The climatology of sea breezes on Sardinia

Abstract

Hourly wind speed and direction data from 12 coastline stations on Sardinia, Italy, are analysed in order to characterize sea breezes in the region. A set of criteria based on the diurnal reversal of wind direction, and the thermal gradient necessary to drive the circulation, is used to identify sea breeze days. Statistics are presented that describe the occurrence, duration, and strength of the sea breezes. On a stationwide basis, sea breezes are most frequent in the summer months (May-August), when they appear on more than one-third of the days. Sea breeze occurrence and duration are the greatest for the stations on the east coast of the island. The all-station average sea breeze duration reaches a maximum of about 9 h in June. The strength of the sea breezes is roughly 3 m s −1 during summer months on average over all stations in the sample.An analysis of mean daily hodographs for the stations in the sample shows clearly the onshore-offshore nature of the sea breeze circulation, and the response of the sea breezes to the local coastline. Sea breezes are shown to develop simultaneously on all coasts of the island under appropriate synoptic conditions.

Diurnal Variations in Summertime Surface Wind upon Japanese Plains: Hodograph Rotation and Its Dynamics

“…2 (left) and 4a show that midnight points (near the X symbols) and some midafternoon points tend to stagnate, with the former defining a tighter cluster than the latter. This finding demonstrates that the rotation rate changes over the course of a day, as reported in previous studies (e.g., Staley 1957;Furberg et al 2002). By definition, such an asymmetric rotation rate cannot be explained solely in terms of the diurnal component.…”

“…According to Haurwitz's (1947) theory, the rotation direction should always be clockwise, and the rotation rate should be the same between during the daytime and during the nighttime; however, subsequent observational studies have reported anticlockwise rotation directions (e.g., Mori 1982;Furberg et al 2002) and different rotation rates from those predicted by Haurwitz (e.g., Neumann 1977;Zhong and Takle 1992;Furberg et al 2002).…”

Sea breezes at Cotonou and their interaction with the West African monsoon

“…Our analysis is based on sea breeze detection criteria developed in Steyn and Faulkner (1986) and Furberg et al (2002). Steyn and Faulkner (1986) encountered major difficulties in establishing the criteria for determining sea breeze and non-sea breeze days, mainly due to the difficulty of separating local, thermally driven circulations from synoptic-scale circulations.…”

“…Climatological studies of sea breeze are found in literature for many regions throughout the world such as Lower Fraser Valley, B.C. (Steyn and Faulkner, 1986), St. Johns, Newfoundland (Banfield, 1991), West Coast of Sweden (Gustavsson et al, 1995;Borne et al, 1998), Sardinia (Furberg et al, 2002), Northern Adriatic (Maja, 2003), Arabian Gulf region (Eager et al, 2008), Alicante (Azorin-Molina et al, 2009), among others.…”

“…Simpson (1994) reported that tropical sea breezes occur on at least two-thirds of the days in the non-monsoon (winter) season. Abayomi et al (2007) reported the existence of two regimes characterized by two peaks in the monthly distribution of sea breeze days on Nigerian sea breezes (low latitude), but this is not the case in the middle and high latitude where the monthly variation of sea breeze occurrence exhibits only one maximum (Steyn and Faulkner, 1986;Furberg et al 2002).…”