Long-term air temperature changes in Ljubljana (Slovenia) in comparison to Trieste (Italy) and Zagreb (Croatia)

Abstract The cities of Ljubljana, Trieste and Zagreb are proximate in terms of distance but differ in terms of geographical and climatic conditions. Continuous meteorological measurements in these cities began in the mid-19th century. The 100-year trends of changes in mean annual and seasonal air temperatures for these cities are presented here, evaluating the differences between them which result from their different geographical and climatic positions. Differences in trends between Ljubljana and Zagreb that result from different measurement histories and the impact of urban climate are also presented: the impact of city growth on air temperatures in Ljubljana after 1950 was not completely eliminated in the process of data homogenization. The lowest air warming trends occur in the maritime climate of Trieste (mean annual air temperature: + 0.8 °C × 100 yr−1), where measurements were continuously performed in the densely built-up section of the city. The strongest trends occur in Ljubljana, mainly due to city growth (mean annual air temperature: + 1.1 °C × 100 yr−1). Comparing the linear trends in Zagreb-Grič and in Ljubljana, the impact of Ljubljana's urban heat island on the 100-year warming trend was assessed at about 0.2 °C, at 0.3–0.4 °C for the trend after 1950, and if non-homogenized data are used, at about 0.5 °C.

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Green roofs and cool materials as retrofitting strategies for urban heat island mitigation: Case study in Belgrade, Serbia

Thermal Science ◽

10.2298/tsci171120086l ◽

2018 ◽

Vol 22 (6 Part A) ◽

pp. 2309-2324

Author(s):

Marija Lalosevic ◽

Mirko Komatina ◽

Marko Milos ◽

Nedzad Rudonja

Keyword(s):

Green Roofs ◽

Urban Heat Islands ◽

Temperature Changes ◽

Heat Islands ◽

Air Temperatures ◽

Urban Heat ◽

Microclimatic Conditions ◽

Typical Summer ◽

Planning And Construction ◽

The Impact

The effect of extensive and intensive green roofs on improving outdoor microclimate parameters of urban built environments is currently a worldwide focus of research. Due to the lack of reliable data for Belgrade, the impact of extensive and intensive green roof systems on mitigating the effects of urban heat islands and improving microclimatic conditions by utilizing high albedo materials in public spaces were studied. Research was conducted on four chosen urban units within existing residential blocks in the city that were representative of typical urban planning and construction within the Belgrade metropolitan area. Five different models (baseline model and four potential models of retrofitting) were designed, for which the temperature changes at pedestrian and roof levels at 07:00, 13:00, 19:00 h, on a typical summer day, and at 01:00 h, the following night in Belgrade were investigated. The ENVI-met software was used to model the simulations. The results of numerical modeling showed that utilizing green roofs in the Belgrade climatic area could reduce air temperatures in the surroundings up to 0.47, 1.51, 1.60, 1.80 ?C at pedestrian level and up to 0.53, 1.45, 0.90, 1.45 ?C at roof level for four potential retrofitting strategies, respectively.

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Smart tools of urban climate evaluation for smart spatial planning

Moravian Geographical Reports ◽

10.1515/mgr-2015-0017 ◽

2015 ◽

Vol 23 (3) ◽

pp. 47-57 ◽

Cited By ~ 7

Author(s):

Hana Středová ◽

Tomáš Středa ◽

Tomáš Litschmann

Keyword(s):

Urban Heat Island ◽

Spatial Planning ◽

Urban Climate ◽

Quality Data ◽

Heat Island ◽

Corine Land Cover ◽

Air Temperatures ◽

Urban Heat ◽

Gis Methods ◽

The Impact

Abstract Air temperature and humidity conditions were monitored in Hradec Králové, Czech Republic, by a network of meteorological stations. Meteorological sensors were placed across a representative variety of urban and suburban environments. The data collected over the 2011–2014 period are analysed in this paper. The data from reference standard meteorological stations were used for comparison and modelling purposes. Air temperatures at the points of interest were successfully modelled using regression relationships. The spatial expression of point measurements of air temperatures was provided by GIS methods in combination with CORINE land cover layer, and satellite thermal images were used to evaluate the significance of these methods. The use of standard climate information has low priority for urban planners. The impact of the urban heat island on city residents and visitors was evaluated using the HUMIDEX index, as it is more understandable for urban planners than temperature conditions as such. The aim of this paper is the modification, description and presentation of urban climate evaluation methods that are easily useable for spatial planning purposes. These methods are based on comprehensible, easily available but quality data and results. This unified methodology forms a theoretical basis for better urban planning policies to mitigate the urban heat island effects.

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The implications of climate change conditions in the pavement design

10.5592/co/cetra.2020.1193 ◽

2021 ◽

Author(s):

Dominika Hodáková ◽

Andrea Zuzulová ◽

Silvia Cápayová ◽

Tibor Schlosser

Keyword(s):

Climate Change ◽

Air Temperature ◽

Input Parameter ◽

Road Construction ◽

Climatic Conditions ◽

Design Solution ◽

Model Calculations ◽

Air Temperatures ◽

The Impact

The design of pavement structure is as a set of several activities related to the design of road construction, dimension and model calculations. This includes calculations of load effects, taking into account the properties of the materials, the subgrade conditions, and the climatic conditions. The measurements of climatic conditions in Slovakia were the basis for assessing changes in average daily air temperatures in individual seasons. Since the 19th century we have seen in Slovakia an increase in the average air temperature of 1.5 ° C. Currently, there are scenarios of climate change until 2100. An increase in air temperature is assumed, with an increase in average monthly temperatures of 2.0 to 4.8 °C. In road construction, as well as in other areas of engineering, we must respond to current climate change and also to expected changes. The average annual air temperature and the frost index are the critical climatic characteristics are the main for the design (input parameter) and evaluation of pavement. From the practical side it is possible to use the design maps of average annual air temperature and frost index according to STN 73 6114 from year 1997. In cooperation with the Slovak Hydrometeorological Institute from the long-term monitoring of temperatures, different meteorological characteristics were measured in the current period. From the measurements of twelve professional meteorological stations for the period 1971 to 2020, the dependence between two variables in probability theory is derived. The average annual air temperatures used for prognoses are collected from long-term measurements (fifty years). The design of road constructions and calculations of road construction models, which are in the system design solution (comparative calculations of asphalt pavement- and cement-concrete pavement models), we have also tested road construction materials - especially asphalt mixtures. The results were used to correct the values of input data, design criteria, as well as measures to reduce the impact of changes in climate conditions.

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Heatwaves and Summer Urban Heat Islands: A Daily Cycle Approach to Unveil the Urban Thermal Signal Changes in Lisbon, Portugal

Atmosphere ◽

10.3390/atmos12030292 ◽

2021 ◽

Vol 12 (3) ◽

pp. 292 ◽

Cited By ~ 1

Author(s):

Ana Oliveira ◽

António Lopes ◽

Ezequiel Correia ◽

Samuel Niza ◽

Amílcar Soares

Keyword(s):

Climate Change ◽

Air Temperature ◽

Wind Direction ◽

Urban Heat Islands ◽

Daily Cycle ◽

Local Climate ◽

Thermal Signal ◽

Air Temperatures ◽

Local Climate Change ◽

Urban Heat

Lisbon is a European Mediterranean city, greatly exposed to heatwaves (HW), according to recent trends and climate change prospects. Considering the Atlantic influence, air temperature observations from Lisbon’s mesoscale network are used to investigate the interactions between background weather and the urban thermal signal (UTS) in summer. Days are classified according to the prevailing regional wind direction, and hourly UTS is compared between HW and non-HW conditions. Northern-wind days predominate, revealing greater maximum air temperatures (up to 40 °C) and greater thermal amplitudes (approximately 10 °C), and account for 37 out of 49 HW days; southern-wind days have milder temperatures, and no HWs occur. Results show that the wind direction groups are significantly different. While southern-wind days have minor UTS variations, northern-wind days have a consistent UTS daily cycle: a diurnal urban cooling island (UCI) (often lower than –1.0 °C), a late afternoon peak urban heat island (UHI) (occasionally surpassing 4.0 °C), and a stable nocturnal UHI (1.5 °C median intensity). UHI/UCI intensities are not significantly different between HW and non-HW conditions, although the synoptic influence is noted. Results indicate that, in Lisbon, the UHI intensity does not increase during HW events, although it is significantly affected by wind. As such, local climate change adaptation strategies must be based on scenarios that account for the synergies between potential changes in regional air temperature and wind.

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Nature-based cooling potential: a multi-type green infrastructure evaluation in Toronto, Ontario, Canada

International Journal of Biometeorology ◽

10.1007/s00484-021-02100-5 ◽

2021 ◽

Author(s):

Vidya Anderson ◽

William A. Gough

Keyword(s):

Urban Agriculture ◽

Air Temperature ◽

Green Infrastructure ◽

Urban Climate ◽

Surface Air Temperature ◽

Green Roofs ◽

Near Surface ◽

Green Walls ◽

The Impact ◽

Agriculture Systems

AbstractThe application of green infrastructure presents an opportunity to mitigate rising temperatures using a multi-faceted ecosystems-based approach. A controlled field study in Toronto, Ontario, Canada, evaluates the impact of nature-based solutions on near surface air temperature regulation focusing on different applications of green infrastructure. A field campaign was undertaken over the course of two summers to measure the impact of green roofs, green walls, urban vegetation and forestry systems, and urban agriculture systems on near surface air temperature. This study demonstrates that multiple types of green infrastructure applications are beneficial in regulating near surface air temperature and are not limited to specific treatments. Widespread usage of green infrastructure could be a viable strategy to cool cities and improve urban climate.

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The Street Air Warming Phenomenon in a High-Rise Compact City

Atmosphere ◽

10.3390/atmos9100402 ◽

2018 ◽

Vol 9 (10) ◽

pp. 402 ◽

Cited By ~ 4

Author(s):

Xiaoxue Wang ◽

Yuguo Li ◽

Xinyan Yang ◽

Pak Chan ◽

Janet Nichol ◽

...

Keyword(s):

Thermal Comfort ◽

Air Temperature ◽

Thermal Environment ◽

Urban Climate ◽

Pollutant Dispersion ◽

Urban Morphology ◽

Air Temperatures ◽

Significant Difference ◽

Sensitivity Studies ◽

Weather Stations

The street thermal environment is important for thermal comfort, urban climate and pollutant dispersion. A 24-h vehicle traverse study was conducted over the Kowloon Peninsula of Hong Kong in summer, with each measurement period consisting of 2–3 full days. The data covered a total of 158 loops in 198 h along the route on sunny days. The measured data were averaged by three methods (direct average, FFT filter and interpolated by the piecewise cubic Hermite interpolation). The average street air temperatures were found to be 1–3 °C higher than those recorded at nearby fixed weather stations. The street warming phenomenon observed in the study has substantial implications as usually urban heat island (UHI) intensity is estimated from measurement at fixed weather stations, and therefore the UHI intensity in the built areas of the city may have been underestimated. This significant difference is of interest for studies on outdoor air temperature, thermal comfort, urban environment and pollutant dispersion. The differences were simulated by an improved one-dimensional temperature model (ZERO-CAT) using different urban morphology parameters. The model can correct the underestimation of street air temperature. Further sensitivity studies show that the building arrangement in the daytime and nighttime plays different roles for air temperature in the street. City designers can choose different parameters based on their purpose.

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The Incidence of Climatic Conditions Favourable to Coffee Berry Disease in Kenya

Experimental Agriculture ◽

10.1017/s0014479700023309 ◽

1971 ◽

Vol 7 (4) ◽

pp. 303-314 ◽

Cited By ~ 10

Author(s):

J. M. Waller

Keyword(s):

Air Temperature ◽

Spore Germination ◽

Growing Season ◽

Climatic Conditions ◽

Tree Canopy ◽

Disease Development ◽

Spore Dispersal ◽

Coffee Berry ◽

Coffee Berry Disease ◽

Air Temperatures

SUMMARYClimatic conditions affecting the development of CBD are assessed by measuring wetness within the tree canopy and air temperature. Saturation of the tree canopy, necessary for spore dispersal, occurs most frequently at the tops of trees and the duration of wetness permitting spore germination is most prolonged at night. Night air temperatures are closest to berry temperatures and are important in assessing infection periods. Disease development in 1968 and 1969 was related to the number of infection periods during the growing season. Polythene tree covers which kept trees sufficiently dry to stop disease development were used in determining infection at different times of the year.

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Local Weather Types by Thermal Periods: Deepening the Knowledge about Lisbon’s Urban Climate

Atmosphere ◽

10.3390/atmos11080840 ◽

2020 ◽

Vol 11 (8) ◽

pp. 840

Author(s):

Cláudia Reis ◽

António Lopes ◽

Ezequiel Correia ◽

Marcelo Fragoso

Keyword(s):

Hot Spots ◽

Urban Areas ◽

Urban Climate ◽

Specific Humidity ◽

Air Masses ◽

Air Temperatures ◽

Hourly Data ◽

Urban Heat ◽

Thermal Patterns ◽

Local Weather

Urbanized hot spots incorporate a great diversity of microclimates dependent, among other factors, on local meteorological conditions. Until today, detailed analysis of the combination of climatic variables at local scale are very scarce in urban areas. Thus, there is an urgent need to produce a Local Weather Type (LWT) classification that allows to exhaustively distinguish different urban thermal patterns. In this study, hourly data from air temperature, wind speed and direction, accumulated precipitation, cloud cover and specific humidity (2009–2018) were integrated in a cluster analysis (K-means) in order to produce a LWT classification for Lisbon’s urban area. This dataset was divided by daytime and nighttime and thermal periods, which were generated considering the annual cycle of air temperatures. Therefore, eight LWT sets were generated. Results show that N and NW LWT are quite frequent throughout the year, with a moderate speed (daily average of 4–6 m/s). In contrast, the frequency of rainy LWT is considerably lower, especially in summer (below 10%). Moreover, during this season the moisture content of the air masses is higher, particularly at night. This methodology will allow deepening the knowledge about the multiple Urban Heat Island (UHI) patterns in Lisbon.

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DOES HARMFUL CLIMATE INCREASE OR DECREASE MIGRATION? EVIDENCE FROM RURAL HOUSEHOLDS IN NIGERIA

Climate Change Economics ◽

10.1142/s2010007819500131 ◽

2019 ◽

Vol 10 (04) ◽

pp. 1950013

Author(s):

CRISTINA CATTANEO ◽

EMANUELE MASSETTI

Keyword(s):

Climate Change ◽

Adaptation Strategy ◽

Climatic Conditions ◽

Marginal Effect ◽

Cross Sectional ◽

Temperature Changes ◽

And Migration ◽

Migrant Households ◽

The Impact

This paper analyzes whether migration is an adaptation strategy that households employ to cope with climate in Nigeria. We estimate our model using the cross-sectional variation in climate and long-term migration decisions because we are interested in the average response to long-term climatic conditions. For households that operate farms, we find that the relationship between climate and migration is nonlinear. In particular, climates closer to ideal farming conditions are associated with a higher propensity to migrate, whereas in the least favorable climatic conditions, the propensity to migrate declines. The marginal effect of rainfall and temperature changes on migration varies by season. We estimate the impact of climate change on the number of migrant households in 2031–2060 and 2071–2100, ceteris paribus. With current population levels, climate change generates between 3.6 and 6.3 million additional migrants, most of them being internal. However, these estimates are not statistically significant.

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Heatwaves during low tide are critical for the physiological performance of intertidal macroalgae under global warming scenarios

Scientific Reports ◽

10.1038/s41598-020-78526-5 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Marta Román ◽

Salvador Román ◽

Elsa Vázquez ◽

Jesús Troncoso ◽

Celia Olabarria

Keyword(s):

Global Warming ◽

Iberian Peninsula ◽

Air Temperature ◽

Sublethal Effects ◽

Seawater Temperature ◽

Critical Factor ◽

Physiological Performance ◽

Air Temperatures ◽

Cystoseira Tamariscifolia ◽

The Impact

AbstractThe abundance and distribution of intertidal canopy-forming macroalgae are threatened by the increase in sea surface temperature and in the frequency and intensity of heatwaves caused by global warming. This study evaluated the physiological response of predominant intertidal macroalgae in the NW Iberian Peninsula (Bifurcaria bifurcata, Cystoseira tamariscifolia and Codium tomentosum) to increased seawater temperature during immersion and increased air temperatures during consecutive emersion cycles. We combined field mensuration and laboratory experiments in which we measured mortality, growth, maximum quantum yield and C:N content of the macroalgae. Air temperature was a critical factor in determining physiological responses and survivorship of all species, whereas high seawater temperature had sublethal effects. Cystoseira tamariscifolia suffered the greatest decreases in Fv/Fm, growth and the highest mortality under higher air temperatures, whereas C. tomentosum was the most resistant and resilient species. Two consecutive cycles of emersion under atmospheric heatwaves caused cumulative stress in all three macroalgae, affecting the physiological performance and increasing the mortality. The potential expansion of the warm-temperate species B. bifurcata, C. tamariscifolia and C. tomentosum in the NW Iberian Peninsula in response to increasing seawater temperature may be affected by the impact of increased air temperature, especially in a region where the incidence of atmospheric heatwaves is expected to increase.

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