van Diedenhoven Bastiaan, Fridlind Ann M, Cairns Brian, Ackerman Andrew S, Yorks John E
Center for Climate System Research, Columbia University, New York, New York, USA.
NASA Goddard Institute for Space Studies, New York, New York, USA.
Geophys Res Lett. 2016 May 16;43(9):4586-4593. doi: 10.1002/2016GL068548. Epub 2016 Mar 27.
A novel technique is used to estimate derivatives of ice effective radius with respect to height near convective cloud tops ( /) from airborne shortwave reflectance measurements and lidar. Values of / are about -6 m/km for cloud tops below the homogeneous freezing level, increasing to near 0 m/km above the estimated level of neutral buoyancy. Retrieved / compares well with previously documented remote sensing and in situ estimates. Effective radii decrease with increasing cloud top height, while cloud top extinction increases. This is consistent with weaker size sorting in high, dense cloud tops above the level of neutral buoyancy where fewer large particles are present, and with stronger size sorting in lower cloud tops that are less dense. The results also confirm that cloud-top trends of effective radius can generally be used as surrogates for trends with height within convective cloud tops. These results provide valuable observational targets for model evaluation.
一种新的技术被用于根据机载短波反射率测量和激光雷达来估计对流云顶附近冰有效半径相对于高度的导数（/）。对于低于均匀冻结层的云顶，/的值约为-6米/千米，在估计的中性浮力层以上增加到接近0米/千米。反演得到的/与先前记录的遥感和现场估计结果吻合良好。有效半径随着云顶高度的增加而减小，而云顶消光增加。这与中性浮力层以上高密度云顶中较弱的粒径分选一致，那里存在的大粒子较少，也与较低密度的低云顶中较强的粒径分选一致。结果还证实，有效半径的云顶趋势通常可以用作对流云顶内高度趋势的替代指标。这些结果为模型评估提供了有价值的观测目标。
