The urban environment directly influences Urban Boundary Layer (UBL) dynamics. Commonly proposed heat adaptation strategies focused on reducing the impacts of global change and urban induced warming are also expected to decrease the intensity of convective mixing thereby reducing UBL depth, with important consequences for air pollutant dilution and dispersion. We use 20-km grid spacing Regional Climate Model decadal scale simulations that account for end of twenty-first century greenhouse gas emissions, urban development and intensive and uniform implementation of a suite of heat adaptation strategies, to investigate the individual and combined impacts of such drivers on UBL dynamics over the Continental US (CONUS). Results indicate that combined impacts of climate change and urban development are expected to increase summer (JJA) daytime UBL height in the eastern CONUS. Heat adaptation strategies lead to a summer daytime UBL depth reduction of several hundred meters across CONUS regions, primarily as a consequence of reduced surface sensible heat fluxes and associated turbulence. Our results confirm that heat adaptation is expected to increase the static stability of both daytime and nighttime UBLs and decrease the magnitude of vertical winds, inducing stronger subsidence. In addition, the large geographical scale of our analysis indicates that adaptation impacts are greater inland and smaller over coastal cities. In Southern California, the adaptation induced increase in latent heat can counterbalance the projected decrease in UBL depth. Future work addressing these projected UBL impacts with convection permitting, high-resolution coupled atmosphere-chemistry simulations is needed to explicitly determine potential unintended consequences for urban air quality.

城市环境直接影响城市边界层（UBL）动态。普遍提出的旨在减少全球变化和城市引起的变暖影响的热适应策略也有望降低对流混合的强度，从而减小UBL的深度，对空气污染物的稀释和扩散产生重要影响。我们使用20公里网格间距的区域气候模型年代际规模模拟来解释二十一世纪末的温室气体排放，城市发展以及一套统一的热适应策略的密集和统一实施，以研究此类影响的个体影响和综合影响美国大陆（CONUS）上UBL动态的驱动程序。结果表明，气候变化和城市发展的综合影响预计将在东部CONUS的夏季（JJA）日间UBL高度增加。热适应策略使整个CONUS地区的夏季白天UBL深度减少了数百米，这主要是由于减少了表面显热通量和相关湍流的结果。我们的结果证实，热适应有望提高白天和夜间UBL的静态稳定性，并减小垂直风的强度，从而引起更强的沉降。此外，我们分析的地理范围较大，表明适应影响对内陆地区的影响更大，对沿海城市的影响较小。在南加州，适应引起的潜热增加可以抵消UBL深度的预计减少。