In situ observations of reduced stratospheric water vapor combined with those of ice particle formation are rarely conducted. On the one hand, they are essential to broaden our knowledge about the formation of polar stratospheric clouds (PSCs). On the other hand, the observed profiles allow the comparison with global circulation models. Here we report about a balloon‐borne observation above Sodankylä, Finland on 26 January 2005. The frostpoint hygrometer detected layers of reduced water vapor by up to 2 ppmv from 18.5 to 23 km. Beneath, a 1‐km‐deep layer of increased water vapor was identified. An aerosol backscatter sonde measured the presence of stratospheric ice clouds. According to meteorological analysis the PSCs were formed upstream above the east coast of Greenland due to mountain wave‐induced cooling. The inertia‐gravity waves generated a large and persistent stratospheric wake far downstream of Greenland and led to the observed dehydration. Comparing the most recent ERA5 data with operational analyses from 2005, we find an improved representation of mesoscale internal gravity waves, dehydration and PSC formation for this particular event.

中文翻译：

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格陵兰岛上激发的山浪对平流层脱水和补水的远距离影响

很少进行平流层水汽减少与冰粒形成相结合的现场观察。一方面，它们对于拓宽我们对极地平流层云（PSC）形成的认识至关重要。另一方面，观察到的剖面可以与整体环流模型进行比较。在这里，我们报道了2005年1月26日在芬兰Sodankylä上空进行的气球观测。霜点湿度计检测到了从18.5到23 km最多减少2 ppmv的水汽层。在下面，发现了1公里深的增加的水蒸气层。气溶胶反向散射探空仪测量了平流层冰云的存在。根据气象分析，由于山浪引起的降温，PSCs在格陵兰岛东海岸上方形成。惯性重力波在格陵兰岛的下游产生了巨大而持久的平流层尾流，并导致了观测到的脱水。通过将最新的ERA5数据与2005年的运行分析进行比较，我们发现该特殊事件的中尺度内部重力波，脱水和PSC形成得到了改进。