities
Based on an awareness that it is necessary to make fundamental changes in lifestyles and social structures, such as cities and transportation (systems), in order to create a low-carbon society, efforts have been
made to select leading cities that implement low-carbon urban development through a comprehensive
approach as eco model cities, and these efforts have been centered on the Cabinet Secretariat’s Urban
Renaissance Headquarters. During the application period, which ran from April 11 to May 21, 2008, 82
municipalities from throughout Japan applied for the designation, and 13 were selected.
Approach and criteria for selecting eco model cities
Requirements of proposals• Include concrete measures to effectively reducegreenhouse gases• Exhibit a comprehensive
approach that can beused throughout Japan• Exhibit a future image ofan attractive city andregion

Proposal perspective(1) Dramatic reduction ingreenhouse gases(2) Initiative and ability to
act as model(3) Regional adaptability(4) Implementable(5) Sustainable

Selection criteria and perspective(1) Dramatic reduction in greenhouse gases(2) Initiative and ability to act asmodel(3) Regional adaptability(4) Implementable(5) Sustainable* The smaller the city, thegreater the focus on the initiative and model-traits is

Selection Results
Selected in July 2008
Major cities:
Core provincial cities:
Small cities, towns, villages:

Yokohama-shi, Kita-Kyushu-shi
Obihiro-shi, Toyama-shi
Shimokawa-cho (Hokkaido), Minamata-shi

Selected February 2009
Candidate cities were selected in July 2008, and the final selection was made in January after an action plan was createdMajor cities:
Kyoto-shi, Sakai-shi
Core provincial cities:
Iida-shi, Toyota-shi
Small cities, towns, villages:
Yusuhara-cho (Kochi), Miyakojima-shi
Tokyo wards:
Chiyoda-ku

3. Examination of Low-Carbon City Development Guidelines
The city plan is a mechanism to comprehensively examine the ideal form of a city from various perspectives, including society, economy, and environment, and to realize this ideal form. It is also necessary that
global warming countermeasures be examined. Measures must also be developed from a long-term perspective taking into consideration the distinguishing characteristics of the city including the surrounding
natural environment, the city structure, and form of greenhouse emissions, which is related to the scale ofcommerce and industry, population density, land use, and the state and use of public transportation of theparticular city, and to build up measures.
However, reductions in greenhouse gases have mainly been promoted through sector-specific countermeasures, such as hybrid cars, energy-efficient home electronic appliances, and well-insulated housing,and there has been insufficient consideration from a city perspective such as forming a compact city structure and making area-wide use of energy. Staff of local governments, who operate the various systems
related to the city plan, have not been provided with a systematic explanation of how to create low-carbon
cities. Therefore, efforts are being made to establish Low-Carbon City Development Guidelines to be used

when local governments develop city plans and measures based on these plans, and the guidelines willachieve two objectives–(1) indicate items that should be considered in order to create a low-carbon city,and the basic philosophy on efforts and various other issues such as how to promote countermeasures,and (2) provide both methods to ascertain the benefits of the measures and related data. These guidelines
are envisioned to be used in various situations including the following: (1) conducting city-wide examinations of low-carbon city planning at various times such as when revising the city’s master plan; (2) considering how to create a low-carbon city when promoting various efforts such as redevelopment projects, andthe construction of facilities included in the master plan; (3) examining city development measures whencreating the new implementation plan; (4) analyzing the impact of measures to create a low-carbon city.
While adaptation measures are not covered this time, they are extremely important from a perspective of
responding to global warming, and they will be a topic for future examination.
When conducting an examination, a determination is made regarding the fields that should be targetedby city measures (figure 2). In addition to areas such as energy, transportation, and city structure, which are
the sources of many CO2 emission, focus is on the area of greenery, which includes increasing CO 2 absorption sources and using land in a manner that preserves greenery from a perspective of reducing the use ofland for city purposes that generate CO2 emissions. After that, the basic philosophy (figure 3) and effective
measures (figure 4) are organized. To the extent that benefits can be calculated and based on the assumption that the measures are thought to contribute to reductions in CO2 emission function sufficiently, the following calculations were made in order to determine what the possible greatest reductions in CO2 emissions would be in the above three fields through measures within the city plan.
Using the case of the Sendai metropolitan area, reductions in CO2 emissions in the fields of transportation, city structure, and energy were calculated assuming the development of measures to create a compact city structure.
Regarding the population distribution, the population in 2050 was estimated based on a scenario using
existing research1, and it is assumed that people were induced to concentrate in the city center and coreareas. It is also assumed that various transportation measures were implemented: hardware related measures include building railroads (airport access line and subways) and roads (car-only roads and roads
appearing in the city plan), and transportation demand management (TDM) related measures include
increasing the frequency of trains, creating new city bus routes such as a loop line and core routes andrestructuring branch lines. As a result, it would possible to reduce CO2 emissions 24% compared to the curCO2 Emissions (MtC)

Factors impacting CO2 emissions

Scenario A: urban structure; aim for a more
comfortable, convenient society; per capita
GDP growth of 2%

Overall

Population: 95 million

Industry

6
24

38• Producing and eating seasonal products

GeneralpublicImproved energy efficiency 24• Use of more energy efficient boilers and motors

Decline in carbon intensity 10• Shift from petroleum and coal to natural gas• Promote the diffusion of the well-insulated houses and buildings

Decline in service demand 13• Optimize energy consumption through the use of HEMS and BEMS

Improved energy efficiency 38• Spread the use of all-electric houses

Transportation• Spread the use of solar panels

Transportation
䊶 Make an advanced use of land and concentrate on urban functions

Decline in service demand 7

41

䊶 Promote a modal shift to public transportation (trains, LRT, and buses)䉰䊷䊎䉴㔛ⷐૐᷫ 7

Improved energy efficiency 28

36
CCS

Energy related
60 MtC• Develop and spread the use of fuel cells

Decline in carbon intensity 9

7 MtC

17

Part likely
related to thecity

General public• Spread the use of highly-efficient heat pump HACV units, water heaters, and lighting

28

Transportation
related
7 MtC• Spread the use of electric cars and cars powered by fuel-cell cars
• Spread the use of efficient cargo trucks

Energytransformation

Decline in carbon intensity 17• Raise the energy efficiency of rail, ship, and air transportation

Energy transformation• Move to low-carbon energy sources (such as natural gas, nuclear power, renewable energy)

Decline in carbon intensity 41

CO2emissions2050

70% reduction

CO2 emissions 2000

CO2 emissions 1990

9
7
Transportation
related:• Shift to service industries, decline in number of households, decline in demand
for transportation (all of which will lead to a decrease in CO2 emissions)

Decline in demand for services 1
Industry

10
13Energyrelated- 60
MtC• Economic growth, increase in demand for services, increase in the office floor
space (all of which will lead to increase in CO2 emissions)

Carbon capture and storage 36• Make an effective use of electricity at night and expand the energy storage• Supply hydrogen for the renewable energy sources
Produce CO2-free electricity
Produce CO2-free hydrogen

Energy +transportation

1

Factors envisioned in 2050 scenario

Change in activity 6

67
MtC

ImpactImpact ofof measures
measures toto reduce
reduce CO
CO22 emissions
emissions 70%
70% byby 20502050- total
total ofof 230230 MtC
MtC
Of
emissions related
related toto citiescities- 67
67 MtC,
MtC, aroundaround 30%
30% ofof total
total
Of this,this, reduction
reduction inin CO
CO22 emissions
Source: Examination of the Possibility of 70% Reduction in Greenhouse Gases (revised June 2008)

Figure 2Transformation of city structure
Land Use

Compact

Transportation

Policy 3 Walking and Bicycle measures• Create area-wide walking spaces and environment for
using bicycles

Complex

Coexistencewith nature

Efficiency andCoexistence withthe environment

Efficiency andgreater mobility

Figure 3

Policies for Creating a Low-Carbon City
Transportation andcity structure area

Green area

Land Use

Energy area
Options 11- Measures to reduceenergy burden(1) area energy management (AEMS),(2) shopping area ESCO
Options 12- Measures to increase theefficiency of energy use(1) area-wide energy use (a) district
heating and cooling (b) flexible building
heating
Options 13- Measures to make use of
untapped energy sources(1) exhaust heat from garbage
incinerators, (2) untapped energy ofsewer facilities, (3) energy from thethermal differences in sewer water, (4)energy from the thermal differences inriver and sea water, (5) exhaust heatfrom factors, (6) exhaust heat fromsubways and underground areas,(7) cooling from snow
Options 14- Measures to use
renewable energy(1) use of solar energy (a) use ofelectricity, (b) use of heat, (2) use ofgeothermal heat, (3) use of biomassenergyFigure 4

Options 15- Measures based on the city master
plan, city plan, and ordinances(1) green-land measures tied to public
transportation and land use, (2) green-belt concept,(3) effective use of fallow land (4) introduce
greenery into empty land
Options 16- Promote the creation of greenery
into parks and the city
(1) tree-planting project, (2) Social andEnvironmental Green Evaluation System (SEGES)
Options 17- Measures to manage and develop
greenery(1) Green-shade road project, (2) citizen’s forest
Options 18- Green tax and payment,(1) green tax on residents of the prefecture, (2)green tax ordinance, (3) payment for introducing
greenery, (4) carbon offsets, (5) corporate sponsors
Options 19- Preserve and properly manage
large scale green areas(1) natural regeneration projects, (2) recycling
system for wood resources
Options 20- Use reusable energy source ofwood biomass(1) forest management and projects using wood, (2)promotion of forest measures and use of woodbiomass, (3) projects to generate electricity fromwood biomass
Options 21- Use of the composed or chippedwood biomass(1) introduce greenery along highways
Options 22- Heat-island measures (broad area)(1) macro simulations, (2) grand design for urban
environment infrastructure, (3) Special greenerypreservation zones
Options 23- Heat-island measures (city level)(1) Weather maps for the urban environment, (2)green area system, (3) water and greenery network,(4) water and greenery network taking into
consideration issues such as wind corridors
Options 24- Heat-island measures (local level)(1) development taking into consideration issues
such as wind corridors, (2) green curtains, (3)introduction of lawns into parks, (4) green coverage
ratio, (5) creation of green shade

Compact

Complex

Coexistencewith nature

Efficiency andCoexistence withthe environment

Efficiency andgreater mobility

Realizing a low-carbon, compact city structure

Options 1- create public transportation(1) LRT (2) bus-only lanes/BRT
Options 2- Promote the use of public
transportation(1) improve railway and road fee system, (2)improve operation of railways and roads, (3)improve bus fee systems, (4) introduce community
buses, (5) bus lanes, (6) priority to buses atintersection, (7) priority to buses at bus stops (8)improve bus service in terms of bus, (9) improveCity
bus service in terms of route facilities, (10)functionsimprove bus service in terms of bus stops, (11)
P&R, (12) P&BR, (13) K&R, (14) R&R, (15) C&R,
(16) C&BR
Options 3- Promote the use of bicycles(1) network of bicycle roads, (2) build bicycle
parking at train stations, (3) preferential treatment
for bicycles, (4) rental bicycles and community
bicycles in cities
Options 4- Create pedestrian zones(1) Woonerf community roads, (2) traffic calming
Greenerymeasures, (3) mall and transit malls
Options 5- Regulations and enticements for car
traffic(1) zone system and traffic cell system, (2) trafficcolor slot, (3) license plate number restrictions, (4)one-way streets throughout the city, (5) roadpricing, (6) other restrictions to limit driving in thecity
Options 6- Creative use of cars
(1) Car pooling, (2) car sharing, (3) self restraint in
Buildings the use of cars and no car days, (4) review ofbusiness and social practices, (5) elimination ofprivate importing of cars
Options 7- Enticement through parking(1) fringe parking, (2) restrictions on supply of
parking, (3) strengthen regulations on illegal
parking, (4) system of parking permission or
priority, (5) regulate parking fee
Options 8- Reduce traffic demand(1) telecommuting, (2) compressed work
Options 9- Level traffic demand
Transportation (1) staggered work/flex-time
Options 10- create urban structures(1) urban village, (2) urban growth border (UGB)

Realizing a low-carbon, compact city structure

Policy 2 Create city structure that is supported by public
transportation• Create comprehensive transportation infrastructure• Traffic-demand measures

Policy 10 Improving the heat environment through heat-island measures• Heat-island countermeasures to meet various cases

Buildings

Policy 8 Ensure absorption sources• Create and preserve green areas

Transformation of the city structure will create
the conditions for efforts in the area of energy
and greenery and will be the impetus for thatdevelopment.

Greenery-related policies

Policy 9 Promote the use of biomass• Preserve and maintain green area and use as biomass for urban areas

GreeneryPolicy 7 Use of untapped, renewable energy• Match demand to existing resources of untapped energy• Make use of renewable energy• Promote the introduction of untapped, renewable energy throughout the area whendeveloping the city

Policy 4 Realize efficient city structure with compact cities• Concentrate functions in areas to become hubs and existingclusters• Operate community buses

Policy 6 Area-wide energy use
䊶Introduce area-wide energy systems in various situations such as reinvigorating thecity center

City
functions

Energy-related policies

Policy 5 Renovate building taking into consideration the goal of a low-carbon society• Increase the efficiency of energy use when renovating buildings through concentration• Encourage energy efficient structures that incorporate the surrounding area

Policy 1 Realize compact use of land, etc.
• Encourage housing at locations and transportation hubs
where public facilities and service facilities are located• Level energy demand by mixed use• Encourage the construction of facilities with strong demandfor heat at areas around unused energy sources• Preserve green areas in the suburbs and create green
networks in hubs

Results of Estimate

Estimate assumptions: Cause of change in 2050
(1) Total population and social structure of the greater Sendai metropolitan area
㸢 Assumptions about population (night/day), employment rate for men and women,
and generation composition
2) Urban structure measures (establish compact city structure)㸢 Encourage people to move from the suburb and peripheral urban areas to areas
around train stations and the existing city center

CO2 emissions from transportation in a compact city in
2050(1) compared to the current conditions: -24.0%
Due to transformation to compact city structure
Due to population decline
Due to transportation measures
Of which is due to the creation of transportation infrastructure
due to TDM measures-12.0%
-7.1%
-4.9%
-3.8%
-1.2%

(2) compared to 2050 trend scenario: -18.2%
Night time Population

Present

Future (2050)-24%

Nigh-time population density
A: City center
78ψ120 people/ha
B: Hub50ψ80 people/ha
C: Transportation axis 46ψ60 people/ha
D: Surrounding area
40ψ20 people/ha
E: Suburbs
3.3ψ0.9 people/ha䋨ੱ䋯㪿㪸䋩
㪇䌾㪉㪇
㪉㪇䌾㪋㪇
㪋㪇䌾㪎㪇
㪎㪇䌾㪈㪇㪇
㪈㪇㪇䌾-18%3) -1 Transportation measures that contribute to reduction in CO2 emissions(transportation network) 㸢 assumptions about state of trains and roads3) -2 Transportation measures that contribute to reductions in CO2 (TDM measures)
㸢 assumptions about items such as frequency of trains and buses

Passenger car
2,517

Buses 256

Passenger car
3,654

2050

ㆇⴕ㗫ᐲ䋾㪈㪇ಽ㑆㓒㪌ಽ㑆㓒䋼ㆇⴕ㗫ᐲ㻡㪈㪇ಽ㑆㓒ㆇⴕ㗫ᐲ㻡㪌ಽ㑆㓒㚞Freight cars 4,229

After implementing measures
Trains 75㋕㆏

Buses 281

Trains 111
2050

Freight cars 4,740

Current trend scenario䊋䉴ㆇⴕ㗫ᐲ䋾㪈㪇ಽ㑆㓒㪌ಽ㑆㓒䋼ㆇⴕ㗫ᐲ㻡㪈㪇ಽ㑆㓒ㆇⴕ㗫ᐲ㻡㪌ಽ㑆㓒ၮᐙ䊋䉴䋨ㆇⴕ㗫ᐲ㪌ಽ㑆㓒䋩ㇺᔃᓴⅣ䊋䉴䋨ㆇⴕ㗫ᐲ㪌ಽ㑆㓒䋩

Trains 94

Current transportation networkmain TDM measures

Future transportation networkmain TDM measures

Buses 259
Passenger car
4,077

2002

᦭ᢱ⥄േゞኾ↪㆏ㇺ⸘㆏䊶࿖㆏䊶⋵㆏Ꮢ↸᧛⇇

Freight cars 4,965

Present conditions
㪇

㪈㪃㪇㪇㪇

㪉㪃㪇㪇㪇

㪊㪃㪇㪇㪇

㪋㪃㪇㪇㪇

㪌㪃㪇㪇㪇

㪍㪃㪇㪇㪇

㪎㪃㪇㪇㪇

㪏㪃㪇㪇㪇

㪐㪃㪇㪇㪇

㪈㪇㪃㪇㪇㪇

(t-CO2/ᣣ㧕CO2 emissions by the residents in the compact city in 2050
(1) Compared to current conditions, decline 26%– benefit of efficient use of energy due to compact city structure: -8.1%,
benefit of smaller population: -17.9%* Decline in CO2 emissions of around 1.9 t-CO2/year due to a certain percent of population moving to city center choosing to live in apartments orcondominiums (possible for further reductions through the introduction of energy efficient equipment when renovating buildings)(2) Compared to 2050 trend- decline 9.9%

Figure 5rent level and 18% compared to the trend scenario for 2050.
In addition, assuming that a certain percentage of the population enticed to move into the city center or
hubs chose to live in apartments or condominiums instead of detached houses, CO 2 emissions would
decline 26% compared to the current level and 10% compared to the 2050 trend scenario (figure 5).
In the area of energy, a trial calculation was made for Otemachi, Marunouchi, and Yurakucho (Daimaru)
areas of Chiyodu-ku, Tokyo, assuming that business floor space is the same as that for 2025, and energy
measures are implemented for the whole area. It was assumed that measures included those for individual
buildings, expanded district heating and cooling, introduction of large-scale cogeneration facilities, introduction of waste water heat system, use of exhaust heat from incineration plants, and the introduction of renewable energy. Assuming the total floor space increases 50% through 2025 and the CO2 emission coefficientfor electric power improves 16%2, CO2 emissions would decline 15% compared to the current level and at
most 40% compared to the case in which no measures are implemented (figure 6).
In the field of land use to preserve greenery, the greater Tokyo metropolitan area and Oita-shi were used
as cases, and a trial calculation was made assuming absorption sources increased through the creation of
new green areas and the preservation of existing ones. In terms of creating new green areas, assuming
there is an increase in the green coverage ratio for urban areas and a certain percentage of fallow agricultural land is planted with greenery such as trees and, in terms of preservation, there is an increase inabsorption sources through forest management3, the amount of CO2 absorbed in both the greater Tokyo
metropolitan area and Oita-shi would increase 200% (figure 7). The guidelines will reflect other data including the results of other case studies and are expected to be created in March 2010.
notes:
1. The following are assumption for 2050: 2050 Japan Low-Carbon Society: Examination of the Possibility of 70%
Reduction in Greenhouse Gases (created in February 2007 and revised in June 2008) and the night population
declines 18% and the working population falls 13% based on estimates by the National Institute of Population andSocial Security Research.
2. Assumption based on the 2000 actual emissions coefficient (average) for Tokyo Electric Power Company.
3. Absorption volume was set based on the report by Japan to the United Nations Framework Convention on Climate
Change (new tree planning, forest management, and regeneration of plants based on article 3.3 and 3.4 or the
Kyoto Protocol)

0

100

200

300

400

Trial calculation assumptions (2025): Cause of change
Scope: area 120 ha, 104 buildings
Future conditions:
Building floor space: 600 ha (2000) ă 900 ha (2025)* the building floor space in 2025 is assumed to be half current buildings and half new buildings (2-foldincrease in floor space), which is 1.5 times the figure for 2000
Improvement in CO2 emissions coefficient for the electric system: 0.334 (2000) 㸢 0.28 (2025)* An increase in the coefficient for Tokyo Electric Power Company of 516% compared to the actual figure for2000 (average)
CO2 reduction measures options• Individual building measures: 50% of the buildings in the area (on a floor space basis) are renovatedimproving energy efficiency• Area-wide measures on the region and city level• Area use of energy• Improvement in refrigeration efficiency• Total efficiency improves to 1.05 (2025) from 0.75 (2000) through expanded use ofexisting district heating and cooling• Connections between district heating and cooling pumps: networking• Introduction of large cogeneration plants: introduction of system to use sewer heat
• Introduction of roof-top greenery• Use of roof-top greenery on redeveloped buildings throughout the area by concentrating heat source
equipment (cooling towers)• Introduction of renewable energy• Installation of roof-top solar panels• Use of food waste from local restaurants as biogas to generate fuel for the district heating and coolingplants• Transportation of heat from the incineration of garbage at the Harumi Garbage Processing Plant• Use of heat source for the district heating and cooling pump

500

Use
of sewer water energy: use untreatedɦ൦ǨȍȫǮȸƷ෇ဇᲴ‫ע‬ғϋƷɦ൦࠴
water from main sewer lines and pumpsዴŴɦ൦ȝȳȗ৑Ʒசϼྸɦ൦Ǜ&*%as
DHC cooling water and heat sourcewaterƷϬҲ൦Ŵ༏เ൦ƱƠƯ෇ဇᄢᚻ↸࿯࿾඙↹ᢛℂ੐ᬺ

Create a cool air corridor: water-retentive
paving on Gyoko-dori and intensiveϬൢ‫ݰ‬λᆰ᧓ƷૢͳᲴ႐‫އ‬ƷϬൢƷᛔ‫ݰ‬
introduction of greenery, includingែƱƠƯࣂ࠳ᡫǓሁƷ̬൦ࣱᑄᘺŴౡఎ
planting
trees and introducing greenery inbuildings
along the street, will create aƱඝᢊ࡫ཋƷᨼɶႎƳዯ҄corridor for cool air form the Imperial
PalaceTypeof measureኻ╷඙ಽBase lineᐕ2000 ࡌ࡯ࠬ࡜ࠗࡦ

Reduction in೥ᷫ㊂consumption

Detailsౝኈ࡮ኻ⽎

t-CO2/year
㧔V%1
㧞ᐕ㧕

Ყ₸

Comparison

㪈㧙㧙

Replace existing district heating andଏ‫؏ע܍‬Ϭଡ଼Ʒ୼ૼᲴϐ᧏ႆȓȫƷ࡫ᚨcoolingequipment: build and expand
DHC
central plants
and sub-plants whenƴӳǘƤƯ&*% ǻȳǿȸȗȩȳȈȷǵ
constructing buildings duringȖȗȩȳȈǛૢͳȷਘΪ
redevelopment
projects

Increaseᐥ㕙ⓍߩჇട
in floorspaceᬺോᯏ⢻㓸Ⓧ
ᐕ
2005 ㇺᏒ᭴ㅧ㓸⚂ൻ
Electric system measures♽⛔㔚ജኻ╷

Improvement in emissionsឃ಴ଥᢙᡷༀ
coefficient



Networking
flexibleofǨ ȍ ȫ Ǯ ȸenergyȗ ȩ ȳplants:ȈƷ ȍȃ Ȉ ȯuseȸǯ
excess steam for cogeneration҄ᲴᙐૠƷ༏̓ዅғ؏᧓ưǳȸǸǧȍ˷
equipment
between multiple heat supply
zonesйᔕൢƷᗡᡫ

Individual buildingᑪ▽න૕ኻ╷
measures

Redeveloped building 
ౣ㐿⊒ࡆ࡞



㪌



㪍

Large-scaleᄢⷙᮨ㩄㩆㩨㨴㩒
cogeneration

㪎

Redevelopmentౣ㐿⊒㩕㩨㩣╬building, etc.





㪏

Introduction ofSolar panelsౣ↢น⢻㨾㩒ዉ౉ᄥ㓁శ⊒㔚

㪐





㪈㪇





㪈㪈



㪉

㪊㪋Improve efficiency ofEnergy-area use㨾㩒㩣㩁㩨㨺㕙⊛೑↪
಄ಓല₸ะ਄
refrigeration
Use of heat form Harumi Garbageฌੈ߻‫ئ‬੎༏Ʒ෇ဇᲴ୑ෙฌੈ߻‫ئ‬ƷᔕProcessing
Plant: transport the heat fromthe
Harumi Garbage Processing Plantȗȩ
ൢǛȑǤȗȩǤȳư੿ᡛƠŴ&*%using a pipeline and use as an alternativetoȳȈưᣃࠊǬǹˊஆ༓૰ƱƠƯ෇ဇcity gas in DHC plant‫⋭ޝ‬㧯㧻 㧞ኻ╷ ࿑ಠ଀ ‫ޞ‬㧦ᄢᚻ↸࡮ਣ ߩౝ࡮ ᦭ᭉ↸࿾඙▸࿐㕙⊛⋭%1Area CO㧞2ኻ╷㧦࿾ၞ಄ᥦᚱ ᾲଏ⛎ ▸࿐㧦 ᐕએ㒠ᑪᦧ߃ࡆ࡞
㧦ᑪᦧ߃Ꮏ੐ ࡮⸘↹ ࡆ࡞㧦㧰㧴㧯ࡔࠗ ࡦࡊ࡜ ࡦ࠻㧔ᣂ⸳ᣢ⸳㧕Reduction
Measures 㸢41%
೥ᷫ㊂ߩ㧑
reduction in CO2㩗㨺㩇㩡㨼㩧ߩ㧑㩨 emissions

Introduction of roof㕙⊛ደ਄✛ൻ
top greenery

renewable energy




㧦㧰㧴㧯ࠨࡉ ࡊ࡜ࡦ ࠻㧔ᣂ⸳ᣢ⸳㧕

Garbage biomass↢ߏߺ㩔㩨㨼㨿㩙㩇୑ෙฌੈ߻‫ئ‬
Exhaust heat from Harumi
Garbage Processing Plantᷡ᝹Ꮏ႐ឃᾲ

*Source for building area data: Summary of Otemachi, Marunouchi, Yurakucho Zone
Redevelopment Project Council (pamphlet) September 2002/December 2006

Total reductions
೥ᷫ㊂ว⸘

15% reduction⃻⁁ߦኻߒߡ
compared tocurrent
state
㧑೥ᷫ





40% reductionኻ╷ήߒ㩃㨺㩇ߦ
compared to noኻߒߡ㧑೥ᷫmeasures

Figure 6

Results

Assumptions for estimates• TargetGreater Tokyo metropolitan area
(existing city areas and suburban
development areas)• Cause of change
Calculate reduction in CO2emission from the following
perspective

a. Create green areas
Assume the green coverage ratio is
30% in urban areas (current 9% in
the greater Tokyo metropolitan area),
with 50% accounted for by trees.
Assume that 50% of the agriculturalland in the area around Tokyo(suburban development areas andadjustment areas) projected to go
fallow is planted with trees (currently
around 18,000 ha in the greater
Tokyo metropolitan area)

Increase the volume absorbed and reduced around 3 fold compared to the current
state through “creation” and “preservation” of the green land.
ᵣᶖᶎᶃᶁᶒᶃᶂᴾᵡᵭᵐ
ᵿᶀᶑᶍᶐᶎᶒᶇᶍᶌ䊶Create green areas in the city䊶Plant new forest areas
䊶Increase from support for forest maintenance䊶Forest maintenance (current level)

䋺 9.81t-CO2/ha䍃year䋺13.57t-CO2/ha䍃year䋺 6.53t-CO2/ha䍃year䋺 3.00t-CO2/ha䍃year㪈㪃㪇㪇㪇㪃㪇㪇㪇㪏㪇㪇㪃㪇㪇㪇

Current state⃻ᴫCreation
ഃ
಴

଻ో

Use↪
೑

Preservation

3-foldincreaseover current
state

㑆ធ
ലᨐ

㪍㪇㪇㪃㪇㪇㪇

Area
䇼Current state䇽⃻ᴫ䈱Indirectbenefits
䋳୚

㪇
㪉㪇㪇㪌ᐕ
2005

Reduction

Trees in current city areas
Trees in suburban
development zones
Introduction of roof-top
greenery㪋㪇㪇㪃㪇㪇㪇
㪉㪇㪇㪃㪇㪇㪇
t-CO2

Source
units

2050
㪉㪇㪌㪇ᐕ

3 foldincreaseovercurrentlevel䇼Creation䇽
Create urban green areas inexisting urban areas
Create new areas with trees insuburban development zones
Introduction of roof-top greenery
䇼Preservation䇽
Properly manage forest areas in
the suburban development areasb. Preserve green area

Items that can be expected to reduce
CO2 emissions in an indirect manner

Improve function as an absorption
source by properly managing forestsin the area around Tokyo

Use biomass generated through the proper
management of forested areas as wood pellets
and bio-ethanol
Reduce heating and cooling burden byintroducing roof-top greenery* Indirect benefit
Make use of the green areas, etc.

Figure 7

Eﬀorts to Create a Low-Carbon City in Chiyoda-ku
Mitsuo Otsuka / Deputy Director (responsible for environmental technology)
Chiyoda-ku Environment Safety Department● Introduction

Chiyoda-ku (one of the 23 wards of central Tokyo) is the political and economic center of Japan, and is
the location of many administrative functions.
On the other hand, the ward possesses a rich natural environment with water and greenery, centered on
the Imperial Palace. The ward encompasses an area of 11.64 km2 and has a population of 46,000; however
the daytime population is 850,000, around twenty times larger than the number of residents.
A breakdown of Chiyoda-ku’s CO2 emissions by sector reveals that 73% of emissions are generated by
the business sector, particularly offices. In terms of energy sources, around 69% of CO2 emissions are dueto the use of electricity.
It is projected that the business floor area will increase and CO2 emissions will grow as economic activity
expands and city functions are updated. (In 2005, the business floor area was 2,019.5 ha, which was 23%
greater than that in 1990. Total CO2 emissions in 2005 for the ward were 2.803 million tons, 13% larger thanthe 2.49 million tons in 1990. In addition, BAU emissions are forecast to increase approximately 33% to3.311 million tons by 2020). CO2 omissions for the ward will continue to increase if no measures are implemented.
Therefore, the ward enacted a Chiyoda-ku Global Warming Countermeasure Ordinance in December
2007 in order to balance the economy and environment and to promote global warming countermeasures.
The ordinance was the first of its kind for a local government in Japan and includes a medium-term goalof reducing CO2 emission 25% by 2020 compared to 1990 levels.

Industrial
sector 3%

Householdsector 4%

Transportation
sector 20%

Fossil fuels
17%City gas
14%

Business
sector 73%

Chiyoda-ku CO2 Emissions by Sector (2005)

Growing Chiyoda-ku

If nothing is done, CO2
emissions will continue toincrease

Electricity
67%

Chiyoda-ku CO2 Emissions by Energy Source (2005)

Stop global warming

Start with what you can

Chiyoda-ku Global
Warming
Countermeasure
Ordinance
Establish the Chiyoda-ku Global
Warming Countermeasure
Ordinance

Solar panels● Three pillars for creating a low-carbon cityThree policies form the core of Chiyoda-ku’s efforts to create a low-carbon city.
The first policy is “energy measures for advanced buildings,” which refer to measures aimed at raising theenergy efficiency of buildings. The second one is “area-wide measures–using urban development opportunities and venues”, area-wide measures for the whole ward which make use of the unique characteristics ofthe local area, namely the high concentration of businesses. The third policy is “urban and human resource
development through community partnerships”, which includes measures to create a low-carbon city center

(1) Energy measures for advanced buildings
Establish an advising counter to provide advice andguidance, support energy-eﬃcient measures for both
new and existing buildings(2) Area-wide measures‒using urban development
opportunities and venues
Eﬀectively implement global warming countermeasuresthrough area-wide urban development such asredevelopment projects and support transportation
measures that are environment friendly.

(3) Urban and human resource development
through community partnerships
Work to reduce CO2 emissions in cooperation
with provincial cities and train
people so that they can conduct environment
friendly activities

and reinvigorate the local area through partnerships with the community and measures to develop humanresources who will undertake environment friendly activities through numerous efforts including the Chiyoda-ku Eco System (CES) and environmental education.

(1) Energy measures for advanced buildings
Measures targeting buildings (both new and existing buildings), a source of CO 2 emissions, will be promoted with the goal of achieving several objectives including introducing renewable energy and rationalizing energy use in and raising the energy efficiency.
In terms of new buildings, the central government’s Act on the Rational Use of Energy and the Tokyo
Metropolitan Ordinance on Environmental Preservation require stronger global warming countermeasures.
Within Chiyoda-ku, there are plans to create a building environmental plan system (tentative name) forsmall- and medium-size buildings as one step toward implementing the required countermeasures. The
system requires that when a new building is constructed, a plan covering various issues be submitted, andthese issues include not only reducing the building’s heat burden through improved insulation for exterior
walls and windows and the use of greenery, but also cutting energy consumption through more efficientfacilities, including heating, air conditioning, and ventilation (HVAC) equipment, lighting, and water heaters,
and promoting the use of renewable energy such as electricity generated from solar panels. This system
will lead to the construction of more energy-efficient buildings.
As for existing buildings, their energy efficiency will also be raised through “green stock strategies”.
“Green stock strategy” is a word coined from stock (existing buildings) and green (energy efficiency).
There are around 12,000 existing buildings in Chiyoda-ku, and increasing the energy efficiency of thesebuilding is the key to reducing CO 2 emissions for the overall ward. The green stock strategy takes two
forms- one targeting individual buildings and one targeting the whole ward or particular area such as shopping districts or neighborhoods.
Currently, the Kanda-station Nishiguchi area, which is centered on a shopping district around 7 ha large
bordered by two streets and includes around 260 buildings has been designated a model area. A promotion
committee, centered on the shopping district association, was launched in July 2009, and energy audits arebeing conducted.
Improvements will be made to operations and facilities will be renovated based on the results of theseaudits, and there are plans to promote energy efficiency throughout the whole area by publicizing theresults of these efforts.

In the future, the ward would like to reduce costs and improve efficiency through joint efforts for energy
efficient renovations to buildings and joint purchasing of equipment such as HVAC equipment. In addition,
the ward would like to raise awareness of greater energy efficiency and global warming countermeasuresby implementing a series of green stock strategies, which will strengthen the local community.

Energy measures for advanced buildings
New Buildings

Existing building

Introduce a building environment
plan system (tentative name)

Implement green stock measures(make existing buildings moreenergy eﬃcient)Work to spread and educate people
about energy eﬃciency

Require plans for the energy-eﬃciency measures
Promote greener building through theintroduction of top-level facilities and equipment
and use of untapped, reusable energy

Details
of
each
plan

Conduct energy eﬃciency audits
Improve building operations andreplace equipment

SupportComprehensive
advising counter

SupportCommunicate information

Support for improving theenergy eﬃciency of existingand new buildings.

Communicate information(2) Area-wide measures–using urban development opportunities and venues
There is a large concentration of corporate headquarters and government ministries and agencies in Chiyoda-ku, and this dense concentration of administrative bodies has resulted in extremely high use of energy
in a small area. Therefore, efforts are being made to raise the efficiency of energy use on various levels
including particular areas and the whole ward, and area-wide global warming countermeasures will be
implemented in an intensive manner.
Areas that are expected to be redeveloped, areas with existing district heating and cooling where buildings are being renovated, and similar areas are considered good locations for area-wide urban development. In consultation with businesses and local land owners, and after an agreement is reached, a community council is established, and the area is designated a Global Warming Countermeasure Promotion Area
(envisioned action areas are Otemachi, Marunouchi, the Daimaru area in Yurakucho, and Kasumgasekiarea). An action program that includes medium- and long-term reduction targets is created in cooperation
with the local government, and the local government and businesses work together to implement the plan.
To promote area-wide use of energy, existing district heating and cooling equipment will be made more
efficient, and untapped, renewable energy sources will be introduced. Chiyoda-ku has 11 district heating
and cooling zones, and most of them are close to needing upgrades. Using this opportunity, efforts will bemade to raise the efficiency of heat-source equipment, expand the supply area, and make the system more
flexible through bypass conduits.
In addition, examinations will be made of using untapped energy sources such as exhaust heat frombuildings and garbage incineration plants. A leading project related to energy efficient urban development
was the project to connect the district heating and cooling conduits of the Marunouchi 1-chome district tothose of the Marunouchi 2-chome, which was completed in March 2008 through cooperation between businesses, the central government, and the ward. This resulted in a 4% improvement in energy efficiency andreduction in CO2 emissions.
As for area-wide heat island countermeasures, various projects are being planned. With the removal of
the Tokyo Station Daimaru Department Store, a station square will be constructed, Gyoko-dori will be pavedwith water-retentive asphalt, in which water will be sprinkled on, and Ginkgo trees will be planted along theroad. Other expected projects include constructing a wind corridor that connects the Imperial Palace toTokyo Bay and introducing clean energy in Tokyo Station as a model project (massive solar panels will be
installed on the roof of the Tokaido Shinkansen platform which will generate around 450kw of power)

Area-wide measures‒using urban development opportunities and venues(1) Designate a Global WarmingCountermeasure Promotion Area

Improve the eﬃciency of district heating
and cooling and use reusable energy

Specify area based on agreement withlocal community

When constructing or replacing district
heating and cooling facilities

Envisioned areas‒
Areas that are expected to be redeveloped
Areas with existing district heating andcooling, and buildings that are being
renovated
Public facilities, universities, hospitals/welfare
facilities, and the surrounding area

Work to increase the eﬃciency of the heat-source
facilities and expand the supply area
Highly eﬃcientheat-source facilities

Storage heat pump, cogeneration, etc.

Extend and connect
conduits

Implement global warming
countermeasures in a concentrated manner
Heat emitted from building, sewer system, river water,
underground water, etc.

Employ untapped energy (heat emitted from buildings,
sewers, etc.) and renewable energy (solar power, wind
power, etc.)

Dramatically reduce CO2 emissions

(3) Urban and human resource development through community partnerships
For urban development through community partnerships, efforts will be made to revitalize the local community and promote the creation of a low-carbon city through partnerships with other local governments,
and these efforts will include acting as a broker of renewable energy projects, such as wind power electricity generation, for businesses located in the ward in order to realize a low-carbon local city. In December

2009, in cooperation with the Tokyo Metropolitan Government and Aomori Prefecture, Chiyoda-ku concluded an agreement for a community partnership project that will bring raw green electricity generated
through various methods such as wind turbines to Chiyoda-ku from Aomori Prefecture.
As for human resource development, Chiyoda-ku established its own environment management system,
the Chiyoda-ku Eco System (CES). The system makes it easy for parties such as residents, individualstores, and small- and medium-size companies to implement measures that fit their particular situation andis simpler and more economical than ISO14001. In order to promote these efforts, the CES Promotion
Council, composed of residents, universities, corporations, and the ward, was founded in April 2008, andthe council is working to train people to undertake various efforts such as spreading environment-friendly
activities and environmental education.
Efforts are also being made to provide and disseminate information in order to promote activities tocombat global warming among residents of the ward and businesses. In addition to running a series of articles related to new energy sources and energy efficiency in publications and holding events such as environment and recycling exhibitions sponsored by the ward, Chiyoda-ku is actively participating in and supporting environment related events sponsored by other organizations such as neighborhood councils.
The ward is publishing free research guides and holds hands-on classes for children. For general ward
residents, various events are held including symposiums attended by environmental journalists and ward
eco tours, in which participants visit parties such as wards, and corporations undertaking environment
friendly activities.

● Promotional system

In order to promote global warming countermeasures, it is necessary that all parties, including the ward,
residents of the ward, and businesses, fulfill their particular role. In October 2008, the ward established the
Chiyoda-ku Global Warming Countermeasures Promotion Headquarters, headed by the deputy major, andthe headquarters works to thoroughly educate people about basic ideas on and policies related to global
warming countermeasures and to promote systematic efforts. In addition to creating a system that makes it
easy for ward residents and businesses to take part in global warming countermeasures, the headquarters

promotes related measures.
The Energy Efficiency Support Center (tentative name) is expected to be launched in 2010 as a comprehensive advising office and information hub regarding global warming countermeasures. In particular, thecenter will provide advice on making buildings more energy efficient and draw up environmental plans, conduct energy efficiency audits, provide information on subsidies for energy-efficient or new energy equipment, and accept applications and registrations.
A Global Warming Countermeasures Evaluation Committee (tentative name), composed of various parties including academics, business people, and resident representatives, will also be created in the future,and the committee will conduct various activities including ascertaining progress in implementing measuresand various plans, examining and evaluating benefits, and providing advice on appropriate revisions andimprovements, which will continually be reflected in measures.
● Conclusion

In January 2009, the central government designated Chiyoda-ku an eco model city (one of the 13 cities
throughout Japan and the only ward of Tokyo), a local government that is fulfilling its role as a leader andmodel for realizing a low-carbon society. The ward has also been actively working on the previously mentioned global warming countermeasures.
The measures are extensive and many cannot be implemented without the understanding, action, andcooperation of residents and businesses. In order to pass on a healthy global environment to the next generation, the ward would like to marshal the wisdom and power of many people and steadily implement
global warming countermeasures even if only gradually by balancing the environment with the economy.

Reference material:
Chiyoda Ward website: http://www.city.chiyoda.tokyo.jp/
Chiyoda-ku Global Warming Countermeasure Ordinance and Chiyoda-ku Eco Model City Plan: http://www.
city.chiyoda.tokyo.jp/service/00105/d0010539.html
Eco Model Cities: http://www.kantei.go.jp/jp/singi/tiiki/080722kankyo-kouhyo.pdf

HOW TO MITIGATE THE HEAT ISLAND PHENOMENON IN SMALL CITIES:
Akinobu MURAKAMI / Lecturer, Graduate School of Systems and Information Engineering, University of Tsukuba

1. Introduction
In Japan, the heat island phenomenon has become a serious urban problem. Moreover, in recent years,
the heat island phenomenon has begun to affect not only large cities, but small cities as well. The outdoor
thermal environment in the summer has become very disagreeable in such cities and should be improved.
Improving the summer outdoor thermal environment would decrease the indoor air-conditioning load.
Therefore, improvement of the summer outdoor thermal environment is important with respect to both
energy savings and exhaust heat reduction.
The utilization of greenery is one method by which to improve the summer outdoor thermal environment.
Compared to large cities, many small cities have more green and open spaces. Therefore, small cities are
better able to use greenery as a countermeasure against the heat island phenomenon.
In this paper, the condition of urban heat island phenomenon in small cities will be described taking thecase study of Tonami, Toyama, Japan and the countermeasures against heat island in a small city will be
discussed. Tonami is a small city in Japan in which the urbanized area has been affected by the heat island
phenomenon. Since Tonami is located on the Tonami plain, which is covered by paddy fields, the cooling
effects of paddy fields could be used to mitigate the heat island phenomenon. However, the characteristicsof the urban form and the cooling effects of paddy fields must be understood in order to apply cooling

Figure 1 Surface temperature distribution of Tonami, Toyama, Japan in daytime of summer.

effects in environmental management. Therefore, the objectives of this study are (1) to examine the characteristics of the urban form and the state of heat island in the Tonami district using land cover maps and surface temperature maps and to determine appropriate observation points and (2) to clarify the degree ofcooling effects by paddy fields in the Tonami urbanized area in summer.

2. Characteristics of land cover distribution and outline of the thermal environment of Tonami
Observation by air-borne multi-spectral scanner (MSS) was performed in order to generate land covermaps and surface temperature maps of the Tonami district for April and July of 2002. The two observation
altitudes were 6,000 m (high), which allowed observation of the entire Tonami plane, and 1,500 m (low),which allowed observation of detailed ground surface information.
In the present study, the state of heat island of the Tonami urbanized area is examined using surface
temperature distribution maps. Before conducting the observations, the surface temperature distribution
maps were generated using the low-altitude data collected for June, and the mean surface temperatures ofeach land cover in Fig. 2 were calculated (Table 1).
Among the mean surface temperatures, both the day and night temperatures were lowest in greeneryareas. Compared to the air temperatures collected by the Tonami AMeDAS, the mean surface temperaturesof the greenery areas were equivalent to the air temperatures during the day and during the night. The
mean surface temperature of buildings was 26oC and bare areas were 16oC higher than the air temperatureduring the day. Whereas at night, the mean surface temperatures in these land cover types were slightly

Figure 2 Land cover map around the Tonami urbanized area during the summer (Observation Point at
Location U1, U2, U3 and Fig. 3
Table 1 Mean surface temperatures of each land cover in Fig. 2
Land cover
Greenery
Pavement
Buildings
Bare areas
Air temperaure

Mean surf. temp. [℃ ]
day
night
37.4
26.0
56.0
35.1
58.8
27.4
48.3
29.0
32.4
29.1
(Tonami AMeDAS)

less than the air temperature. The mean surface temperatures in pavement areas were higher than the airtemperature both during the day and during the night. Both during the day and during the night, the pavement land cover type increased the air temperature.

3. Method for field surveys to clarify the cooling effects of paddy fields
3.1Observation of the cooling effects of wind flow from the paddy fields area to the urbanizedarea
A field survey of the microclimate was conducted in order to determine the effects on air temperature of
the wind flow from the paddy field area to the urbanized area of Tonami.
Measurements were taken around the culmination hour (day) and around sunset (night) on 3 and 10
August 2003. The weather was fine. The highest temperatures were 33 oC on 3 August and 29oC on 10
August, as indicated by Tonami AMeDAS. In the present study, in order to observe the cooling effects of the
paddy fields surrounding the urbanized area, observation points were positioned along the road running
through from outer paddy fields area to the central urbanized area as follows: observation point U1 waspositioned at the border between the urbanized area and the paddy fields area, observation point U2 waspositioned 350 m nearer the central urbanized area than U1, and observation point U3 was positioned 600
m nearer the central urbanized area than U1 (Fig. 2). Low-rise wooden buildings were present on the bothsides of the road, and the width of the road was 12 m. Observation of the microclimate was also conducted
at a point approximately 2 km northwest of Tonami Station in order to clarify the features of the microclimateof the paddy field area surrounding the Tonami urbanized area.
At the observation points, a 0.1-mm-diameter T-type T/C and the macromolecule humidity sensor of an
Assman ventilated psychrometer were positioned at an elevation of 120 cm above the ground in order tomeasure air temperature and humidity. A hot-wire anemometer was positioned at an elevation of 180 cm
above the ground in order to measure wind speed, and an propeller vane anemometer was positioned at anelevation of 150 cm above the ground in order to measure wind direction. In addition, a photo-diode pyranometer was positioned on the ground in order to measure the solar radiation. The observations were conducted by the fixed-point observation method at two-second intervals.

3.2Observation of the cooling effects of paddy fields interspersed among other types of land
cover around the periphery of the urbanized area
Using the land cover map discussed in Section 2, a cluster of paddy fields interspersed with other typesof land cover was extracted and was designated as the observation site. In addition, in order to clarify theeffects of the paddy fields, observation points were positioned on both the windward and leeward sides ofthese paddy fields. This cluster of paddy fields was surrounded by middle-rise and low-rise buildings, andthe land cover type at the observation points was pavement (Fig. 2 and Fig. 3).
Before observation of the cooling effects, the wind system
around this site was confirmed. Both wind direction and windspeed were measured at the rooftop of a three-story building near the observation site. These winds were equatedwith gradient winds. The inflow points (windward side) andoutflow points (leeward side) of the gradient winds at the sitewere determined for each wind direction. As a result, when
the wind direction was from the northwest (NW), P1, P5, P6
and P8 in Fig. 3 were located on the windward side and P2
Figure 3 Observation site.
and P3 were located on the leeward side, and when thewind direction was from the northeast (NE), P2, P3, P4, P5 and P7 were located on the windward side andP1 was located on the leeward side. There were multiple windward-side points at the site. Thus, the airtemperature at the one leeward-side point was compared to the temperatures at multiple windward-side
points.
Measurements were taken around the culmination hour (day) and around sunset (night) on 4 and 7
August 2003. The weather was fine. The highest temperatures were 32ºC on 4 August and 33ºC on 7
August, as indicated by Tonami AMeDAS. Eight observation points were positioned around the paddy
fields. The measuring instruments described in Section 3.3 were positioned at the observation points. The
observations were conducted by the fixed-point observation method at two-second intervals.
4. Results
4.1 Cooling effects of the wind flow from the paddy fields area to the urbanized area
The weather on 3 August was clear, and the wind direction in the paddy fields area was stable W or NW
until 19.00. The weather on 10 August was fine, and the solar radiation showed sharp fluctuation. The winddirection in the paddy fields area was not stable during the day and was mainly NW or NE, and the winddirection was stable during the night and was N or NE.
In order to analyze the relationship between air temperature and wind, the mean values for 10-minuteintervals were calculated. The mean solar radiation indicates the trend of solar radiation during each interval. In addition, in order to clarify the relationship between temperature and wind speed, the mean air temperature was calculated for each 10-minute interval and wind speed range (below 1 m/s, over 1 m/s andbelow 2 m/s, and over 2 m/s). In addition, the data for the wind directions of NW and NE were considered in
the analysis because the primary wind direction is NW or NE in this region during summer.
First, the wind direction data collected at the observation points in the urbanized area were sorted
according to wind direction in the paddy fields area. As a result, when the wind direction was NW in the
paddy fields area, the wind direction at all observation points in the urbanized area were along the roadfrom the paddy fields area. When wind direction was NE in the paddy field area, the wind directions at U1and U2 were not stable, and that of U3 was stable NW.
For the mean air temperatures during the observation, the air temperatures in the urbanized area wereapproximately 1.2ºC to 2.7ºC higher than in the paddy fields area. On 3 August, when the wind direction
was stable along the road, the air temperatures increased towards the center of the city. On 10 August,however, the air temperature at U2 was 0.3ºC higher than at U3 during both the day and the night, and the
air temperatures at U2 and U3 were identical.
The mean air temperature differences for 10-minute intervals between the paddy fields area and theurbanized area for three wind speed ranges when the wind direction was NW and NE on 10 August are
shown in Fig. 4. When the wind direction was NW in paddy fields area, the air temperatures increased
toward the center of the city, for all but one period of data. This trend was applied to 3 August, for all but
one period of data. When the wind direction was NE in the paddy field area, the air temperature at U2 was
the highest until 17.30, and increased toward the center of the city after 17.30. Factors other than air inflow
were thought to affect the air temperature because the wind speed was low after 17.30. In addition, theradiation condition was thought to have appeared because there were no waste heat sources near theobservation points. Therefore, there was a large sensible heat flux toward the center of the city. The
increased wind speed was thought to have brought the air from near the ground level and higher levels. In
this survey, the relationship between the air temperatures at U2 and U3 reversed according to the winddirection in paddy fields area, indicating that the inflow of lower-temperature air in the paddy fields area
affected the air temperature at the observation points in the urbanized area when the wind direction was
NW.
The differences in mean air temperatures between 10-minute intervals for the wind speed range of below 1
m/s, and other wind speed ranges, at three observation points in the urbanized area on 3 August when thewind direction in the paddy fields area was NW, are shown in Fig. 5. During the day, when the wind speed
increased, the air temperature decreased, and the maximum decrease was 1.0ºC at U2, comparing windspeeds range of below 1 m/s and over 2 m/s. The air temperature reduction during the night tended to besmaller than that during the day. Summarizing the above results, the decrease in air temperature in the urbanized area was shown to have occurred due to the inflow of air from the paddy fields area along the road.

Figure 4 Mean air temperature differences for 10-minute intervals between the paddy fields area and theurbanized area for three wind speed ranges on 10 August.

Figure 5 Differences mean air temperatures between 10-minute intervals for the wind speed range of below 1
m/s, and other wind speed ranges, at three observation points in the urebanized area when the winddirection was NW (3 August)

4.2Cooling effects of the paddy fields interspersed with other types of land cover in the urbanized area
The solar radiation fluctuated sharply during the observation period. Therefore, in order to analyze therelationship between the air temperature and wind speed, the mean values for 10-minute intervals were
calculated. The mean solar radiation indicates the solar radiation trend at each term. In order to clarify the
relationship between temperature and wind speed, the mean air temperature was calculated for each

10-minute interval and each wind speed range (below 1 m/s, over 1 m/s and below 2 m/s, and over 2 m/s).
The direction of the gradient wind was NW on 4 August and NE on 7 August. Thus, P2 and P3 were locatedon the leeward side on 4 August, and P1 was located on the leeward side on 7 August.
The differences in mean air temperature during the observation period between the windward and leeward sides when P1, P2 or P3 was located on the leeward side are shown in Fig. 6. All three observation
points showed low mean air temperatures, and the differences were approximately 1.5ºC during the day.
The distribution of mean air temperature values for 10-minute intervals of P1 and P2 when the wind direction was NW or NE are shown in Fig. 7. On 4 August, the air temperature at P2, on the leeward side, waslower than that at P1. However, on 7 August, the air temperature at P1, on the leeward side, was lower thanthat at P2. In this survey, the relationship between the air temperatures at P1 and P2 reversed according to
the wind direction. Therefore, the inflow of the air from the paddy fields affected the air temperature on theleeward side. The mean air temperatures for 10-minute intervals for three the wind speed at P2 when P2
was located on the leeward side during the day are shown in Fig. 8. When the wind speed increased, theair temperature decreased, and the maximum decrease was 0.6ºC, comparing the mean wind speeds
range of below 1 m/s (mean value is 0.7 m/s) and over 2 m/s (mean value is 3.2 m/s). When the solar radiation was low, the differences in air temperature were reduced. In addition, the maximum decrease was
0.6ºC at P1 and 0.3ºC at P3 during the day. The air temperature reduction during the night tended to besmaller than that during the day.
Summarizing the above results, around the paddy fields that are interspersed among other types of land
cover in the urbanized area, the air temperature on the leeward side was lower than on the windward sides
and when the wind speed increased, the air temperature decreased on the leeward side.

5. Conclusions
In the present study, in order to mitigate the heat island phenomenon in the Tonami urbanized area, thecharacteristics of urban form and the state of the heat island of Tonami district were examined and fieldsurveys were conducted so as to clarify the degree of the cooling effect of paddy fields in Tonami urbanized

Figure 6 Differences in mean air temperature during the observation period between the windward andleeward sides when P1, P2, or P3 was located on the leeward side.

Figure 7 Distribution of mean air temperature values
for 10-minute intervals of P1 and P2 when thewind direction was NW or NE.

Figure 8 Mean aire temperatures for 10-minuteintervals for three wind speed ranges at
P2 when P2 was located on the leeward
side during the day.

area during summer. The findings of the present study are as follows:
1) The forms of the paddy fields were classified as either extensive paddy fields surrounding the urbanizedarea or small paddy fields interspersed among other types of land cover in the urbanized area.
2) During the day, as the wind speed increased, the air temperature was decreased by the air from theouter paddy fields, and the maximum value was 1.0ºC at 350 m inside the edge of the urbanized area on
the road running through from the outer paddy fields area to the central urbanized area.
3) Around the paddy fields interspersed with other types of land cover around the periphery of the urbanized area, the mean air temperatures on the leeward side were lower than on the windward side, and thedifferences between the windward and leeward sides were approximately 1.5ºC during the day. When
the wind speed increased, the air temperature decreased by a maximum of 0.6ºC, comparing the mean
wind speeds of approximately 1 m/s and 3 m/s, as measured on the leeward side of the paddy fields.
These results have implications for urban planning and design. This study investigated only small andmoderately large paddy fields, and studies should be undertaken to determine the optimum size of green
open spaces (i.e. the point of diminishing returns). The results of this study support the commonly-held
opinion that there should be many green open spaces distributed throughout urban areas, and streetsshould open onto these spaces as much as possible. Streets should also be oriented with prevailing windsthat occur during the hottest weather in summer.
Besides, it is well stated that the mixture of urban and rural landscapes is a key feature of Asian cities.
Many of small cities in Japan are surrounded by agricultural land, mainly paddy fields, and there are manyof paddy fields even in city area. The mixture of urban land use and paddy fields can be observed everywhere in small and local cities in Japan. The results of this study indicate such mixture would alleviate heatisland problems.
The 21st century is projected to be the century of the environment. The future of human beings isdependent on the actions we will take on behalf of the environment at the beginning of the next century.
Responding to such concern on the environment, “controlled mixture of urban and rural landscapes” should
be considered as a workable concept for the future. Vegetated open spaces in urban fringe areas, including
agricultural lands, are known to have many ecological functions. They may provide habitats for wildlife,
become recreational spaces such as allotment gardens and aesthetically pleasuring gardens, and maintaincomfortable living environment, as indicated by the results of this study.

References
Yamada, H., 1993. Study on the distribution of air temperature in Kurihashi, Saitama pref. and the effects
of open spaces on the urban climate in summer days. J. Jap. Inst. Landscape Architect,. 56 (5): 331-336.
(In Japanese with English Abstract)
Yokohari, M., 1998. Effect of paddy fields on summertime air temperature in urban fringe areas; a casestudy in Kasukabe city, Saitama prefecture. J. Jap. Inst. Landscape Architect,. 61 (5): 731-736. (In Japanese with English concrete)ANALYSIS OF THE COOLING EFFECT OF URBAN GREENERY IN SUBSTANTIAL
URBAN AREA USING 3-D CAD
Rihito SATO / Research Associate, Interdisciplinary Graduate School of Science and Engineering,Tokyo Institute of Technology

1. Introduction
Changes in land cover conditions and the increasing amount of anthropogenic heat released into the outdoor spaces aggravates the outdoor thermal environment in urban areas and increases energy consumption. And, in turn, the increased energy consumption further aggravates the outdoor thermal environment.
Therefore, a countermeasure against the heat environment problems must be implemented to break thisvicious cycle. In the past, the cooling effect of greenery was the focus of numerous studies. However, it is
not clear whether urban greenery is effective in a variety of urban spaces.
Recently, studies have examined the cooling effect of greenery in urban areas broadly using remotesensing and GIS-based modeling. However, these studies were difficult to evaluate in three-dimensions. In
addition, a few studies have tried to model the outdoor thermal environment of substantial urban areasusing three-dimensional numerical simulations. Unfortunately, the vast quantity and variety of urban greenery could not be evaluated accurately in these simulations.
This study uses a different approach to evaluate the cooling effect of urban greenery on the outdoor thermal environment. The urban element information for a substantial urban area is collected precisely andbroadly, and is used to generate a three-dimensional CAD model, to which material data and physical properties were added. Then, a numerical simulation is conducted to determine the cooling effect of urban
greenery. This approach is verified through a case study on the center of Tokyo, which contains various
urban structures and greenery.
2. Method for generating a 3D-CAD model for the evaluation of outdoor thermal environment
First, the building and ground composition materials were considered and a region was selected for evaluation. Then, building form and material data were collected for the substantial urban area. These data
were then used to develop a three-dimensional CAD model, to which material data and physical properties
were added.

Figure 1 GIS based model and generating model

3. Calculation of the surface temperature distribution using numerical simulation
By evaluating each urban block in which the land cover and the land use are similar, the impact to theurban thermal environment can be evaluated. Therefore, the three-dimensional CAD model was next
divided into urban blocks. The surface temperature distribution for each block was calculated using a
numerical simulation system.

A cluster analysis was first performed on the building site, floor number, and the building-to-land ratio asa variable. The urban blocks were assigned according to the cluster analysis, land use, and building structures. Then, the urban blocks and the border buildings were determined.
This study used the numerical simulation system which was developed by authors to evaluate the effectsof spatial forms and materials on the outdoor thermal environment.1) The composition and flow of the simulation program are described below:(1) Building structures and tree shapes are drawn using the all-purpose 3D-CAD software(2) Material data are selected from the database(3) The 3D-CAD model generated by this process is then transformed into a “mesh model,” which is used
to calculate radiative heat transfer and the surface heat balance(4) The heat balance and one-dimensional heat conduction are determined for each mesh. Solar andatmospheric radiation are calculated from the sky factor of each mesh. The convective heat transfer calculation assumes that there are no air temperature or wind velocity distributions in the outdoor space.
The weather data used for this calculation uses the vertical quantity of total solar radiation, air temperature, relative humidity, wind velocity, and cloud coverage. This study assumed a clear sky day insummer, Tokyo.
Three indices were used to evaluate the outdoor thermal environment:1)(1) Surface temperature distribution determined by the 3D-CAD model
The CAD model allows for the observation of the surface temperature distribution from almost any viewpoint and at various times to fully evaluate the effects of specific spatial forms and materials.
(2) MRT distribution at a height of 1.5 m
The MRT (Mean Radiant Temperature) is the weighted average of the radiant interactions in a given
space. A 1.5 m-high MRT distribution was used as an index to evaluate the thermal comfort of outdoor
living.
(3) HIP (Heat Island Potential)
HIP(Heat Island Potential) which was proposed by the authors is the expressed by Equation (a). The HIP
is an index of the sensible heat flow rate on all surfaces in an urban block. In this equation, HIP is the heatisland potential (°C), Ts is the temperature of the microscope surface (°C), Ta is the air temperature (°C),
and dS is the area of the microscope surface expressed in urban blocks (m2).
(a)

4. Numerical simulation results
An example of the surface temperature distribution for the entire evaluation area, as shown in Fig. 2. At
10:00, the surface temperature of a wooden house's roof increased to approximately 20 degrees higher
than the air temperature. This can be explained by the roof material’s small heat capacity. Other materialsof low solar reflectivity were also approximately 20 degrees higher than the air temperature. On the other
hand, the surface temperatures of commercial/business building roofs were nearly 10 degrees higher than
the air temperature due to their large heat capacity. The surface temperature of the park block was lessthan 10 degrees higher than the air temperature.
At 12:00, the surface temperatures of the ground and roofs were 20 to 30 degrees higher than the airtemperature for the entire area. However, the park block covered with turf grass and trees was only 10
degrees higher than the air temperature. The wall temperatures of high-density buildings were approximately equivalent to the air temperature because of lower quantity of direct solar radiation.
At 15:00, the surface temperature on the west side of the buildings rose due to the location of the sun.
However, the surface temperature of buildings with numerous windows did not increase because of theindoor air conditioning. The surface temperatures of buildings that had tall buildings on their west sidedecreased to the air temperature due to the effect of the shadow.
At 20:00, the surface temperatures of commercial/businesses and warehouse blocks were 10 degrees

10:00

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Figure 2 Surface temperature distribution for the entire area (12:00)

higher than the air temperature. The main reason for this characteristic is the large heat capacity of thecomponent materials. On the other hand, the surface temperature of the park block decreased approximately air temperature due to radiational cooling. The effect of the setting sun on the surface temperature
distribution was evident across the entire evaluation area.
Fig. 3 shows the relationship between the HIP and the vegetation cover ratio at specific times of the day.
Before dawn, the wooden housing block and the park block were approximately 0°C or less. At this point,a clear correlation between the HIP and vegetation cover ratio was not clear.
At 12:00, the correlation between the HIP and the vegetation cover ratio were evident. The differences inthe HIP values decrease as the vegetation cover ratio increases. At 15:00, the HIP values of the wooden
housing block became lower than for the RC building block. And correlation between the HIP and vegetation cover ratio was also evident in this time frame. At 20:00, the HIP distribution was similar to that at
15:00, with values between 5 and 10 lower than 15:00 in most blocks.

5. Conclusions
The simulation performed in this paper provided a number of insights into the urban effect of greenery on
the outdoor thermal environment. First, urban elements were collected using both existing data and field
investigations. And an accurate three-dimensional CAD model was developed to analyze the outdoor thermal environment in a substantial urban area. Material and physical property data were also included in themodel.
The outdoor thermal environment and cooling effect of urban greenery were studied using a numericalsimulation system. The simulation revealed that a correlation exists between the HIP and vegetation coverratio during the daytime. Building structures and materials strongly affected their surface temperatures. The
setting sun also played a role on building surface temperature distributions in the evening hours.
Urban blocks with 10% or less vegetation cover ratios have little open space. The cooling effect of vegetation affected part of the block. Therefore, planting trees with large crowns, as well as rooftop vegetation,is effective. On the other hand, urban blocks having 20% vegetation cover ratios include various species ofvegetation and rich open spaces. Surface temperatures in these blocks were dependent upon the speciesof vegetation. However, many of these blocks include high buildings that cause high HIP values into the

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Figure 3 Relationship between the HIP and the vegetation cover rationight. Therefore, it would be advantageous to combine various species of vegetation and to limit the heightof buildings. Urban blocks with 30% or higher vegetation cover ratios were all park blocks. HIP values forthese blocks were low compared with other urban blocks during the day. However, the surface temperatureof arid soil increases during the daytime, so it would be effective plant turf grass or trees.

References
1) A. Hoyano, T. Asawa, K. Nakaohkubo 2004.12, Environmental design tool by combining outdoor thermal
environment simulation with 3D-CAD, AIJ journal of technology and design NO.20, pp. 195-198.