The World Urban Database and Access Portal Tools (WUDAPT) is an international community-based initiative to acquire and disseminate climate relevant data on the physical geographies of cities for modeling and analysis purposes. The current lacuna of globally consistent information on cities is a major impediment to urban climate science toward informing and developing climate mitigation and adaptation strategies at urban scales. WUDAPT consists of a database and a portal system; its database is structured into a hierarchy representing different levels of detail, and the data are acquired using innovative protocols that utilize crowdsourcing approaches, Geowiki tools, freely accessible data, and building typology archetypes. The base level of information (L0) consists of local climate zone (LCZ) maps of cities; each LCZ category is associated with a range of values for model-relevant surface descriptors (roughness, impervious surface cover, roof area, building heights, etc.). Levels 1 (L1) and 2 (L2) will provide specific intra-urban values for other relevant descriptors at greater precision, such as data morphological forms, material composition data, and energy usage. This article describes the status of the WUDAPT project and demonstrates its potential value using observations and models. As a community-based project, other researchers are encouraged to participate to help create a global urban database of value to urban climate scientists.

The study of urban-scale energy consumption due to buildings follows the archetype approach where samples of representative buildings are analysed and then results are extrapolated across the city. Lack of reliable data has so far been the main reason hindering different approaches; nevertheless, significant improvements have been achieved recently. In this work we use the Westminster Borough of London City, as a case study to illustrate how a dynamic high-resolution dataset for the energy demands of the whole area can be analyzed using the Multi-Resolution Analysis (MRA) to provide insights into the urbanand sub-urban (e.g. district) scale energy demand and therefore suggest how such an analysis can be exploited to guide smart urban energy-demand management. Specifically, we analyze full-day (24-hr) evolutions of the urban-scale energy heating/cooling demands together with high-resolution information on the building density, height and the population. By introducing the scale-adaptive approach, our analysis provides suggestions for e.g. peak hour identification and localization, as well as the identification for example of best-neighboring candidate zone area for extra energy supply in case of power failures.

Given rapid population growth and urbanization, it might be apt to characterize this and the last few centuries as the Urban Epoch of the Anthropocene, Earth's most recent and human influenced geologic time period (Crutzen and Stoermer, 2000). Human activities in this urban epoch have enormous influence and consequence on current and future climate. Urbanization is unavoidable and without proper management can lead to disastrous, extreme, and unexpected events. We now design powerful computer models for use as tools applicable on a global scale for guidance on climate change. More than half of the planet’s population resides in urban areas and the degree of urbanization is projected to increase rapidly; thus it is important that modeling tools be available and suitable for urban applications to develop rational urbanization approaches and guidance to mitigate deleterious effects of urbanization and supporting design for urban resiliency. The form and function of structures in urban area creates its own unique climate, which influences and impacts the quality of life, and associated environmental impacts and risks to its inhabitants. Cities and their climate will further evolve to accommodate global and regional climate changes, further population increases and availability of resources. Computer models have the potential to be applied to simulate weather, climate and air and water quality for any and all urban areas around the globe, they are

Although more than half of the Earth’s population live in urban areas, we know remarkably little about most cities and what we do know is incomplete (lack of coverage) and inconsistent (varying definitions and scale). While there have been considerable advances in the derivation of a global urban mask using satellite information, the complexity of urban structures, the heterogeneity of materials, and the multiplicity of spectral properties have impeded the derivation of universal urban structural types (UST). Further, the variety of UST typologies severely limits the comparability of such studies and although a common and generic description of urban structures is an essential requirement for the universal mapping of urban structures, such a standard scheme is still lacking. More recently, there have been two developments in urban mapping that have the potential for providing a standard approach: the Local Climate Zone (LCZ) scheme (used by the World Urban Database and Access Portal Tools project) and the Global Human Settlement Layer (GHSL) methodology by JRC. In this paper the LCZ scheme and the GHSL LABEL product were compared for selected cities. The comparison between both datasets revealed a good agreement at city and coarse scale, while the contingency at pixel scale was limited due to the mismatch in grid resolution and typology. At a 1 km scale, built-up as well as open and compact classes showed very good agreement in terms of correlation coefficient and mean absolute distance, spatial pattern, and radial distribution as a function of distance from town, which indicates that a decomposition relevant for modelling applications could be derived from both. On the other hand, specific problems were found for both datasets, which are discussed along with their general advantages and disadvantages as a standard for UST classification in urban remote sensing.

Mesoscale weather and climate models are useful tools toward improved understanding and providing important insights regarding climate change mitigation and adaptation in urban environments for institutional stakeholder and urban planner communities. For urban applications, the complexities of the urban fabric for each urban area require scale dependent descriptions of the land use and activity patterns, to account for the effects of subgrid scale urban surface cover and buildings in order to better predict the wind, turbulence, and concentration fields. A commonly used method is the inclusion of a set of urban canopy parameters (UCPs) into mesoscale meteorological models to parameterize building-induced drag and turbulence production and the building-modified surface energy balance (eg Martilli et al., 2002). Current UCPs used in mesoscale models attempt to capture major structural and material features considered to control the momentum and thermodynamics of the flow. It is anticipated that through the WUDAPT (Ching et al., 2014), being initiated by IAUC, scale dependent UCPs will soon become available for model applications.In this presentation, we illustrate and explore sensitivity of model outputs to scale dependent UCP inputs to better understand and articulate their implication to model user communities. The MRA (Mouzourides et al, 2013, Mouzourides et al 2014) provides a powerful means to perform weather and climate model scale dependent sensitivity study for urban applications of models. The MRA is a method that can take into consideration the inherent information residing in urban landscapes, and convey this …

Mesoscale numerical weather prediction models using fine-grid [0(1) km] meshes for weather forecasting, environmental assessment, and other applications capture aspects of larger-than-grid-mesh size, convectively induced secondary circulations (CISCs) such as cells and rolls that occur in the convective planetary boundary layer (PBL). However, 1-km grid spacing is too large for the simulation of the interaction of CISCs with smaller-scale turbulence. The existence of CISCs also violates the neglect of horizontal gradients of turbulent quantities in current PBL schemes. Both aspects poorly resolved CISCs and a violation of the assumptions behind PBL schemes are examples of what occurs in Wyngaard's "terra incognita," where horizontal grid spacing is comparable to the scale of the simulated motions. Thus, model CISCs (M-CISCs) cannot be simulated reliably. This paper describes how the superadiabatic layer in the lower convective PBL together with increased horizontal resolution allow the critical Rayleigh number to be exceeded and thus allow generation of M-CISCs like those in nature; and how the M-CISCs eventually neutralize the virtual temperature stratification, lowering the Rayleigh number and stopping their growth. Two options for removing M-CISCs while retaining their fluxes are 1) introducing nonlocal closure schemes for more effective removal of heat from the surface and 2) restricting the effective Rayleigh number to remain subcritical. It is demonstrated that CISCs are correctly handled by large-eddy simulation (LES) and thus may provide a way to improve representation of them or their effects. For some applications, it may suffice to allow M-CISCs to develop, but account for their shortcomings during interpretation.

Environmental issues and impacts to society will be exacerbated with increased population, diminishing resources and the prospects for extreme weather events and climate changes. Current community-based models available for weather, climate and air quaity applications are powerful state-of-science modeling systems, which, with careful considerations, can be employed to address the impact of these issues fo urban areas. Given the complex and high degree of spatial inhomogeneity of the underlying surface area we will review mesh size, appropriate multi-scale science and morphological descriptions and their data requirements including unique city specific gridded morphology and material composition for their forecasting and climate applications. For this presentation, we discuss, describe and show examples from an ongoing but preliminary prototypic collaborative effort, whose design bases is to provide the experience and recommendations toward extending the scope of the National Urban Database and Access Portal Tools (NUDAPT) to worldwide coverage (WUDAPT). WUDAPT would thus provide requisite gridded data for urban applications of advanced forecast and climate models throughout the world. Strategically, the prototypic efforts will be designed to provide proven protocols for the facilitaton of the data gathering and processing based on available remote sensing and ground-based sampling. Tactically, we employ an iterative approach first obtaining coarse gridded Local Climate Zone (LCZ) classification derived from available Web-based products such as Google-Earth, and Landsat satellite magery. Further sub-class discretization of LCZs and the application of GeoWiki technology facilitates further refinements and ground truthing to yield the desired gridded building morphological distribution parameters and their material composition. Local experts would be encouraged to become involved to ensure factors unique to their area in the world would be incorporated. Finally, given that model applications may require data with different grid resolution we present an outline that employs the new and powerful Multiple Resolution Analyses scheme that can address this need within the scope of WUDAPT.

Environmental issues and impacts to society will be exacerbated with increased population, diminishing resources and climate changes. Current models available for weather, climate and air quality applications are powerful state-of-science modeling systems can be employed to address the impact of these issues. This paper reviews a selected subset of such systems, considered representative of community-based publically available modeling systems and focus on their utilization for urban applications. Special attention is required given the complex and high degree of spatial inhomogeneity of the underlying surface areas. Such applications optimally require relatively fine grid meshes and scale appropriate science description for the varied and complex land surface atmospheric processes commensurate to the fine scale land surface variability structure. This article provides a brief review and perspective on means and science parameterizations for urban focused modeling in these major modeling systems. Several issues, limitations as well as innovative opportunities specific to the optimal operations of these urban systems, with focus on fine mesh size and data needs are identified and discussed.