Transport of mesospheric H 2 O during and after the stratospheric sudden warming of January 2010: observation and simulation
Transport of mesospheric H 2 O during and after the stratospheric sudden warming of January 2010: observation and simulation
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DOI：
10.5194/acp-12-5413-2012
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发表时间：
2011-12
影响因子：
6.3
通讯作者：
C. Straub;Brigitte Tschanz;K. Hocke;N. Kämpfer;Anne K. Smith
中科院分区：
文献类型：
--
作者：
C. Straub;Brigitte Tschanz;K. Hocke;N. Kämpfer;Anne K. Smith
抽象的。2010年1月至6月，便携式地面微波辐射计MIAWARA-C监测了芬兰索丹基拉（北纬67.4度，东经26.6度）上空平流层上部和中间层下部的水汽分布。1月底，MIAWARA-C在芬兰开始运行约两周后，平流层突然变暖（SSW）扰乱了中层大气的环流。在SSW爆发后不久，水蒸气的压力在1至0.01 hPa之间迅速增加。后向轨迹计算表明，这种强烈的增加是由于极涡的崩溃和副热带空气的纬向平流到北极USLM地区。此外，中层上升流的过程中的SSW导致增加观测到的水汽之间的0.1和0.03百帕。在SSW之后，MIAWARA-C观测到由于极地地区贫H2O气团的下沉，中层水汽体积混合比（VMR）降低。后向轨迹分析和Aura卫星微波临边探测器（Aura/MLS）的纬向平均水汽分布表明，从50° N到北极存在两种环流体制：（1）整个2月的纬向混合增强体制和（2）3月初至春分之间在USLM区域重建的东向环流体制。根据MIAWARA-C的百万分之5.2体积（ppmv）等值线，在2月上旬至3月上旬的0.6至0.06百帕气压范围内，极移速率为350 p 40 m d −1。对于相同的时间间隔，在相同的压力范围内的下降率确定使用转换欧拉平均（TEM）风场模拟的全大气社区气候模式与特定的动力学（SD-WACCM）。SD-WACCM TEM垂直风的平均值为325 m d −1，而沿着轨迹的垂直位移为335 m d −1。相似的下降率表明模型和MIAWARA-C的测量结果之间具有良好的一致性。
Abstract. The transportable ground based microwave radiometer MIAWARA-C monitored the upper stratospheric and lower mesospheric (USLM) water vapor distribution over Sodankyla, Finland (67.4° N, 26.6° E) from January to June 2010. At the end of January, approximately 2 weeks after MIAWARA-C's start of operation in Finland, a stratospheric sudden warming (SSW) disturbed the circulation of the middle atmosphere. Shortly after the onset of the SSW water vapor rapidly increased at pressures between 1 and 0.01 hPa. Backward trajectory calculations show that this strong increase is due to the breakdown of the polar vortex and meridional advection of subtropical air to the Arctic USLM region. In addition, mesospheric upwelling in the course of the SSW led to an increase in observed water vapor between 0.1 and 0.03 hPa. After the SSW MIAWARA-C observed a decrease in mesospheric water vapor volume mixing ratio (VMR) due to the subsidence of H 2 O poor air masses in the polar region. Backward trajectory analysis and the zonal mean water vapor distribution from the Microwave Limb Sounder on the Aura satellite (Aura/MLS) indicate the occurrence of two regimes of circulation from 50° N to the North Pole: (1) regime of enhanced meridional mixing throughout February and (2) regime of an eastward circulation in the USLM region reestablished between early March and the equinox. The polar descent rate determined from MIAWARA-C's 5.2 parts per million volume (ppmv) isopleth is 350 p 40 m d −1 in the pressure range 0.6 to 0.06 hPa between early February and early March. For the same time interval the descent rate in the same pressure range was determined using Transformed Eulerian Mean (TEM) wind fields simulated by means of the Whole Atmosphere Community Climate Model with Specified Dynamics (SD-WACCM). The average value of the SD-WACCM TEM vertical wind is 325 m d −1 while the along trajectory vertical displacement is 335 m d −1 . The similar descent rates found indicate good agreement between the model and MIAWARA-C's measurements.