1. The French participation is quite light. During the last meeting at Cheju, K. Suhre (Laboratoire d’Aérologie), D. Martin and T.J. Song (Laboratoire des Sciences du Climat et de l’Environnement have expressed their interest in the modeling of the Lagrangian experiments thanks to the French 1D Meso NH/chemistry model. Furthermore, P. Chazette (LSCE) and co-workers were interested in the closure experiment performed from a ground station and using a lidar. In other respects, at this period, China refused the clearance of the US aircraft over the Chinese area. Thus, D. Martin has proposed the use of a Chinese aircraft equipped with the SYIMCA kit. The SYIMCA instrumentation has been developed for urban pollution studies and is described in the table 1. Chinese scientists aboard a Chinese aircraft would set up such a kind of device. Its use should help to a better characterization of initial conditions.

 
2. K. Suhre has given up his research activities and will moved to Germany in January 2000. C. Mari, who is also involved in the PEM-W project, will now take on the French modeling activities. P. Chazette has preferred to focus his research activity to other source regions. However, H. Cachier , L. Gomes and co-workers are now more directly involved in Ace-Asia.

 
3. Beside the modeling aspects, the French participation would now be focused onto three experimental points.
   

   The closure experiment

   • L. Gomès will characterize the soil mineralogy of some desert areas, and will investigate the determination of the wind speed threshold, which allows the particle uptake. The closure experiment will be performed from a ground station located in a desert region. The experimental site is still to be defined.
   Source estimation
   Our main topics will deal with:
   • Dust (L. Gomès)
   • Carbonaceous Aerosols (H. Cachier and C. Liousse): Emission factor determination, partitioning the organic and the soot (black carbon), fraction of the aerosol. Size distribution characterization. Determination of the total carbonaceous aerosol source strength(collaboration G. Carmichael).
   Gas particle interaction in source region.
   • Interaction between dust and the ozone precursors (NOx, VOC) (D. Martin and L. Gomès)
   • Interaction between urban aerosols and the ozone precursors (NOx, VOC) (D. Martin and H. Cachier)
   • Study of the heterogeneous nature of particles according to different sampling sites (sulfate and organic coating)
4. Tools to be needed

In China

• Ground measurements for the estimation of EF and OC/BC of aerosols, (analyses to be done in parallel in Chinese and French laboratories. Intercomparison exercises currently underway).
• Ground measurements for the estimation of dust fluxes (roughness, wind speed threshold, mineralogy, size distribution).
• Ground measurements for total aerosol during dust episodes and determination of the optical depth.
• Airborne measurements with the SYIMCA kit (Table 1) allowing the evaluation of the urban aerosol sources and of the O3 precursor source. This kit could be set up in any light unpressurized aircraft or platform.
In France
Several developments are going on to improve SYIMCA.
• Multigaz analyzer (O3, CO, NO, NOy) developed by Environment SA. It would be available by the end of 2000
• The NOxTOy instrument (NO, NO2, NOy, PAN, HNO3) developed by a Swiss company, MetAir. It has been funded and would be available by the end of 2000
• -The Automatic Airborne Aerosol Analyzer (AAAA) will characterize the aerosol origin (dust, sea salt, urban). M. Schulz develops it at the LSCE. Its use is not expected before the end of 2001.

The SYIMCA kit (SYstème Intégré de Mesure de Constituants Atmosphériques) is composed by different modules (see below). 24V batteries provide the power supply. Data outputs are stored in a PC. Depending on the airborne instrumentation, the weight of the instrument does not exceed 50-60kg. The unique interface with the platform is the air inlets.
 
 

Function	Principe	Detection limit	Response time
O3	UV Absorption	2 ppbv	7s
CO	IR correlation Spectrometry	75 ppbv	30s
NO2	Luminol Chimiluminescence	100 pptv	1s
CO2	IR Differential Absorption	0.1 ppm	1s
Black carbon	visible differential Absorption	100 ng/m3	15s
PTU	P : piezo-electric T : Ni resistance U : Capacitive sensor	Resolution : 0.02 hPa °C. 0.13 %	1s
Latitude, longitude	GPS		1s
Data Acquisition	PCMCIA, Labview, PC
NMHC	12 inox flasks	10 pptv	Laboratory analysis