Conceptual approach to measure the potential of Urban Heat Islands from Landuse datasets and Landuse...

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12.04.2023

Climate Researchin Hamburg


Conceptual approach to measure the potential of Urban Heat Islands from Landuse datasets and Landuse projections

12.04.2023

Christian Daneke, Benjamin Bechtel, Jürgen Böhner, Thomas

Langkamp, Jürgen Oßenbrügge

Universität Hamburg

Introduction

Why do we need an UHI Landscape Metric?

Method

How does it work?

Calibration and Validation

How well does it work?

Conclusion

Applying the metric to Hamburg

Outlook

3 Christian Daneke 12.04.2023

Urban Surfaces have an impact on the local climate and by changing this influence changes as well


Oßenbrügge & Bechtel (2010)

What is the problem and why do we need an UHI-Potential Landscape Metric?


Landuse Dataset for Hamburg Metropolitan Region based on Classification Scheme


Resolution 100 m

24 Classes in Total,

10 Urban Classes

Created for:

1960, 1990, 2005

Based on:

Aerial Photographs,

Topographic Maps,

Corine, ATKIS, 3D-

Building Data

Daneke (2011)

Several Criteria need to be considered for the calculation


• Landuse• Morphology

• Neighborhood

• Patch Shape• Patch Size

• Location

The calculation of the metric in a nutshell


• Based on a Habitat

Fragmentation Metric

proposed by Keppler

(1997)

• Including all requirements

needed for UHI potential

• Assume following

landuse with two classes

• Resistance

• Fraction

• For every cell the

surrounding is

investigated based on a

search radius and scores

calculated

• In this case resistance

• Green = 1000

• Red = 1



7001

4004

4004 2006 4004

3005 8 3005

4004 2006 4004

5003

𝐴′=∑𝑤 i𝑎0



47,21

35,70

35,70 25,27 35,70

30,93 1,60 30,93

35,70 25,27 35,70

39,91

• Based on scores an

equivalent radius is

calculate

• And the cells weighted

according to the distance

to the centroid

𝑟 ′=√ 𝐴′ /𝜋

𝑣=exp(− 𝑟 ′

𝑟 0)



3,15E-21

3,13E-16

3,13E-16 1,061E-11 3,13E-16

3,701E-14 0,2027525 3,701E-14

3,13E-16 1,061E-11 3,13E-16

4,666E-18

• Based on scores an

equivalent radius is

calculate

• And the cells weighted

according to the distance

to the centroid

𝑟 ′=√ 𝐴′ /𝜋

𝑣=exp(− 𝑟 ′

𝑟 0)



0,01

0,02

0,02 0,07 0,02

0,04 0,73 0,04

0,02 0,07 0,02

0,02

• Accounting for

• Compactness (V)

• Fraction (F)

• Final values calculated

by:

𝑠=∫0

∞

𝑣𝑓𝑑𝑟

𝐾𝑂𝑉=( 𝑠𝑟 0 )

𝑧

UHI Potential for 2005


• Final calibration

• Parameters:

• Fraction of

Influence

• Resistance

• Search radius:

1,5 pixels

• Power Z: 0,8

Calibration was done based on Ellenberg Indicators as Temperature Proxies


• Calibration /

Validation using

Ellenberg Indicators

as proxy data for

temperatures over a

long period

• On a 1 km Grid

• Plants sampled and

analysed if they

prefer „warm“ or

„cold“

Bechtel (2011)

Scatterplot of the modeled UHI Values and the Prox Dataset


• Regression analysis

• R = 0,662

• R2 = 0,438

• Only cells which

have more than 25

% built up area

Urban Heat Island Potential

Pla

nt In

dica

tor

Tem

pera

ture

Val

ues

Standardized Residuals on the 1Km Fishnet


• Mapping

standardized

residuals on the 1km

raster

• Relatively good fits

within the city

• Problems

• Water

• Outskirts

Standardized Residuals overlayed with Waterbodies


• Mapping

standardized

residuals on the 1km

raster

• Relatively good fits

within the city

• Problems

• Water

• Outskirts

Calculating the changing potential from 1960 - 2005


• Considering the Urban

Development from

1960 to 2005

• Removing smaller

Parks in 1960 to

simulate „Greening

Policy“

Conclusion and Outlook

• Proposed a Method to estimate UHI Potential from Landuse

Datasets

• Enables to investigate land use scenarios from models and study

possible implications for the urban climate

• First calibration on a 1km scale comparing to temperature proxy

data showed a solid fit

• Further validation of the method based on bus measurements at a

higher resolution



Dipl.-Geogr. Christian [email protected]

Thank You!

Institut für GeographieUniversität Hamburg

Bundesstraße 5520146 Hamburg

The Urban Heat Island in Hamburg, as presented during the last summer


Wetterspiegel (2010)

Core Dense Multistory Perimeter Blocks

Large Blocks Terraced Housing Regular Housing

Morphological Classification Scheme for Landuse-Datasets needed in UHI related studies


Daneke (2011)

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Conceptual approach to measure the potential of Urban Heat Islands from Landuse datasets and Landuse...

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