weighting function for cirrus

So far cirrus cloud particle sizes are inferred by using satellite remote sensing. But cirrus clouds often stratify in the vertical direction. Cloud particle sizes decrease from cloud base to cloud top. If you assume homogeneous cirrus clouds whose cloud particle size is constant in the vertical direction, retrieved cloud particle sizes are underestimated due to the stratification. A retrieval method developed in this work using 1.38-micron solar reflected radiance infers vertical variation of cloud particle sizes. Averaged cloud particle sizes are not underestimated, i.e., more accurate.

迄今为止，卷云粒子尺度均通过卫星遥感手段反演得到。但卷云通常在垂直方向上呈现分层结构，云粒子尺度从云底至云顶逐渐减小。若假设卷云为均匀介质，即其粒子尺度在垂直方向上保持恒定，则由于垂直分层的存在，反演得到的云粒子尺度会被低估。本研究提出的反演方法利用1.38微米波段的太阳反射辐射率，能够反演云粒子尺度的垂直分布变化，该方法得到的平均云粒子尺度不会被低估，即反演结果精度更高。