Mega cities and large urban complexes

1. Mega cities and large urban complexes ——Challenges and Opportunities LUO Yunfeng CAS MG Meeting 23-25 May, 2013

2. Global urbanization has become an irreversible trend World population estimates from 1800 to 2100, based on UN 2010 projections (red, orange, green) and US Census Bureau historical estimates (black). • The world population, as of today, is estimated to excess 7 billion with half living in the urban areas. • Current projections show the global population expect to 8 billion in 2025, of which nearly 5 billion will live in urban areas, and in 2030 the percent of urban population will be 60%. 1/23

3. Growth of Mega-Cities 68.3 (5) 266.7 (19) • In 1955, 29% of the world's population. • In 2000, 47% of the world's population • In 2015, 53% of the world's population. • In 2030, 60% of the world's population. blue = coastal city (18) green = inland city (5) 379.3 (23) （Source: UN Population Division, March 2000, revised 2007. ） The increase in the urban population has formed and will inevitably bring: --hundreds of large cities (over 1 million population) --many megacities (with over 10 million population), --a series of large urban complexes. It is also estimated that there will be 23 megacities in 2015 in the world, among which 18 are coastal cities, and most are located in the developing countries. 2/23

4. Urban Effects on Weather and Climate • Atmospheric Impacts (“response”) • Turbulence intensity • Stability • Mixing height • Wind speed, direction, shear • Cloudiness • Energy fluxes • Runoff • Temperature • Solar and UV radiation • Visibility • Air quality • Precipitation • Some Urban Phenomena: • Pedestrian weather: winds; temperature; humidity; insolation • Street canyon winds • Urban weather modification (inadvertent) and convection • Heat island • Flooding • Wildfire at wildland interface • Air quality （e.g.PM2.5) • Dispersion • Visibility • Heat-AQ stresses • Urban “Forcing” Factors • Roughness • Albedo • Permeability • Thermal conductivity • Volumetric heat capacity • Anthropogenic heat flux • Emissivity Urbanization alters the “Forcing” Factor such as roughness, albedo, permeability, emissivity…etc. and causes the atmospheric “response “ (turbulence intensity, stability, mixing height…, etc. results the special urban phenomena (heat island, flooding…. etc.) 3/23

5. Effects of urbanization processes affects local and regional scales The man-made urban landscape alters the thermal, radioactive, and aerodynamic process, thereby modifying the urban atmospheric and hydrologic environment. In addition waste heat and particulate and gaseous emissions further alter the atmospheric state and composition, increase turbidity, decrease radiation and visibility, exacerbate air pollution and provide a wealth of condensation nuclei for the formation of clouds, fog and precipitation. Cleugh and Grimmond (2012) in Future World Climates. This fig. shows the processes that urbanization affects local and regional scales weather/climate : (1) concentration of population and activity, land cover change;(2) Urban emissions(heat, Gases and particulates, and water); (3) heat ,water balance and CO2 budget 4/23

6. Urban socio-ecosystem as a driver and responder to Regional and Global Climate Change Urban socio-ecosystem is not only a urban local phenomena, it is also a driver and responder to regional and global climate change through the altered BGC cycles, altered hydrosystems, GHGs and biodiversity, etc. 5/23

7. Better urban weather and environment service • Owing to decreasing resilience and increasing vulnerabilities related with: • --dense urban population, dense infrastructure, intensive economic activities. • Urbanization brings a greater risk of natural hazards and huge environment pressures, • --Urban settlements are already at risk from heat waves, floods, local channeling wind, increased air pollution episodes, water contamination, public health issues, security threats (terrorism, explosion… ), and other hazards. • --The coastal megacities are also facing the amplification of impact of sea level rise and storm surge. • possess significant challenges to the crisis and risk management in the urban areas; WMO’s increasing focus Megacities, such as GAW Doc Cg XVI Para 3.2.22, PWS Cg-XVI 4.1, etc. Understanding, scientific adaptation and responses to the weather and environmental issues have become an urgent task of sustainable development in the megacities and large urban complexes. 6/23

8. Challenges of weather & environmental service in the megacities and large urban complexes. • There are a wide range of users that need information about urban weather and environment, including the following aspects: 1. Weather and environmental service for better city operations 2. Urban air quality forecast and environmental emergency response 3. Weather and environment Service for public health 4. Mitigation and adaptation to climate change and sustainable development 7/23

9. 1 Weather and environmental service for better city operations • Different urban sectors need different weather/environment service, • for example: • Urban Flood Control: • --forecast of quantified precipitation (rain, snow) distribution, • -- rainfall and snowmelt runoff, • --the water storage capability of urban pervious surface, • --drainage system, and water logged ground, etc. • Electric Power : • --high-resolution air temperature forecast for assessing energy demand and related loads on the electric grid. • --Some cities also need forecast on wind and solar radiation for renewable energy assessments. • Transport management: • --observation and forecast on strong wind (especially channeling wind), • --precipitation and its forms (i.e. rain, freezing rain, sheet or snow), • --representations of surface observations, and high-resolution spatial forecasts(e.g. roadway scale) , etc. • Emergency response : • --in great need of timely and accurate forecast on extreme weathers. 8/23

10. 2 urban air quality forecast and environmental emergency response • Cities are the main source of air pollution emissions • Cities also modify their ambient weather, in ways that often negatively affect the dispersion, transformation and concentration of those pollutants. Urban managers, including agencies of environmental protection, public safety, emergency response, all need the information of: Air quality forecast and warnings on multi-levels of region, city, and street, --atmospheric circulation and higher temporal, vertical, and horizontal spatial resolution data (e.g. urban boundary layer structure and mixing layer heights, vertical profiles of winds, turbulence, temperature inversion). --In addition to conventional air pollutants, toxic chemicals and agents may be emitted from industrial and transport accidents, and occasionally deliberate . Quantifying the transport and diffusion of these chemicals is needed, although it is extremely complicated . --The concentration patterns of the pollution is dispersed in a field of buildings. 9/23

11. 3 Weather and environment Service for public health • Urban residents are especially at a higher risk of heat-related mortality as a result of the urban heat-island effect, catastrophic events (flooding, torrential storms), air pollutions etc. Public health agencies may need weather and environment service, including: • Forecast on human comfort and UVI • Solar radiation, wind, humidity, air temperature, even UV index at matching scales for health related forecast (e.g. heat index, wind chill, UVI). • Assessment on thermal & wind environment • Consistent urban heat island and urban wind flow data sets for vulnerability and risk assessments. • Weather and environment based health forecast • Different scale meteorological information for heath weather forecast, such as heat waves and cold waves, and infectious disease epidemics, etc. • Health exposure of air pollution • Street-level air quality for assessment of the health exposure 10/23

12. 4 Mitigation and adaptation to climate change and sustainable development • The urban area used to be one of the most sensitive and high impact areas of climate change, at the same time it is also major contributor to climate change. Governments and all those interested in urban development and climate changes paid attention to : • Urban areas’ contribution to climate change • -- Measuring greenhouse gas emissions from urban sectors (transport, energy supply, etc). • Urban climate change impacts • --Qualifying the impacts upon physical infrastructure, economy development, public health and social activities; and identifying cities that are vulnerable to climate change. • Mitigation and adaptation measures to climate change • -- Implementing the mitigation and adaptation measures (i.e. through the better design and use of the built environment, energy and transportation network, etc. 11/23

13. Technical support for weather and environmental service • Urban observation and boundary reanalysis • Urban Modeling and Seamless prediction technique • Impact forecast and impact assessment techniques of weather and environment Understand the weather/environment issues in the mega cities and large complexes and supply more and more good service for all above needs, the following techniques support are needed: 12/23

14. 1 Urban observation and boundary reanalysis Urban boundary layer observations should not only focus on thephysical elements, but also concerns on the chemical composition; not only on the reasonable spatial resolution, but also on the vertical profiles; and integration and application of these measurements can provide the observation support of modeling, forecast and service. Should pay attention to: (1) Design on extended urban meteorological observation network, guideline of urban measurement stations and networks, and metadata management. (2) More multi-scale networks with specific temporal and spatial resolution(meso-scale, urban, neighborhood, roadway, etc.) and different platforms(radar, wind profiler, photography, ground-based, aero-born, satellite based, in-situ observation or sampling, etc.) (3)Co-shared and effectively managed international urban data archives(including boundary measures, urban GIS information, and social statistics, etc.) are needed. (4) Building capability on intelligently combining observationsthrough a variety of platforms, by using a data assimilation system 13/23

15. 2 Urban Modeling and Seamless prediction technique Urban modeling and seamless prediction is a core technique for urban weather and environment service. • Should pay attention to: • Improve/incorporate data assimilationof meteorological (especially urban boundary observations) and update pollution emission inventoryfrom improved observation network. • Develop urban land surface modeland boundary layer parameterizationscheme, and coupled with of weather and environment models. • Develop the double–way coupled model of the weather model (atmosphere, land, and hydrology) and environment model, to realize a multi-scale simulation and forecast. • Build up an integrated and seamless NWP and ensemble prediction forecast systemfor all time scales, and to describe the uncertainty by importing probability forecast. 14/23

16. 3 Impact forecast and impact assessment techniques of weather and environment City management needs to establish a risk-based decision-making system, within which extreme weathers and air pollution act as an important part. Should pay attention to: (1) Conduct research on regularities of weather disasters, and enhance monitoring of weather warnings and its risk management; (2) Conduct assessment on urban exposure and vulnerability in the respects of transport network, water and energy networks, etc. (3) Explore impact forecast techniques in the fields of city operation (energy supply, water supply, transport, etc.) (4) Develop intelligent weather products and update techniques on product editing and releasing. (5) Assess impacts from climate change and research related adaptation and response policies. 15/23

17. In past years, WMO has sponsored and co-sponsored several pilot project. Significant progress has been made by carrying out these projects, which advanced the city service ability of weather and environment laid the foundation for the future development. • Urban observation • --BUBBLE, Joint Urban 2003, Helsinki Testbed, TOMACS, BUBLEX(Beijing), etc. • Modelling and seamless forecast • --ULSM inter-comparison, probability forecasts , etc. • Weather and environment research and services • GURME projects in Latin American Cities, New Delhi, Moscow, Beijing and Shanghai, • Weather Information Service Engine(WISE) in Republic of Korea, Tokyo Metropolitan Area Convection Study(TOMACS) in Japan, • MEGAPOLI project and COST actions in Europe, • Multi-hazard Early warning systems in France and Shanghai, • Heat/health warnings in many mega cities and infectious disease epidemics warnings based on climate information in Africa through international cooperation, communication and integration. 16/23

18. Pilot megacity----Shanghai’ urban weather and environment service WMO has sponsored and co-sponsored a series of showcase or pilot projects providing technical supporting the weather & environment services in Shanghai, including: --Shanghai World EXPO 2010 Nowcasting Service Demonstration Project(WENS) --GURME project— GURME-Shanghai, --Shanghai Multi-Hazard Early Warning System, --Landing typhoon forecast techniques --Weather/climate and human health—Shanghai heat/health watch & warning system --etc. 17/23

19. Density urban monitoring network in Shanghai Shanghai has been and are being established an integrated 3-D high density urban monitoring network (Shanghai Testbed) 18/23

20. Shanghai Multi-hazard Early Warning System (WMO showcase project) Shanghai has been and are being established a Multi-Hazard Early System (WMO showcase project) 19/23

21. Shanghaiweather/environmentserviceforhumanhealth An integrated weather and services for public health system in Shanghai are also being developed, with multi-department cooperation. 20/23

22. Urban Framework for Climate Service (UFCS): Case in Shanghai (From Tang Xu’s presentation, 2012) Target to be a demonstration city of GFCS, Shanghai are making efforts to be more innovative and proactive in addressing the urban challenges 21/23

23. Recommendation 1: Research promoted on pilot projects • Develop Strategies: • ----Emphasize on the establishment and implement of Urban Framework Climate Service (UFCS)while implementing GFCS and, • --- Improve the weather and environment service for mega-cities and large complexes to deal with weather, climate and environmental problems, and improve related service; • Encourage Showcase projects: • ----Improve GURME project on establishment of case studies for understanding air pollution, health and climate connections in different types of mega cities, and implement health- meteorology forecast and warnings. • ----Enhance Urban Test Beds that integrated in situ and remote sensing observations with modeling efforts and promote opportunities for various end-users; • ----Support and extend the urban multi-hazard early warning system. • Encourage integrated urban observations and Model comparison • ---- Enhance urban meteorological and environmental monitoring capabilities; • ----Organize research on high resolution urban weather and environmental models and encourage inter-comparison high resolution urban boundary models for different urban types. 22/23

24. Recommendation 2 Education, communication and collaborations • Coordinated and Collaboration: • --Coordinated effort across broad spectrum of activities, e.g. PWS, GDPFS, AER, WWR, WHO. CBS and CAS can provide collaborative leadership. • --Improve multidisciplinary collaborations and knowledge exchange between meteorological, environment, health , emergency, and transportation, etc. • Communication: • --Build up communication between end user(urban manager, public) and urban weather and environment service providers. • Education: • --Ensure widespread training of public about urban weather, urban climate, urban environment and its impacts on economic production and human health, • --improve the capacity to deal with the extreme weather and pollution episodes and awareness of green and low carbon development. 23/23

25. Thank you!