Local-Scale Urban Meteorological Parameterization Scheme (LUMPS): longwave radiation parameterization and seasonality related developments

Journal article, 2011

Recent developments to the Local-scale Urban Meteorological Parameterization Scheme (LUMPS), a simple model able to simulate the urban energy balance are presented. The major development is the coupling of LUMPS to the Net All-Wave Radiation Parameterization (NARP). Others include that the model now accounts for: changing availability of water at the surface; seasonal variations of active vegetation; and the anthropogenic heat flux; while maintaining the need for only commonly available meteorological observations and basic surface characteristics. The incoming component of the longwave radiation (L↓) in NARP is improved through a simple relation derived using cloud cover observations from a ceilometer collected in central London. The new L↓ formulation is evaluated with two independent multi-year datasets (Łódź, Poland and Baltimore, USA) and compared to alternatives that include: the original NARP and a simpler one using the U. S. National Climatic Data Center cloud observation database as input. The performance for the surface energy balance fluxes is assessed using a two year dataset (Łódź). Results have an overall RMSE < 34W m-2 for all surface energy balance fluxes over the two year period when using L↓ as forcing, and RMSE < 43 W m-2 for all seasons in 2002 with all other options implemented to model L↓.