Features of the Caribbean low level jet

Abstract

ABSTRACT:The Caribbean Low Level Jet (CLLJ) is shown to be a real and dominant climatological feature of the early summer Caribbean climate. It manifests as an intensification in the trade winds in the western Caribbean basin (70°W-80°W) with an east-west axis along 15°N. It is confined to heights below 600 mb and has maximum wind speeds approaching 16 m/s near the surface. The study shows that there is variability in the strength and zonal extent of the CLLJ which can be related to zonal SST gradients between the eastern equatorial Pacific and the north tropical and/or equatorial Atlantic. When the gradient is driven by the Pacific (as in an EL Niño event) the CLLJ winds are intensified to the north and in its southwesternmost quadrant. When the winds are driven by the tropical north Atlantic there is uniform wind intensification about the jet axis. The CLLJ is also linked to a precipitation maximum over the near waters and along the Caribbean coast of Central America (up to 16°N) during June and more so, in July. There is evidence of variation at the northern extent of this wet zone depending on the ocean basin forcing the SST gradient. The CLLJ is also linked to moderate drying in the main Caribbean basin.

A review of observed and projected changes in climate for the islands in the Caribbean

“…We further note that the CLLJ also has a bimodal seasonal cycle with maxima in July and February associated with the movement of the NASH and heating over the tropical South America (Wang and Lee, 2007;Cook and Vizy, 2010). A number of studies note a strong negative correlation between Caribbean precipitation and the strength of the CLLJ (Muñoz et al, 2008;Whyte et al, 2008;Cook and Vizy, 2010;Taylor et al, 2012), particularly during the wet season months. An increase in the CLLJ intensity in July is associated with a decrease in precipitation, whereas a minimum in CLLJ strength in OctoberNovember coincides with peak precipitation in the region.…”

“…2g, h) unlike the precipitation seasonal cycle, but the seasonal cycle of local SLP has two peaks. SLP peaks in boreal winter (the dry season) and again during mid-summer and is also associated with peak intensities in easterly trade winds in the Caribbean Sea (Wang, 2007;Amador, 2008;Muñoz et al, 2008;Whyte et al, 2008). This latter feature is commonly known as the Caribbean low-level jet (CLLJ), which is essentially the intensified easterly trade winds along the southern flank of the NASH resulting from a large meridional pressure gradient in the region.…”

Daily near-surface large-scale atmospheric circulation patterns over the wider Caribbean

“…The CLLJ transports moisture from the tropical Atlantic into the Caribbean Sea, Gulf of Mexico, and influences rainfall in the United States (Gamble and Curtis 2008;Wang 2007;Amador 2008;Cook and Vizy 2010;Muñoz and Enfield 2011). The CLLJ exhibits maximum wind speeds at the 925 hPa level with wind speeds up to 16 m/s (Amador 2008; Whyte et al 2008) while wind speeds at the 10 m level are between 8 and 10 m/s (Chadee and Clarke 2014). It experiences monthly maximum wind speeds in January and July with minima in May and October (Wang and Lee 2007;Wang 2007).…”

“…The CLLJ bifurcates into two branches, one that flows over Central America and into the Pacific while the other connects with the Great Plains low-level jet in the United States (Cook and Vizy 2010). It is modified by SSTs in the Caribbean (Wang and Lee 2007), the ENSO (Amador 2008;Whyte et al 2008), and the North Atlantic Oscillation (NAO) (Wang 2007). The semi-annual cycle of the CLLJ and its relationship to precipitation in the Caribbean have been used to evaluate general circulation and regional climate models (Martin and Schumacher 2011;Taylor et al 2013).…”

Improved long‐term mean annual rainfall fields for Colombia

“…First, the westerly low-level Chocó jet flowing onshore from the Pacific Ocean, tightly linked to the clear-cut diurnal dynamics of mesoscale convective systems over the region (Velasco and Frisch, 1987;Poveda and Mesa, 2000;León et al, 2001;Mapes et al, 2003aMapes et al, , 2003bMejía and Poveda, 2005). Second, the so-called San Andres or Caribbean low-level jet (Amador and Magaña, 1999;Poveda and Mesa, 1999;Wang, 2007;Whyte et al, 2007) and third, a mid-atmosphere jet at 700-600 hPa over Central Colombia . Interestingly, the Chocó and the Caribbean low-level jets exhibit out-phased annual cycles.…”