Lower Thermospheric Material Transport via Lagrangian Coherent Structures

Abstract

Material transport in the lower thermosphere is of scientific interest. Transport is affected by interactions of the ionized layer with neutral particles. Nitric oxide (NOx) transport is modulated by plasma behavior (Knipp et al., 2017), and in turn, NOx modulates the warming and cooling rates. Material in the lower thermosphere, when transported, can manifest in the mesosphere as well, for example, in the formation of polar mesospheric clouds (PMCs) (Stevens et al., 2003).However, winds and transport in the lower thermosphere are challenging to investigate observationally. Larsen (2002) aggregated decades of chemical release experiments to show significant shear in the altitude range of 100-110 km. A unique opportunity to observe material transport in the lower thermosphere arose toward the end of the U.S. space shuttle program during which time a number of orbiting sensors were also operational. Shortly after launch, the shuttle would deposit about 350 tons of water vapor at about 100-115 km altitude, at an almost identical geographic location every time. This water vapor was then tracked by a combination of satellite and ground-based observations over subsequent days.Early work on shuttle plumes tied them to evidence of PMC formation (Stevens et al., 2003). Later Stevens et al. (2005 detected the photodissociated water vapor plume via Thermosphere, Ionosphere, Mesosphere, Energetics, and Dynamics (TIMED) satellite global ultraviolet imager (GUVI) Lyman-alpha observations and related it to PMCs in the Antarctic. Siskind et al. (2003) showed the water to be detectable in TIMED Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) water vapor measurements.

Evaluation of Polar Winter Mesopause Wind in WACCMX+DART

“…It is also necessary to have accurate knowledge of the winds at high spatial and temporal resolution to fully understand the transport of constituents. For example, large horizontal and vertical wind shears (e.g., Larsen, 2002; Liu, 2007) affect the transport of space shuttle water vapor (e.g., Datta‐Barua et al., 2021; Yue et al., 2013), which has been linked to variability in polar mesospheric clouds (e.g., Stevens et al., 2014). In addition to accurate knowledge of the composition, accurate neutral winds would aid in understanding how the residual circulation in the upper mesosphere (Holton, 1983) interacts with an opposing global circulation in the lower thermosphere that is simulated in models (Smith et al., 2011) and how this interaction may vary as a function of local time, season, and solar cycle.…”

Alignment of High‐Latitude Ionospheric and Thermospheric Lagrangian Coherent Structures

“…Fluid elements on opposites sides of an LCS will tend to separate into distant parts of the domain during the time interval. More details on the FTLE calculation in ITALCS can be found in Wang et al (2018) and on the interpolation in the appendix of (Datta-Barua et al, 2021).…”

“…More details on the FTLE calculation in ITALCS can be found in Wang et al. (2018) and on the interpolation in the appendix of (Datta‐Barua et al., 2021).…”

Coordinated Observations of Rocket Exhaust Depletion: GOLD, Madrigal TEC, and Multiple Low‐Earth‐Orbit Satellites

“…(2010, 2011) reported 2D dayglow images of rocket exhaust in the Lyman‐alpha line (121.6 nm). The emission comes from sunlight scattered by hydrogens (e.g., Vorburger & Wurz, 2021, Table 3), which result from dissociation of H 2 O in rocket exhaust (Stevens et al., 2005) and can be used as tracers of atmospheric transport (e.g., Datta‐Barua et al., 2021). Niciejewski et al.…”