Solar Radiation Measurements on HALO

将在HALO上开发用于太阳辐射光谱测量的新仪器，并在两个示范任务（OMO、ML-CIRRUS）中应用。目标量是(i)确定大气太阳辐射收支的光谱辐照度和（ii）通过光解过程控制大气光化学的光谱光化通量密度。为了遥感目的，将同时测量最低点方向的太阳光谱辐射。在辐照度测量中，准确区分飞机顶部和下方余弦接收器上的上涌和下涌通量密度是非常重要的。因此，计划采用稳定平台来跟踪飞机的运动，并在足够的时间响应下纠正接收机的位置。对于光化通量密度，主要的挑战是在UV-B范围内建立高时间分辨率和高精度的测量，通过使用光谱单色器和检测器的适当组合。除了其他过程外，这对量化臭氧光解作用至关重要。仪器的设置、测试和操作将由本提案中要求的两名博士生完成。这些测量将提供(i)光谱云辐射强迫和（ii）光解频率，这是两个示范任务ML-CIRRUS和OMO以及应用期内可能的其他任务的基本目标。

New instruments for spectral measurements of solar radiation on HALO will be developed and applied in two demonstration missions (OMO, ML-CIRRUS). The target quantities are (i) spectral irradiance which determines the solar radiation budget of the atmosphere, and (ii) spectral actinic flux density which controls atmospheric photochemistry through photo-dissociation processes. Solar spectral radiance from the nadir direction will be measured simultaneously for remote sensing purposes. For the irradiance measurements it is of great importance to accurately distinguish between up-welling and down-welling flux density incident on cosine receivers on top and underneath the airplane. It is therefore planned to apply stabilizing platforms which track the movements of the airplane and correct the position of the receivers with sufficient time response. For the actinic flux density the main challenge is to establish measurements with both high time resolution and high accuracy in the UV-B range by using suitable combinations of spectral monochromators and detectors. This is crucial to quantify ozone photolysis besides other processes. Setup, tests and operations of the instruments will be made by two PhD students requested within this proposal. The measurements will provide (i) spectral cloud radiative forcings and (ii) photolysis frequencies which are essential objectives of the two demonstration missions ML-CIRRUS and OMO and possibly further missions within the application period.