The high plateaus in west China may provide suitable sites for astronomical observations with the institute's middle-range telescopes and possibly with larger telescopes. Under China-Japan collaborations for site survey in west China, we have been conducting searches for good sites and monitoring their characteristics over several years. As recent results of our site survey show, sites in west Tibet are revealed with a high possibility of good astronomical observations. Weather characteristics at Gar in Ali, Tibet, show its high clear-sky ratios, especially in winter, com- parable to Mauna Kea, Hawaii. But it has some wind problem in winter, where stronger wind speeds, over 20m/sec, occur frequently even though the sky is clear. To find calmer sites, we have conducted numerical simulations for the Ali area using the Japan Meteorological Agency NonHydrostatic Model. We have found another site, named ZoZo Hill, near Gar. We will continue to monitor the Gar site to clarify weather characteristics over the whole year and hopefully start to negotiate for site monitoring at ZoZo Hill this year.

The wind field and precipitable water vapor over the Tibetan Plateau are analyzed using the numerical model WRF. The spatial and vertical distributions of the relevant meteorological factors are summarized, providing evidence for selecting and further evaluating an astronomical site. This study serves as a further demonstration towards astro-climate regionalization, and provides us with an essential database for an astronomical site survey over the Tibetan Plateau.

The working group for an infrared telescope(IRT) toward East Asian Observatory has been set up in EAMA6. This report declares the membership of IRT working group, reviews briefly the activities of promoting the IRT, and puts forward the future plan.

The program of site survey in western China has been initiated by the National Astronomical Observatories of China(NAOC) toward large telescope facilities. The program is carried out in aspects of remote studies and local surveys. The preliminary results show that the eastern Pamirs and Ali area in Tibet may be the best candidates for further monitoring. The site survey group of NAOC will proceed to set up site testing stations on the selected sites and perform monitoring and campaign in 2005.