Urban Heat Island and Urban Form in Durham, NC Levers for ...

Urban Heat Island and Urban Form in Durham, NC

&

Levers for Change

1

Carolina Climate Resilience Conference

September 12-14, 2016

Charlotte, North Carolina

Elizabeth M. B. Doran, Ph.D.

Division of Earth & Ocean Sciences

Levers of Change

2

Challenge(e.g. Urban Heat Island)

TechnologyEconomic

IncentivesPolicy

Behavior

Change

Goal #1: Assess magnitude of the global challenge of urban climate at the local scale

in Durham, North Carolina, USA.

Physical observations and experiments

Goal #2: Link physical science to local planning and development objectives to

enable resilience in the face of change.

Address gap in methods for translation to practiceDoran, 2016

Urbanization Trends: World

3UN, 2011


4

UN, World Urbanization Prospectus, 2014


5

UN, World Urbanization Prospectus, 2014

Urbanization and GeomorphologyTransition from native materials, and low engineered land-uses and land covers

To highly engineered materials, highly engineered land uses and land covers

6Stewart & Oke, 2012

HOTTER!

Urban Heat Island

7Oke, 1982

R R

UQuantified using

ground based

Meteorological Station

Networks

Definition:

Closed isotherms indicating an

area of the surface that is relatively

warm; most commonly associated

areas of human disturbance such

as towns and cities.

The physiographic analogy derives from the

similarity between the pattern of isotherms and

height contours of an island on a topographic map.

Heat islands commonly also possess "cliffs" at the

urban–rural fringe and a "peak" in the most built-

up core of the city. The annual mean temperature

of a large city (say 106 inhabitants) may be 1°–

2°C warmer than before development, and on

individual calm, clear nights may be up to 12°C

warmer. The warmth extends vertically to form an

urban heat dome in near calm, and an urban heat

plume in more windy conditions.

American Meteorological Society Glossary of

meteorology, 2012

Urban Heat Island: 3 Types

Planetary Boundary Layer UHI

(BLUHI)

(CLUHI)

(SUHI)8

Voogt; Oke, 1997

Prior Work

9

Prior Work

10

Prior Work

11

Prior Work

12

My ResearchAddressing Gaps in the UHI Literature and Developing Methods for Translation

to Practice

13

Question #1

Meso-scale

UHI

• What is the intensity and distribution of the UHI in the Raleigh-Durham Region, North Carolina

• Methods: Extensive climatic data + Remote Sensing

Question #2

Local-scale

UHI

• What is the intensity and dynamic behavior of the local scale UHI in the study area of Durham, North Carolina?

• Methods: Sensor Networks + Mobile Transects

Question #3

Urban Form

• Can urban form be used to help explain the intensity and distribution of the nocturnal UHI in the study area?

• Methods: Urban Form Characterization Methods + UHI

Urbanization Trends: Southeast

14EPA, 2009; Carlyle, 2014; Todorovich et al., 2011

2010 U.S. Housing Density Map

Raleigh, NC

2nd Fastest rowth, 2014

Charlotte, NC

8th Fastest Growth, 2014

Atlanta, GA

12th Fastest Growth, 2014

Piedmont

Megalopolis

South:

2005: 36.9% of US Population

2030: ~40% of US Population

Site Selection Rationale• Raleigh-Durham is part of the fastest growing region in the country (EPA, 2009; Carlyle,

2014; Todorovich et al., 2011)

• Previous research on UHI in Raleigh-Durham is limited (King & Davis, 2007)

• Sits at the boundary between increased cooling and decreased heating from UHI (Sun, Augenbroe, 2014)

• Local research means infrastructure is highly accessible for sensor deployment

and observation & access to willing partners and collaborators

Piedmont

MegalopolisUS Census Bureau; Capitol Area Metropolitan Planning

Organization (CAMPO)Durham City: 251,893

Raleigh City: 439,896

Wake-Durham-Orange Counties:

1,466,504US Census Population Estimates, 2015

1 Million

UHI Observations Methods Overview

16

Mesoscale(1-100km)

Local scale (100m -1km)

2. Satellite Remote Sensing

Landsat-8 OLI-TIRS (USGS)

Day + special request night campaign

Processed to land surface temperature (SUHI)

& vegetative indices

3. Transects

Onset HOBO U23-002 (Temp/RH)

Custom test rig vehicle mounted (CLUHI)

64km transect in < 2hrs

Transects every 4hrs for 72hrs(Sun et al., 2009; Voogt, 2000)

1. Standard Weather Stations

Historical Record (1945-2015)

Hourly weather observations (CLUHI)

Focus on optimal conditions

4. Field Sites

(Non-Standard Weather Stations)

Onset HOBO U23-001 (Temp/RH)

12 sites; 15 minute sampling rate;

3m height(Coseo & Larsen, 2014;

Schatz & Kucharik, 2014;

Oke, 2004, 2006)


to Practice

17

Question #1

Meso-scale

UHI



Question #2

Local-scale

UHI



Question #3

Urban Form



Meso Scale

18

91mASL

11/1/55

COOP-TP

LCZsc D

112mASL

1/25/03

AWOS-III

LCZsc D

79mASL

1/1/1893

COOP-TP

LCZsc 9D

76mASL

8/2/03

ECONet –Tower

LCZsc 9D

133mASL

7/1/48

ASOS-Standard

LCZsc 6D

172mASL

3/30/00

RAWS

LCZsc D

186mASL

12/14/00

AWOS-III

LCZsc D

Standard

Weather Stations

/

U

R

R

R

R

19

UHI = 5.2°C (9.4°F)

R2pop = 0.36R2

LULC = 0.36

20

UHI = 5.2°C (9.4°F)

R2pop = 0.36R2

LULC = 0.36

21

UHI = 5.2°C (9.4°F)

R2pop = 0.36R2

LULC = 0.36

22

Landsat-8 Scene Capture Time: 21 June 2015 10:52:44 EST

UHI = 8°C (14.4°F)

UHI = 2°C (3.6°F)

23

UHI magnitude depends on method (CLUHI: 1.2°C vs. 5.2°C;

SUHI: 2°C)

Passive control of climatological conditions accounts for ~3°C

UHI is growing over time, best correlated with population growth

and land use change

Urban areas are warmer than rural areas, but significant variation

exists across the urban fabric

Doran, E.M.B. & Golden, J. S. (IN REVIEW). Climate & Sustainability Implications of Land Use Alterations in

an Urbanizing Region: Raleigh-Durham, North Carolina. Special Feature on Land Use Management and

Sustainability; Journal of Environmental Protection.

Question #1

Meso-scale

UHI




to Practice

24

Question #1

Meso-scale

UHI



Question #2

Local-scale

UHI



Question #3

Urban Form



25

UHImax = 6.9°C (12.4°F) UHImax = 8.7°C

(15.6°F)

26


(15.6°F)

27


(15.6°F)

28

CLUHI = 8.7°C (field sites) 6.9°C (transects)

Nocturnal Maximum UHI 1-3 hrs after sunset

Evapotranspiration dominant UHI driver

High dewpoint (>20°C threshold for human

thermal comfort) observed during daylight hours

Doran, E.M.B. & Golden, J. S. (IN REVIEW). Multi-method Local Scale Characterization of the

Urban Heat Island in Durham, North Carolina, USA. Journal of Applied Meteorology and

Climatology

Question #2

Local-scale

UHI




to Practice

29

Question #1

Meso-scale

UHI



Question #2

Local-scale

UHI



Question #3

Urban Form



30Stewart & Oke, 2012; Coseo & Larsen, 2014; Wilson & Song, 2009; Homer et al. 2015

Mean Urban Form Characterization Method by Census Block Group, and Nocturnal

SUHI in Durham, NC 21 June 2015, 20:04:45

34

Mean Urban Form Characterization Method by Census Block Group, and Nocturnal

SUHI in Durham, NC 21 June 2015, 20:04:45

35

Mean UHI by

Urban Form

Characterization

Method

Linear regression model summary: UCA for CLUHI Evening

Category Variable UCA NLCD B SE beta B SE beta B SE beta B SE beta

TreeCanopy x -0.36 0.33 -0.07

OpenArea x 0.78 0.67 0.05

ResidentialLandUse x -2.52*** 0.29 -0.46

CommercialLandUse x 1.72 0.93 0.17

IndustrialLandUse x 23.85*** 3.46 0.37

Multi-familyResidentialLandUse x -1.92 1.12 0.16MeanBlockSize(perimeter) x -0.01*** 0.001 -0.16

MeanResidentialLotSize x -48.30** 16.62 -0.14

Busstops x 0.10*** 0.01 0.68

ModifiedAndersonLandCover

ClassificationSystem(1976)x

SingleFamilyResidentialLots x -0.003*** 0 -0.32

Intersections x 0.05*** 0.002 1

Cul-de-sacs x -0.05*** 0.01 0.23

Streetlength x

Sidewalk x

(Constant) 3.92*** 0.27 4.65*** 0.12 3.3.2*** 0.09

n 222 234 234

AdjustedR2 0.74*** 0.40*** 0.70***

Notes: *p<0.05

**p<0.01

***p<0.0005

UrbanFormVariablesUrbanForm

Method

CLUHIEvening

Model1 Model2

LandUse

andLandCover

Building

Configur-

ation

Model3 Model4

36

Linear regression model summary: LCZ and MLCZ for CLUHI Evening

Category Variable LCZ MLCZ B SE beta B SE beta B SE beta B SE beta

ImperviousSurface x x 3.74*** 0.66 0.75

PerviousSurface x 0.94 0.63 0.17

BuildingSurface x x 6.03* 2.56 0.35

ImperviousSurfaceBuilding x -3.02*** 0.81 -0.21

TreeCanopy x -0.22 0.48 -0.04 -3.29*** 0.23 0.68

AspectorUrbanCanyonRatio x x 1.09 1.28 0.33

HeightofRoughnesselements

(inclbuildings)x x

0.03 0.05 0.22

SiteOrientation x 0.16 0.42 0.12

SurfaceAlbedo x 9.10*** 1.82 0.32

DistancetoDowntown x -0.39*** 0.06 -0.62

DistancetoWater x -0.57 0.48 -0.10

NearbyUpwindIndustrial x 0.01 0.26 0.004

NearbyUpwindPark x 0.23* 0.1 0.13

NearbyUpwindFreeway x -0.44*** 0.11 -0.22

(Constant) 2.56*** 0.36 4.6*** 0.48 5.73*** 0.56 5.87*** 0.13n 226 12 84 234

AdjustedR2 0.79*** 0.03 0.80*** 0.47***

Notes: *p<0.05**p<0.01

***p<0.0005

UrbanFormVariablesUrbanForm

Method

CLUHIEvening

Model2 Model3 Model4

LandUse

andLand

Cover

Building

Configur-

ation

Thermal

Properties

Model1

37

NLCD 2011 best correlated to UHI intensity and distribution in study area; LCZ

methods also useful

UCA method not useful, but variables hold promise for better model generation

and interdisciplinary translation

Land cover (e.g. impervious surface fraction, pervious surface fraction &

albedo) consistently highly correlated across methods, thermal properties also

useful; building configuration requires additional attention

Doran, E.M.B. & Golden, J. S. (IN REIVEW). Evaluating Urban Form Characterization Methods in the Context

of the Urban Heat Island. Landscape and Urban Planning

Question #3

Urban Form



Policy Levers

38Doran, 2016

Policy Levers

39Doran, 2016

Summary& Conclusions

40

What we’ve learned… Significant UHI magnitude and

growing over time

Dominated by evapotranspiration

and land cover including the

balance of impervious and pervious

surface covers

Potential exists to leverage the

urban form characterization

methods from diverse research

communities to translate the science

of UHI to practice

Policy levers in the local context

have been identified

Future Work Impact of UHI to energy use in

buildings

Impact on human health and

comfort

Mitigation techniques in context

Socio-economic factors and

distribution

Effect of urban agglomeration on

UHI

Novel observation techniques

Levers of Change

41


TechnologyEconomic

IncentivesPolicy

Behavior

Change

Levers of Change

42


TechnologyEconomic

IncentivesPolicy

Behavior

Change

AcknowledgementsCommittee:

Lincoln F. Pratson, EOS, Chair

Jay S. Golden, EOS, Co-Chair, Advisor

Timothy L. Johnson, EOS

Billie L. Turner, II, ASUDurham City & County Government

Tobin Fried, Director of Sustainability

Pete Nicholas, Transportation Engineer

Aaron Cain, Hannah Jacobs, Planning Department

Patrick McDonough, Go Triangle

Technical Support

Adrienne Wootten, NC State Climate Office

Gene Fosnight, USGS

William Stefanov, NASA

Crystal Schaaf & Shuai Yanmin, UMass Boston

Peter Haff, Duke

Brandon Morrison, Duke

Financial Support

Center for Sustainability & Commerce

Division of Earth & Ocean Sciences

Nicholas School of the Environment

43

“Durham’s vitality is built upon

The health of our residents

And the capacity of our community

To foster and enhance

The wellbeing of every citizen.”

—Durham County Human Services

44

QUESTIONS?

45

Elizabeth M. B. Doran(née Elizabeth M. Bloomhart)

Education

M.S., Duke University, 2011

Mechanical Engineering

B.S., Tufts University, 2005

Environmental Engineering

Committee

Lincoln F. Pratson, EOS, Chair

Jay S. Golden, EOS, Co-Chair, Advisor

Timothy L. Johnson, EOS

Billie L. Turner, II ASU, Minor Area Representative (via

teleconference)46

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