Intercomparison of the POES/MEPED Loss Cone Electron Fluxes With the CMIP6 Parametrization
Intercomparison of the POES/MEPED Loss Cone Electron Fluxes With the CMIP6 Parametrization
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DOI：
10.1029/2018ja025745
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发表时间：
2019-01
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影响因子：
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通讯作者：
H. Tyssøy;A. Haderlein;M. Sandanger;J. Stadsnes
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作者：
H. Tyssøy;A. Haderlein;M. Sandanger;J. Stadsnes
中能电子（>40 keV）沉降的定量测量是了解粒子沉降对大气总体影响的关键。NOAA/极地轨道环境卫星上的中能质子和电子探测器仪器有两套电子望远镜，分别指向与当地垂直线成~0°和~90°的方向。俯仰角各向异性随粒子能量、位置和地磁活动而变化，使得0°探测器测量对沉淀电子通量的估计较低。在为耦合模式相互比较项目（CMIP）6（v3.2）推荐的太阳强迫中，基于0°探测器测量的Ap对降水进行了参数化，因此提供了通量水平的一般低估。为了评估Ap模型的准确性，我们将模拟的电子通量与使用两种探测器的损失锥通量的估计值进行比较，并结合来自波粒相互作用理论的电子俯仰角分布。Ap模型在再现与强磁暴（Ap > 40）相关的通量水平和变率以及导致太阳周期内系统性偏差的共转相互作用区风暴的持续时间方面存在缺陷，福尔斯。当Ap参数化的通量达到Ap > 40的平台时，模型反映与通常较高的Ap值相关的先前太阳活动周期的通量水平的能力受到质疑。这种比较的目的是了解高能粒子降水应用CMIP 6粒子能量输入的潜在不确定性，以评估其对大气的后续影响。
Quantitative measurements of medium energy electron (MEE) precipitation (>40 keV) are a key to understand the total effect of particle precipitation on the atmosphere. The Medium Energy Proton and Electron Detector (MEPED) instrument on board the NOAA/Polar Orbiting Environmental Satellites (POES) has two sets of electron telescopes pointing ~0° and ~90° to the local vertical. Pitch angle anisotropy, which varies with particle energy, location, and geomagnetic activity, makes the 0° detector measurements a lower estimate of the flux of precipitating electrons. In the solar forcing recommended for Coupled Model Intercomparison Project (CMIP) 6 (v3.2) MEE precipitation is parameterized by Ap based on 0° detector measurements hence providing a general underestimate of the flux level. In order to assess the accuracy of the Ap model, we compare the modeled electron fluxes with estimates of the loss cone fluxes using both detectors in combination with electron pitch angle distributions from theory of wave‐particle interactions. The Ap model falls short in respect to reproducing the flux level and variability associated with strong geomagnetic storms (Ap > 40) as well as the duration of corotating interaction region storms causing a systematic bias within a solar cycle. As the Ap‐parameterized fluxes reach a plateau for Ap > 40, the model's ability to reflect the flux level of previous solar cycles associated with generally higher Ap values is questioned. The objective of this comparison is to understand the potential uncertainty in the energetic particle precipitation applying the CMIP6 particle energy input in order to assess its subsequent impact on the atmosphere.