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The atmospheric boundary layer along the coastal-urban transect differs from that of urban or rural regions due to the distinctive interaction between the sea breeze and the urban heat island effect. In this manuscript, we present the observations of the atmospheric boundary layer in the Houston, Texas, area during the Coastal Urban Boundary Layer Experiment (CUBE) from June through September 2022. In order to understand the unique characteristics of the coastal urban boundary layer, we collected mean and turbulence data from micrometeorological towers and ground-based remote sensing instruments installed in the urban, coastal, bay, and rural sections within the greater Houston region. Furthermore, an urbanized weather research and forecast (WRF) model incorporating the Building Effect Parameterization and Building Energy Model (BEP-BEM) scheme is used to recognize the spatial variability of the meteorological conditions in the Houston Metro area. Compared to non-urban sites, the urban site exhibits a higher near-surface temperature throughout the day, with the highest temperature difference occurring at night due to the redistribution of the stored heat as sensible heat. During the dry period in June, we observed comparatively higher sensible heat flux in the urban site, demonstrating the heat island effect and lower latent heat flux due to lack of vegetation. The urban site had higher TKE values throughout the day than other sites because of the uneven roughness of the landscape. One of the unique findings of this study is the shift in spectral characteristics along the coastal-rural-urban transect. The power and co-spectra of zonal and vertical velocities and the vertical heat flux during the convective periods varied significantly across all the sites. The coastal site was influenced mainly by the local bay breeze shifting the peak to higher frequencies. The boundary layer height in the urban site was generally greater than in bay and rural sites due to increased convection in urban areas resulting from anthropogenic modification of land cover and waste heat from air conditioning use. The balance between the urban thermal and mechanical roughness effects was seen during the sea breeze front (SBF) event on the highest heat index day as SBF was triggered and accelerated by UHI. 

Abstract Extreme heat events are becoming more frequent and intense. In cities, the urban heat island (UHI) can often intensify extreme heat exposure, presenting a public health challenge across vulnerable populations without access to adaptive measures. Here, we explore the impacts of increasing residential air-conditioning (AC) adoption as one such adaptive measure to extreme heat, with New York City (NYC) as a case study. This study uses AC adoption data from NYC Housing and Vacancy Surveys to study impacts to indoor heat exposure, energy demand, and UHI. The Weather Research and Forecasting (WRF) model, coupled with a multilayer building environment parameterization and building energy model (BEP–BEM), is used to perform this analysis. The BEP–BEM schemes are modified to account for partial AC use and used to analyze current and full AC adoption scenarios. A city-scale case study is performed over the summer months of June–August 2018, which includes three different extreme heat events. Simulation results show good agreement with surface weather stations. We show that increasing AC systems to 100% usage across NYC results in a peak energy demand increase of 20%, while increasing UHI on average by 0.42 °C. Results highlight potential trade-offs in extreme heat adaptation strategies for cities, which may be necessary in the context of increasing extreme heat events. 

Abstract A multi-agency succession of field campaigns was conducted in southeastern Texas during July 2021 through October 2022 to study the complex interactions of aerosols, clouds and air pollution in the coastal urban environment. As part of the Tracking Aerosol Convection interactions Experiment (TRACER), the TRACER- Air Quality (TAQ) campaign the Experiment of Sea Breeze Convection, Aerosols, Precipitation and Environment (ESCAPE) and the Convective Cloud Urban Boundary Layer Experiment (CUBE), a combination of ground-based supersites and mobile laboratories, shipborne measurements and aircraft-based instrumentation were deployed. These diverse platforms collected high-resolution data to characterize the aerosol microphysics and chemistry, cloud and precipitation micro- and macro-physical properties, environmental thermodynamics and air quality-relevant constituents that are being used in follow-on analysis and modeling activities. We present the overall deployment setups, a summary of the campaign conditions and a sampling of early research results related to: (a) aerosol precursors in the urban environment, (b) influences of local meteorology on air pollution, (c) detailed observations of the sea breeze circulation, (d) retrieved supersaturation in convective updrafts, (e) characterizing the convective updraft lifecycle, (f) variability in lightning characteristics of convective storms and (g) urban influences on surface energy fluxes. The work concludes with discussion of future research activities highlighted by the TRACER model-intercomparison project to explore the representation of aerosol-convective interactions in high-resolution simulations.