Observation of strato-mesospheric CO above Kiruna with ground-based microwave radiometry – retrieval and satellite comparison
Observation of strato-mesospheric CO above Kiruna with ground-based microwave radiometry – retrieval and satellite comparison
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DOI：
10.5194/amt-4-2389-2011
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发表时间：
2011-11
影响因子：
3.8
通讯作者：
C. Hoffmann;U. Raffalski;M. Palm;B. Funke;S. Golchert;G. Hochschild;J. Notholt
中科院分区：
文献类型：
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作者：
C. Hoffmann;U. Raffalski;M. Palm;B. Funke;S. Golchert;G. Hochschild;J. Notholt
抽象的。 CO 是极地冬季中层大气动态的示踪剂。这项工作介绍了位于瑞典北部（北纬 67.8°，东经 20.4°）的基律纳微波辐射计 KIMRA 对 2008/2009 年和 2009/2010 年冬季地面 CO 测量值的检索和表征。此外，该数据集还用于与 Aura 上的最新卫星仪器 MLS、ACE-FTS 和 Envisat 上的 MIPAS 进行广泛比较。使用最佳估计方法检索 vmr 配置文件。对平均核函数进行了详细分析，显示了 40 至 80 km 高度之间测量的灵敏度、16 至 22 km 的垂直分辨率以及高达 130 km 高度区域的残余影响。误差评估揭示了检索到的剖面的总误差，该误差随着海拔高度的增加而增加，约为50 公里高度时为 ±0.1 ppmv，80 公里高度时为 ±3 ppmv。造成总误差的主要因素是测量噪声和所用温度曲线的不确定性。在检索的时间序列中定性地识别了极地冬季中层大气的预期动力学特征，但这里没有进行定量分析。使用密集的 MLS 数据集来研究搭配标准对卫星比较的影响，结果表明放宽距离标准会导致 MLS 出现较高偏差。由于巧合的数量很少，因此很难对其他仪器进行比较。然而，这表明 KIMRA 与 65 km 高度以下的卫星仪器之间存在总体一致性，但在该高度以上 KIMRA 存在较高偏差。此外，KIMRA 剖面的形状似乎与卫星剖面有系统的不同。
Abstract. CO serves as a tracer for dynamics in the polar winter middle atmosphere. This work presents the retrieval and the characterization of ground-based CO measurements from the winters 2008/2009 and 2009/2010 by the Kiruna microwave radiometer KIMRA, located in northern Sweden (67.8° N, 20.4° E). Furthermore, the dataset is used for an extensive comparison to the recent satellite instruments MLS on Aura, ACE-FTS, and MIPAS on Envisat. The vmr profiles are retrieved using the optimal estimation approach. A detailed analysis of the averaging kernel functions is carried out, showing sensitivity of the measurements between 40 and 80 km altitude, a vertical resolution of 16 to 22 km, as well as a residual influence of the region up to 130 km altitude. An error assessment reveals a total error of the retrieved profile that increases with altitude and is approx. ±0.1 ppmv at 50 km altitude and ±3 ppmv at 80 km altitude. The main contributions to this total error arise from the measurement noise and the uncertainty of the used temperature profiles. The expected dynamical features of the polar winter middle atmosphere are qualitatively identified in the retrieved time series, but are not quantitatively analyzed here. The dense MLS dataset is used to investigate the influence of the collocation criteria on the satellite comparison, showing that relaxing the distance criterion causes a high bias for MLS. The comparison including the other instruments is difficult because of the small number of coincidences. However, it suggests that there is a general agreement between KIMRA and the satellite instruments below 65 km altitude, but a high bias for KIMRA above this altitude. Furthermore, the shape of the KIMRA profile appears to be systematically different from the satellite profiles.