Climate alteration in the metropolitan area of Bari: temperatures and relationship with characters...

Climate Alteration in the Metropolitan Area of Bari: Temperatures and Relationships with

Characters of Urban Context

Pierangela Loconte Claudia Ceppi

Giorgia LubiscoFrancesco Mancini

Claudia Piscitelli Francesco Selicato

Polytechnic University of Bari(Italy)

GeneraleObjective

To consider the urban climate aspects into the planning phases

Studies about relationships between

Urban Heat Island Several urban features

- - - -- - - - - Cl imate Alterati on in the Metropol i tan Area of Bar i : Temperatures and Relati onship with Characters of Urban Context - - - -- - - - -Pierangela Loconte – Claudia Ceppi – Giorgia Lubisco – Francesco Mancini – Claudia Piscitelli – Francesco Selicato

Strategic Project ECOURB Analysing and modelling air and thermo pollution for

urban ecolabelling systems

Provide guidelines for planners to frame urban form planning and environmental quality

SpecificObjective

Indentify how urban geometry can be related with climate alterations

Quantitative Analysis about Relationships between

Surface temperatureFactor of urban climate alteration

Characters of Urban Context


Introduction

Outline

1. Identification of the case study

2. Factor Analysis

Analysis of the urban environment

Processing of thermal data


3. Analysis bivariate correlation

4. Results and comment

5. Conclusion and future perspectives

1. Case study : Metropolitan Area of Bari

Location: 41°7’N – 16°51’E, South of Italy, Apulia Region

The Province of Bari.


Location: 41°7’N – 16°51’E, South of Italy, Apulia Region

Size: Area of 116 sqkm

Resident Population: 326 915 inhabitants

Density: 2813 ha/sqkm

Climate: Mediterranean, with mild winter and hot dry summer

Peculiarities: - Long coastal area (12,79 km) - Several urban morphologies - Natural elements able to link agricultural systems with the city


1. Case study : Metropolitan Area of Bari

2. Factor Analysis

ASTER –VNIR (Visible and Near Infrared) and TIR granules at 15 and 90 meters of ground resolution respectively


Dataset of diurnal ASTER images spanning on a period from July 2001 to February 2006

Transformation from the radiance levels to temperature values by ENVI algorithm.

SURFACE TEMPERATURE MAPS

Processing of thermal data

ASTER thermal data over wintertime (February 1th, 2006)


2. Factor Analysis Processing of thermal data

ASTER thermal data over summertime (August 9th, 2001)


2. Factor Analysis Processing of thermal data


In order to characterize urban structures, a set of factors able to affects urban climate and UHI phenomenon have been recognized:

Land Use

Absolute Rugosity

Site Coverage

Urban Morphologies

2. Factor Analysis

Analysis of the urban environment


2. Factor Analysis Analysis of the urban environment

Land use

Urban ecosystems provide services and perform functions that are able to regulate and balance the heat flux dynamics within the urban materials textures

It’s necessary to define a system characterization of the urban ecosystems strongly related with thermal phenomenon

The land use analysis factors set has been taken in consideration all the typologies of urban and peri-urban natural landscapes

AGRICULTURAL AREAS GREEN URBAN AREAS



Land use

It include all the different green typologies recognized inside the city:

- urban parks- sport areas

Urban Green Areas

The city of Bari has a lack of green spaces they are fragmented and localized



Land use Urban Green Areas



Land useIt includes:

- arable land- permanent crops - meadowlands - mixed agricultural land

The main element showing features able to connect land use to thermal studies has been classified in relationship with soil coverage (i.e presence of tree canopy, predominance of herbaceous coverage).

Agricultural Areas

agricultural herbaceous coverage

agricultural arboreal coverage



Land use

Residual natural areas have been included into the agricultural macro category

Agricultural Areas

They have been characterized in order to their coverage, according to the agricultural areas

In the case of study, they are essentially constitute by Mediterranean shrubs vegetation and residual Mediterranean forests.



Land use Agricultural Areas



Absolute Rugosity It has been introduced to take the real urban fabric into account by evaluating the three-dimensional spaceIt explains the role of density of urban tissues on temperature and, then, the ability of air to flow within the urban volume introduced by Adolphe (2001)

R = Vbuilt / A cellSite Coverage

The factor has been designed To take into account the role of anthropogenic influence on temperatures

It is the ratio of the total floor area of the building to the area of the cell. It is referred to the ground floor, so it also refers to impervious surfaces and represent an index of building density focused over the bi-dimensional cell

SC = Abuildings / A cell



Urban Morphologies

It required the recognizing of the urban tissues by taking the 90 mt post spacing as reference spatial resolution.

Each cell is related to a reference tissue representing the area with its percentage of surface occupied

Classification of urban tissues of the city of Bari:- residential- industrial- mixed function



Urban Morphologies - Classification

Residentiala. Old coreb. Regular high compact tissuec. Medium compact tissued. Low compact tissuee. Modern organic tissuef. Open tissueg. Detached tissue

h. Industrial tissue

i. Mixed Functional tissue




Analisys of relationship between surface temperatures and urban morphologies

Dual analysis of satellite data - wintertime (February 1th, 2006)- summertime (August 9th, 2001)




Old core: historical tissue of the city, characterized by high density, irregular texture of urban block, traditional building constructed until XIX century, located in the central core of the city;




Medium compact tissue: structured on a semi-regular grid, built during XIX century and characterized by high density and bigger block dimensions, located near some main infrastructure of the city (principal street, railway);

Detached tissue: structured on isolated group of buildings, located in suburban/rural areas


3. Bivariate correlation analysis

Surface temperature 02012006


SURFACE TEMPERATURE Number of cases 7952 7973

AGRICOLTURE HERBACEOUS COVERAGE

Pearson Correlation ,256 ,161

Sig. (2-tailed) ,000 ,000

AGRICOLTURE ARBOREOUS COVERAGE

Pearson Correlation -,070** -,009

Sig. (2-tailed) ,000 ,482

NATURAL HERBACEOUS COVERAGE

Pearson Correlation -,047 ,145*

Sig. (2-tailed) ,518 ,044

WOODLANDS Pearson Correlation ,015 ,114

Sig. (2-tailed) ,560 ,000

URBAN GREEN AREAS Pearson Correlation -,586 -,606

Sig. (2-tailed) ,036 ,022

The interaction between the urban structures, as represented by the selected variables, and the surface temperature, has been performed by the SPSS 17.0 statistical package through a cell by cell (90 mt) correlation analysis. The bivariate correlation between surface temperature and the selected variables are expored, were estimated by Pearson's coefficient, like shown in the next table for the land use



The coefficients obtained between the surface temperature and areas with the types of land use called agriculture and natural herbaceous coverage, agriculture arborous coverage, and woodlands, don’t shows a high correlation

This Kind of land use, of course, don’t characterize inner parts of the city but the suburbs or the beginning of the rural border town

The coefficient that takes a significant negative value for both thermal maps, is the percentage of area covered by urban green areas

Land use




SITE COVERAGE Pearson Correlation -,261 -,409

Sig. (2-code) ,000 ,000

ABSOLUTE_RUGOSITY Pearson Correlation -,318 -,435

Sig. (2-code) ,000 ,000


Characteristics of the built

The site coverage of the buildings shows a negative weak correlation with the surface temperature while the behavior of the absolute rugosity showed a slightly negative uncorrelated trend with respect to temperature

By the analysis of thermal images, this trend is reinforced by the fact that areas outside the city and the open spaces in general, show a higher temperature than the densely urbanized areas


4. Results and commentThe urban morphology

The compact fabric, and in particular old core around the average temperatures lower, is characterized by a narrower range than other types. It reads like the decrease of the compactness of the urban surface temperatures are higher. In this regard, compare the behavior of Old core, for example, and the types of open tissue and detached tissue, such as the evidently are concerned have both broader range of temperatures, which temperatures average higher

The behavior of the temperature decrease with increasing dispersion of the buildings, is quite closely and confirmed in a quantitative way, by the correlations between two variables as temperature and site coverage and absolute rugosity.



The correlation analysis shows that the phenomenon of UHI is reversed for the city of BariDensely urbanized zones reveal lower temperatures than the peripherals areas.The analysis of urban morphology provides an explanation about the spatial temperature trend even though the use of vegetation indices (such as the NDVI)The urban morphology summarize the behavior of the remain variables. The quantitative relationship between urban morphology and surface temperatures have been highlighted.In the case of study, materials and surfaces with higher thermal capacity values didn’t have enough time to accumulate and release after being illuminated by the Sun’s radiation. Shaded areas were not warmed up by the solar radiation in the early morning period. Open areas are more exposed to solar radiations and exhibits a more pronounced heating of the ground surface



Develop a more complete description of the fabric is required (within the index of roughness) to better summarize the range of possible morphologies and rates of porosities of the fabric

Taking in account the difference in the elevation of buildings to investigate the relationships between shaded/sunny areas and surface temperatures

Study the phenomenon using other satellite data in a different period and time of day (around 10.00 am for this study).

THANK YOU FOR YOUR ATTENTION!

Polytechnic University of Bari(Italy)

Climate alteration in the metropolitan area of Bari: temperatures and relationship with characters...

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Transcript of Climate alteration in the metropolitan area of Bari: temperatures and relationship with characters...