Papastefanou C, Ioannidou A, Stoulos S, Manolopoulou M
Department of Nuclear Physics, Aristotle University of Thessaloniki, Greece.
Sci Total Environ. 1995 Aug 18;170(1-2):151-6. doi: 10.1016/0048-9697(95)04608-4.
Atmospheric (tropospheric) depositional fluxes of the naturally occurring 7Be of cosmogenic origin and 137Cs from fallout of the Chernobyl accident were measured over a 7-year period (January 1987-December 1993) at Thessaloniki, Greece (40 degrees 38' N, 22 degrees 58' E). The annual total deposition fluxes of 7Be varied between 854 Bq/m2 (1987) and 1242 Bq/m2 (1992), showing a minimum in the years 1988-89. The annual total deposition fluxes of 137Cs varied between 183 Bq/m2 (1987) and 16.4 Bq/m2 (1992), showing a significant decrease as expected for natural removal and radioactive decay and no new releases from nuclear facilities or weapons testing. The annual average total deposition velocity for 7Be was from 0.3 cm/s (1988) up to 0.8 cm/s (1991), while for 137Cs the corresponding values were much higher, hence 137Cs was associated with larger atmospheric particles. High 7Be concentrations in air were related to the very little solar activity (1987-88 and 1993-94), while low 7Be concentrations in air related to the high solar activity (1989-91). Maximum 137Cs concentrations in air were registered during the spring 1991 and 1992, reflecting some stratospheric inputs. An unusual highly elevated value of 137Cs concentration in air, reaching 0.25 mBq/m3, was observed during the summer 1990.
在1987年1月至1993年12月的7年期间，于希腊塞萨洛尼基（北纬40度38分，东经22度58分）测量了宇宙成因的天然7Be以及切尔诺贝利事故沉降物中的137Cs的大气（对流层）沉积通量。7Be的年总沉积通量在854 Bq/m²（1987年）至1242 Bq/m²（1992年）之间变化，在1988 - 1989年出现最小值。137Cs的年总沉积通量在183 Bq/m²（1987年）至16.4 Bq/m²（1992年）之间变化，如预期的自然去除和放射性衰变那样显著下降，且没有来自核设施或武器试验的新释放。7Be的年平均总沉积速度从0.3 cm/s（1988年）到0.8 cm/s（1991年），而137Cs的相应值要高得多，因此137Cs与更大的大气颗粒相关。空气中7Be的高浓度与极少的太阳活动（1987 - 1988年和1993 - 1994年）有关，而空气中7Be的低浓度与高太阳活动（1989 - 1991年）有关。空气中137Cs的最高浓度在1991年和1992年春季记录到，反映了一些平流层输入。在1990年夏季观察到空气中137Cs浓度出现异常高值，达到0.25 mBq/m³。
