Linear breeze scaling: from large‐scale land/sea breezes to mesoscale inland breezes

Abstract

Sea/land breezes and inland breezes have in common the 'breeze' appellation but are essentially different. The land/sea-breeze horizontal extent exceeds 100 km, with the Coriolis effect dominating its dynamics. Conversely, inland breezes are confined between alternating patches of cold and warm surface temperature, over horizontal ranges never exceeding a few kilometres, with negligible Coriolis effect. Both land/sea-breeze and inland-breeze systems are embedded within the planetary boundary layer. Despite their superficial resemblance, however, their physics differs and this article attempts to determine the parameters controlling the transition between the processes driving large-scale land/sea breezes and those driving inland breezes.Rotunno's linear model of the sea breeze is extended in order to describe the transition from the sea-breeze regime to the inland-breeze regime, especially in terms of scaling laws. The scaling in the sea-breeze regime obtained by Rotunno is recovered. In this regime, the breeze cell tends to have a horizontal extent comparable to the Rossby radius. For the inland-breeze regime previously studied by Anthes, an important contribution of the present work is to take into account the effect of friction. This effect is non-trivial, as it introduces an inner region with depth controlled by friction. We demonstrate this effect by performing an asymptotic analysis over a range of horizontal scales that are smaller than the Rossby radius but still much larger than the planetary boundary-layer depth, hence near-hydrostatic. All the dominant terms of the breeze circulation budget are within the inner layer, where friction and buoyancy dominate the Coriolis effect and the outer-layer terms and determine the breeze-cell shape and intensity.

North-western Mediterranean sea-breeze circulation in a regional climate system model

“…The sea breeze front thus penetrates inland over a horizontal range of about 100-150 km in the Rhône valley which is also in agreement with the measurements ( Fig. 2; see also Table 2 in Drobinski et al 2006) and scaling laws which predict the typical horizontal extent to be of the order of the Rossby deformation radius z i N∕f ∼ 100 km (with z i ∼ 1 km the atmospheric boundary layer depth, N ∼ 10 −2 s −1 the Brunt-Väisälä frequency and f ∼ 10 −4 s −1 the Coriolis parameter at about 45° latitude; see Rotunno 1983;Dalu and Pielke 1989;Drobinski and Dubos 2009;Drobinski et al 2011). However, both the CTL and CPL simulations still overestimate significantly the onshore surface air temperature by nearly +5 °C (Fig.…”

“…The wind systems alternate between nocturnal katabatic flow combined with land breeze and diurnal anabatic flow combined with seabreeze which typically blow between 2 m s −1 at night and 4 m s −1 during daytime . Such values are consistently with scaling laws (Walsh 1974;Rotunno 1983;Niino 1987;Steyn 1998;Dalu and Pielke 1989;Steyn 2003;Drobinski and Dubos 2009;Drobinski et al 2011). The typical 2 m s −1 diurnal amplitude is more difficult to capture in the observations than in the simulations which simulate a much clearer diurnal cycle with typical nighttime wind speed of 1-2 m s −1 and daytime of 4-5 m s −1 .…”

“…The east-west SST gradient is present in the CPL simulation with however a too warm SST in the region of the persisting cold anomaly (+1°) and a fairly accurate value of SST east of 5°E. The modifications of the SST due to atmosphere/ocean coupling are visible over the whole investigated domain and therefore at a distance of typically 100 km from the shore where they can affect the atmospheric response and the land-sea breeze system (Rotunno 1983;Drobinski and Dubos 2009). …”

“…Such differential heating produces breeze systems which can extend over a horizontal range of 100-150 km inland and play an important role in inland transport of moisture (Bastin et al 2005a. The horizontal extent of the breeze circulation is expected to be even larger in the Southern shore of the Mediterranean region as it scales as the Rossby deformation radius, which is inversely proportional to the Coriolis parameter (Rotunno 1983;Dalu and Pielke 1989;Drobinski and Dubos 2009;Drobinski et al 2011). The inland penetration which controls inland moisture advection and often determines the band where convection is triggered during warm seasons, can be modulated by interaction with mountain slopes (Kusuda and Alpert 1983;Bastin and Drobinski 2005), channeling in local valleys (Bastin et al 2005a, b) or by synoptic wind (Estoque 1962;Arritt 1993), and particularly by Mistral or by major urban areas (Lemonsu et al 2006).…”

Sea and Lake Breezes: A Review of Numerical Studies

“…The following topics are not extensively discussed: pollutant dispersion models (Clappier et al 2000;Melas et al 2006), land-surface models (Cheng and Byun 2008), linear and analytical models (Rotunno 1983;Niino 1987;Dalu and Pielke 1989;Qian et al 2009;Drobinski and Dubos 2009), laboratory experiments (Simpson 1997;Cenedese et al 2000;Hara et al 2009), land breezes (Buckley and Kurzeja 1997), and convective internal boundary-layer growth Kuwagata et al 1994;Levitin and Kambezidis 1997;Liu et al 2001;Miller et al 2003).…”