Case Studies of the Vertical Structure of the Direct Shortwave Aerosol Radiative Forcing During TARFOX
Case Studies of the Vertical Structure of the Direct Shortwave Aerosol Radiative Forcing During TARFOX
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TARFOX期间直接短波气溶胶辐射强迫垂直结构的实例研究
DOI：
10.1029/1999jd901042
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发表时间：
2000
影响因子：
--
通讯作者：
P. Russell
中科院分区：
文献类型：
--
作者：
J. Redemann;R. Turco;K. Liou;P. Hobbs;W. S. Hartley;R. Bergstrom;E. Browell;P. Russell
气溶胶引起的地球对流层辐射通量变化的垂直结构影响局部加热率，从而影响对流过程、云的形成和寿命，并因此影响化学成分的分布。我们目前的直接短波气溶胶辐射强迫的垂直结构的观测为基础的估计两个案例研究的对流层气溶胶辐射强迫观测实验（TARFOX）发生在美国东海岸在1996年7月。气溶胶辐射强迫的计算采用了Fu-Liou宽带辐射传输模式。辐射传输模拟中使用的气溶胶光学特性是通过使用在华盛顿大学研究飞机上测量的原位粒度分布剖面，根据两到三个不同垂直层中复杂气溶胶折射率的独立垂直分辨估计来计算的。由此确定的450 nm处气溶胶单次散射反照率范围为0.9至0.985，而不对称因子范围为0.6至0.8。根据气溶胶的光学特性得出的瞬时短波气溶胶辐射强迫在大气顶部约为−36 W m−2，在地表约为−56 W m−2。
The vertical structure of aerosol-induced radiative flux changes in the Earth's troposphere affects local heating rates and thereby convective processes, the formation and lifetime of clouds, and hence the distribution of chemical constituents. We present observationally based estimates of the vertical structure of direct shortwave aerosol radiative forcing for two case studies from the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX) which took place on the U.S. east coast in July 1996. The aerosol radiative forcings are computed using the Fu-Liou broadband radiative transfer model. The aerosol optical properties used in the radiative transfer simulations are calculated from independent vertically resolved estimates of the complex aerosol indices of refraction in two to three distinct vertical layers, using profiles of in situ particle size distributions measured aboard the University of Washington research aircraft. Aerosol single-scattering albedos at 450 nm thus determined range from 0.9 to 0.985, while the asymmetry factor varies from 0.6 to 0.8. The instantaneous shortwave aerosol radiative forcings derived from the optical properties of the aerosols are of the order of −36 W m−2 at the top of the atmosphere and about −56 W m−2 at the surface for both case studies.