Oral Presentation

A China-Japan Collaborative Site Survey in west Tibet - Sky clearness at Gar/Ali, Tibet -

Toshiyuki Sasaki(NAOJ), Yongqiang Yao(NAOC), Norio Ohshima(NAOJ), Yoshitaka Mikami(NAOJ), Michitoshi Yoshida(Hiroshima Univ.), Norio Okada(NAOJ), Hisashi Koyano(NAOJ), Kazuhiro Sekiguchi(NAOJ), Liyong Liu(NAOC)

The high plateaus in west Tibet may provide suitable sites for astronomical observations with institute's middle-range telescopes and possibly with larger telescopes. Under China-Japan collaborations on site survey in west Tibet, we have been conducted to search for good sites and have monitored their astronomical observation characteristics for several years at Karasu (Xinjiang Uighur), Oma(Tibet) and currently at Gar/Ali(Tibet). Recent results of our site survey show sites in west Tibet are revealed with high possibility of good astronomical observations. We present the characteristics on weather conditions at Gar/Ali, compared to previous monitored data at Oma, and show its suitable high clear-sky ratios at Gar/Ali.