| dc.description.abstract | Deep convection that penetrates the tropopause, otherwise known as overshooting convection, is capable of lifting tropospheric air well into the stratosphere. In addition to moisture, these overshoots also transport many chemical species from the boundary layer, affecting the chemistry and radiative equilibrium in the stratosphere. However, it is not currently known how much trans-port is a result of this mechanism. Therefore, in an attempt to better understand overshooting convection, this study aims to characterize the durations of overshooting events. To achieve this, radar data from Next Generation Weather Radar (NEXRAD) network is composited onto a high-resolution, three-dimensional grid at 5-minute intervals. The resulting product, GridRad, provides echo-top heights that are then compared with tropopause estimates derived from ERA5 reanaly-sis data. These overshoots are then linked by proximity from one timestep to the next to form tracks. This tracking process is performed for twelve 4-day sample windows in the months May-August of 2017-2019, producing a total of 72,779 tracks. Track characteristics such as duration, mean overshoot area, mean tropopause-relative altitude, and mean column-maximum reflectivity are investigated. Exponential distributions are found for many of these characteristics, with the exception of mean overshoot area, which follows a power-law distribution, and mean column-maximum reflectivity, which has a more complicated distribution. Positive correlations are found between track duration and the remaining track characteristics. A diurnal cycle is observed, with peak track initiation around 16-17 local time. Track-mean duration peaks a few hours earlier, while track-mean area and tropopause-relative height peak a few hours later. | |
