Urban Climate: From cold air outflow to heat islands

SANDER + PARTNER provides meteorological input data for modelling of urban climate with the PALM-4U model.

Munich, June 2021

PALM-4U is a next generation urban climate model. For the first time this model explicitly resolves buildings and other urban structures.

Until now, the influence of buildings on the urban climate could only be roughly modeled with the old generation of urban climate models (such as FITNAH, MUKLIMO, ENVI-met, etc.). PALM-4U is a next generation urban climate model that fills this gap.

PALM-4U was funded with more than 10 million Euro by the German Federal Ministry of Education and Research. The software of the PALM-4U model is available free of charge.

SANDER + PARTNER provides the necessary meteorological input data for PALM-4U to enable a realistic analysis of urban climate or air quality issues. Our meteorological input data are accurate to the hour and replace rough climatological assumptions that were still necessary for the old urban climate models. Those hourly input data are produced with high-resolution weather models. These kind of data are necessary to properly represent, for example, the morning decay of an inner-city cold air flow or the development of heat islands between buildings.

The image shows the development of the urban climate in the northern part of Munich as influenced by Alpine pumping on June 25, 2021. The urban climate model PALM-4U was driven with meteorological input data from a high-resolution weather model. The weather model runs about 10 times finer than a usual weather forecast. In the image, built-up areas are visible as strong heat islands, but cool areas also form in the shadow of tall houses. The (relatively) cold lakes remain as refreshing elements of the city.

This animation (30MB) shows hour by hour of June 25, 2021, how Alpine pumping developed in the Alpine foothills (modeled with a weather model) affects the development of Munich's urban climate (simulated with PALM-4U). The simulation is close to reality and can be directly validated with measured meteorological data.

At a glance

  1. PALM-4U is a next generation urban climate model able to resolve buildings and other urban structures.
  2. PALM-4U replaces other outdated urban climate models such as FITNAH, MUKLIMO, ENVI-met etc.
  3. With PALM-4U, crude climatological assumptions, which were still necessary for the old urban climate models, become obsolete and are replaced by realistic meteorological input data.
  4. Realistic simulations of the urban climate use hourly input data from high resolution weather model.
  5. SANDER + PARTNER adds 20 years of experience using weather models. Our input data enable a realistic simulation of the urban climate using PALM-4U.


SANDER + PARTNER provides services at the cutting edge between science and industrial needs. We provide consultancy services with focus on renewable energies, climate change and other topics related to met-ocean applications. Our services are asked by clients in the financing industries, banks, devloppers of re-newable energies and ministries around the World.

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Contact: info@sander-partner.com
or call:
Dr. Johannes Sander +49(0)89.55 00 66 30