Deposition of beryllium-7 in Hsinchu, Taiwan

作者：Chao J H^*; Chiu Y J; Lee H P; Lee M C

来源：Applied Radiation and Isotopes, 2012, 70(2): 415-422.

DOI：10.1016/j.apradiso.2011.10.009

• Beryllium-7
• Solar activity
• Cosmogenic radionuclides
• Rainfall
• Radioactivity measurement

In the present study, factors that influence the distribution and variation of Be-7 in Hsinchu, Taiwan were elucidated. The Be-7 activity including the deposition flux and air concentration was continuously monitored and recorded throughout a 15-year period (1996-2010). To explain the observed variability in the Be-7 activity over time, air concentration and deposition flux of Be-7 were correlated to rainfall and solar activity. The monthly average deposition flux and air concentration of Be-7 were inversely related to solar activity with the 11-year cycle and were not strongly correlated to rainfall. The highest seasonal deposition flux of Be-7 occurred in March, which is commonly referred to as the spring maximum, due to air-mass mixing processes in the troposphere. The air concentration of Be-7 was seasonally variable and was significantly affected by monsoons. The lowest deposition flux and air concentration of Be-7 were observed in July and August due to the occurrence of southwest monsoons from low latitudes, which carry air masses with low concentrations of Be-7. The deposition flux was enhanced by precipitation. which increased the deposition velocity, transferring more Be-7 from the troposphere to the ground. The fraction of dry to total deposition varied seasonally and was equal to 9.86%, on average.

• 出版日期2012-2
• 单位清华大学