H 2 O and δD profiles remotely-sensed from ground in different spectral infrared regions
H 2 O and δD profiles remotely-sensed from ground in different spectral infrared regions
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不同红外光谱区地面遥感的 H 2 O 和 δD 剖面
DOI：
10.5194/amt-3-1599-2010
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发表时间：
2010
影响因子：
3.8
通讯作者：
T. Leblanc
中科院分区：
文献类型：
--
作者：
M. Schneider;G. Toon;J. Blavier;F. Hase;T. Leblanc
抽象。我们在四个不同的光谱区域进行了地面FTIR（傅里叶变换红外）水汽分析：790-880，1090-1330，2650-3180和4560-4710 cm−1。所有四个区域都可以分别以约3、6和10公里的垂直分辨率检索对流层低、中、高层的水汽量。此外，在1090-1330和2650-3180 cm−1处的分析允许分别以3和10 km的垂直分辨率反演对流层下部和中/上部的δD值。一个理论和经验的误差评估-同步Vaisala RS 92无线电探空仪测量作为参考-表明，在高波数检索的H2O数据比在低波数检索的精确度略高。我们推断出H2O廓线的精度和准确度一般优于20%，除了在790-880 cm−1的低波数反演，其中对流层中/上部H2O的评估精度上限为35%。四种不同反演方法得到的H2O剖面的离散度一般在20%以下，偏差在10%以下，边界层除外，其偏差可达24%。这些值很好地证实了理论和经验误差评估，并且与大约一个数量级的巨大对流层H2O变化相比相当小，从而证明了不同H2O剖面反演之间的大一致性。通过比较两种δD廓线，我们推知对流层低层和中高层δ D廓线的精度分别约为8 ‰和17‰。然而，在同一时间，我们观察到的两个反演之间的系统差异高达40‰的中/上层对流层，这是一个很大的值相比，典型的对流层δD变化只有80‰。
Abstract. We present ground-based FTIR (Fourier Transform Infrared) water vapour analyses performed in four different spectral regions: 790–880, 1090–1330, 2650–3180, and 4560–4710 cm−1. All four regions allow the retrieval of lower, middle, and upper tropospheric water vapour amounts with a vertical resolution of about 3, 6, and 10 km, respectively. In addition the analyses at 1090–1330 and 2650–3180 cm−1 allow the retrieval of lower and middle/upper tropospheric δD values with vertical resolutions of 3 and 10 km, respectively. A theoretical and empirical error assessment – taking coincident Vaisala RS92 radiosonde measurements as a reference – suggests that the H2O data retrieved at high wavenumbers are slightly more precise than those retrieved at low wavenumbers. We deduce an H2O profile precision and accuracy of generally better than 20% except for the low wavenumber retrieval at 790–880 cm−1, where the assessed upper precision limit of middle/upper tropospheric H2O is 35%. The scatter between the H2O profiles produced by the four different retrievals is generally below 20% and the bias below 10%, except for the boundary layer, where it can reach 24%. These values well confirm the theoretical and empirical error assessment and are rather small compared to the huge tropospheric H2O variability of about one order of magnitude thereby demonstrating the large consistency between the different H2O profile retrievals. By comparing the two δD profile versions we deduce a precision of about 8 and 17‰ for the lower and middle/upper troposphere, respectively. However, at the same time we observe a systematic difference between the two retrievals of up to 40‰ in the middle/upper troposphere which is a large value compared to the typical tropospheric δD variability of only 80‰.