A Sea Breeze Study during Ticosonde-NAME 2004 in the Central Pacific of Costa Rica: Observations and Numerical Modeling

Abstract

Surface and upper air observations and MM5v3 simulations examined the structure and inland penetration of sea breeze (SB) along the Grande de Tárcoles river basin (GTRB), central Pacific, Costa Rica, for two different intensity regimes of the Caribbean Low-Level Jet (CLLJ). Data comprise the period of 1 July to 16 September 2004 from Ticosonde-North American Monsoon Experiment, and a local University of Costa Rica-National Meteorological Institute field campaign. Maximum precipitation occurs between 14:00–17:00 LST, showing a time lag of 2 to 3 h after the temperature maximum, suggesting that local diurnal heating is key to convection. July–August precipitation exhibited a rainfall decrease along GTRB due to the SB dynamical processes interaction with a strong CLLJ. The SB maximum inland incursion was 24 km, with no evidence of its penetration into the Central Valley. The MM5v3 simulations for two convective and boundary layer (BL) schemes captured some SB structure features along the GTRB. Comparison of model results with observed data shows deficiencies in the model representation of the surface flow near coastal regions. Differences may be the result of time lag model’s poor responses to actual early morning BL sea–land temperature gradients. MM5v3 configurations used in this study resulted in biased wind speed simulations.

WWLLN Hot and Cold-Spots of Lightning Activity and Their Relation to Climate in an Extended Central America Region 2012–2020

“…Diurnal land-sea breezes are also relevant modes of mesoscale circulation in this region, however, convective activity and potential lightning variability depend on the interaction of local winds with the trade wind system, especially with the seasonal strength of the Caribbean Low-Level Jet. A recent study of sea breeze (SB), using observations in the Pacific coast of Costa Rica, showed that observed precipitation was a maximum between 14:00-17:00 LST, in agreement with local diurnal heating and the development of convection [47]. Data comprised the period of 1 July to 16 September 2004 from Ticosonde-North American Monsoon Experiment, and a local University of Costa Rica-National Meteorological Institute field campaign.…”

“…The ECA is characterized, besides the CLLJ, by other low-level wind streams: the Chocó jet (CJ) [24] in the ETP, the jet over the Venezuelan Llanos [46], and the so-called gap winds along Central America [23,34,35]. These strong currents have significant relevance to local circulations such as sea breezes [47], intense convective activity, and regional precipitation distribution. The CJ located near Colombia, is composed of winds that are colder and moister than continental air.…”

Tropical Easterly Waves Over Costa Rica and Their Relationship to the Diurnal Cycle of Rainfall

“…The near surface zonal and meridional winds (Figure 2f) also indicate some sensitivity to TEW phase, with more southwesterly conditions favored during the late morning and early afternoon of active phases. That is, TEW active phases promote an enhancement in the diurnal evolution of winds at the observation site, which exhibit a partial reversal in direction between the daytime and nighttime hours (Mora et al., 2020). This behavior may be indicative of a local mountain‐valley breeze circulation, with daytime upsloping (southerly/southwesterly) flow toward the higher topography to the north and east of SJO (see Figure S1 in Supporting Information ).…”

“…Coupling with the diurnal cycle is a potentially significant consideration for evaluating and interpreting the TEW-precipitation relationship over land. Indeed, as with many land regions in the Tropics (Liu & Zipser, 2008;Rapp et al, 2014;Yang & Slingo, 2001), rainfall over Costa Rica exhibits a pronounced late afternoon peak (Mora et al, 2020; see also Figure 1 below). To leading order, such diurnal phasing over land arises from interaction with the surface, as solar heating over course of the day grows and destabilizes the atmospheric boundary layer.…”

Sensitivity of precipitation and atmospheric low-level circulation patterns to domain size and choice of parameterization schemes in RegCM4.4 over Central America

“…In this respect, the CLLJ is considered an important dynamical mechanism associated with the regional rainfall distribution at different temporal and spatial scales (e.g. Mora et al 2020 for sea breeze, Amador & Arce-Fernández 2022 for regional lightning densities). Therefore, the CCA domain at 50 km (0.44°) horizontal resolution and 18 sigma vertical levels (model top at 50 hPa), with a relaxation zone of 10° around the boundaries (CCA+) is the basis to increase domain size in the RegCM4.4 model.…”