Surface Pressure Fluctuations Produced by the Total Solar Eclipse of 1 August 2008

Abstract

During a solar eclipse, the moon's shadow progressively occults a part of Earth from the solar flux. This induces a cooling in the atmospheric layers that usually absorb the solar radiation. Since the eclipse shadow travels within the atmosphere at supersonic velocity, this cooling generates a planetary-scale bow wave of internal gravity waves. The purpose of this article is to estimate the surface atmospheric pressure fluctuations produced by the passage of the 1 August 2008 total solar eclipse and to compare these pressure fluctuations with those recorded by a temporary network of microbarographs and by the infrasound stations of the International Monitoring System. The surface pressure fluctuations expected at all the measurement sites are estimated using a linear spectral numerical model. It is shown that the cooling of both the ozonosphere and the troposphere can produce detectable pressure fluctuations at the ground surface but that the tropospheric cooling is likely to be the predominant source. Since the expected eclipse signals are in a frequency range that is highly perturbed by atmospheric tides and meteorological phenomena, the pressure fluctuations produced by these latter synoptic disturbances are characterized and removed from the recorded signals. Lowfrequency gravity waves starting just after the passage of the eclipse are then brought to light at most measurement sites. The time-frequency characteristics of these waves are similar to those obtained from the model, which strongly suggests that these waves were produced by the passage of the 1 August 2008 solar eclipse.

On the detection and attribution of gravity waves generated by the 20 March 2015 solar eclipse

“…In particular, insufficient cooling due to cloud cover and the time of year could be a major factor as to why distinctive pressure perturbations were not detected. The results agree with other studies seeking eclipse-induced gravity waves, such as [ 8 ] and those discussed in [ 13 ], which have encountered similar problems due to disturbed weather conditions.…”

“…The ozone oscillations were similar to oscillations observed in temperature and humidity at the surface, suggesting a possible link between the surface and mid-level atmosphere during the eclipse. Despite the encouraging findings of most of the above studies, it must be remembered that eclipse-induced waves are not always evident [ 13 ]. Care should be taken to separate perturbations that are eclipse-driven from those that are associated with normal meteorological influences.…”

Surface Radiation during the Total Solar Eclipse over Ny-Ålesund, Svalbard, on 20 March 2015

“…In the Ny Ålesund surroundings, these are favourable conditions for prevailing katabatic winds from the glaciers (Jocher et al, 2012). In these cases, the common south-east-oriented near-surface atmospheric flow along the fjord axis (Beine et al, 2001;Maturilli et al, 2013) is often interrupted by south-westerly katabatic winds from the mountains and glaciers south of Ny-Ålesund, bringing cold air to the station. On 20 March 2015, such cold air outflow events are reflected in the surface air temperature ( Fig.…”

Surface radiation during the total solar eclipse over Ny-Ålesund, Svalbard, on 20 March 2015

“…The pressure perturbations and induced gravity waves generated by a solar eclipse have been studied for several eclipse events (e.g. Schödel et al, 1973;Goodwin and Hobson, 1978;Seykora et al, 1985;Marty et al, 2013). Gravity wave forcing by a solar eclipse has also been found related to ozone photochemistry in the middle atmosphere (Fritts and Luo, 1993).…”