9th International Conference on Urban Climate

12th Symposium on the Urban Environment

20-24 July 2015, Toulouse, France

Estimation of spatial air temperature distribution atsub-mesoclimatic scale using the LCZ scheme and

mobile measurements

François Leconte1,2,4, Julien Bouyer1, Rémy Claverie1,3, Mathieu

Pétrissans4

1CEREMA Direction Territoriale Est, 71 Rue de la Grande Haie, 54510 Tomblaine,

France2ADEME, 20 Avenue du Grésillé, BP 90406, 49004 Angers Cedex 01, France

3GEMCEA, 149 rue Gabriel Péri, 54500 Vandoeuvre-les-Nancy, France4LERMAB, Boulevard des Aiguillettes, BP 70239, 54506 Vandoeuvre les Nancy

Cedex, France

Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Introduction

Background

I Take into account urban climate and urban heat islandphenomenon for urban planning operations

I Local Climate Zone schemeI Suitable to provide quantitative climatic data to urban

planners and institutional stakeholders

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Introduction

De�nition

I Local Climate ZoneI Speci�c screen-height thermal behaviorI Minimum diameter of 400 m

Recent research topics...

I Spatial homogeneity of urban indicators vs. Spatialhomogeneity of air temperature

I Thermal comparison between LCZ types

Aim of the study

How the relative position of a given Local Climate Zone within theconurbation in�uences their thermal features?

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Summary of the study

Step 1 : Local Climate Zones in the Nancy Area

Step 2 : Mobile measurements within Local Climate Zones

Step 3 : Distance to conurbation's center and thermal behavior

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Step 1 : Great Nancy Area

286,000 inhabitantsTemperate climate, warm summer, without dry season (Köppen-Geiger: �Cfb�)

July mean air temperature: maxima 25.1°C, minima 13.7°C

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Step 1 : Local Climate Zones building process

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Step 1 : Issues on residential areas

F. Leconte, J. Bouyer, R. Claverie, M. Pétrissans. 2015. Using Local Climate Zone scheme for UHIassessment: evaluation of the method using mobile measurements. Building and Environment 83 : 39-49

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Step 1 : Local Climate Zones in the Nancy Area

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Step 2 : Mobile measurements within LCZ

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Step 2 : Mobile measurements within LCZI Measurement hours

I Middle of afternoon, from 2 pm to 5 pmI 3 hours after sunset, from 12 am to 3 am

I Meteorological conditionsI Anticyclonic conditionsI Nebulosity below 2 octasI Low wind speed (below 9 m.s-1, wind speed at 10 meters high)I 24 hours free of precipitation, dry road

I Vehicle featuresI Probe installed inside a

ventilated cylinderI Response time < 100 ms,

Accuracy ± 0.2°CI Car speed above 15

km.h-1

I Air temperature recordedevery 3 m

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Nocturnal air temperature amplitude within LCZ

I Amplitude mostly below 2°CI Thermal homogeneity of LCZ acceptable

F. Leconte, J. Bouyer, R. Claverie, M. Pétrissans. 2015. Using Local Climate Zone scheme for UHIassessment: evaluation of the method using mobile measurements. Building and Environment 83 : 39-49

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Mean air temperature di�erence between LCZ types

I Air temperature di�erenceI Within 1°C at daytimeI Over 4°C at nighttime

F. Leconte, J. Bouyer, R. Claverie, M. Pétrissans. 2015. Using Local Climate Zone scheme for UHIassessment: evaluation of the method using mobile measurements. Building and Environment 83 : 39-49

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Step 3 : Mean nocturnal air temperature di�erences vs.

distance to the center of the conurbation

I Center (CEN) : referencetemperature

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Step 3 : Mean nocturnal air temperature di�erences vs.

distance to the center of the conurbation

I LCZ types matter, independently of the distance to center

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Step 3 : Mean nocturnal air temperature di�erences vs.

distance to the center of the conurbation

I Similar distance to centerI Air temperature gap due to LCZ type

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Step 3 : Mean nocturnal air temperature di�erences vs.

distance to the center of the conurbation

I Residential areas (Open Lowrise / Sparsely Built)I Larger distance to center = lower air temperature

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Step 3 : Relative temperature vs. distance travelled

I Mean relative temperatureexpressed regarding thecoldest area of the route (150 m)

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Step 3 : Relative temperature vs. distance travelled

I LCZ Compact Midrise

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Step 3 : Relative temperature vs. distance travelled

I LCZ Open Midrise

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Step 3 : Relative temperature vs. distance travelled

I LCZ Large Lowrise

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Step 3 : Relative temperature vs. distance travelled

I LCZ Open Lowrise / Sparsely BuiltI Within the conurbation + reduced distance to the center =

relative temperature above Low Plants temperature

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Step 3 : Relative temperature vs. distance travelled

I LCZ Open Lowrise / Sparsely BuiltI Outside the conurbation + signi�cant distance to the center =

relative temperature similar to Low Plants temperature

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Conclusion and ongoing work

Conclusion

I Within the conurbation:I LCZ type in�uentialI Distance to center signi�cant for Open Lowrise / Sparsely

Built : Necessity to take into account this parameter

I Open Lowrise / Sparsely Built outside the conurbation:I Negligible thermal in�uence from the conurbationI Relative temperature similar to the non urbanized LCZ nearby

: because of their small size?I How to perform temperature extrapolation based on LCZ types

outside the conurbation?

Ongoing work

I Automatic LCZ building (using GIS)

I Semi-empirical modeling of LCZ's nocturnal cooling

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Acknowledgements

This work has been supported by the French Environment andEnergy Management Agency (ADEME).

Thank you for your attention

francois.leconte@cerema.fr

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Air temperature distribution regarding wind direction

Wind direction : North East Wind direction : South East

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Air temperature distribution regarding wind direction

Mean speed : 1.1 m/s−1 Mean speed : 3.1 m/s−1

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Introduction LCZ in the Nancy Area Mobile measurements Distance to center Conclusion

Diurnal air temperature amplitude within LCZ

OUE type 2

CEN type 2

TRM type 2

NAT type 5

THL type 5

SMA type 5

MBR type 8

PVE type 8

JAR type 6/9

SEI type 6/9

PUL type 6/9

CE1 type D

CE3 type D

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