中高层OH自由基在紫外波段的临边散射辐射正演模拟与敏感性分析（英文）

Forward Model and Sensitivity Analysis for Limb-Scattered Radiation of Mesospheric OH Radicals Emission in Ultraviolet Band

OH自由基是中高层大气中重要的氧化剂,决定着臭氧以及其他温室气体的浓度变化,甚至气候变化。为了实现中高层大气OH自由基的精细探测与精确反演,需要构造正演模型,模拟得到仪器接收到的大气中的A2Σ+-X2Π(0,0)309nm波段的太阳共振荧光发射信号。本文基于分子光谱能级跃迁理论计算得到OH(0,0)振动能级上的荧光发射率因子g,结合辐射传输模型SCIATRAN模拟出的太阳辐照度和观测视线路径上的OH柱量,模拟出OH荧光发射光谱,叠加上大气背景光谱并卷积仪器函数,最终模拟得到仪器接收的包含OH浓度信息的光谱。模拟结果与国外在轨仪器MAHRSI(Middle Atmosphere High-Resolution Spectrograph Investigation),SHIMMER(Spatial Heterodyne Imager for Mesospheric Radicals)的在轨实测结果一致性较好。还分析了影响模拟结果的因素,在之后的正演过程中加以修正,使正演模型更接近实际辐射传输过程。

Hydroxyl,one of the principal oxidants in the atmosphere,determines the density of ozone and other greenhouse gases even the change of climate.In order to achieve high resolution vertical profiles of OH radical in mesosphere,an accurateforward model should be built up for its retrieval.In this paper,this forward model simulates limb-scattered signal including OH solar resonance fluorescence around 309 nm.We calculate OH band rotationalemission rate factor g based on molecular spectroscopy theory,and combine it with OH slant column calculated by SCIATRAN to synthesize OH fluorescence emission spectra.By superimposing atmospheric background signal and do a convolution with instrument line shape function,we could obtaina simulated spectra containing OH concentration information.These results are ingood agreement with previous measurements by MAHRSI(Middle Atmosphere High-Resolution Spectrograph Investigation)and SHIMMER(Spatial Heterodyne Imager forMesospheric Radicals).Then we analyze several factors that may influence the forward model.By modifying these parameters,forward model could be more accurateand closer to the actual radiative transfer process in the future.