Thirty samples of total suspended particles were collected at a site in western part of Lhasa,Tibet from August 2006 to July 2007.The 10Be concentrations were determined by Accelerator Mass Spectrometer (AMS).Analysis of correlation between 10Be concentrations and meteorological factors revealed that the wet scavenging has little effect on 10Be.10Be can be used as a proxy of transport processes of the upper atmosphere over the Tibetan Plateau.Analysis of correlation between 10Be concentrations and NCEP reanalysis data demonstrated that higher 10Be concentrations in spring were probably caused by the atmosphere exchange from stratosphere to troposphere during February to June.Lower 10Be concentrations during August to September were consistent with the synchronous lower O3 values,suggestive of both 10Be and O3 were probably influenced by the atmosphere exchange from troposphere to stratosphere.
High topographies, such as the Tibetan plateau （TP） in China, have been considered as the sensitive areas in response to global climate change. By analyzing the relationship between warming structure and altitude （1 000-5 000 m） in the TP and its vicinities using the 46-year January mean observed temperature data, we found that there was a significant altitude effect of temperature warming onset time （mutation time） on the plateau and the neighboring regions： the higher the altitude, the later the climate warming happens, and vice versa. There also seems a slight altitude effect on warming magnitude： the higher the altitude, the less the warming magnitude. Therefore, the temperature warming in the high altitude area of the TP （below 5 000 m） responds to global warming less sensitively than the low-altitude neighboring areas both in onset time and magnitude, which may be mainly caused by high albedo and large thermal capacity of the ice/snow cover on the higher part of the plateau and possible heat island effect in the lower part of the plateau.
The work presents microparticle concentrations in snowpits from the East Rongbuk Glacier on Mt. Qomolangma (Everest) (ER) (28.02°N, 86.96°E, 6536 m a.s.l.), the Zhadang Glacier on Mt. Nyainqentanglha (NQ) (30.47°N, 90.65°E, 5800m a.s.l.), and the Guoqu Glacier on Mt. Geladaindong (GL) (33.95°N, 91.28°E, 5823m a.s.l.) over the Tibetan Plateau (TP). Variations of microparticle and major ions (e.g. Mg2+, Ca2+) concentrations in snowpits show that the values of the microparticles and ions in the non-monsoon seasons are much higher than those in the monsoon seasons. Annual flux of microparticle deposition at ER is lower than those at NQ and GL, which could be attributed to the long distance away from the possible dust source regions as well as the elevation for ER higher than the others. Compared with other remote areas, microparticle concentrations in the southern TP are much lower than those in the northern TP, but still much higher than those in Greenland and Antarctica. The seasonal and spatial microparticle variations are clearly related to the variations of atmospheric circulation according to the air mass 5-day backward trajectory analyses of HYSPLIT Model. Resultingly, the high microparticle values in snow are mainly attributed to the westerlies and the strong dust storm outbreaks on the TP, while the monsoon circulation brings great amount of precipitation from the Indian Ocean, thus reducing in the aerosol concentrations.
