Table 3.

Comparative characteristics of Integrated Urban Systems for the four case study cities.

Characteristics/ City	Hong Kong	Toronto	Mexico City	Paris
Main hazards
Flooding: fluvial/pluvial	✓	✓	✓	✓
Flooding: coastal	✓	✓
Convective weather	✓	✓	✓
Heatwaves	✓	✓	✓	✓
Coldwaves	✓	✓
Air quality	✓	✓	✓	✓
Other	Tropical cyclones, water scarcity, urban ventilation	Strong winds	Geophysical hazards: wildfires, landslides, earthquakes
IUS Initiation and scope	Weather, climate and environmental services for: (i) extreme weather hazards, climate change impacts and AQ issues, (ii) Social, population and economic growth, (iii) Urban development	A more efficient development and distribution of weather and climate products in support of a high-attendance sporting event with products targeting games organizers, police, and public health	Provide timely multi-hazard information to decision makers & residents	Assess urban adaptation studies to climate change.
IUS Components
Observations	✓	✓	✓	✓
Modelling/Forecast	✓	✓	✓	✓
Communications	✓	✓	✓
Applications (see text for category descriptions)	CAT 1, 2, 3, 4	CAT 1,4	CAT 1, 2, 3, 4	CAT 2, 4
Challenges	•High density urban setting for measurement and forecast resolution and accuracy •Growing need by special users & community sectors •Communications	•Merging R&D tools with operations •Identifying the most useful outputs for decision makers to optimize resources •Coordination among participants •Acquiring urban measurement locations	•Coordination, integration and continuity among/between agencies •Social and spatial inequality of users and vulnerability to climate change •Capacity building / human resources •Communications	•Model development to address relevant impacts at the appropriate scale •Model evaluation necessitating specialized observations •Coordination
Scientific novelty & Innovation of solutions	•Integration with government, private sector and research communities •Social media and big data •A.I. and crowdsourcing •Impact- and risk-based services	•New high resolution measurements and modeling for the region •R&D advances on integration	•Development of an AQ risk index targeted to vulnerable population •Research to show evidence of health benefits has informed decision making •Open data practices	•Model developments that have integrated vegetation, building energy use, and human behavior to better test adaptation scenarios
Level of integration	•Multi-hazard early warning system: Q4 •Urban Planning Q3 •Daily/Routine Forecasts Q2	•Multi-hazard early warning system: Q4 •Urban Planning Q2	•Daily/Routine Forecasts: Q4	•Multi-hazard early warning system: (Paris) Q1 •Urban Planning: (Paris) Q4
Observations, Databases and Data Sharing: What & how to measure - for what purpose?	•Weather station networks (>200) •Upper air soundings •Remote sensing •Co-WIN network •16 air quality monitoring stations	•Dedicated mesonet (> 50) •Mobile observations for specific conditions - e.g. lake-breeze fronts that could affect high-impact weather (convective storms) •Hheat stress conditions •Air pollution (fixed and mobile)	•Meteorological network •Air quality network •Open data with high access and transparency is an important element.	•Observations associated with pavement watering test. •Results exchanged among stakeholders
What city data are needed/used? Collaboration for integrated observations; big data: new methods/technology	•Urban morphology and land use •Public health information •Water resources •Energy consumption •Demographic •Transportation (land, sea air, etc) •Insurance	•Urban morphology and land use •Transportation (land) •Event information •GHG emissions	•High temporal and spatial resolution health data •AQ emissions inventory •Industry surveillance •Risk atlas	•Urban morphology and land use •Identification of where to put results into formal (legal) planning documents
Modelling & prediction; diversity of applications;	•Nowcasting, 9 day, seasonal and climate projections •Warnings for different weather related hazards •Custom meteo-services for various weather-sensitive users: health, energy, water, urban infrastructure •24 h AQHI forecast	•Nowcasting / forecasting down to the sports venue scale •Climatological information •weather warnings, forecasting (down to the sports venue scale), •AQHI forecast •Marine forecast	•Air quality modeling/forecasting •Meteorological modeling /forecasting •AQ risk index •Hydrometeorological forecast	•Heatwave prediction •Urban scale future climate modeling for adaptation studies •Urban heat island modeling
Long-term IUS applications	•Urban planning for sustainable development •Infrastructure design for disaster risk reduction •Climate change adaptation and mitigation measures	The initial short-term project led to initiation of longer-term projects for mitigation and adaptation strategies that can be applied both within Toronto and other cities Canada	•Risk atlas •Building evidence of benefits in health through improvements to AQ	•Development of numerical modeling tools to better understand risks related to climate change in the city •Assessing urban scale climate adaptation/ mitigation strategies
Multidisciplinarity of Urban Service delivery and communication	•Stakeholder partnerships through big data support •Liaison with government departments and public utilities during severe weather •Traditional and social media •Websites and apps for real-time data	•Implemented regular briefings for event organizers •Service integration implement in the communication plan. •Weather data portal •Push and pull-type communications	•C5 Centre integrates multiple Mexico City agencies reporting continuously to the Mayor •Real-time data reporting to public via website, mobile application and media •Risk atlas development	•collaboration with social scientists in model development and application
Partnerships and user connections;	Partnerships Academia, public utilities, government departments and professional bodies Users: General public, Government departments, Public utilities (water and energy), Building industry, Health sector, Insurance sector, Tourism sector, Transportation sector, Disaster risk management, Emergency services	Partnerships developed between ECCC, Health Canada, public health regional & municipal organizations and network of governments Main users: Event organizers, Police (Security), Public Health	Partnerships with national and international research institutions and private sectors; Users: government agencies, industries, hospitals, public and news media	Partnerships & users: co-construction of UCS via urban planning agencies engaging in research projects at the community level, incorporation of sociologists, lawyers in order to facilitate knowledge transfer to formal planning documents;
Decision-making, decision support and human behavior	•Planning of major events/social activities •Precautionary measures, emergency preparedness, DRR measures for inclement weather / high air pollution eventsClimate change adaptation and mitigation measures/policies •Infrastructure design and urban planning •Public education and stakeholder engagement activities	•Decision support provided by web-based technologies, push and pull communication types •Services provided with briefing to take into account human interactions	•Decision-making supported by data and knowledge from different areas including human interactions as well as social and political situation. •Social networks a source of information about human behavior •outreach and stakeholder engagement activities to promote positive changes in reducing exposure and behavioral practices	•Human behavior is an element being built into the TEB modeling system •Decision-making aided by the modeling system and wide range of scenarios tested. •Decision support aided by the modification of legal planning documents to help incorporate energy and microclimate issues in future urban development.
Lessons learned	•Climate partnership and interdisciplinary collaborations •Diversity of services to cope with extreme weather, climate change •Data accessibility •Public communication, education •Utilization of R&D and modern technologies	•Important gains in communication between project members and end-users •Need to educate end users on products and/or to provide risk integrated indicators	•Research a key element for designing, implementing and proving services; •collaboration with research institutions and coordination between City agencies •evidence of health benefits from air quality improvements •human resources a key priority	•recognize need for field observations to complement models; •need for improved modeling tools to handle the necessary adaptation scenarios •Need to incorporate other disciplines in order to facilitate knowledge transfer