Suomi‐NPP CrIS radiometric calibration uncertainty
Suomi‐NPP CrIS radiometric calibration uncertainty
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DOI：
10.1002/jgrd.50809
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发表时间：
2013-09
期刊：
影响因子：
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通讯作者：
D. Tobin;H. Revercomb;R. Knuteson;Joe K. Taylor;F. Best;L. Borg;D. DeSlover;G. Martin;H. Buijs
中科院分区：
文献类型：
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作者：
D. Tobin;H. Revercomb;R. Knuteson;Joe K. Taylor;F. Best;L. Borg;D. DeSlover;G. Martin;H. Buijs
跨轨红外探测器 (CrIS) 是 Suomi 国家极地轨道合作伙伴 (NPP) 卫星上的高光谱分辨率光谱辐射计，为天气和气候应用提供大气层顶部热红外辐射光谱的业务观测。本文描述了基于发射前和在轨工作的 CrIS 辐射校准不确定性，以估计校准参数不确定性，并提供了最近发射后验证工作的示例结果，以评估预测的不确定性。对于高于 250 K 的黑体场景温度，针对实验室测试环境计算的发射前辐射不确定性 (RU) 估计值小于 ~0.2 K 3 sigma，主要不确定性来自校准黑体温度、校准黑体反射辐射项和探测器非线性。长波带探测器和中波带探测器之间的预发射 RU 的变化是由于探测器非线性程度不同造成的。描述了一种在轨调整非线性校正参数的方法，以减少对 RU 的总体贡献并减少视场 (FOV) 到 FOV 的可变性。由此产生的地球视图光谱在轨 RU 估计值在中波和短波频段小于 0.2 K 3 sigma，在长波频段小于 0.3 K 3 sigma。评估 CrIS 辐射校准的发射后验证工作正在进行中；迄今为止的验证结果表明在轨 RU 估计具有代表性。 CrIS 辐射产品预计将于 2014 年初达到“验证”状态。
The Cross‐track Infrared Sounder (CrIS) is the high spectral resolution spectroradiometer on the Suomi National Polar‐Orbiting Partnership (NPP) satellite, providing operational observations of top‐of‐atmosphere thermal infrared radiance spectra for weather and climate applications. This paper describes the CrIS radiometric calibration uncertainty based on prelaunch and on‐orbit efforts to estimate calibration parameter uncertainties, and provides example results of recent postlaunch validation efforts to assess the predicted uncertainty. Prelaunch radiometric uncertainty (RU) estimates computed for the laboratory test environment are less than ~0.2 K 3 sigma for blackbody scene temperatures above 250 K, with primary uncertainty contributions from the calibration blackbody temperature, calibration blackbody reflected radiance terms, and detector nonlinearity. Variability of the prelaunch RU among the longwave band detectors and midwave band detectors is due to different levels of detector nonlinearity. A methodology for on‐orbit adjustment of nonlinearity correction parameters to reduce the overall contribution to RU and to reduce field of view (FOV)‐to‐FOV variability is described. The resulting on‐orbit RU estimates for Earth view spectra are less than 0.2 K 3 sigma in the midwave and shortwave bands, and less than 0.3 K 3 sigma in the longwave band. Postlaunch validation efforts to assess the radiometric calibration of CrIS are underway; validation results to date indicate that the on‐orbit RU estimates are representative. CrIS radiance products are expected to reach “Validated” status in early 2014.