Patterns of urban cloud modifications

Abstract

<p>Clouds in the urban boundary layer interact with the urban land surface via different linkages, resulting in prominent spatial and temporal patterns over or downwind of cities - called here patterns of urban cloud modifications. Depending on meteorological context, an enhancement of fair-weather cumulus clouds or a faster dissipation of fog and low stratus can be encountered. As the role of clouds in the climate system is among the largest remaining uncertainties in climate science, a more complete understanding of cloud systems is required and the dynamic urban setting may serve as a testbed. </p><p>The aim of the study is the spatiotemporal quantification of urban cloud patterns and properties over Europe. Changes of low-cloud properties including cloud occurrence frequency and microphysical properties are spatially and seasonally mapped for the urban centres of Europe using satellite observations (MODIS, SEVIRI). The identification of spatial patterns of urban cloud modifications for specific cloud types and season will provide essential information on location, thermodynamic conditions and intensity of urban centres impacting low clouds. A systematic quantification of the overall spatial and temporal patterns of urban clouds would therefore set a basis for studying drivers of urban cloud modifications and their feedbacks on the urban climate.</p>