The dynamical response of the middle atmosphere to the tropospheric solar signal
The dynamical response of the middle atmosphere to the tropospheric solar signal
复制标题
中层大气对对流层太阳信号的动力学响应
DOI：
10.1029/2006jd008237
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发表时间：
2007
影响因子：
--
通讯作者：
Neil Arnold
中科院分区：
文献类型：
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作者：
P. Berg;B. Christiansen;P. Thejll;Neil Arnold
为了评估太阳对行星波可能的调制作用，我们对NCEP/NCAR和ERA40两个主要再分析数据集的300 hPa位势高度进行了研究，以确定1963-1999年三个太阳周期的太阳活动最大值和最小活动年之间的差异。我们发现，从12月到2月，北太平洋上空出现了显著的正差异，这与早期研究中发现的海平面压力相似。此外，从位势高度提取的前两次行星波在气候状态上存在显著的振幅差异。我们还进行了对对流层太阳信号的中层大气响应的模型研究。在以恒定太阳周期最小辐射强迫运行的中大气模式中，使用300 hPa位势高度作为下边界，因此只有下边界对中大气有强迫作用。利用模式试验研究了与位势高度分析相同年份的北方冬季纬向风和300-0.01 hPa温度。两个数据集均值的差异再现了观测和再分析数据中看到的结构和幅度。这究竟是对流层太阳强迫的直接影响，还是平流层太阳强迫的反馈耦合，目前尚不清楚，但对流层行星波的调制似乎对观测到的平流层太阳调制很重要。
[1] To assess a possible solar modulation of the planetary waves, the 300 hPa geopotential height of the two major reanalysis data sets, NCEP/NCAR and ERA40, is studied for the difference between years of solar maximum and minimum activity for three solar cycles in the period 1963–1999. We find a significant positive difference over the North Pacific ocean for December through February which resembles that found in sea level pressures in earlier studies. Furthermore, there are statistically significant amplitude differences in the climatological state of the first two planetary waves extracted from the geopotential heights. We also perform a model study of the middle atmospheric response to the tropospheric solar signal. The 300 hPa geopotential height is used as the lower boundary in a middle atmosphere model which is run with a constant solar cycle minimum radiative forcing, so that only the lower boundary is forcing the middle atmosphere. The zonal wind and temperature at 300–0.01 hPa from the model experiment are studied in boreal winter for the same years that were studied in the geopotential height analysis. Differences of the means of the two data sets reproduce the structure and amplitude seen in observations and in reanalysis data. Whether this is a direct effect of the solar forcing of the troposphere or a feedback coupling of the solar forcing of the stratosphere is not presently clear, but the modulation of the tropospheric planetary waves seems to be important for the observed solar modulation of the stratosphere.