Urban Climatic Map and Standards for Wind Environment - Feasibility Study Report … ·...

Planning Department: Urban Climatic Map and Standards for Wind Environment – Feasibility Study REPORT ON TECHNICAL EXPERTS ENGAGEMENT

Report on Technical Experts Engagement_final.doc Last printed 7/3/2009 3:09:00 PM

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Urban Climatic Map and Standards for Wind Environment - Feasibility Study

Report on Technical Experts Engagement May 2009

C U H K


Department of Architecture, CUHK of 23

VERSION 19 May 09 Submission to Planning Department



CONTENT 1. INTRODUCTION 4 1.1 Background to the Study 4

1.2 Purpose of the Technical Experts Engagement 4 2. TECHNICAL EXPERTS ENGAGEMENT PROCESS 5 3. KEY COMMENTS AND RESPONSES 6

3.1 Overall Observation 6 3.2 Support for UC-AnMap 6 3.3 Factors not considered in UC-AnMap 7 3.4 UC-AnMap Layers 8 3.5 Urban Climatic Classes in the UC-AnMap 9 3.6 Wind Information for UC-AnMap 10 3.7 Wind Information for Air Ventilation Assessment (AVA) 12 3.8 Use of Remote Sensing Data 12 3.9 Interpretation of the UC-AnMap 13 3.10 Application of the UC-AnMap 13 3.11 Dissemination of UC-AnMap Information 14 3.12 Urban Climatic Planning Recommendation Map (UC-ReMap) 14 3.13 Overseas Experience of UC-Map 16 3.14 Updating of UC-Maps 17

4. CONCLUSION AND NEXT STEPS 19 APPENDIX 1 LIST OF WORKSHOP INVITEES / PARTICIPANTS 21



1 INTRODUCTION 1.1 Background to the Study In response to Team Clean’s final report on “Measures to Improve Environmental Hygiene in Hong Kong”, released on 9 August 2003, a “Feasibility Study for Establishment of Air Ventilation Assessment System” (AVAS Study) was conducted and completed by the Planning Department in November 2005. The AVAS Study led to promulgation of a set of planning guidelines for better air ventilation in the Hong Kong Planning Standards and Guidelines (HKPSG) in 2006. In tandem, a Technical Circular no. 1/06 on Air Ventilation Assessments was jointly issued by the then Housing, Planning and Lands Bureau (HPLB) and Environment, Transport and Works Bureau (ETWB) requiring all major government projects to include AVA as one of the planning and design considerations. In July 2006, the Planning Department commissioned the “Urban Climatic Map and Standards for Wind Environment – Feasibility Study” to take forward the recommendations of the AVAS Study. The key tasks of this Study include the establishment of the Urban Climatic Analysis Map (UC-AnMap), the Urban Climatic Planning Recommendation Map (UC-ReMap), the optimum wind performance criteria that could be practically adopted for AVAs in Hong Kong, a refined methodology for conducting AVA and recommendations for necessary changes, if any, to the Urban Design Guidelines of the HKPSG. The Study would involve substantial technical input including urban climatic data collection and analysis, user’s wind comfort survey, field measurement and wind tunnel testing work. 1.2 Purpose of the Technical Experts Engagement The draft Urban Climatic Analysis Map of the Study was largely completed. A series of related technical studies, including the first batch benchmarking tests, field measurements and users’ wind comfort survey were also completed and provided relevant inputs to the draft UC-AnMap. A Technical Experts Engagement Workshop was held as part of the Study to tap expertise in the relevant fields with a view to confirming the Study approach and methodology before finalizing the UC-AnMap and proceeding to the preparation of the UC-ReMap. The focus of the Technical Experts Engagement Workshop was to solicit technical experts’ feedback on : - the Study approach and methodology to the formulation of the draft UC-AnMap;

and the main findings of the related technical studies; - the classification and evaluation of the draft UC-AnMap in the various urban

climatic classes and zones; and - their views and suggestions on how the UC-ReMap can be envisioned.



2 TECHNICAL EXPERTS ENGAGEMENT PROCESS The Technical Experts Engagement Workshop was held on 7 February 2009 at Planning Department. In view of the highly technical nature of the UC-AnMap as the main Study findings at this stage, technical experts who were expected to have relevant interest and knowledge to comprehend the subject and contribute to the technical process of the Study were target participants of the Workshop. Prior to the Workshop, a Digest for Technical Experts Engagement was sent to the invitees to invite their written comments. A similar Technical Digest was also uploaded to the Planning Department’s website for public viewing at www.pland.gov.hk. The Workshop was well represented by technical experts from various consultant groups, academic institutes and government departments. The list of workshop invitees and participants is in Appendix 1. The Workshop consisted of two sessions : the first session on a presentation of the approach and major findings of the Study completed so far followed by general questions and answers; the second session on focus group discussion. The first session was attended by all the participants. In the second session, the participants were divided into two separate groups, one on the technical aspect and the other on the general application aspect of the UC-AnMap, for more focused discussion. The participants were free to choose which group they wished to attend depending on their interest and to rotate from one group to another during discussion. The focus group discussion involved a wide range of topics relevant to the Study and the views of all the participants were summarized at the end of the Workshop. After the workshop, evaluation forms were sent to all participants and invitees who did not attend the Workshop to invite their post-Workshop feedback by 21 March 2009. Five complimentary returns and no negative feedback had been received at the end of the period.



3 KEY COMMENTS AND RESPONSES This section summarises the comments collected during the technical experts engagement, including one written comment, and the Consultant’s responses. It is not the purpose of this report to duplicate the information already documented in the various reports of the Study currently available on Planning Department’s website in the responses. It should also be noted that the comments and responses included in this report at this stage are by no means conclusive, as another round of engagement exercise to involve wider stakeholders will be conducted later prior to finalisation of the Study. 3.1 Overall Observation In general, the Workshop generated many beneficial discussions with no adverse or divergent comments on the Study approach, methodology and findings at this stage. The responses indicated general support for the need to establish Urban Climatic Maps for Hong Kong and integrate urban climatic considerations into the town planning process. There was keen interest to seek more clarifications and explanation on the underlying assumptions and technicalities of the Study, some of which have been documented in other related technical papers, with no major methodological or fundamental issues. Comments raised were reasonable from the perspectives of the consultees’ specific fields of expertises and not substantive to undermine what the Study has progressed and achieved so far. By and large, the discussions were productive and contributed to better understanding on the concepts and application of the draft UC-AnMap providing a good basis for further work. Overall, the technical experts engagement was encouraging to confirm the Study direction to move on to the next stage in finalizing the draft UC-AnMap and formulating the draft UC-ReMap for Hong Kong. The comments are elaborated, grouped and responded to by topics in the subsequent paragraphs. 3.2 Support for UC-AnMap Comments There was a general recognition of the importance of formulating UC-AnMap, which would contribute to better planning decision-making. There was concern that urban climatic considerations have not received sufficient attention in the past and such has caused a wide range of impacts on the air ventilation of the city and human thermal comfort.



Response Noted. 3.3 Factors not considered in UC-AnMap Comments A number of questions were posed regarding some factors which had not been considered in the UC-AnMap namely, air pollution, relative humidity, anthropogenic heat, building façade materials, and traffic movement. Responses Air Pollution In accordance with the Study brief, the UC-AnMap was drafted and structured based on the outdoor thermal comfort and quality living environment points of view. Air pollution can technically be factored in the UC-AnMap such as in the case of Germany but air pollution is not within the scope of this Study. However, air pollution concerns would be taken into account in the town planning process. The air paths to be identified in the Urban Climatic Planning Recommendation Map (UC-ReMap), apart from facilitating air ventilation, can help disperse air pollutants, but it is beyond the scope of the current Study to quantify their effects. However, relevant departments if needed, could add such information into the GIS framework of the UC-Maps for their use in understanding air pollution spatially in the future. Relative Humidity Relative humidity has been factored in the calculation of physiological equivalent temperature (PET) value. PET gives a synergetic indication of human thermal comfort and that provides the basis of the UC-AnMap (refer para. 3.8 for more detailed elaboration of the PET concept). Anthropogenic Heat Although the information on anthropogenic heat was not directly analysed in the draft UC-AnMap due to the lack of precise information, it has been a general practice in Germany that the Building Volume layer (Layer 1 of the UC-AnMap) can serve as an indirect indicator of anthropogenic heat production due to building related uses e.g. air conditioning, that is, higher building volume implying higher anthropogenic heat production. Traffic Movement Traffic movement adds to the anthropogenic heat input to urban climate. However, heat production from traffic movement was not considered in the UC-AnMap as based on recent studies by researchers in Tokyo, its areal contribution to urban



climate in a district is minor (around 0.2 deg C at peak hours). The intense heat at street level in Hong Kong is mostly contributed by trapped solar heat in the street canyons rather than the heat sources from traffic movement. The UC-AnMap mainly focuses on the impact on urban morphology to assist town planning and traffic movement is more a matter of transport policy. Building Façade Materials Surface properties of individual buildings are not crucial factors for UC-AnMap making which is not targetted at building level. With a 100m x 100m grid resolution of the UC-AnMap, the effects of the different façade materials on thermal loads would even out and not contribute to any significant differences amongst the grids. In addition, as building materials are detailed matters not normally within the town planners’ control, they have not been selected as parameters in the urban climatic map analysis. 3.4 UC-AnMap Layers Comments The approach to focus on the two aspects of Thermal Load and Dynamic Potential in generating the draft UC-AnMap and the definitions of the Thermal Load and Dynamic Potential were generally agreeable. One comment was raised on the possible effects of tall buildings in the building volume layer and tall buildings with sufficient separation should not have problems. The relative order of importances of the different layers in the draft UC-AnMap was also discussed. Clarification was also sought in whether various factors considered in the UC-AnMap layers may overlap with each other e.g. landuse, open space and greenery. If that is the case, the overlaps should be addressed with care. Responses Effects of Tall Buildings The possible effects of tall buildings have been indirectly factored in through the analysis of building volume. Calibration of thermal load is based on cubic meters of building volumes translated into Sky View Factor (SVF), which is a major factor reflecting the influence of slowing radiative cooling effect in the city at night. The most important of this effect is that built-up areas with high building volume and tall buildings would predominantly obstruct the open sky and delay the cooling of the surface during clear and calm nights, thus, increasing the thermal load. As large ground coverage has been found to have significant impact on dynamic potential, tall buildings should be planned with care to ensure sufficient separation and gaps at ground level.



Relative Order of Importances of UC-AnMap Layers Building Volume and Ground Coverage, both important parameters of how the city is planned and designed, are the most important factors contributing to the thermal load and dynamic potential of urban climate in Hong Kong. This understanding is justified considering the high-density urban morphology of Hong Kong. High building volume contributes to the thermal load of the city and increases the urban air temperature. High ground coverage blocks wind and increases urban roughness and hence, reduces the potential of wind penetration and effectiveness to discharge stored heat. To mitigate the negative effects of high building volume and high ground coverage, increase in greenery, open space, proximity to vegetated hill slopes, and the waterfront are beneficial. Overlapping of Layers Factors considered in the UC-AnMap have been classified into three main categories, namely Thermal Load, Dynamic Potential and Wind Information. The contribution of various factors, both positive and negative, towards urban climate were summated to become the UC-AnMap. The drafting of the UC-AnMap follows international experience and understanding, with a focus on Hong Kong’s urban conditions. The risk of overlaps or “double counting” of layers has been minimised. The UC-AnMap has also been calibrated using field-measured data; this should provide further counterchecks to further rectify minor overlaps, if any, towards the end results. 3.5 Urban Climatic Classes in the UC-AnMap Comments There was discussion on the assumptions of the environmental conditions in generating the urban climatic classes. The possibility of averaging urban climatic class values and setting a target class value for specific areas was also discussed as there was a general recognition of its importance as the basis for formulation of planning recommendations and the corresponding mitigation measures. Some suggested that benchmarking of urban climatic classes would contribute to a better use of the UC-Map for practitioners so that appropriate mitigation measures can be implemented to improve the microclimatic environment of urban areas. Responses Physiological Equivalent Temperature (PET) PET is used in the generation of urban climatic classes in the UC-AnMap. PET is the temperature of a reference environment based on a heat balance model that combines various climatic and physiological variables including air temperature, relative humidity, solar radiation, air movement, clothing and metabolic rate to give a synergetic indication of human thermal comfort. Climatic factors have therefore, been already considered when PET value was calculated.



Generation of Urban Climatic Classes The generation of urban climatic classes in the UC-AnMap was based on knowledge interpretation of their likely sensual impact on urban thermal comfort in summer outdoor and shaded condition of Hong Kong (Air Temperature Ta =28 deg C), ranging from moderate cooling (Class 1) to very strong warming effect (Class 8). The PET interval between 2 classes is in the order of about 1 deg C in PET, validated by field measurements. The impact on thermal comfort is evaluated and categorized using PET based on the intra-urban temperature differences due to Thermal Load and Dynamic Potential. Target Urban Climatic Class Value 8 urban climatic classes have been resolved in the draft UC-AnMap. The impact on thermal comfort ranges from “moderate cooling” to “very strong warming”. Class 3 is “neutral” and class 4 is “slight warming”, they can in theory be considered as target class values. However, it is neither necessary nor practical to design the entire city to meet these target values. Different planning measures may be needed even for the same urban climatic class but in different districts. It is more useful to consider an approach to recognize the diversity of thermal conditions in the city based on differences in the intra-urban temperature. Mitigation Measures for Enhanced Urban Climate In Hong Kong, three types of mitigation measures are more important and feasible to be implemented, namely controlled building volume and ground coverage and provision of greenery; because these could be regulated through the existing planning and development policy frameworks. For built-up areas, as the existing building form cannot be easily altered, it is important not to worsen the current built-up situation and to provide further greenery; such efforts could possibly help improve the urban climatic class in the UC-AnMap. Major new development areas should avoid leading to any major change in urban climatic class through strategic planning of mitigation measures. 3.6 Wind Information for UC-AnMap Comments Wind information can be wide ranging from regional wind pattern to local wind characteristics. Some comments sought clarification on the sources and assumptions of wind data as input to the UC-AnMap. There were also comments on how winds of different heights and directions at different time and seasons were accounted for in the draft UC-AnMap as there are vast variations in wind environment within the urban environment. It was suggested that local wind characteristics such as the effect of land-sea breezes are important and may be critical to air ventilation in some districts.



Responses Sources of Wind Data According to international experience, UC-Map is a useful planning tool to identify critical conditions that require actions of the government and the community. The wind information provided by the Hong Kong Observatory (HKO), as well as the MM5/CALMET simulations provided by HKUST, were used to evaluate the wind characteristics (mainly the prevailing wind directions) of the various urban areas, including land-sea breezes. Hourly data of HKO and MM5/CALMET wind information in summer months have been used to understand the Hong Kong background wind and the land-sea breeze effect. Summer daytime and nighttime data have been used to examine the effect of land-sea breezes. The UC-AnMap of Hong Kong focuses on the summer afternoon scenario. Due to Hong Kong’s position in the southeast coast of the Asiatic continent, the Monsoon circulation could be broadly understood based on a winter and summer delineation. At a very large scale, the general direction of winter airflow is from the continent (i.e. north-east) because of the cooling of the great landmass in winter. The summer airflow is mainly from the sea (south-west). The summer’s prevailing south-westerly directions are modified locally due to the topography and the land and sea breezes. Height and Direction of Wind The typical height of urban canopy layer in Hong Kong is about 60m, therefore MM5/CALMET wind data at 60m and HKO wind data at their respective station-anemometer height were used and evaluated. Once the wind information is summarized and coded onto the GIS platform of the UC-AnMap, it would be expertly evaluated for the prevailing wind characteristics for preparation of the UC-ReMap. Time and Seasonal Differences of Wind As the thermal comfort level survey has identified that the summer conditions (especially afternoon from 1 to 5 pm) are more critical to Hong Kong when the temperature is extremely high and the wind condition is generally very weak, therefore, the summer (June-July-August) wind conditions will be considered primarily while annual wind conditions will also be considered for preparation of the UC-ReMap. Land Sea Breeze The possible benefits of land-sea breezes to the urban areas were considered in Layer 6a (Proximity to Waterfront Map) of the draft UC-AnMap, and will be presented in Layer 7 (Wind Information) that will be added to the final version of the UC-AnMap. Layer 6a indicates the potential areas where land-sea breezes are likely to be experienced while Layer 7 will show the wind directions of the land and sea breezes based on expert evaluation.



For the MM5/CALMET simulation, the thermal effects due to the temperature difference between land and sea were considered, so the land-sea breezes are fully represented in the simulated wind field. This simulated wind field has compared well with observed data (Yim et al. 2007). In addition, the resolution of the wind field is very fine which is down to 100m resolution which is high enough to capture the complex terrain effects over Hong Kong. Wind Information Layer For the development of the wind information layer in the final version of the UC-AnMap, the main prevailing wind directions will be evaluated based on expert evaluation of available wind information. Detailed descriptions of the wind information will be provided later in the WP1A Addendum - Report of Wind Information of Hong Kong. 3.7 Wind Information for Air Ventilation Assessment (AVA) Comments There was a general discussion on how wind information would be interpreted and translated into planning recommendations in the later stages. Some queries were also raised on whether summer or annual wind information should be adopted for AVAs. Responses Currently, for the AVA methodology under the HPLB / ETWB’s Technical Circular on AVA, only annual wind needs to be studied. The need to use summer wind information for AVA will be further studied and elaborated when the AVA methodology is refined. 3.8 Use of Remote Sensing Data Comments Some comments suggested the use of satellite images for the UC-AnMap to identify the thermal phenomenon in Hong Kong, as satellite images can provide high-resolution data on surface temperature. Responses Remote sensing data can be useful for understanding the urban climate. However, there are constraints in using satellite images for a comprehensive study of thermal phenomenon. For example, satellite images are temporal and cannot give longer timeframe data for reliable mapping of thermal phenomenon over a period



in Hong Kong. The Consultant has compared the draft UC-AnMap with a limited number of satellite images that have resolved the surface temperatures into air temperatures. The patterns of intra-urban temperature variations of the two were found to be largely consistent. 3.9 Interpretation of the UC-AnMap Comments The interpretation of the 100m x 100m grids of the UC-AnMap was discussed. Some expressed concern on the urban climatic classes in the UC-AnMap if they were to be interpreted rigidly at individual pixel scale. Responses The UC-AnMap is presented at 100m x 100m grid and the computation is based on this grid resolution. The information in each layer is classified based on their respective contribution to an increase or decrease of PET value, being an indicator of urban thermal comfort. Furthermore, the UC-AnMap should be interpreted on a broad-brush level and it is not proper to read the map grid by grid. The overall patterns and relationship of grids should be look at in aggregate. 3.10 Application of the UC-AnMap Comments The application of the UC-AnMap within the current planning framework and the need to distinguish the application at broad district level and site levels were discussed. There was suggestion that the UC-AnMap could provide a basis to impose statutory / mandatory requirement in order to properly control future development and improve the environmental condition. Responses The UC-ReMap would provide the background and broad-brushed urban climatic information and relevant planning guidance for district and Outline Zoning Plan (OZP) planning levels. At the more detailed site level, microclimatic studies, such as those conducted for public housing developments and AVA would be appropriate for individual developments. There should be sound planning justifications to impose statutory planning or mandatory control apart from urban climatic considerations. Mandatory building heights and building setbacks have been introduced to some sites at OZP level



taking into account air ventilation and wind characteristics among other considerations. 3.11 Dissemination of UC-AnMap Information Comments The complexity of the Study was also recognized and appreciated. Some noted that the dissemination of the UC-AnMap information, including the individual input layers to the practitioners is important since the UC-AnMap itself may not provide sufficient information required by practitioners. The supply of the associated information would facilitate a more comprehensive framework for environmental and planning studies in the future. It was suggested that the UC-AnMap should be presented to the public with caution, as the public may tend to focus on small areas. Moreover, the information provided by the UC-AnMap could be sensitive and this may cause unnecessary speculation in concerns regarding land values, public health and hygienes. Responses The draft UC-AnMap has been uploaded to Planning Department’s website. Dissemination of other draft UC-AnMap information is premature at this stage as the draft UC-AnMap will be refined and is yet to be finalized. It is agreed that the information contained in the UC-AnMap must be carefully interpreted. The UC-AnMap is intended to be read and applied at district-scale to understand the general pattern and distribution of the urban climatic classes, rather than focusing on a particular grid or location. We agree that the release of the UC-AnMap information and other Study findings to the public should be based on a coherent strategy taking into account public’s comprehensibility and sensitivity. The strategy will be carefully formulated in the next stage of stakeholders engagement. 3.12 Urban Climatic Planning Recommendation Map (UC-ReMap) Comments There was interest to know how scientific information can be translated into planning recommendations and whether the recommended planning actions would be implemented and prioritized based on the relative importances of the parameters. There was also support for a holistic approach rather than based solely on urban climatic considerations to formulate planning recommendations for



the UC-ReMap. It was suggested that planning actions should be implemented to suit the varying characteristics of different areas, with guidelines and mitigation measures appropriate for different districts. Responses Translation into Planning Recommendations The UC-AnMap provides a scientific analysis of the urban climatic situations at district-scale. Based on the district climatic characteristics and urban climatic classes identified in the UC-AnMap, possible planning measures would be developed in the UC-ReMap. The UC-ReMap will aim to bridge the gap between urban-climatic science and pragmatic town planning considerations. Appropriate planning recommendations could be formulated to protect, preserve, enhance or mitigate the urban climatic condition of an area or a district. Implementation and Priority of Planning Actions While planning actions and mitigation measures would be desirable, the feasibility and implementation aspects would need to be carefully considered in relation to practical constraints and other relevant factors within the existing institutional framework. Though the planning recommendations are well based on scientific findings, the resultant planning actions could inevitably be a balanced consideration of various factors, some of which would go beyond pure urban climatic considerations. Planning actions to be recommended in the UC-ReMap should be practical and justifiable to suit different characteristics of various districts. The priorities of planning actions would not only depend on the order of importances of the parameters, but also the area’s characteristics e.g. greening would be more needed in a congested area than an open area, ease of or constraints in implementation and available scope for changes within the developed areas. Stakeholders will be involved to discuss the draft UC-ReMap and implementation issues before finalisation. Holistic Approach for Planning Recommendations A holistic approach taking into account the urban climatic information and other relevant planning considerations would be adopted to formulate appropriate planning recommendations for individual districts. Key attributes to be considered will include the broad urban setting (old urban area, new town, rural area or new development area), existing and permissible development intensity, existing and planned uses, availability and configuration of continuous open space and corridor, availability and location of green coverage, current development control mechanism, and any need for policy change or refinement that could improve the general built environment of Hong Kong.



3.13 Overseas Experience of UC-Map Comments Desktop studies of the applications of UC-Map in Germany and Japan as well as other countries were recognized as useful to provide a strategic framework for the Study. In particular, elaboration on the ways in which UC-Maps were implemented in other countries were considered important to provide insights into how UC-Maps could be successfully implemented to assist planning decision-making in Hong Kong. Some also suggested that reference to sub-tropical countries with similar climatic conditions should be considered for refinement of the UC-AnMap as both Germany and Japan are higher-latitude countries, and their experiences may not be directly applicable to Hong Kong in certain circumstances. Responses UC-Map Methodology in Germany The Hong Kong UC-Map was modeled on the methodology used in Germany. In 1997, “Guideline VDI3787 Part1 : Environmental Meteorology - Climate and Air Pollution Maps for Cities and Regions, 1997” was published as a national standard for Germany by the work group of Urban Climatic Map Committee of Applied Climatology. It aimed to offer expert advices on the methodology of creating UC-Map and also define the micro-climatic and meso-climatic symbols and representations used in UC-AnMap and UC-ReMap. Germany led the world in the UC-Map field, and it becomes the international guideline and reference for conducting UC-Map studies around the world. Implementation of UC-Map in Stuttgart, Germany In Stuttgart, Germany, the UC-Map and planning-relevant climate studies have been written into a “Climate Booklet for Urban Development – References for Zoning and Planning”; released both in printed literature and on the internet by the office for Environmental Protection of Stuttgart and the Ministry of Economy of the Federal State BADENWUERTTEMBERG.Fundamentals, selected topics, and planning recommendations are elaborated in the booklet. Planning, technical, and legal possibilities and limitations for a climate-sensitive urban development are explained. All the summarized materials in this Climate Booklet for Urban Development are accessible to the public. The Ministry of Economy hopes to assist all those concerned with urban development and planning to have a proper consideration of climatic concerns. The UC-Map serves as an “information tool” rather than a regulation tool on proposed developments.



Implementation of UC-Map in Kassel, Germany In Kassel, Germany, the climatic recommendation map was incorporated into a master plan by Regional Planning Board. According to the climatic recommendation map, climatically critical areas are pinpointed for detailed investigations. When these areas are subject to development and constructions, a detailed climatic study should be specifically conducted by consultants for the projects, developers or Government for designated areas. From the study, another UC-Map with a larger scale of 1:2000 for that particular area will then be prepared by listed certified consultants. This larger-scale UC-map will be finally referred back to the Regional Planning Board for ultimate decision-making. Implementation of UC-Map in Tokyo Metropolitan Area The Tokyo Metropolitan Government produced a “Thermal Environment Map” in April 2005. This Thermal Environment Map shows the atmospheric impact (Thermal Load) of anthropogenic heat release (caused by humans) and surface cover conditions in Tokyo’s central 23 wards. Based on this map, Tokyo Metropolitan Government designated four areas as “areas for the implementation of urban heat island effect mitigation measures”. Furthermore, in July 2005, the Tokyo Metropolitan Government developed the “Guidelines for Urban Heat Island Mitigation Measures” to encourage private businesses and the public to develop mitigation measures according to the thermal environment in which they operate or live. These guidelines comprise i) the Thermal Environment Map; ii) an area-specific mitigation measures guidelines; and iii) a building-specific mitigation measures guidelines. References of UC-Map in Sub-tropical Climates Studies of similar sub-tropical climate as Hong Kong are very limited worldwide. Salvador (Brazil), with a similar climatic environment as Hong Kong, has already conducted UC-Map study and Singapore has also conducted initial studies on UC-Map as well. The key consultant leaders for this Study had participated in the above mentioned studies and therefore, the UC-AnMap for Hong Kong has already taken into account experiences in sub-tropical countries to ensure that issues associated with sub-tropical climatic conditions of Hong Kong will be adequately addressed. 3.14 Updating of UC-Maps Comment The need on updating of the UC-Maps was raised and discussed. Response It is recognised that the UCMs will require updating. The UC-AnMap is compiled using a GIS system so it would be easy to update the UC-AnMap by inputting



updated information on various layers. It is tentatively recommended that the UC-AnMap should be updated every 5 years. The UC-ReMap will need expert inputs for updating and its updating should synchronize with the UC-AnMap.



4. CONCLUSION AND NEXT STEPS The Technical Experts Engagement for the Study has provided an invaluable platform for views sharing and better understanding of the concept of UC-Map for technical experts and practitioners. On the whole, the UC-AnMap approach, methodology and findings at this stage are unquestioned. The feedback provides a good basis for refinement of the UC-AnMap and preparatory work for the draft UC-ReMap and other subsequent tasks by the Consultant. The next stage of work will take into consideration all relevant comments from the technical experts and focus in the following key areas: Finalisation of the UC-AnMap Wind information is being collated for the finalisation of the UC-AnMap. The work will include coding of further wind information into GIS for evaluation. These wind information will be included as a new layer in the finalized version of the UC-AnMap together with an update of the building information layers. Formulation of Planning Recommendations Based on the urban-climatic information on the UC-AnMap, the Study will formulate planning recommendations at a broad district planning level in the form of UC-ReMap. Comments on the need for holistic and cautionary approach, practical planning guidelines and mitigation measures to take into account public sensitivity will be appropriately addressed. Refinement of the Air Ventilation Assessment System Supporting technical studies will continue including more wind tunnel benchmarking tests, computational fluid dynamic test for Tsim Sha Tsui area, formulation of wind standards, and review of wind data and methodology to be adopted for AVAs in future. These technical studies would provide inputs for refinement of the current air ventilation assessment system adopted in the HPLB / ETWB Technical Circular on AVA for more site-specific assessment of impacts of developments on air ventilation. Further Stakeholders Engagement Prior to finalisation of the Study recommendations, another round of wider engagement would be held to solicit views from the technical experts again and other concerned stakeholders, as the general stakeholders will be more concerned about the planning recommendations and their implications on existing policies or practices, if any. All relevant completed Study reports and technical papers including this report will continually be uploaded to Planning Department’s website when available as the Study proceeds.



Reference Yim, S. H. L., J. C. H. Fung, A. K. H. Lau, and S. C. Kot (2007), Developing a high-resolution wind map for a complex terrain with a coupled MM5/CALMET system, J. Geophys. Res. VOL. 112, D05106, doi:10.1029/2006JD007752, 2007.



Appendix 1 LIST OF WORKSHOP INVITEES / PARTICIPANTS PlanD Study Team Ms Phyllis Li AD/SD, PlanD (Chairperson) Ms S C Lau CTP/UD&L, PlanD Mr Lawrence Chau STP/UD (3), PlanD Ms Johanna Cheng TP/UD4, PlanD Mr Raymond Leung TP/UD7, PlanD Ms Joyce Ng TPG/UD Consultant Team Prof Edward Ng Dept of Architecture, CUHK Prof Lutz Katzschner University of Kassel Dr Peter Hitchcock CLP Power Wind / Wave Tunnel Facility, HKUST Mr Derek Sun EDAW City Planning Dr Rumin Yin Ove Arup & Partners Hong Kong Ltd. Mr K S Wong Dept of Architecture, CUHK Ms Chao Ren Dept of Architecture, CUHK Mr Kevin Lau Dept of Architecture, CUHK Mr Justin He Dept of Architecture, CUHK Prof. Bernard Lim Dept of Architecture, CUHK Prof Jimmy Fung Dept of Mathematics, HKUST Prof S C Kot Dept of Mechanical Engineering, HKUST Advisors to Consultant Team Prof Edmund Choi Dept of Building and Construction, CityU Prof Janet Nichol Dept of Land Surveying and Geo-Informatics, PolyU Steering Group Members Mr Eddie Choy Buildings Department Mr L C Shum Buildings Department Mr Frederick Ng Civil Engineering and Development Department Mr Stephen Yim Housing Department Ms W Y Chan Housing Department Dr T C Lee Hong Kong Observatory Mr Silas Liu Information Systems and Land Supply, Planning Department Mr Dave Ng Mass Transit Railway Corporation



Consultants Mr Alex Ngai Cinotech Consultants Limited Mr H F Chan Cinotech Consultants Limited Ms K S Lee Cinotech Consultants Limited Mr David Yeung ENVIRON Hong Kong Limited Mr Calvin Chiu ENVIRON Hong Kong Limited Mr Peter Lee ENSR Asia (HK) Limited Ms Christine Tam ENSR Asia (HK) Limited Mr S P Ma ENSR Asia (HK) Limited Mr Casey Chan ENSR Asia (HK) Limited Mr Vincent Cheng Ove Arup & Partners Hong Kong Limited Mr Y F Pin Parsons Brinckerhoff (Asia) Limited Mr Steven K H Lai Parsons Brinckerhoff (Asia) Limited Mr Thomas Lee Star Vision Limited Academia Dr Square Fong Dept of Building Science and Technology, CityU Dr John Lin Dept of Building Science and Technology, CityU Prof Johnny C L Chan Guy Carpenter Asia-Pacific Climate Impact Centre, CityU Mr Bosco Fung Department of Geography and Resource Management Mr Douglas S T Lau Dept of Architecture, CUHK Ms Debra T M Cheung Dept of Architecture, HKU Dr C H Liu Dept of Mechanical Engineering, HKU Mr Botao Su Dept of Urban Planning and Design, HKU Dr. C N Ng Dept of Geography, HKU (also representing Hong Kong Meteorological Society) Prof Y K Tung CLP Power Wind / Wave Tunnel Facility, HKUST Mr Steve Yim Dept of Mathematics, HKUST Mr M S Wong Dept of Land Surveying and Geo-Informatics, PolyU Mr Eugene Ng Dept of Applied Physics, PolyU Dr. K S Lam Dept of Civil & Structural Engineering, PolyU (also

representing Hong Kong Meteorological Society) The following were also invited but did not attend the workshop : Steering Group Members Architectural Services Department, Development Bureau, Environment Bureau, Environmental Protection Department, Hong Kong Housing Society, Lands Department, Urban Renewal Authority



Consultants Allied Environmental Consultants Limited, Atkins China Ltd., BMT Asia Pacific Ltd., CH2M Hill Hong Kong Ltd., CO2nnsulting Limited, EDMS (Hong Kong) Ltd., ERM-Hong Kong Ltd., Red Consultants Limited, Scott Wilson Ltd., WSP Asia Ltd. Academia CityU, Department of Physics and Material Sciences Hong Kong Baptist University (HKBU), Faculty of Science HKBU, Department of Geography PolyU, Department of Building and Real Estate HKU, Department of Civil Engineering HKUST, Institute for the Environment

Urban Climatic Map and Standards for Wind Environment - Feasibility Study Report … ·...

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