Toward a consistent reanalysis of the upper stratosphere based on radiance measurements from SSU and AMSU‐A
Toward a consistent reanalysis of the upper stratosphere based on radiance measurements from SSU and AMSU‐A
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基于 SSU 和 AMSU-A 的辐射测量对平流层上层进行一致的重新分析
DOI：
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发表时间：
2009
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通讯作者：
S. Uppala
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作者：
Shinya Kobayashi;M. Matricardi;D. Dee;S. Uppala
平流层探测装置（SSU）和高级微波探测装置（AMSU-A）的辐射测量是卫星时代再分析平流层温度的主要信息来源。为了提高再分析的时间一致性，需要在同化系统中正确理解和考虑辐射偏差。对SSU和AMSU-A辐射观测之间的星间差异的研究表明，这些差异不能被TIROS操作垂直探测器（RTTOV-8）的辐射传输模型的操作版本准确地再现。我们发现，在RTTOV的这种不足主要是由于塞曼效应（分裂的氧吸收线在60 GHz）的治疗和SSU仪器的光谱响应函数的变化，不表示在RTTOV。在此基础上，我们提出了一个修正版本的RTTOV，可以更准确地再现SSU和AMSU-A星间辐射差异。
Radiance measurements from the Stratospheric Sounding Unit (SSU) and the Advanced Microwave Sounding Unit (AMSU‐A) are the primary source of information for stratospheric temperature in reanalyses of the satellite era. To improve the time consistency of the reanalyses, radiance biases need to be properly understood and accounted for in the assimilation system. The investigation of intersatellite differences between SSU and AMSU‐A radiance observations shows that these differences are not accurately reproduced by the operational version of the radiative transfer model for the TIROS Operational Vertical Sounder (RTTOV‐8). We found that this deficiency in RTTOV was mainly due to the treatment of the Zeeman effect (splitting of the oxygen absorption lines at 60 GHz) and to changes in the spectral response function of the SSU instrument that are not represented in RTTOV. On this basis we present a revised version of RTTOV that can reproduce SSU and AMSU‐A intersatellite radiance differences more accurately.