Two urban schemes within the Joint UK Land Environment Simulator (JULES) are evaluated offline against multi-year flux observations in the densely built-up city centre of London and in suburban Swindon (UK): (i) the 1-tile slab model, used in climate simulations; (ii) the 2-tile canopy model MORUSES (Met Office–Reading Urban Surface Exchange Scheme), used for numerical weather prediction over the UK. Offline, both models perform better at the suburban site, where differences between the urban schemes are less pronounced due to larger vegetation fractions. At both sites, the outgoing short- and longwave radiation is more accurately represented than the turbulent heat fluxes. The seasonal variations of model skill are large in London, where the sensible heat flux in autumn and winter is strongly under-predicted if the large city centre magnitudes of anthropogenic heat emissions are not represented. The delayed timing of the sensible heat flux in the 1-tile model in London results in large negative bias in the morning. The partitioning of the urban surface into canyon and roof in MORUSES improves this as the roof tile is modelled with a very low thermal inertia, but phase and amplitude of the grid box-averaged flux critically depend on accurate knowledge of the plan-area fractions of streets and buildings. Not representing non-urban land cover (e.g. vegetation, inland water) in London results in severely under-predicted latent heat fluxes. Control runs demonstrate that the skill of both models can be greatly improved by providing accurate land cover and morphology information and using representative anthropogenic heat emissions, which is essential if the model output is intended to inform integrated urban services.

针对英国人口稠密的伦敦市中心和英国史云顿郊区的多年流量观测，对联合英国陆地环境模拟器（JULES）中的两个城市方案进行了离线评估：（i）1块平板模型，用于气候模拟；（ii）2砖瓦顶盖模型MORUSES（Metuses-Met Office-Reading Urban Surface Exchange Scheme），用于英国的数值天气预报。在离线状态下，这两种模型在郊区站点的性能都更好，在郊区站点，由于植被比例较大，城市方案之间的差异不太明显。在两个位置上，短波和长波辐射比湍流的热通量更准确地表示出来。伦敦模特技能的季节性变化很大，如果没有代表大城市中心的人为热量散发，那么在秋季和冬季的显热通量将被严重低估。伦敦1-tile模型中显热通量的延迟时间导致早晨产生较大的负偏差。MORUSES中将城市表面划分为峡谷和屋顶的方法改善了这一点，因为屋顶瓦片的热惯性非常低，但是网格盒平均通量的相位和幅度严重取决于对平面面积分数的准确了解。街道和建筑物。在伦敦不代表非城市土地覆盖（例如植被，内陆水）会导致严重低估的潜热通量。