Meteorological effects of the eclipse of 11 August 1999 in cloudy and clear conditions

Abstract

Sensitive high-resolution meteorological observations revealed dynamical atmospheric e¬ects despite the presence of cloud. Short-term eclipse-related changes dominated over temperature, wind speed and wind directions associated with the synoptic conditions, and 35 min period gravity waves were detected in surface-pressure observations. Theoretical calculations for solar radiation changes were compared with observations made during the 97% partial eclipse in clear skies at Reading, Berkshire, and used to predict the radiative changes expected at Camborne, Cornwall, during totality. At Camborne, a vertical array of sensitive ne-wire thermometers was operated with a high-resolution sonic anemometer, logged at 5 Hz. Despite cloudy conditions, which reduced the eclipseinduced thermal perturbations, small temperature and wind changes were detected which were consistent with theory. The cold out®ow from the umbra was unambiguously detected for the rst time in cloudy conditions.

The total solar eclipse of March 2006: overview

“…Temperature, relative humidity, wind and cloudiness are among the most common meteorological parameters measured and observed in experimental campaigns during solar eclipses (e.g. Anderson, 1999;Fernandez et al, 1993Fernandez et al, , 1996Aplin and Harrison, 2002). Although the results of most meteorological studies provide similar patterns of temperature changes, the precise drop may differ depending on several factors (timing, synoptic situation, surrounding environment, percentage of sun occultation etc).…”

“…An "eclipse wind" has been also reported during many eclipses (e.g. Aplin and Harrison, 2002), although in some cases it could be also related to subjective perception of a pronounced wind chill effect (Anderson, 1999). According to recent observations (e.g.…”

On the variability of near-surface screen temperature anomalies in the 20 March 2015 solar eclipse

“…Wind direction changes have variously been attributed to dynamic effects associated with cooling in the umbra and penumbra (e.g. [11]), the development of local drainage flows [12,[19][20][21] or suppression of sea breeze circulations (e.g. [23]).…”

“…[2,5,7,9,11,12,15,19,25]) and are usually attributed to the increase in near-surface stability which reduces turbulent mixing, sometimes allowing near-surface flow to decouple from the geostrophic flow. Segal et al [15] showed that NSAT decreases were more rapid following the decoupling of winds at low levels.…”

“…[2,3,[5][6][7]10]), while others compare observations from multiple sites (e.g. [11][12][13]). Improvements in data availability have allowed analyses to be constructed using data from a much larger set of sites for some of the more recent events, sometimes with large geographical spread (e.g.…”