Response of the Land‐Atmosphere System Over North‐Central Oklahoma During the 2017 Eclipse

Abstract

On 21 August 2017, a solar eclipse occurred over the continental United States resulting in a rapid reduction and subsequent increase of solar radiation over a large region of the country. The eclipse's effect on the land‐atmosphere system is documented in unprecedented detail using a unique array of sensors deployed at three sites in north‐central Oklahoma. The observations showed that turbulent fluxes of heat and momentum at the surface responded quickly to the change in solar radiation. The decrease in the sensible heat flux resulted in a decrease in the air temperature below 200 m, and a large decrease in turbulent motions throughout the boundary layer. Furthermore, the turbulent mixing in the boundary layer lagged behind the change in the surface fluxes, and this lag depended on the height above the surface. The turbulent motions increased and the convective boundary layer was reestablished as the sensible heat flux recovered.

The Total Solar Eclipse of 2017: Meteorological Observations from a Statewide Mesonet and Atmospheric Profiling Systems

“…The top of the PBL following the eclipse (1.4 km) was about 0.2 km lower prior to the eclipse. A pronounced time lag of about 1 h in boundary layer collapse and restoration is noted in both the DWL and 915-Hz SNR and SW measurements, consistent with more limited measurements during previous solar eclipse events (Turner et al 2018). Further inspection of the DWL w patterns reveals the presence of regular wave motions, which appear to be most significant near the capping inversion around the time of totality.…”

“…The response of solar radiation and its reduction observed by the Kentucky Mesonet is consistent with the findings from Lee et al (2018) and Turner et al (2018). Note that the observations from the latter study were not exposed to the full total eclipse and did not focus on the surface meteorology, possibly because data were collected from only three locations.…”

“…This research is extensive and complementary to the studies conducted by Lee et al (2018) and Turner et al (2018). Lee et al (2018) analyzed continental-scale meteorological data from the Climate Reference Network while Turner et al (2018) assessed data from three closely located sites in north-central Oklahoma that were far from the path of the totality. Our study is focused on the meso-and regional-scale response of the atmosphere observed by a statewide meteorological network and atmospheric profiling systems, augmented by atmospheric modeling.…”

Land‐Atmosphere Responses to a Total Solar Eclipse in Three Ecosystems With Contrasting Structure and Physiology

“…The stable surface layer during the eclipse was flanked by very unstable conditions before and after, which is typical for a day in August. In Oklahoma, where the maximum obscuration was only 89%, the boundary layer dynamics showed a similar pattern: a convective boundary layer of ~1.3‐km depth collapsed to a stable boundary layer (~200–300‐m depth) during the eclipse, and became convective again (~1.3‐km depth) afterward (Turner et al, ). Although we observed large variations in K ↓ , R n , LE , and H , the concomitant decreases in T air were relatively muted at ~1.5–2.5 °C (Figures e and h).…”

“…At sites that were unaffected by convective activity (forest and prairie), there was a particularly strong eclipse effect that elicited rapid declines and increases in σ u , σ w , LE , and H . In general, the dynamics of air temperature, turbulence, radiation, and energy fluxes and stability displayed the expected responses to the eclipse solar forcing (Antonia et al, ; Eaton et al, ; Foken et al, ; Mauder et al, ; Stewart & Rouse, ; Turner et al, ). There were large changes in the surface energy balance between first and fourth contacts, with LE being completely suppressed and the direction of H changing from away from to toward the surface, which resulted in a strong stabilization of the surface layer (Figures e and h).…”