中国北方地区春季气溶胶光学特性地基遥感研究

基于中国北方地区地基太阳直接/散射辐射计观测,分析了2001年春季气溶胶光学厚度、尺度和吸收特性。沙尘期间,气溶胶光学厚度显著升高,而尺度上升,粗粒子浓度显著增加,大气气溶胶表现出中性或异常消光特征。除沙尘活动之外,中国华北地区人为排放也是导致气溶胶光学厚度偏高的一个重要原因。中国沙尘源区气溶胶单次散射反照率小于以往观测和模式结果。北京和香河两地气溶胶光学厚度、Angstrom指数和尺度谱基本相似,说明华北地区人为排放与沙尘活动类似,也表现出区域尺度的特点。由于沙尘气溶胶与人为排放气溶胶相比,折射指数实部偏大、虚部偏小,从而北京地区沙尘期间单次散射反照率明显大于非沙尘期间,特别是在近红外波段,说明沙尘活动不仅可以通过增加气溶胶光学厚度,同时也通过改变气溶胶物理、辐射特性来影响下游地区的气溶胶辐射强迫。

Ground-based Remote Sensing of Aerosol Optical Properties over North China in Spring

Aerosol properties including optical depth, size distribution, absorption, etc were studied based on ground-based sun/sky radiometer measurements in the spring of 2001 over North China. Rapid increase of aerosol optical depth and coarse particle concentration, as well as aerosol neutral or anomalous extinction was observed during dusty periods. Anthropogenic emissions also contributed to high aerosol optical depth except dust input over Huabei Plain. The results showed that dust single-scattering albedo was less than those used in the model. Aerosol optical depth and Angstrom parameter in BJ and XH showed close relation, which indicated the regional anthropogenic influence on atmospheric environment. Dust activities might affect aerosol radiative forcing over the downwind regions through input of large volume of dust aerosols, and also through their effects on aerosol physical and radiative properties.