气象模拟误差对异戊二烯排放估算的影响

利用MEGAN模式估算了珠三角地区2006年异戊二烯的排放情况,并设计了两组敏感性实验深入探讨了气象模拟误差对异戊二烯排放的影响.估算结果显示,2006年珠三角地区异戊二烯的排放量为95.56×106kg(以C计),且主要分布在珠三角地区周边植被覆盖较高的地方;受气象条件季节变化的影响,异戊二烯的排放表现出显著的季节和日变化特征,最大异戊二烯排放通量季节出现在夏季,为0.920t·km-2(以C计),最大排放速率均出现在13:00.敏感性实验结果显示,气象模拟误差能显著影响异戊二烯的排放,升高(降低)太阳辐射的输入,异戊二烯的排放量增加(减小)36.20%～50.70%(30.73%～41.88%),大于温度改变引起的排放量变化;升高(降低)气象输入并不会改变异戊二烯排放的日变化特征,但能显著影响排放速率的大小.上午8:00或下午17:00,异戊二烯排放速率的改变最为明显.

Impacts of errors in meteorological simulations on estimation of isoprene emission

The MEGAN model was used to quantify isoprene emission in the Pearl River Delta (PRD) region for 2006. Two sensitive experiments were conducted in order to investigate the impacts of uncertainties in simulated, meteorological, near-surface weather elements on modeled isoprene emission. The results showed that the annual isoprene emission was 95.56×106 kg C in the PRD in 2006. Due to variations of meteorological conditions, the isoprene emission displayed a remarkable seasonal and diurnal variation. The highest seasonal emission flux was in summer with a value of 0.920 t·km-2. Considering diurnal patterns, the highest emission rate was at 13:00 local time. The results of sensitive experiments revealed that errors in MM5-simulated meteorological elements significantly impacted isoprene emission while overestimated (underestimated) solar radiation could increase (decrease) the emission rate by 36.20%~50.70% (30.73%~41.88%), which was larger than changes caused by temperature. However, changes in meteorological inputs did not affect the diurnal pattern of isoprene emission, just the emission rate. The emission rate of isoprene changed mostly at 8:00 in the morning or at 17:00 in the afternoon.