Statistical characterization of the sea‐breeze physical mechanisms through in‐situ and satellite observations

Abstract

The physical mechanisms that take place under sea-breeze (SB) conditions in the Palma basin (Mallorca island, western Mediterranean sea) are analysed through the inspection of data from automatic weather stations (AWS) during the period 2009-2017. Satellite-derived land-surface and sea-surface temperatures (LST and SST, respectively) are used to compute the surface temperature difference (LST-SST) in the Palma basin. It is found that during daytime hourly averages for each month of this difference are always positive and maximal during summer time. A method is proposed to select the SB events using data from AWS. SB conditions are mainly reported during the warm months of the year (from April to September). Results from the statistical analysis of the selected SB events show that the morning reversal strongly depends on the speed and direction of the large-scale winds. Besides, weak wind conditions are reported during the morning reversal and once the SB starts the cold advection from the sea counteracts the radiative heating and the 2-m temperature levels off. The maximum surface temperature difference under SB conditions is larger than 5 C and it is often reported several hours after the morning reversal. About 2 hr later the maximum wind speed is formed, strongly influenced by the amount of soil moisture.

Synoptic Impacts on the Occurrence of Mesoscale Boundaries and Their Associated Convection Over an Area of Sharp Vegetation Contrast

“…The mean 2-m temperature at 0800 LST is basically 3°C higher in T1 and T5 than in T2. As suggested in Grau et al (2020) based on high-resolution satellite observations, a higher environmental temperature tends to accompany a larger land-sea ΔT, which contributes to the establishment of sea breeze circulation. Here, it is difficult to use the global reanalysis data to directly resolve a realistic value of ΔT between the irrigated and arid areas.…”

“…To understand the synoptic pattern preference, the near‐surface temperature and ambient flow were investigated. These two factors have been widely recognized as playing the most fundamental role in determining sea/lake breeze occurrence (e.g., Atkins & Wakimoto, 1997; Biggs & Graves, 1962; Grau et al., 2020; Laird et al., 2001), but their impacts on vegetation‐contrast‐induced boundaries are less well documented.…”

“…(2020) showed that a higher environmental temperature tended to accompany a larger surface temperature difference (Δ T ) between land and sea, which contributed to the establishment of sea breeze circulation. Observational (e.g., Atkins & Wakimoto, 1997; Azorin‐Molina & Chen, 2008; Grau et al., 2020; Laird et al., 2001) and numerical (e.g., Arritt, 1993; Crosman & Horel, 2010; Seroka et al., 2018; Zhong & Takle, 1993) studies have shown that an opposing (i.e., offshore) synoptic‐scale flow, rather than a supporting (i.e., onshore) flow, serves to strengthen sea/lake breeze circulations. For the sea breezes over the Florida peninsula, offshore (onshore) flow days are observed when the east‐west ridge axis of the Bermuda high is south (north) of the Florida peninsula (Atkins & Wakimoto, 1997).…”

Impacts of Coastal Breezes on the Environment and Human Life: The Case of Mallorca (Western Mediterranean)

“…The sea breeze develops as long as the thermal difference between sea temperature (SST, averaged sea surface temperature) and land temperature (LST, averaged land surface temperature) is maintained. Under sea-breeze conditions in the bay of Palma, Grau et al [24] found that the difference between LST and SST is greater than 5 • C during the central hours of the day.…”

Lake-land breezes over a small elongated lake (Kozjak, Plitvice Lakes, Croatia)

“…While numerous studies address SLBs (e.g., Simpson, 1996;Miller et al, 2003 and references therein;Nitis et al, 2005;Klaić et al, 2009;Babić et al, 2012;Jiménez et al, 2016;Grau et al, 2020) or LLBs over large lakes (e.g., Keen and Lyons, 1978;Arritt, 1987;Comer and McKendry, 1993;Laird et al, 2001;Sills et al, 2011;Gu et al, 2016), only a few authors have reported on LLBs produced by small lakes or reservoirs (Asefi-Najafabady et al, 2012;Giovannini et al, 2015). In terms of morphometry, small, medium, and large lakes correspond to maximum lake fetches (d) of d < 50 km, d ≈ 50-100 km, and d > 100 km, respectively (e.g., Crossman and Horel, 2010).…”