Abstract
This experiment is the first ultraviolet radiance assimilation for atmospheric ozone in the troposphere and stratosphere. The experiment has provided better understanding of which observations need to be assimilated, what bias correction scheme may be optimal, and how to obtain surface reflectance. A key element is the extension of the Community Radiative Transfer Model (CRTM) to handle fully polarized radiances, which presents challenges in terms of computational resource requirements. In this study, a scalar (unpolarized) treatment of radiances was used. The surface reflectance plays an important role in assimilating the nadir mapper (NM) radiance of the Ozone Mapping and Profiler Suite (OMPS). Most OMPS NM measurements are affected by the surface reflection of solar radiation. We propose a linear spectral reflectance model that can be determined inline by fitting two OMPS NM channel radiances at 347.6 and 371.8 nm because the two channels have near zero sensitivity on atmospheric ozone. Assimilating a transformed reflectance measurement variable, the N value can overcome the difficulty in handling the large dynamic range of radiance and normalized radiance across the spectrum of the OMPS NM. It was found that the error in bias correction, surface reflectance, and neglecting polarization in radiative transfer calculations can be largely mitigated by using the two estimated surface reflectance. This study serves as a preliminary demonstration of direct ultraviolet radiance assimilation for total column ozone in the atmosphere.
Highlights
Atmospheric ozone plays a crucial role in the series of intricate feedback mechanisms that dynamically link the troposphere and the stratosphere
Measurements of the ozone distribution are an important component of a more realistic treatment of the stratosphere in operational weather forecasts. This is especially true in the vicinity of jet streams at the mid and high latitudes, which play a major role in the formation and steering of tropospheric weather systems, including largescale thunderstorm complexes and hurricanes
Satellite System in Section 2; the Ozone Mapping and Profiler Suite (OMPS) sensor data record is described in Section 3; Section 4 reviews the community radiative transfer model (CRTM), the core tool for radiance assimilation; Section 5 describes a very simple radiance assimilation scheme; the experimental results of the OMPS radiance assimilation for atmospheric ozone are given in Section 6; the last section leads to the summary and discussions
Summary
Atmospheric ozone plays a crucial role in the series of intricate feedback mechanisms that dynamically link the troposphere and the stratosphere It blocks most of the harmful ultraviolet solar radiation from reaching the Earth’s surface and impacts air quality near the surface. Measurements of the ozone distribution are an important component of a more realistic treatment of the stratosphere in operational weather forecasts This is especially true in the vicinity of jet streams at the mid and high latitudes, which play a major role in the formation and steering of tropospheric weather systems, including largescale thunderstorm complexes and hurricanes. Infrared hyperspectral radiances for measuring atmospheric ozone have been directly assimilated for weather forecasts. Sensors is only conducted in retrieval space because of the challenge of radiative transfer modelling and the lack of accurate knowledge about UV data quality control and bias correction for direct radiance assimilation. Satellite System in Section 2; the OMPS sensor data record (calibrated radiance) is described in Section 3; Section 4 reviews the community radiative transfer model (CRTM), the core tool for radiance assimilation; Section 5 describes a very simple radiance assimilation scheme; the experimental results of the OMPS radiance assimilation for atmospheric ozone are given in Section 6; the last section leads to the summary and discussions
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