The Greater Ho Chi Minh City Metropolitan (GHCM) is located in southeastern region of Vietnam, north of the Mekong Delta. Since the opening of the country in mid-eighties, the metropolitan and surrounding area has been undergoing a rapid urbanization accompanied with a high population growth and an ongoing influx of migrants. In 2009, the entire metropolitan has population of about 17 million and covers the area of more than 30000 square km. The rapid urbanization causes dramatically land use changes in the surrounding rural areas and has direct impact on the urban climate, especially, on the increasing of urban heat island (UHI) effect. Despite this very fast urbanization, the studies on the impact of urbanization on urban climate change have still not been done sufficiently. The purpose of this study is to assess the impact of urbanization on urban climate change, especially in case of increasing of UHI effect for GHCM, using regional climate model coupled with urban canopy model. The simulations were conducted under synoptic condition for April, last month of dry season in this region, for three year 2009~2011. Three land-use (LU) and anthropogenic heat (AH) release patterns; corresponded with urban conditions for 1989, 1999 and 2009 were used for separated simulations. First, it was confirmed that the simulated climatological average temperature and relative humidity distribution with using the LU and AH data for 2009, agreed well with observed data. The comparison among simulations results was carried out to investigate the impact of urbanization on the change of UHI effect. The main results have shown that urbanization has impact on increasing of temperature in urban area than surrounding rural area, especially in early morning. At core part of urban, for 20 years, the real observed increase rate of temperature was 0.64° C, while the simulations results demonstrated that due to urbanization temperature increase rate was 0.31° C, equivalent to 50% of real total increase rate.

Significant climate change rates in Moscow, capital of Russia and the biggest city in Europe, are caused as by global climate change, which is especially rapid within East-European plain (IPCC, 2013) and also by intensive urban growth rates (population of Moscow has increased from 9 to 12 million people during last twenty years), which leads to intensification of urban heat island effect. Prospects of further climate change and urban grows requires better understanding, how this changes will affect local climate and life quality conditions in case of one or another scenarios of further development, which is really important for choosing optimal urban planning solutions and mitigation negative effects of climate change. Instrument, available for preparing detailed climatic forecast with taking into consideration urban influence and different scenarios of city development, is required for solving this problem.

In this study we attempted to use regional COSMO-CLM model, coupled with TEB urban scheme (Masson, 2000, Trusilova et. al., 2013), where some new modifications were implemented. Urban surface parameters, required for urban scheme, were calculated from free OpenStreetMap (OSM) data.

Model sensitivity to different options of COSMO-CLM model itself, TEB urban scheme options and modifications and surface parameters was investigated with several model experiments for modern climate (with ERA-Interim reanalysis and CMIP-5 historical simulations uses as boundary conditions for regional model). This allows finding optimal model configuration and making its validation for modern climate. Simulations for future climate were launched with boundary conditions from CMIP-5 simulations according RCP8.5 scenario and different scenarios of city development.

1. IPCC (2013), IPCC Fifth Assessment Report: Climate Change 2013 (AR5) Rep.,Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

2. Masson V. A Physically-Based Scheme for the Urban Energy Budget in Atmospheric models// Bound. Layer Meteor. 2000. V. 94 (3). P. 357-397.

3. Trusilova K., Früh B., Brienen S., Walter A., Masson V., Pigeon G., Becker P. Implementation of an Urban Parameterization Scheme into the Regional Climate Model COSMO-CLM. J. Appl. Meteor. Climatol., 52, 2296–2311.

La ville de Annaba, composé de trois entités hydrologiques, est régulièrement touchée par les inondations. Les eaux proviennent de plusieurs bassins versants qui déversent une grande quantité d’eau. Les différentes études menées à ce jour, ainsi que les réalisations dans le programme de lutte ont donné un résultat non-conforme à la hauteur des investissements et ont aggravé le problème dans certains endroits. Le problème des inondations persiste et s’aggrave d’année en année. La ville est devenue de plus en plus vulnérable. Les événements provoquant des inondations ont une occurrence de plus en plus élevée. Deux erreurs fondamentales ont été commises que ce soit par rapport à l’aléa ou la vulnérabilité. La wilaya de Annaba chevauche entre le Côtier constantinois centre et le bassin de la Seybouse. Les stations de référence pris en compte dans toutes les études se trouvent dans des entités hydrologiques complètement différentes; ce qui fausse toute approche statistique classique et l’utilisation de la pluie synthétique. Par conséquent les pluies et débit de projet utilisés ne sont pas réalistes, d’où une mauvaise projection du système d’assainissement. Pour pallier à cet état de fait, nous nous proposons de régionaliser les paramètres climatiques qui rentrent directement dans le dimensionnement des ouvrages de lutte contre les inondations et le réseau d’assainissement. Les courbes I.D.F pour la région de Annaba ont été établis après avoir déterminé toutes les caractéristiques pluviométriques des neuf (09) stations de la région. L’interprétation des courbes nous a permis de tirer toutes les informations nécessaires notamment l’exposant climatique b et l’intensité moyenne maximale de durée 15mn et de période de retour 10ans. Les résultats obtenus sont interpolées sur toute la région d’étude. L'approche de régionalisation par la méthode d’inverse des distances a permis la création d’une carte d'isovaleurs d'exposant climatique et du débit pluvial dans la région d’Annaba. Nous espérons approfondir cette étude afin de proposer aux concepteurs et aux gestionnaires une méthodologie adéquate pour la lutte contre les inondations.

The time of peak discharges in rivers is considered a good indicator in the climatological changes in the rivers basins reflecting their values for long periods. The water quantities of the melted snow during spring season is one of the main sources feeding rivers in world such as the Tigris river and its tributaries locating in Turkey and Iraq. The climate variation on the rivers basins lead to variation in their hydrographs specially in their peak discharge values and arrival time. The monthly discharges data for three hydrological stations located on the Tigris river tributaries (Greater Zab, Lesser Zab and Khazir rivers) for forty years (1965-2004) was analysed after dividing into two periods (1965-1984) and (1985-2004). A mathematical criteria used in analyzing the time of the peak discharges measured at each river like the annual center time of the discharges (CT) was applied. This is the time at which half of annual volume of flowing discharges is passed. The recorded maximum air temperature in the climatological stations was depended in this analysis as climate change indicator. An early arrival time of peak discharge as a result of an advancement in the melting snow was observed to be (6.2, 7.1,10.4) days for the three studied rivers stations respectively. This is due to an increasing of 3.3°C in the average maximum recorded air temperature in the climatological stations during the previous forty years.

Keywords: Climate warming; Peak discharge; Center time; Tigris tributaries .

Within the framework of the ACCEPTED project (an Assessment of Changing Conditions, Environmental Policies, Time-activities, Exposure and Disease), a high-resolution urban dynamical downscaling technique has been applied for the cities of Paris and Brussels. In this study downscaling simulations of present and future urban climate over Brussels and Paris areas are conducted. The downscaling strategy was first evaluated for a 10-years period [2001-2010] using ERA-INTERIM re-analysis data. In a next step, a downscaling simulation for the period 2046-2055 under the A1B scenario was performed. Results from our simulations indicate that while both cities warm substantially for the 2050s horizon (1.5 °C and 1.8 °C for Brussels and Paris respectively), climate change will have a neutral impact on annual mean urban heat island (UHI) intensity. The most important increase is noted for the nocturnal UHI during the winter (+15% for both Brussels and Paris) and the most important decrease is noted for the daytime UHI during the summer (-43% for Brussels and -40% for Paris), the physical explanation is put forth. However, the model projects an increase of stable situations in the lower atmosphere during winter which may tend to keep pollutants concentrated over urban areas, with the associated health effects.

Within the framework of the ACCEPTED project (an Assessment of Changing Conditions, Environmental Policies, Time-activities, Exposure and Disease), a high-resolution urban dynamical downscaling technique has been applied for the Brussels Capital Region. Regional climate simulations were performed with a new version of the limited-area model of the ARPEGE-IFS system running at 4-km resolution called ALARO coupled with the Town Energy Balance scheme (TEB). Downscaling simulations of present and future urban climate of the Brussels areas are conducted. The downscaling strategy was first evaluated for a 10-years period [2001-2010] using ERA-INTERIM re-analysis data. In a next step, a downscaling simulation for the period 2046-2055 under the A1B scenario was performed. Results from our simulations indicate that while both urban and rural areas warm substantially for the 2050s horizon (1.5 °C), climate change will have a neutral impact on annual mean urban heat island (UHI) intensity. However, the model projects an increase of stable situations in the lower atmosphere during winter which may tend to keep pollutants concentrated over urban areas, with the associated health effects. Two approaches has been used to examine meteorological conditions that are unfavourable for the dispersion of air pollution under climate change conditions.: (i) a transport index, based on the wind speed and Brunt-Väisälä frequency, that characterizes a typical length of horizontal and vertical transport, (ii) state-of-the-art chemistry transport models CHIMERE coupled to the 4km regional climate simulations. The results from both approaches will be compared to assess future concentrations at urban scale.

Background: The program aim at contributing to improved effectiveness and efficiency of climatic management systems by strengthening the capacity to intervene in an appropriate, effective and timely fashion in the districts of Kampala, Tororo and Jinja.

Methods: The districts of implementation were selected because they hold the most eminent industrial centers and trading hubs of the country that are sources of environmental degradation and industrial emissions.

Results: The program seeks to reduce the vulnerability of Ugandans and improving their coping mechanisms to effects of climate change. Environmental aspects in Uganda that have an effect on climate change include; industrial emissions and discharges, vehicle fumes, poor garbage disposal, encroachment on swamps and forest reserves. In return climate change affects the environment as well agricultural production. The unpredictable rains have led to loss of crops because rain has been either too much or too little and too late during planting or harvesting seasons. Climate change is making it difficult for people to feed themselves as crops become susceptible to diseases and unpredictable weather patterns.

Conclusions: In order to achieve long term positive effects, the capacity of environment users should be built such that they provide eco-system services through adoption of environmentally friendly practices that mitigate carbon activities, protect and restore water catchments system like massive tree planting, installation of waste treatment mechanisms, advocacy and enactment of legislations as well as installing locally designed incinerators at institutional, community public points, municipal garbage centers and households.

Key words: Mitigating, Environmental degradation, Global warming, Climate change.

The urban heat island effect may induce enhanced heat stress on warm summer days, which may lead to reduced labour productivity, thermal discomfort and higher morbidity and mor-tality for vulnerable groups. The projected climate change may also raise the thermal dis-comfort. To implement measures to prevent adverse health conditions, robust estimates of the future human thermal comfort are required. This study analyses the future human thermal comfort for both coastal and inland Dutch cities and countryside. Based on the KNMI-06 climate scenarios, observed weather data from 1976-2005 are transformed to future weather design data for 2050. Subsequently, human thermal comfort expressed in the Physiological Equivalent Temperature is determined for these future scenarios. A substantial increase heat stress abundance is foreseen in all KNMI-06 scenarios, for both urban and rural areas, particularly under the most intense warming. In these scenarios, the frequency of hours with heat stress more than double, and the increase will develop faster in an urban canyon than in rural areas. However during (most) extreme heat stress, urban canyons can also provide more shading, which leads to lower PET values.

The objective of this study is to analyze the long-term effects of the changes in land use and land cover on the water and energy balances at a suburban areas (Sunset and Oakridge) in Vancouver, Canada. The Surface Urban Energy and Water Balance Scheme (SUEWS) is used to simulate the urban water and energy balances. The required meteorological forcing variables (solar radiation, air temperature, precipitation, wind speed, air pressure and relative humidity) are obtained from the WATCH forcing data (WFD, (Weedon et al. 2011, J. Hydrometeorol.) and WFDEI, (Weedon et al. 2014, Water Resources Research)). These datasets were derived from ERA-40 and ERA-Interim reanalysis products via sequential interpolation to half-degree resolution. The required surface cover information includes the plan area fractions, building and tree heights and population density. Changes in surface cover in the studied neighborhoods were analyzed and digitized from historic aerial photographs for the area.

The model has previously been found to perform well when evaluated for a short period at the Sunset site using observed turbulent fluxes and water balance components. In this study, SUEWS was run for the period 1949 to 2012. The numerous measurements undertaken in this region are used to assess various aspects of the model performance.

Based on the SUEWS results, long-term changes in the surface energy balance and surface runoff are evaluated. Analysis of the modeled results allows assessment of the impact of changes of land cover, people’s behavior and meteorological conditions. Thus, the results of this study could support urban planning and environmental management decisions.

This study explores the responses of urban heat island intensity (UHII) to future urbanization and global climate change by taking the case of record-breaking July 2010 heat wave over Beijing Metropolitan Area (BMA). The analyses are built on detailed observations from a ground-based observational network and numerical simulations of WRF model coupled with single-layer UCM for current and future urbanization and climate projections.

Model results reproduce the heat wave with current climate condition and present urban scenario. Three datasets, JRA-55, ERA-interim and NCEP FNL, are used to provide boundary/initial conditions for the simulations. Model validations against observations show that the ERA-interim generated unbiased distribution of 2-m air temperature differences and better spatial pattern of regional mean temperature than the other two datasets. Future climate conditions were provided using the Pseudo-Global-Warming downscaling (PGW-DS) approach, which is based on the differences of current climate and future climate projections (2070s) from the outputs of CCSM climate run. Additional climate model outputs are being considered so as to reduce the uncertainty of future climate projections.

Two future urbanization scenarios are projected. Both scenarios are equipped with equally increased urban coverage but contrasting patterns: compact-city versus dispersed-city, which is also a related aim of this study as to how does urban morphology affect urban heat island intensity. Initial results show that dispersed-city scenario reduces UHII by 0.4°C for the whole simulation period under current climate conditions, as compared to compact-city scenario with an increase of 0.1°C instead. Simulations under future climate conditions are being processed, and will be presented in full details.

Undoubtedly, climate change is the greatest challenge facing the human being nowadays as the Earth’s climate is getting warmer. The National Oceanic and Atmospheric Administration (NOAA) and the National Aeronautics and Space Administration (NASA) indicated that the average temperature of the Earth’s surface has increased about 1.2 to 1.4 F since 1900. Other climatic aspects experienced changes as well such as patterns of precipitation and storms. The most common reason leads to climate changes is very likely the result of human activities (e.g. fuel combustion). Study area is the most regions of the world affected by climate change impacts according to the fourth report of the Intergovernmental Panel on Climate Change 4th Report of IPCC, 2007, where the report presents a scenario of damaged centers stability in Nile Delta, Port Said and Alexandria(10 million people are at risk), in addition to lose more than 86 square kilometers of the northern lakes, about 200,000 acres of the most valuable agricultural land a result of high temperature and the consequent rise in average sea level. In Egypt, air pollutants (e.g. SO2 and CO2) gave rise to high concentrations of air pollutants especially in Greater Cairo Region. For that reason, a national air quality network (42 stations) has been established by Egyptian Environmental Affairs Agency with the cooperation of the Danish International Development Assistance to monitor the status of the air environment in Greater Cairo region (14 stations), Alexandria (8 stations), Delta and Canal region (10 stations), Upper Egypt (9 stations) and Sinai (1 stations). It is, therefore, notable that concentrations of different pollutants varied considerably in space and time. The major objective of this study is to monitor the air pollution and black cloud influence on Aerosol optical properties over Nile Delta based on Moderate Resolution Imaging Spectroradiometer (MODIS) from 2002-2012, using integrated data obtained from MODIS images, climatic normals, in situ measurements, and national air quality network from 1998 to 2012. To achieve that aims the present study will use the HYDRA visualization software with the characteristics of the MODIS climatic data. MODIS is ideal for monitoring large-scale changes in the biosphere that will yield new insights into the workings of the global carbon cycle. While no current satellite sensor can directly measure carbon dioxide concentrations in the atmosphere, MODIS from both the Terra and Aqua platforms can be successfully used as a climate model to integrated with climate data from stations for linear regression estimates and measure the changes impacts of some elements such as daily maximum and minimum air temperatures changes, clouds cover, aerosols and carbon dioxide concentrations changes at a local scale on Nile Delta. In this work, results obtained from MODIS data is validated using the previously mentioned data sets to reveal nature and characteristics of the climate change, changes in green house gas concentrations and aerosols. Also the results are in agreement with the observed values in the study area, and highly required for many applications related to integrated remote sensing techniques with actual field measurements and data Meteorological Authority in different periods to reduce the risk of climate change.

Key words: HYDRA visualization, Heat Island impacts, MODIS Images (Terra and Aqua).

Scientific data shows that the Ukrainian climate has already started changing (temperature and other meteorological parameters differ from the long-term climate norm). The results of Ukrainian climate modeling show that the air temperature will continue to increase (although the magnitude of change is some what different according to the forecast model) and the amount of precipitation will change throughout the year. This may result in a shift of climatic seasons, change in the growing season duration, reduced duration of stable snow cover, changes in local water resources flow, etc. (Shevchenko et al ., 2014).

In most developed countries urban population reaches 75-80% of the total population; in Ukraine this figure 68%. Thus, one can see the formation of an urban environment or urban ecosystem, which is a whole new physical and geographical condition of the environment resulting from the long-term development of a city. The combination of the negative effects of urbanization and climate change as observed in cities create a unique urban problems that are not incidental to other types of human settlements (Cities and Climate Change, 2011).

The main potential adverse effects of climate change in Ukrainian cities include:

1. Heat stress;

2. Flooding;

3. Reduced areas and disturbance of biodiversity in urban green areas;

4. Extreme weather events;

5. Reduced quantity and quality of potable water;

6. Increased incidence of infectious and allergic diseases;

7. Disturbance of normal operation of urban electric power systems.

There are some factors which make cities much more vulnerable to the climate change:

• Social factors – as city’s population structure and not adequate health care;

• Urban infrastructure (for example, lack of or poorly maintained storm drainage is the reason of increasing of vulnerability to flood);

• The prevalence of artificial surfaces in a city (the high risk of flooding and additional heat in the city);

• Urban air pollution (negative impact on the plants and humans, so higher vulnerability of urban green spaces and the causes of increasing of allergic diseases

and others.

We have assessed vulnerability of seven Ukrainian cities – Donetsk, Khmelnytskyi, Lviv, Odesa, Poltava, Ternopil, Uzhgorod, which situated in different part of the territory of Ukraine (by methodic Shevchenko et al ., 2014). The methodic, which was used, based on seven groups of indicators to identify effects that can be expected for a given city.It requires a complex analysis of the city, taking into account all the factors which can effect on its vulnerability to climate change, so was analyzed a lot of statistic data for assessment each city. In Khmelnytskyi, Odesa, Poltava, Uzhgorod is the most vulnerable to climate change is urban green areas, Ternopil is the most vulnerable to flooding, Donetsk and Lviv – to the heat stress. For example, the vulnerability of Lviv to the heat stress caused by rising temperatures (in 2003-2013 the average annual temperature on 1,1°C higher compared to 1961-1990) and number of days with temperatures over 30°C in summer (during 1961-1990 – 2,7 days per year while in 2003-2013 – 7,6 days) and increase of heat waves cases in the last decade. Features of city building - large areas of artificial surfaces in the city center, lack of water bodies and unevenness of their location on the city, as well as small areas of green zones in the central part of the city - contribute to the formation of heat island in the city center and, therefore, increase the vulnerability of the city to the heat stress. Also, in Lviv a significant percentage of vulnerable groups of populations and low level of health care.

Thorough vulnerability assessment of the city to climate change is the first step to development effective city adaptation strategy and it is very important to define factors which cause the rises of vulnerability for directing adaptation measures to minimize their negative impact on the stability of the city to climate change.

The general warming, between 1951 and 2010, of the annual minimum temperatures of 28 stations in the French Mediterranean region presents significant spatial and temporal variations which are associated with the location and the environment of the stations. The spatial extent of the French Mediterranean region has been determined according to the Koeppen -Jaeger classification revised by Peel (2007). The 28 stations (Météo-France network) have continuous series from 1950 to 2010, except few shorter ones, either starting around 1960 or ending before 2010. A typology of station environments was built from the location of stations analysed with different georeferenced media (satellite images, aerial photographs, topographic maps, CORINE LANDCOVER 2006).

Two successive periods separated by a break can be determined in all the series of annual minimum temperatures. But the year of the break in each series differs depending on the technique used for determining it. The tests usually applied to the series refer to the change from a statistical population to another (Mann- Kandall Test for example), which is different from the research of the year of the beginning of a trend. As it is expected, according to the figures representing the data, to find two successive series the authors have developed a suitable particular method. This method is based on the analysis for each series of two linear trends of increasing duration, one from the beginning of the series, 1951, and a second from its end, 2010, this last one going back in time (Douguédroit and Bridier, 2008). The year of highest variance obtained by the highest determination coefficient was selected in each of two series of the previous trends calculated for each station. In most of the stations the two years were the same or very close each other. The slopes of all the linear trends were calculated and compared.

Profiles of annual minimum temperature data set for each station were grouped according to the similarity of their trends. 6 groups of annual minimum temperature profiles corresponding to 6 groups of environments were obtained: « rural » coastal lighthouse, « rural » inland airport, inland village, center of coastal ancient city, suburbs of coastal city, suburbs of inland city. The curves of all the groups have been simplified and represented by a typical profile. Some groups such as the inland urban centers, are not shown for lack of representative stations.

In the end all the groups have two periods separated by a break between 1970 and 1980 as the curves of global and European temperatures (IPCC, The Physical Science Basis, 2013). Two sets with different temporal variations were defined in the analysis of the profiles of the 6 groups, one for the coast and a second for the inland, each being divided into « rural » and urban areas. The value of the night UHI depends on the topographic location of the « rural » stations.

DOUGUEDROIT A. et S. BRIDIER, 2008, Sur la détermination de la date du début de la tendance actuelle au réchauffement, Actes du XXIème Colloque de l’Association Internationale de Climatologie « Climat et risques climatiques en Méditerranée», Montpellier, 9-13 septembre 2008, p.201-206.

IPCC: CLIMATE CHANGE (2013), The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp.

PEEL M. C., B. L. FINLAYSON, AND T. A. MCMAHON (2007) Updated world map of the Köppen-Geiger climate classification, Hydrol. Earth Syst. Sci., 11, 1633–1644

This presentation gives first results on the impact of climate change and/or land use changes on the urban areas of Belgium. The results are obtained by a high-resolution dynamical downscaling technique applied for Belgium. Similar work has been done for the Brussels capital region by Hamdi et al. (2013).

The climate simulations are done with the regional climate model ALARO, a new version of the limited-area model ALADIN, at a horizontal resolution of 4km. For this resolution, the land surface scheme SURFEX is coupled to the regional climate model. In stand-alone mode, the surface scheme is used to further downscale the regional climate projections to a horizontal resolution of 1km.

Firstly, ALARO is evaluated using ERA-interim for the period of 2001-2010. Secondly regional climate simulations will be done using the CMIP5 version of the ARPEGE global climate model for the next decade, under the RCP4.5 and RCP8.5 scenario.

It was shown by Hamdi et al. (2013) that the urban heat island (UHI) intensity increases during the winter in the Brussels capital region and decreases during daytime for the 2050s horizon. However, this study will focus on the UHI effects for the Belgian region for the nearer future.

According to the renewable energy strategy formulated by the Egyptian Ministry of Electricity and Energy, the wind power will represent a major source of energy sector in Egypt. Thus, several wind turbines and wind farms will be installed by the year 2020. Based on previous studies, wind power has potential environmental impacts on the neighbourhood which should be assessed. Specifically the impacts on weather and climate change are of great importance. In this study a comprehensive environmental impact analysis using computer simulation and modelling will be conducted using the mesoscale model METRAS. All the wind turbines and farms will be simulated in a model area covers the whole Egypt to find out the influence of these adaptation measures on the local climate in terms of wind speed and direction changes as well as the temperature changes. This study is of interest to many sectors involved in the development of power sector in Egypt as well as the decision makers.

For prediction of the future local climate changes in Japanese cities with consideration to the increasing influence of the global warming and urban heat island (UHI) phenomena, and to estimate the potential of adaptation strategies in mitigating climate-change-driven harmful effects upon human health and urban energy efficiency, the authors originally developed an integrated simulation system of urban climate, building energy and human thermal sensation. The system consists of the mesoscale Weather Research and Forecasting (WRF) model, a coupled multilayer urban canopy and building energy model (CM-BEM) for simulation of the interaction between urban climate and buildings' energy demand, and a simple Gagge two-node model of human body heat budget (HBM) which calculates pedestrians’ thermal comfort indices.

The above system named WRF-CM-BEM-HBM was then applied to a Japanese major city Nagoya to simulate the present urban climate and to project its future change in 2050s by use of the pseudo global warming downscaling (PGW-DS) method. The monthly climate differences in the meteorological fields projected by general circulation models (GCMs) between the present and future 2050s were used to generate the initial and boundary conditions for WRF-CM-BEM-HBM in PGW-DS. Those GCMs simulations were performed with a future CO2 concentration scenario named RCP 8.5 in the Intergovernmental Panel on Climate Change’s (IPCC’s) fifth assessment report (AR5). The effects of measures for adaptation to future climate change were also estimated based on the simulated variations in air temperature and human thermal sensation indices near ground surface and that in air-conditioning energy demand in the buildings. Two well-known UHI countermeasures, anthropogenic heat (AH) reduction and urban greening, were incorporated into the simulations as the adaptation strategies. The former countermeasure was considered based on the projected spread of energy-saving technologies in Nagoya in 2050s.

As a result, summertime daily-mean surface air temperature in the Nagoya metropolitan area (NMA) was projected to increase by about 1ºC in 2050s in the case of non-countermeasures. Such warming was predicted to be almost counterbalanced with the measures of AH reduction and urban greening in 2050s. In comparison with AH reduction, urban greening was estimated to have larger influence to improve human thermal comfort indicating the daily maximum decreases in Standard new Effective Temperature (SET*) and Wet-Bulb Globe Temperature (WBGT) both by 0.5ºC in NMA. Additionally, two more scenarios concerning the future changes in land use and land cover (LULC) and urban canopy geometry in NMA were introduced into the numerical experiments. In the former scenario, LULC was modified based on the compact city concept in which future decrease in population and a measure for reducing socioeconomic damage from an expected major earthquake were considered. On the other hand in the latter scenario, urban canopy geometric parameters were altered assuming the increase of tall buildings near railway stations based on the same compact city concept. The simulated impacts of both scenarios on urban climate and thermal comfort in NMA will be additionally presented.

1. Introduction

As cities around the world continue to urbanize, there is an increasing body of evidence suggesting that urbanization has led to the urban heat island (UHI) phenomenon, whereby cities become warmer than the surrounding suburbs. Daily mean UHI typically ranges between 2 and 5 degC. Hong Kong has a high-rise, high-density morphology with tall buildings, which largely aggravate the UHI effects. Some urban areas are already experiencing an UHI of 4 to 5 degC, whist high heat stress creates an unbearable urban thermal environment. Above all, there is a pressing need to cushion the adverse impacts of UHI-induced microclimates by using appropriate mitigation measures.

Mitigation strategies of UHI through proper landscape design with natural elements have received growing interest, since they are able to remedy thermal environment in reasonable cost. The proposed techniques are those targeting (a) to increase the albedo of the urban environment, i.e. high albedo paving material; (b) to expand the green spaces; (c) to use the natural heat sinks to dissipate the excess heat, like water bodies. Here, the outdoor environmental cooling achieved through combination of different heat mitigation strategies will be investigated for subtropical Hong Kong.

2. Methodology

Instead of evaluating those strategies qualitatively and separately, quantitatively parametric study will be conducted to widely investigate, compare and analyze their cooling effects. The environmental benefits caused by aforesaid 3 heat mitigation strategies with different area proportions will be evaluated in a typical urban open space design, which includes the establishment of (a) high albedo pavements; (b) vegetation; and (c) water ponds. The typical urban open space mainly refers to the neighboring space among buildings, characterized with a central open space enclosed by four building blocks located at the corners of the site. Each building block measures 30 m (L) x 30 m (W) x 60 m (H), and rises for 20 stories. Area of the site is 90 m x 90 m (8,100 m2), with a building coverage ratio of 44.4%. The coverage ratios of different heat mitigation strategies are based on the open space, rather than the whole site, different from traditional “coverage ratio” with respect to the entire site area.

The whole site can be equally divided into 9 plots, four building blocks abut on four corners, and the remaining five plots will be filled up by other natural elements of the heat mitigation strategies. Totally 10 scenarios are proposed for comparison. For scenarios 1, 2, 3, and 4, the central open space totally consists of 100% conventional hard surfaces, 100% high albedo pavements, 100% green areas (trees), and 100% water ponds. Scenarios 5 and 6 are centered with high albedo pavements (covering 20%), whist the other 4 plots are filled by water and trees respectively (accounting for 80%). Similarly, scenarios 7 and 8 are centered by trees (20%), while the remaining open spaces are taken up by high albedo pavements and water ponds respectively (80%). Scenarios 9 and 10 have water ponds at the central open plot (20%) and the remaining plots (80%) are filled by trees and high albedo pavements respectively. The possible cooling benefits of different mitigation schemes will be compared by using the ambient temperature at 2 m high. The microclimate simulation tool ENVI-met will be utilized, which is developed according to the fundamentals of thermodynamics and fluid dynamics.

3. Conclusion

Through this study, an effective landscape design through different combination of heat mitigation strategies is established for fighting against UHI. In the proposed scenarios, the coverage ratios for different strategies are used to understand the extent of cooling benefit, and these ratios not be fully practical or site-dependent. In future study, since many heat mitigation strategies are orientation-sensitive and likely with free layout, more comprehensive parametric study will be conducted. In real urban open space design, one must consider various natural elements instead of one, while attempt to synergize and optimize the effect of heat mitigation measures.

We will present two funding programs of the German Federal Ministry of Education and Research, supported by the German Aerospace Center (DLR) addressing the regional and urban dimension of climate change.

Developing a new Urban Climate Model – City Climate Change

Urban areas are highly sensitive to changes in climate like extended heat waves, severe storms or floods. The consequence: Cities must already prepare for climate change. Cities are a place of conflicting goals such as between the increasing population pressures on the one hand and the necessary adjustments to the impacts of climate change on the other. Despite this dilemma, a precautionary city planning must respond to the anticipated specific changes in the urban climate adequately. The bases for future planning decisions in cities are powerful city climate models. However, to date there are no such models that are able to give clearly defined statements on climate change and on climatological interconnections, that could be applied towards sustainable urban development in a further step.

The aim of the funding measure "city climate change" is the development of an innovative urban climate model. This urban climate model should be able to simulate cities the size of Stuttgart to Berlin in a resolution better than 10 m grid cell width to simulate micro-climatic processes. With the help of such a model multidisciplinary analyzes can be carried out and measures, for example, to ensure and improve the urban climate and air pollution, could be planned. This also includes the integration of data on climate change with social or demographic and social data. The model results should help to support decision-making. Addressees of the results, which shall be provided as a usable tool, are users in urban planning or urban climate protection.

Climate adaptation in cities

The planned funding program "Climate Action in Cities and Regions" aims at strengthening regional climate resilience through transdisciplinary research. The program will support actors from science and practice (e.g. local administration, business, civil society) that jointly develop innovative and workable solutions for regional challenges caused by climate change. While the focus is on climate change adaptation, also mitigation and/or other fields of sustainable development have to be addressed. Concretely, the funds will be directed to research aiming at

- Socio-political conditions for climate resilient cities and regions;

- Technical innovations protecting against climate change impacts;

- Preservation of ecological services and adapted use of ecosystems;

- Economic innovations to reduce the vulnerabilities of businesses and regions;

- Preservation and improvement of health and quality of life.

The funding modalities are designed in a way that facilitates applied research and the transdisciplinary co-production of knowledge. Among others, the funding scheme is structured in three phases:

- Definition (one year): The transdisciplinary research consortium is built up and the concrete aims and working packages are defined.

- Research and development (up to three years): Main phase for researching, developing and evaluating measures to reach the planned aims.

- Implementation (up to two years): Optional phase for implementation and institutionalization of the developed concepts.

We will also describe how the program relates to other initiatives and how it contributes to climate change adaptation policies.