Measuring Meteorology in Urban Areas – Some Progress and Many Problems - Meteorological and Air Quality Models for Urban Areas - page 117

(b)

(a)

2000 2000

1600 1600

1200 1200

800 800

400 400

0 0

10 20 30 40 048 2 6

Wind speed (m/s) Virtuel Potential

Temperature (C)

(c) (d) (e)

Fig. 12.6 (a) Ceilometer ( arrow ) mounted on the research ship Galathea; (b) An example of
boundary layer structure measured by the ceilometer during the Galathea expedition. The darker is
the colour the higher is the particle concentration. (c, e) Radiosonde profiles taken with (d) during
thesameevent

potential temperature and a simultaneous decrease of the wind speed from 11 to 3
ms − 1 , ideal conditions for the formation of waves (Fig. 12.6).

12.3 Conclusions

Examples of the use of remote sensing with relevance to the urban areas are pre-
sented. The technique offers possibility to measure the horizontal variability of the
mean wind in the roughness sub-layer over an urban area as well as the wind pro-
file at a specific location. These can add valuable insight into the structure of the
urban boundary layer. The use of remote sensing to estimate the depth of the marine
boundary layer has proven to be very successful. Radiosounding is still an indis-
pensable tool in boundary layer research adding valuable information not available
from other instruments.

Acknowledgments The authors thank Ebba Dellwik for the figures from the forest campaign.
The work is related to activities of the authors within COST-728, COST-732, and COST-735.