Multi-scale approach to quantify the influence of urban green spaces on
climate behavior of the Viladecans-Gavà-Castelldefels conurbation in the
metropolitan area of Barcelona
Abstract
Literature widely recognize the strong influence of urban green spaces
in the microclimatic regulation and its potential applications to
mitigate warming in cities. Promote viable actions to the climate change
adaptation from cities through vegetation and help to palliate the urban
heat island effect (UHI) to reduce health risk during extreme heat
episodes, requires accurate criteria for each context in its different
scales. This study presents a multi-scale approach to quantify the
influence of urban green spaces on climate behavior of the
Viladecans-Gava-Castelldefels conurbation in the metropolitan area of
Barcelona. For this purpose, first, air (Ta) and surface (Ts)
temperature of 124 points located in the interior and surroundings of
seven green spaces are registered through field measurement campaigns
during day and night between July 26 and August 4 of 2018. Then, Land
Surface Temperature (LST) and Normalized Difference Vegetation Index
(NDVI) from Landsat 8 and Sentinel 2 data imagery for a clear-sky day
nearby to the measurement days are retrieved and complemented with the
NDVI of the spring-summer period of 2018 (1m) available in the
Cartographic and Geographic Institute of Catalonia (ICGC). Analytical
methods departed from the UHI characterization of the three-municipal
area, resulted in 1.63°C LST increase in the urban Corine land cover
(CLC) in relation with the rural at the whole ambit. Then, an OLS model
to predict LST is constructed with NDVI and distance to parks (spaces
with NDVI>=0.30) in the whole ambit (R²=0.59) and in the
urban area (R²=0.47). At this point, results indicate that increase a
tenth of NDVI reduces 1.15°C the LST of the whole ambit and 0.73°C on
the urban area (p<0.01); while for each 100m further from
parks, the LST rises 0.61°C for the whole ambit and 1.81°C on urban area
(p<0.01). Particularly for the seven study cases, field
measurements registered coincident spatial distribution with LST and
NDVI, as well as highlighted the UHI effect during night. The
quantification of the intensity and extent of the cooling effect of the
study cases, registered a maximum cooling intensity of 2.7°C with a 300m
buffer area; as well as the cooling effect calculation through
concentric rings resulted between 40 to 130m extents from the parks
boundaries and cooling intensity from 0.29 to 2.15°C. In conclusion,
even when the multiple-scale analysis present coincidences and
discrepancies between the different approaches, the models and methods
applied in this study resulted in values that allow starting to talk
about adequate actions to adapt to climate change in the context of the
metropolitan area of Barcelona. The present study is part of the
“Urban-CLIMPLAN. The urban heat island: effects on climate change and
modeling for territorial and urban planning strategies. Application to
the metropolitan region of Barcelona”, financed by the Ministry of
Economy of Spain (MINECO) and the European Regional Development Fund
(ERDF).