scholarly journals Weather Pattern Classification to Represent the Urban Heat Island in Present and Future Climate

2013 ◽  
Vol 52 (12) ◽  
pp. 2699-2714 ◽  
Author(s):  
Peter Hoffmann ◽  
K. Heinke Schlünzen
Keyword(s):  
Urban Heat Island ◽  
Climate Model ◽  
Global Climate Model ◽  
Limited Area ◽  
Climate Projections ◽  
Heat Island ◽  
Cluster Number ◽  
Statistical Measures ◽  
Urban Heat ◽  
Optimal Cluster

AbstractA classification of weather patterns (WP) is derived that is tailored to best represent situations relevant for the urban heat island (UHI). Three different types of k-means-based cluster methods are conducted. The explained cluster variance is used as a measure for the quality. Several variables of the 700-hPa fields from the 40-yr ECMWF Re-Analysis (ERA-40) were tested for the classification. The variables as well as the domain for the clustering are chosen in a way to explain the variability of the UHI as best as possible. It turned out that the combination of geopotential height, relative humidity, vorticity, and the 1000–700-hPa thickness is best suited. To determine the optimal cluster number k several statistical measures are applied. Except for autumn (k = 12) an optimal cluster number of k = 7 is found. The WP frequency changes are analyzed using climate projections of two regional climate models (RCM). Both RCMs, the Regional Model (REMO) and Climate Limited-Area Model (CLM), are driven with the A1B simulations from the global climate model ECHAM5. Focusing on the periods 2036–65 and 2071–2100, no change can be found of the frequency for the anticyclonic WP when compared with 1971–2000. Since these WPs are favorable for the development of a strong UHI, the frequency of strong UHI days stays the same for the city of Hamburg,Germany. For other WPs changes can be found for both future periods. At the end of the century, a large increase (17%–40%) in the frequency of the zonal WP and a large decrease (20%–26%) in the southwesterly WP are projected.

scholarly journals An examination of urban heat island characteristics in a global climate model

2010 ◽  
Vol 31 (12) ◽  
pp. 1848-1865 ◽  
Author(s):  
K. W. Oleson ◽  
G. B. Bonan ◽  
J. Feddema ◽  
T. Jackson
Keyword(s):  
Urban Heat Island ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Heat Island ◽  
Urban Heat

scholarly journals Climate change over UK cities: the urban influence on extreme temperatures in the UK climate projections

2021 ◽  
Author(s):  
William J. Keat ◽  
Elizabeth J. Kendon ◽  
Sylvia I. Bohnenstengel
Keyword(s):  
Urban Heat Island ◽  
Rural Areas ◽  
Land Surface ◽  
Urban Areas ◽  
Climate Model ◽  
Climate Projections ◽  
Heat Island ◽  
Night Time ◽  
Urban Heat ◽  
The Uk

AbstractIncreasing summer temperatures in a warming climate will increase the exposure of the UK population to heat-stress and associated heat-related mortality. Urban inhabitants are particularly at risk, as urban areas are often significantly warmer than rural areas as a result of the urban heat island phenomenon. The latest UK Climate Projections include an ensemble of convection-permitting model (CPM) simulations which provide credible climate information at the city-scale, the first of their kind for national climate scenarios. Using a newly developed urban signal extraction technique, we quantify the urban influence on present-day (1981–2000) and future (2061–2080) temperature extremes in the CPM compared to the coarser resolution regional climate model (RCM) simulations over UK cities. We find that the urban influence in these models is markedly different, with the magnitude of night-time urban heat islands overestimated in the RCM, significantly for the warmest nights (up to $$4~^{\circ }$$ 4 ∘ C), while the CPM agrees much better with observations. This improvement is driven by the improved land-surface representation and more sophisticated urban scheme MORUSES employed by the CPM, which distinguishes street canyons and roofs. In future, there is a strong amplification of the urban influence in the RCM, whilst there is little change in the CPM. We find that future changes in soil moisture play an important role in the magnitude of the urban influence, highlighting the importance of the accurate representation of land-surface and hydrological processes for urban heat island studies. The results indicate that the CPM provides more reliable urban temperature projections, due at least in part to the improved urban scheme.

scholarly journals Integration of a Building Energy Model in an Urban Climate Model and its Application

2020 ◽  
Author(s):  
Luxi Jin ◽  
Sebastian Schubert ◽  
Daniel Fenner ◽  
Fred Meier ◽  
Christoph Schneider
Keyword(s):  
Temporal Variation ◽  
Urban Heat Island ◽  
Air Temperature ◽  
Indoor Air ◽  
Climate Model ◽  
Building Energy ◽  
Energy Model ◽  
Heat Island ◽  
Energy Fluxes ◽  
Urban Heat

Abstract We report the ability of an urban canopy model, coupled with a regional climate model, to simulate energy fluxes, the intra-urban variability of air temperature, urban-heat-island characteristics, indoor temperature variation, as well as anthropogenic heat emissions, in Berlin, Germany. A building energy model is implemented into the Double Canyon Effect Parametrization, which is coupled with the mesoscale climate model COSMO-CLM (COnsortium for Small-scale MOdelling in CLimate Mode) and takes into account heat generation within buildings and calculates the heat transfer between buildings and the urban atmosphere. The enhanced coupled urban model is applied in two simulations of 24-day duration for a winter and a summer period in 2018 in Berlin, using downscaled reanalysis data to a final grid spacing of 1 km. Model results are evaluated with observations of radiative and turbulent energy fluxes, 2-m air temperature, and indoor air temperature. The evaluation indicates that the improved model reproduces the diurnal characteristics of the observed turbulent heat fluxes, and considerably improves the simulated 2-m air temperature and urban heat island in winter, compared with the simulation without the building energy model. Our set-up also estimates the spatio–temporal variation of wintertime energy consumption due to heating with canyon geometry. The potential to save energy due to the urban heat island only becomes evident when comparing a suburban site with an urban site after applying the same grid-cell values for building and street widths. In summer, the model realistically reproduces the indoor air temperature and its temporal variation.

scholarly journals Multi-model comparison of urban heat island modelling approaches

2018 ◽  
Vol 18 (14) ◽  
pp. 10655-10674 ◽  
Author(s):  
Jan Karlický ◽  
Peter Huszár ◽  
Tomáš Halenka ◽  
Michal Belda ◽  
Michal Žák ◽  
...  
Keyword(s):  
Wind Speed ◽  
Urban Heat Island ◽  
Urban Environment ◽  
Model Comparison ◽  
Climate Model ◽  
Heat Island ◽  
Significant Difference ◽  
Urban Heat ◽  
Urban Parameterizations ◽  
The Impact

Abstract. Cities are characterized by different physical properties of surface compared to their rural counterparts, resulting in a specific regime of the meteorological phenomenon. Our study aims to evaluate the impact of typical urban surfaces on the central European urban climate in several model simulations, performed with the Weather Research and Forecasting (WRF) model and Regional Climate Model (RegCM). The specific processes occurring in the typical urban environment are described in the models by various types of urban parameterizations, greatly differing in complexity. Our results show that all models and urban parameterizations are able to reproduce the most typical urban effect, the summer evening and nocturnal urban heat island, with the average magnitude of 2–3 °C. The impact of cities on the wind is clearly dependent on the urban parameterization employed, with more simple ones unable to fully capture the wind speed reduction induced by the city. In the summer, a significant difference in the boundary-layer height (about 25 %) between models is detected. The urban-induced changes of temperature and wind speed are propagated into higher altitudes up to 2 km, with a decreasing tendency of their magnitudes. With the exception of the daytime in the summer, the urban environment improves the weather conditions a little with regard to the pollutant dispersion, which could lead to the partly decreased concentration of the primary pollutants.

scholarly journals A new method for fine-scale assessments of the average urban Heat island over large areas and the effectiveness of nature-based solutions

One Ecosystem ◽  
2018 ◽  
Vol 3 ◽  
Author(s):  
Dirk Lauwaet ◽  
Ton De Nijs ◽  
Inge Liekens ◽  
Hans Hooyberghs ◽  
Els Verachtert ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Climate Model ◽  
Climate Adaptation ◽  
Urban Climate ◽  
Horizontal Resolution ◽  
Heat Island ◽  
Adaptation Measures ◽  
Mean Wind Speed ◽  
Urban Heat ◽  
The Impact

People living in cities experience extra heat stress due to the so-called Urban Heat Island (UHI) effect. To gain an insight into the spatial variability of the UHI for the Netherlands, a detailed map (10 m horizontal resolution) has been calculated that shows the summer-averaged daily maximal UHI situation. The map is based on a relationship between the UHI, mean wind speed at 10 m height and the number of people living within a distance of 10 km, derived from simulations of over 100 European cities with the extensively validated urban climate model UrbClim. The cooling effect of green and blue infrastructure is also taken into account in the map, based on these simulation results. The presented map will help local authorities in defining target areas for climate adaptation measures and estimate the impact of nature-based solutions.

scholarly journals Future temperature and urban heat island changes in Budapest: a comparative study based on the HMS-ALADIN and SURFEX models

Időjárás ◽  
2021 ◽  
Vol 125 (4) ◽  
pp. 675-692
Author(s):  
Gabriella Allaga-Zsebeházi
Keyword(s):  
Low Temperature ◽  
Urban Heat Island ◽  
Land Surface ◽  
Regional Climate ◽  
Future Climate Change ◽  
Surface Model ◽  
Climate Projections ◽  
Heat Island ◽  
Simple Method ◽  
Urban Heat

Cities, due to their warmer and dryer local climate in addition to their dense population, are subjected to large future climate change risks. Land surface models, with detailed urban parameterization schemes, serve as an adequate tool to refine the rough regional climate projections over the cities. In this study, the future temperature conditions in Budapest are studied with the SURFEX land surface model (LSM), driven by the HMS-ALADIN5.2 regional climate model (RCM) and considering the high-emission RCP8.5 scenario. Special attention is dedicated to explore the differences between the RCM and LSM in terms of the results, their interpretation, and further use in impact models. According to the investigated model combination, the winter season may warm the most, with 1.9 °C in 2021–2050 and 4.3 °C in 2071–2100, although the magnitude of this change is smaller in SURFEX than in ALADIN. Besides the mean changes, four climate indices, based on high and low temperature thresholds, were studied, and it was found that the low temperature indices (frost days and very cold days) may relatively decrease more in SURFEX compared to ALADIN over Budapest, and in the city center compared to the suburbs and rural areas. In addition, the urban heat island (UHI) intensity is projected to decrease in SURFEX mainly in spring and summer (by 2071–2100 with 0.35 °C and 0.32 °C, respectively). Finally, a simple method is provided to correct the SURFEX temperature fields, using the ALADIN model, with eliminated systematic biases and the simulated UHI field.

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