摘要：The study of the interactions between urban surfaces
and the urban boundary layer plays an important
role in urban climatology, especially seen against the
background of increasing urbanisation in most parts
of the world. Measurements of radiation and heat
fluxes suffer from the extreme heterogeneity of the
urban landscape. It is therefore difficult to get accurate
and representative measurements. To bridge the gap
between accurate point measurements and their spatial representation, satellite data from Landsat-TM are
used.
Methods and results of the investigation of radiation
properties, net radiation and heat fluxes of urban areas
in the Basel Region, NW-Switzerland are presented.
In addition to field measurements, satellite data from
Landsat-TM were linked to numerical models to compute net radiation and heat fluxes of the whole region.
By integrating the normalized difference Vegetation
index (NDVI) from multi-spectral satellite data, storage heat fluxes could be estimated with high accuracy.
The next step was to compute latent and sensible heat
fluxes by using a Bowen-ratio approach attributed to a
land use Classification.
Of interest is the Observation that the idea of an
«Urban Heat Island» (UHI) has to be defined very
carefully. Very often an «Urban Cooling Island» may
be found during daytime and under clear sky conditions. This feature could be explained using the results
of the satellite based radiation and heat budget analysis.
