<正>The North Tibet Plateau is the main part of the Qinghai-Tibet Plateau(also known as "the roof of the world").Compared with other areas nearby,the North Tibet Plateau is higher,colder and larger.It has an average elevation of over 5000 meters, a temperature that frequently drops to minus 30 or even minus 40 Degrees Celsius...and a land area of 700,000 square kilometers covering almost all of Nagqu Prefecture,some of Ngari Prefecture in Tibet and part of Qinghai Province.