Water vapour profiles by ground-based FTIR spectroscopy: study for an optimised retrieval and its validation
Water vapour profiles by ground-based FTIR spectroscopy: study for an optimised retrieval and its validation
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地面 FTIR 光谱的水蒸气剖面：优化检索及其验证的研究
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
T. Blumenstock
中科院分区：
文献类型：
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作者：
M. Schneider;F. Hase;T. Blumenstock
地面仪器对对流层水汽含量的红外测量灵敏度一般仅限于对流层中下部。较大的垂直梯度和变率使得对流层上层/平流层下部(UT/LS)的灵敏度较高。在这项工作中，提出了一种优化的检索方法，并证明了与通常应用的方法相比，它提高了FTIR技术的性能。讨论了改进的原因以及该方法可能存在的不足。只有应用本文提出的方法，并利用山地观测站进行的测量，才能以自洽的方式探测UT/LS中的水汽变化。以噪声信号比表示的精度估计为45%。在对流层中下层，精度可达22%。通过将基于实际FTIR测量的反演结果与同步光学气象探空仪的一致测量结果进行比较，证实了这些估计。
The sensitivity of ground-based instruments mea- suring in the infrared with respect to tropospheric water vapour content is generally limited to the lower and mid- dle troposphere. The large vertical gradients and variabili- ties avoid a better sensitivity for the upper troposphere/lower stratosphere (UT/LS) region. In this work an optimised re- trieval is presented and it is demonstrated that compared to a commonly applied method, it improves the performance of the FTIR technique. The reasons for this improvement and the possible deficiencies of the method are discussed. Only by applying the method proposed here and using measure- ments performed at mountain observatories can water vapour variabilities in the UT/LS be detected in a self-consistent manner. The precision, expressed as noise to signal ratio, is estimated at 45%. In the middle and lower troposphere, precisions of 22% are achieved. These estimations are con- firmed by a comparison of retrieval results based on real FTIR measurements with coinciding measurements of syn- optical meteorological radiosondes.