Using IASI to simulate the total spectrum of outgoing long-wave radiances
Using IASI to simulate the total spectrum of outgoing long-wave radiances
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使用IASI模拟出射长波辐射的总光谱
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
S. Tett
中科院分区：
文献类型：
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作者：
E. Turner;Hai;S. Tett
抽象的。本文提出了一种新的方法，可以在整个地球出射长波光谱范围内，得到10181个波段的高分辨率大气顶光谱辐射率。MetOp-A（气象业务）卫星上的红外大气探测干涉仪（IASI）测量的不同通道与未观测到的波数之间的相关性用于估计25.25和644.75 cm-1（FIR）之间以及2760和3000 cm-1（NIR -近红外）之间0.5 cm-1间隔的远红外辐射。逐线辐射传输模型（LBLRTM）模拟的辐射被用来构建预测模型。通过将覆盖整个25.25-3000 cm−1范围的综合最低长波辐射率（INLR）产品与Terra和Aqua卫星上的云和地球辐射能量系统（CERES）仪器在同时最低点处的相应宽带测量值进行比较，对光谱进行了验证。平均差异为0.3 W m−2 sr−1（相对差异为0.5%）。这完全在任何一种仪器所作测量的不确定性范围内。然而，有一个明显的对比，当偏差被分为夜间和白天的场景，后者是显着更大，可能是由于在CERES Ed 3光谱响应函数（SRF）校正方法的错误。在没有隔离远红外区的运行中的星载仪器的情况下，该产品在其所依据的回归模型的限度内为这类测量提供了一个有用的替代物，该回归模型的均方根误差很低。新的高分辨率光谱是全球平均晴朗和所有的天空，FIR显示贡献44%和47%的总INLR，分别。在光谱云效应（云综合最低长波辐射度- CINLR）方面，FIR贡献了19%，在某些亚热带情况下似乎是负的;传统宽带分析无法观察到的结果。
Abstract. A new method of deriving high-resolution top-of-atmosphere spectral radiances in 10 181 bands, over the whole outgoing long-wave spectrum of the Earth, is presented. Correlations between different channels measured by the Infrared Atmospheric Sounding Interfermeter (IASI) on the MetOp-A (Meteorological Operation) satellite and unobserved wavenumbers are used to estimate far infrared (FIR) radiances at 0.5 cm−1 intervals between 25.25 and 644.75 cm−1 (the FIR), and additionally between 2760 and 3000 cm−1 (the NIR – near infrared). Radiances simulated by the line-by-line radiative transfer model (LBLRTM) are used to construct the prediction model. The spectrum is validated by comparing the Integrated Nadir Long-wave Radiance (INLR) product spanning the whole 25.25–3000 cm−1 range with the corresponding broadband measurements from the Clouds and the Earth's Radiant Energy System (CERES) instrument on the Terra and Aqua satellites at points of simultaneous nadir overpass. There is a mean difference of 0.3 W m−2 sr−1 (0.5% relative difference). This is well within the uncertainties associated with the measurements made by either instrument. However, there is a noticeable contrast when the bias is separated into night-time and daytime scenes with the latter being significantly larger, possibly due to errors in the CERES Ed3 Spectral Response Functions (SRF) correction method. In the absence of an operational spaceborne instrument that isolates the FIR, this product provides a useful proxy for such measurements within the limits of the regression model it is based on, which is shown to have very low root mean squared errors. The new high-resolution spectrum is presented for global mean clear and all skies where the FIR is shown to contribute 44 and 47% to the total INLR, respectively. In terms of the spectral cloud effect (Cloud Integrated Nadir Long-wave Radiance – CINLR), the FIR contributes 19% and in some subtropical instances appears to be negative; results that would go unobserved with a traditional broadband analysis.