中国南方典型地区油-稻轮作条件下大气SO2干沉降速率动态变化

以1998年11月～1999年10月中国科学院红壤生态试验站农田小气候观测站气象梯度资料(温度、风速、气压),计算近地面湍流特征参数(u^*、θ^*、L),然后采样阻力模式计算SO₂干沉降速率(V_d),研究了该地油-稻轮作条件下大气SO₂干沉降V_d动态变化。结果表明,一年中大气SO₂于沉降V_d时平均年均值0.124～0.897cm·s^-1(mean±SE=0.507±0.167cm·s^-1).一年中大气SO₂干沉降V_d存在如下规律性:白天>晚上。3～8月份SO₂V_d平均值(0.611cm·s^-1大于9～12、1～2月份SO₂V_d平均值(0.401cm·s^-1)。水稻生长期间(0.605±0.093cm·s^-1)>油菜(0.491±0.166cm·s^-1)>休闲(0.342±0.174cm·s^-1)。

Dynamics of dry deposition velocities (Vd) of atmospheric SO2 on rapeseed/rice rotation systems in selected area of South China

With the profile meteorological data collected from the farmland micro-meteorological experimental substation, Experiment Station of Red Earth Ecology, Yingtan, Jiangxi, Chinese Academy of Sciences during rapeseed/rice rotation from Nov.1998 to Oct.1999, the surface layer turbulence characteristic parameters (u^*,θ^*,L) and the atmospheric SO₂ dry deposition velocities (V_d) were calculated.The results indicated that the hourly mean V_d of SO₂ dry deposition was ranged from 0.124 to 0.897 cm·s^-1 (mean±SE = 0.507±0.167 cm·s^-1), and its regular dynamic pattern was as follows: it was always higher at daytime than at night, and the mean V_d of SO₂ dry deposition during March-August(0.611 cm·s^-1) was obviously greater than that during Sept.- Dec.and Jan.-Feb.(0.401 cm·s^-1).The mean V_d of SO₂ dry deposition during various crop growth stages was decreased as the order of rice (0.605±0.093 cm·s^-1) > rapeseed (0.491±0.166 cm·s^-1) > follow (0.342±0.174 cm·s^-1).