Extended Abstract (496K)3.4
urban surface network in Marseille: network optimisation using numerical simulations and results
Grégoire Pigeon, CNRM-GAME, CNRS Meteo-France, Toulouse, France; and A. Lemonsu, P. Durand, and V. Masson
During the ESCOMPTE program (Field experiment to constrain models of atmospheric pollution and emissions transport) in Marseille between june and july 2001 an important device has been set up to describe the urban boundary layer over the built-up aera of Marseille. There was notably a network of 20 temperature and humidity sensors which has mesured the spatial and temporal variability of these parameters.
Before the experiment the arrangement of the network had been optimized to get the maximum of information about these two varaibilities. We have worked on results of high resolution simulations containing the TEB scheme which represents the energy budgets associated with the gobal street geometry of the mesh. First, a qualitative analysis had enabled the identification of the characteristical phenomenons over the town of Marseille. There are narrows links beetween urban effects and local effects : marine advection and orography. Then, a quantitative analysis of the field has been developped. EOF (empirical orthogonal functions) have been used to characterised the spatial and temporal structures of the field evolution. Instrumented axis have been determined with all these results. Finally, we have choosen very carefully the locations of the instruments at the scale of the street to avoid that micro-climatic effects interfere with the meso-scale effect of the town.
The recording of the mesurements, every 10 minutes, had started on the 12th of june and had finished on the 16th of july. We did not get any problem with the instrument and so all the period has been recorded every 10 minutes.
The analysis of the datas will be led on different way. First, will be done a temporal study. We want to determine if the times when occur phenomenons are linked to the location in the town. We will interest particulary to the warming during the morning and the cooling during the evening. Then, we will look for correlation between the temperature and mixing ratio with the wind direction. The town of Marseille is located in an aera that can know three very different situtations of winds. After the choosing of days very interested, we will try to redraw the fields of temperature and mixing ratio using information of simulation results.
Session 3, Urban field projects: ESCOMPTE/CLU & BUBBLE
Monday, 20 May 2002, 1:30 PM-3:15 PM
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