Observations of the Boundary Layer near Tornadoes and in Supercells Using a Mobile, Collocated, Pulsed Doppler Lidar and Radar

Abstract

During the Second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2), in the spring of 2010, a mobile and pulsed Doppler lidar system [the Truck-Mounted Wind Observing Lidar Facility (TWOLF)] mounted on a truck along with a mobile, phased-array, X-band Doppler radar system [Mobile Weather Radar-2005 X-band, phased array (MWR-05XP)] was used to complement Doppler velocity coverage in clear air near the radar-lidar facility and to provide high-spatial-resolution vertical cross sections of the Doppler wind field in the clear-air boundary layer near and in supercells. It is thought that the magnitude and direction of vertical shear and possibly the orientation and spacing of rolls in the boundary layer have significant effects on both supercell and tornado behavior; MWR-05XP and TWOLF can provide data that can be used to measure vertical shear and detect rolls. However, there are very few detailed, time-dependent and spatially varying observations throughout the depth of the boundary layer of supercells and tornadoes. This paper discusses lidar and radar data collected in or near six supercells. Features seen by the lidar included gust fronts, horizontal convective rolls, and small-scale vortices. The lidar proved useful at detecting highspatial-resolution, clear-air returns at close range, where the radar was incapable of doing so, thus providing a more complete picture of the boundary layer environment ahead of supercells. The lidar was especially useful in areas where there was ground-clutter contamination. When there was precipitation and probably insects, and beyond the range of the lidar, where there was no ground-clutter contamination, the radar was the more useful instrument. Suggestions are made for improving the system and its use in studying the tornado boundary layer.

A review of the remote sensing of lower tropospheric thermodynamic profiles and its indispensable role for the understanding and the simulation of water and energy cycles

“…For all these applications, WV and T DA with advanced observing systems will lead to better forecast skill and advanced understanding of regional water and energy cycles as well as the predictability of atmospheric processes such as precipitation by probabilistic QPF. Particularly, it can be expected that joint DA of clear air TD fields and radar observations in the preconvective environment as well as in and around convective systems will lead to a reduction of the model imbalance at initial time increasing the impact of radar data [e.g., Kawabata et al ., ; Bluestein et al ., ].…”

Narrow‐linewidth injection‐locked Ho:YAG laser by using thulium‐doped fiber laser as pumping source

“…Eye-safe narrow-linewidth lasers are potential sources of coherent Doppler wind lidars (CDWLs) and differential absorption lidars (DIALs) because of the high atmosphere transmission and high absorption for CO 2 , H 2 O, and NO 2 molecules, and can also be used for special gas sensing and laser frequency combs. [1][2][3][4][5][6][7][8][9] In recent years, CDWLs have had extremely important application value in large bridge construction, 10 extreme weather warning, 11 wind energy exploitation, 12 aviation safety 13 , and global climate forecast. 14 Monitoring the greenhouse gases such as CO 2 in the atmosphere with high precision and resolution by the DIALs is a benefit for achieving a global carbon balance.…”

A Background Investigation of Tornado Activity across the Southern Cumberland Plateau Terrain System of Northeastern Alabama

“…Most observational studies investigating the impact of topography on severe storm or tornado behavior have focused on singular events, such as studies of the role of flow channeling up the Hudson River valley in modifying the near-storm environment of tornadic storms on 29 May 1995 (Bosart et al 2006) and 31 May 1998 (LaPenta et al 2005), but the conclusions of these studies are based on limited observations. Additional observational case studies have been performed on the role of topography on tornadic storms in the mountains around Huntsville, Alabama (Goodman and Knupp 1993;Knupp et al 2014); the Sacramento Valley of Northern California (Braun and Monteverdi 1991); the Grand Teton Mountains and Yellowstone National Park in western Wyoming (Fujita 1989); the Appalachian Mountains of central Pennsylvania (Forbes 1998); the Rocky Mountains of northern and central Colorado (Nuss 1986;Bluestein 2000); the Rocky Mountain foothills of northern Colorado and southern Wyoming (Geerts et al 2009); rolling hills across central Alabama (Karstens et al 2013); the Cumberland Plateau and Great Tennessee Valley of east Tennessee (Gaffin and Parker 2006;Schneider 2009;Shamburger 2012); and the Sequoia National Park in California (Monteverdi et al 2014). More recent work has focused on using mobile Doppler radar and data from WSR-88D radar sites in a geographical information system (GIS) framework in order to seek correlations between topography and land surface roughness and tornado intensity (Houser et al 2017).…”

“…A somewhat common feature in the simulations was the event of a corner flow collapse (Lewellen and Lewellen 2007), where a collapse in the corner region of the tornado vortex leads to a rapid increase in the convergence of angular momentum at the surface, leading to a rapid intensification of the tornado vortex near the surface. The occurrence of corner flow collapse, however, has never been observed in nature (Bluestein et al 2014), which, compounded by the numerous outcomes of the LES, leads to considerable variability and uncertainty in determining how topography may directly impact tornado structure.…”