Trends and variability of midlatitude stratospheric water vapour deduced from the re-evaluated Boulder balloon series and HALOE
Trends and variability of midlatitude stratospheric water vapour deduced from the re-evaluated Boulder balloon series and HALOE
复制标题
由重新评估的博尔德气球系列和 HALOE 推导出的中纬度平流层水蒸气的趋势和变化
DOI：
10.5194/acp-8-1391-2008
复制
发表时间：
2007
影响因子：
6.3
通讯作者：
Johannes Stähelin
中科院分区：
文献类型：
--
作者：
Martin Scherer;Holger Vömel;S. Fueglistaler;S. Oltmans;Johannes Stähelin
本文介绍了一个更新的趋势分析的水蒸气在低中纬度平流层的博尔德气球载NOAA的冰点湿度计测量和卤素掩星实验（HALOE）。两个校正仪器偏差均匀化的冰点数据系列，并提出了1991年后的所有探测的质量评估。根据1980-2000年期间的修正数据得出的线性趋势估计数比以前报告的低40%。垂直分辨的趋势和变率的计算与多元回归分析，包括准两年振荡和等效纬度作为解释变量。在380 ~ 640 K位温范围内（14 ~ 25 km），1981 ~ 2006年的霜点资料在0.3±0.3 ~ 0.7±0.1%/yr之间呈现正的线性趋势。同一数据集显示，1992年至2005年期间的趋势在-0.2 ± 0.3%至1.0±0.3%之间。同一时期的哈洛埃数据表明，每年的负趋势从-1.1 ± 0.2%到-0.1 ±0.1%不等。在平流层低层，2000/2001年观测到水蒸气迅速下降，此后变化不大。在海拔较高的地区，过渡较为平缓，2001年至2007年期间浓度缓慢下降。这种模式与进入平流层时水浓度下降引起的变化一致。对于均质化数据，先前注意到的霜点和HALOE之间的趋势和变异性差异仍然存在。由于再分析温度和平流层输送的不确定性，再加上观测的不确定性，无法用这里分析的中纬度测量结果对热带地区进入平流层的水的变化进行定量推断。
This paper presents an updated trend analysis of water vapour in the lower midlatitude stratosphere from the Boulder balloon-borne NOAA frostpoint hygrometer measurements and from the Halogen Occulation Experiment (HALOE). Two corrections for instrumental bias are applied to homogenise the frostpoint data series, and a quality assessment of all soundings after 1991 is presented. Linear trend estimates based on the corrected data for the period 1980–2000 are up to 40% lower than previously reported. Vertically resolved trends and variability are calculated with a multi regression analysis including the quasi-biennal oscillation and equivalent latitude as explanatory variables. In the range of 380 to 640 K potential temperature (≈14 to 25 km), the frostpoint data from 1981 to 2006 show positive linear trends between 0.3±0.3 and 0.7±0.1%/yr. The same dataset shows trends between −0.2±0.3 and 1.0±0.3%/yr for the period 1992 to 2005. HALOE data over the same time period suggest negative trends ranging from −1.1±0.2 to −0.1±0.1%/yr. In the lower stratosphere, a rapid drop of water vapour is observed in 2000/2001 with little change since. At higher altitudes, the transition is more gradual, with slowly decreasing concentrations between 2001 and 2007. This pattern is consistent with a change induced by a drop of water concentrations at entry into the stratosphere. Previously noted differences in trends and variability between frostpoint and HALOE remain for the homogenised data. Due to uncertainties in reanalysis temperatures and stratospheric transport combined with uncertainties in observations, no quantitative inference about changes of water entering the stratosphere in the tropics could be made with the mid latitude measurements analysed here.