Empirically derived parameterizations of the direct aerosol radiative effect based on ORACLES aircraft observations
Empirically derived parameterizations of the direct aerosol radiative effect based on ORACLES aircraft observations
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基于 ORACLES 飞机观测的直接气溶胶辐射效应的经验参数化
DOI：
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发表时间：
2020
影响因子：
3.8
通讯作者：
S. Doherty
中科院分区：
文献类型：
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作者：
S. Cochrane;K. S. Schmidt;Hong Chen;P. Pilewskie;S. Kittelman;J. Redemann;S. LeBlanc;K. Pistone;M. Kacenelenbogen;Michal Segal Rozenhaimer;Y. Shinozuka;C. Flynn;Amie N. Dobracki;P. Zuidema;S. Howell;S. Freitag;S. Doherty
抽象。在本文中，我们使用来自NASA ORACLES的观测数据，
气溶胶上方云及其干扰的观测
通过两个参数化制定一个框架的运动，
建立气溶胶-云之间的区域代表性关系
特性及其辐射效应。这些关系依赖于新的
单次散射散射谱反演气溶胶特性
不对称参数（ASY）。回收物捕捉到了
作为采样的研究区域的变异性，两者都被认为是相当
窄约束（SSA：0.83 ± 0.03，在中可见光，532 nm;
ASY：0.54 ± 0.06（532 nm）。光谱反演非常适合
用于计算直接气溶胶辐射效应（DARE），因为SSA和ASY直接与气溶胶存在时测量的辐照度相关-光谱DARE的输入之一。该框架允许将整个活动概括为一组
参数化对于太阳天顶角的范围，它将
通过第一个参数化：P（AOD，α），将宽带DARE转换为中可见光气溶胶光学厚度（AOD）和下垫面（云或晴空）的气溶胶光学厚度（α）。对于ORACLE，
宽带DARE的大多数情况与情况之间的可变性是
归因于对P（AOD，
α）。第二种扩展的参数化PX（AOD，α，SSA）
通过引入
中可见SSA作为第三个参数。这些参数化建立了从两个或三个中可见光（窄带）参数到宽带DARE的直接联系，隐含地说明了基础的
其驱动程序的光谱依赖性。他们绕过了一些
在从卫星产品或在建模环境中计算DARE时的假设。例如，DARE依赖于气溶胶微物理
属性在P或PX中不是显式的，因为不对称参数变化
从一个案例到另一个案例的差异太小，无法转化为可感知的DARE变化。
虽然这些特定的DARE参数化仅代表ORACLES
数据，他们提出的前景推广的框架，以其他
地区
Abstract. In this paper, we use observations from the NASA ORACLES
(ObseRvations of CLouds above Aerosols and their intEractionS) aircraft
campaign to develop a framework by way of two parameterizations that
establishes regionally representative relationships between aerosol-cloud
properties and their radiative effects. These relationships rely on new
spectral aerosol property retrievals of the single scattering albedo (SSA)
and asymmetry parameter (ASY). The retrievals capture the natural
variability of the study region as sampled, and both were found to be fairly
narrowly constrained (SSA: 0.83 ± 0.03 in the mid-visible, 532 nm;
ASY: 0.54 ± 0.06 at 532 nm). The spectral retrievals are well suited
for calculating the direct aerosol radiative effect (DARE) since SSA and ASY are tied directly to the irradiance measured in the presence of aerosols – one of the inputs to the spectral DARE. The framework allows for entire campaigns to be generalized into a set of
parameterizations. For a range of solar zenith angles, it links the
broadband DARE to the mid-visible aerosol optical depth (AOD) and the albedo (α) of the underlying scene (either clouds or clear sky) by way of the first parameterization: P(AOD, α). For ORACLES, the
majority of the case-to-case variability of the broadband DARE is
attributable to the dependence on the two driving parameters of P(AOD,
α). A second, extended, parameterization PX(AOD, α, SSA)
explains even more of the case-to-case variability by introducing the
mid-visible SSA as a third parameter. These parameterizations establish a direct link from two or three mid-visible (narrowband) parameters to the broadband DARE, implicitly accounting for the underlying
spectral dependencies of its drivers. They circumvent some of the
assumptions when calculating DARE from satellite products or in a modeling context. For example, the DARE dependence on aerosol microphysical
properties is not explicit in P or PX because the asymmetry parameter varies
too little from case to case to translate into appreciable DARE variability.
While these particular DARE parameterizations only represent the ORACLES
data, they raise the prospect of generalizing the framework to other
regions.
使用光声光谱评估基于过滤器的气溶胶吸收测量的偏差
DOI：
10.5194/amt-2018-411
发表时间：
2019
期刊：
--
影响因子：
--
作者：
Davies N
通讯作者：
Davies N