10:00 AM - 10:15 AM
[AAS07-05] Intermittency of the Gravity Waves in the Polar Troposphere and Lower Stratosphere Based on the PANSY Radar Observation
Keywords:gravity waves, polar region, middle atmosphere
One method to describe the intermittency quantitatively is the use of Gini coefficient (Ig) (e.g., Plougonven et al., 2013; Alexander et al., 2016). In any season, Gini-coefficient is large (Ig=0.6–0.7) in the troposphere, while it is small (Ig=0.3–0.5) in the stratosphere. This means that the intermittency in the stratosphere is smaller than in the lower troposphere. Alexander et al. (2016) estimated the Gini coefficient in the lowest stratosphere over the coastal Antarctica as 0.5–0.6 using simulation data from a GW-permitting GCM which contains no GW parameterizations (Watanabe et al., 2008). The mean value of Gini-coefficient estimated in this study roughly accord with but slightly smaller than the value by Alexander et al. (2016). The seasonal variation of the intermittency is found. The region with quite small Gini coefficient (Ig=0.3–0.4) in the stratosphere extends to the upper troposphere, whose usual Gini coefficient is 0.4–0.5, from Jun to July 2016. It is also worth noting that the intermittency of GWs is quite sensitive to the strong disturbances occurring several times a year, which means that the intermittency of GWs varies greatly year to year.