Mountain-wave-induced record low stratospheric temperatures above northern Scandinavia
Mountain-wave-induced record low stratospheric temperatures above northern Scandinavia
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DOI：
10.3402/tellusa.v51i5.14504
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发表时间：
1999-10
期刊：
影响因子：
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通讯作者：
A. Dörnbrack;M. Leutbecher;R. Kivi;E. Kyrö
中科院分区：
文献类型：
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作者：
A. Dörnbrack;M. Leutbecher;R. Kivi;E. Kyrö
1997年1月22日1200世界时，芬兰Sodankyla¨的常规无线电探空仪在26公里处测得零下94.5°C的低温。中尺度数值模拟显示这一天有强烈的山波活动。模拟了两个平流层的最低温度：一个在斯堪的纳维亚山脉的正上方，另一个最低温度在其东侧约500公里处。这两个极小值在全局分析中都没有得到解决。探空剖面和中尺度模式表明，东部中尺度温度异常是由受科里奥利力影响的惯性重力波即静水山波引起的。同日，在瑞典基律纳和芬兰索丹基莱，通过目测和地面激光雷达观测到平流层冰云。这些冰云的形成需要山波的冷却，因为根据全球分析，温度大约比冰点高3k。由于山波冷却而产生的额外极地平流层冰云增加了氯活化的效率，并对北极臭氧消耗产生影响。正在考虑的这一特殊事件发生在冷空气爆发期间，冷锋经过斯堪的纳维亚地形。这一锋面与对流层下层的强风有关。与此同时，北斯堪的纳维亚位于极涡内缘以下，那里天气尺度平流层温度低，极夜急流强。DOI: 10.1034 / j.1600-0870.1999.00028.x
On 22 January 1997 1200 UT, the routine radiosonde from Sodankyla¨ , Finland, measured arecord low temperature of −94.5°C at 26 km. Mesoscale numerical simulations indicate strongmountain wave activity on this day. Two stratospheric temperature minima are simulated: onedirectly above the Scandinavian mountain ridge and another minimum in its lee about 500 kmto the east. Both minima are not resolved in the global analyses. The radiosonde profile as wellas the mesoscale model indicate that the eastern mesoscale temperature anomaly is caused byorographic inertia-gravity waves, i.e., hydrostatic mountain waves influenced by Coriolis force.Stratospheric ice clouds were observed visually and by ground-based lidar at Kiruna, Swedenand Sodankyla¨ , Finland on this day. The formation of these ice clouds required the cooling inthe mountain waves as the temperature according to global analyses was about 3 K above thefrost point. The occurrence of additional polar stratospheric ice clouds due to mountain-wavecooling increases the efficiency of chlorine activation and has implications for the resultingArctic ozone depletion. The extraordinary event under consideration occurred during a coldair outbreak with a cold front passing over the Scandinavian orography. This front was associatedwith strong winds in the lower troposphere. At the same time, northern Scandinavia waslocated below the inner edge of the polar vortex, where low synoptic-scale stratospheric temperaturesand a strong polar night jet are found. DOI: 10.1034/j.1600-0870.1999.00028.x