scholarly journals Impact of the Atlantic Warm Pool on the Summer Climate of the Western Hemisphere

2007 ◽  
Vol 20 (20) ◽  
pp. 5021-5040 ◽  
Author(s):  
Chunzai Wang ◽  
Sang-ki Lee ◽  
David B. Enfield
Keyword(s):  
North Atlantic ◽  
Moisture Transport ◽  
Caribbean Sea ◽  
Warm Pool ◽  
Western Hemisphere ◽  
Trade Winds ◽  
The North ◽  
Atlantic Warm Pool ◽  
Tropical North Atlantic ◽  
The Caribbean

Abstract The Atlantic warm pool (AWP) is a large body of warm water that comprises the Gulf of Mexico, the Caribbean Sea, and the western tropical North Atlantic. Located to its northeastern side is the North Atlantic subtropical high (NASH), which produces the tropical easterly trade winds. The easterly trade winds carry moisture from the tropical North Atlantic into the Caribbean Sea, where the flow intensifies, forming the Caribbean low-level jet (CLLJ). The CLLJ then splits into two branches: one turning northward and connecting with the Great Plains low-level jet (GPLLJ), and the other continuing westward across Central America into the eastern North Pacific. The easterly CLLJ and its westward moisture transport are maximized in the summer and winter, whereas they are minimized in the fall and spring. This semiannual feature results from the semiannual variation of sea level pressure in the Caribbean region owing to the westward extension and eastward retreat of the NASH. The NCAR Community Atmospheric Model and observational data are used to investigate the impact of the climatological annual mean AWP on the summer climate of the Western Hemisphere. Two groups of the model ensemble runs with and without the AWP are performed and compared. The model results show that the effect of the AWP is to weaken the summertime NASH, especially at its southwestern edge. The AWP also strengthens the summertime continental low over the North American monsoon region. In response to these pressure changes, the CLLJ and its moisture transport are weakened, but its semiannual feature does not disappear. The weakening of the easterly CLLJ increases (decreases) moisture convergence to its upstream (downstream) and thus enhances (suppresses) rainfall in the Caribbean Sea (in the far eastern Pacific west of Central America). Model runs show that the AWP’s effect is to always weaken the southerly GPLLJ. However, the AWP strengthens the GPLLJ’s northward moisture transport in the summer because the AWP-induced increase of specific humidity overcomes the weakening of southerly wind, and vice versa in the fall. Finally, the AWP reduces the tropospheric vertical wind shear in the main development region that favors hurricane formation and development during August–October.

Influence of the North American Dipole on the Atlantic Warm Pool

2021 ◽  
Author(s):  
Jinghua Chao ◽  
Guangzhou Fan ◽  
Ruiqiang Ding ◽  
Quanjia Zhong ◽  
Zhenchao Wang
Keyword(s):  
Air Temperature ◽  
North Atlantic ◽  
North American ◽  
Southern Oscillation ◽  
Warm Pool ◽  
Atmospheric Forcing ◽  
The North ◽  
Remote Forcing ◽  
Atlantic Warm Pool ◽  
Tropical North Atlantic

Abstract The Atlantic warm pool(AWP) of water having a temperature above 28.5°C encompasses the Gulf of Mexico, the Caribbean, and the western tropical North Atlantic, influencing the regional and global climate. Much of the AWP interannual variabillity has been thought to be an outcome of external remote forcing by climate variability outside the tropical Atlantic, such as the El Niño-Southern Oscillation (ENSO) or the North Atlantic Oscillation (NAO). This study indicates that the North American dipole (NAD), exemplified by a north-south seesaw in sea level pressure anomalies over the western tropical North Atlantic and northeastern North America, may provide another integral remote forcing source to influence the AWP. Both observational and model data prove that a strong positive (negative) phase of the winter NAD tends to inhibit (favor) the development of AWP in its area and depth in subsequent months. As opposed to the NAO, the NAD plays a more pivotal role in influencing the AWP due to its effectiveness in forcing the TNA SST variability, which means that AWP variability may be more of a lagging response to NAD atmospheric forcing than a lagging response to NAO atmospheric forcing. Additional analysis indicates that the winter NAD-like atmospheric signal may be stored in the following AWP, thus markedly influencing the TNA precipitation and air temperature in summer. It is speculated that the AWP may act as a bridge linking winter NAD to the following summer precipitation and air temperature in the TNA region.

scholarly journals Checklist of the salps (Tunicata, Thaliacea) from the Western Caribbean Sea with a key for their identification and comments on other North Atlantic salps

Zootaxa ◽  
2012 ◽  
Vol 3210 (1) ◽  
pp. 50 ◽  
Author(s):  
CLARA MARÍA HEREU ◽  
EDUARDO SUÁREZ-MORALES
Keyword(s):  
North Atlantic ◽  
Caribbean Sea ◽  
Depth Range ◽  
Tropical Atlantic ◽  
The North ◽  
New Information ◽  
Plankton Biomass ◽  
Western Caribbean ◽  
The Caribbean

In waters of the Northwestern Atlantic pelagic tunicates may contribute significantly to the plankton biomass; however, theregional information on the salp fauna is scarce and limited to restricted sectors. In the Caribbean Sea (CS) and the Gulf ofMexico (GOM) the composition of the salpid fauna is still poorly known and this group remains among the less studiedzooplankton taxa in the Northwestern Tropical Atlantic. A revised checklist of the salp species recorded in the North At-lantic (NA, 0–40° N) is provided herein, including new information from the Western Caribbean. Zooplankton sampleswere collected during two cruises (March 2006, January 2007) within a depth range of 0–941 m. A total of 14 species wererecorded in our samples, including new records for the CS and GOM area (Cyclosalpa bakeri Ritter 1905), for the CS (Cy-closalpa affinis (Chamisso, 1819)), and for the Western Caribbean (Salpa maxima Forskål, 1774). The number of speciesof salps known from the CS and GOM rose to 18. A key for the identification of the species recorded in the region is provided. Studies on the ecological role of salps in several sectors of the NA are scarce and deserve further attention.

Changes across 66°W, the Caribbean Sea and the Western boundaries of the North Atlantic Subtropical Gyre

2018 ◽  
Vol 168 ◽  
pp. 296-309 ◽  
Author(s):  
M. Casanova-Masjoan ◽  
T.M. Joyce ◽  
M.D. Pérez-Hernández ◽  
P. Vélez-Belchí ◽  
A. Hernández-Guerra
Keyword(s):  
North Atlantic ◽  
Caribbean Sea ◽  
Subtropical Gyre ◽  
The North ◽  
The Caribbean ◽  
The North Atlantic

The Intra-Americas Springtime Sea Surface Temperature Anomaly Dipole as Fingerprint of Remote Influences

2010 ◽  
Vol 23 (1) ◽  
pp. 43-56 ◽  
Author(s):  
Ernesto Muñoz ◽  
Chunzai Wang ◽  
David Enfield
Keyword(s):  
Gulf Of Mexico ◽  
North Atlantic ◽  
Caribbean Sea ◽  
Enso Event ◽  
Shortwave Radiation ◽  
Teleconnection Patterns ◽  
The North ◽  
The Pacific ◽  
Sst Anomaly ◽  
The Caribbean

Abstract The influence of teleconnections on the Intra-Americas Sea (IAS; Gulf of Mexico and Caribbean Sea) has been mostly analyzed from the perspective of El Niño–Southern Oscillation (ENSO) on the Caribbean Sea (the latter being an extension of the tropical North Atlantic). This emphasis has overlooked both 1) the influence of other teleconnections on the IAS and 2) which teleconnections affect the Gulf of Mexico climate variability. In this study the different fingerprints that major teleconnection patterns have on the IAS during boreal spring are analyzed. Indices of teleconnection patterns are regressed and correlated to observations of oceanic temperature and atmospheric data from reanalyses and observational datasets. It is found that the Pacific teleconnection patterns that influence the IAS SSTs do so by affecting the Gulf of Mexico in an opposite manner to the Caribbean Sea. These analyzed Pacific climate patterns are the Pacific–North American (PNA) teleconnection, the Pacific decadal oscillation (PDO), and ENSO. The North Atlantic Oscillation (NAO) is related to a lesser degree with the north–south SST anomaly dipole than are Pacific teleconnection patterns. It is also found that the IAS influence from the midlatitude Pacific mostly affects the Gulf of Mexico, whereas the influence from the tropical Pacific mostly affects the Caribbean Sea. Therefore, the combination of a warm ENSO event and a positive PNA event induces a strong IAS SST anomaly dipole between the Gulf of Mexico and the Caribbean Sea during spring. By calculating an index that represents the IAS SST anomaly dipole, it is found that the dipole forms mostly in response to changes in the air–sea heat fluxes. In the Gulf of Mexico the dominant mechanisms are the air–sea differences in humidity and temperature. The changes in shortwave radiation also contribute to the dipole of net air–sea heat flux. The changes in shortwave radiation arise, in part, by the cloudiness triggered by the air–sea differences in humidity, and also by the changes in the convection cell that connects the Amazon basin to the IAS. Weaker Amazon convection (e.g., in the event of a warm ENSO event) reduces the subsidence over the IAS, and henceforth the IAS cloudiness increases (and the shortwave radiation decreases). This study contributes to a greater understanding of how the IAS is influenced by different Pacific and Atlantic teleconnections.

Atlantic Warm Pool: climate variability, thermal ocean-atmosphere interactions and remote response to ENSO and NAO.

2020 ◽  
Author(s):  
Yoania Povea Perez
Keyword(s):  
Climate Variability ◽  
Gulf Of Mexico ◽  
North Atlantic ◽  
Southern Oscillation ◽  
Caribbean Sea ◽  
Warm Pool ◽  
Empirical Orthogonal Functions ◽  
Thermal Component ◽  
Atlantic Warm Pool ◽  
Ocean Atmosphere

<p>The Atlantic Warm Pool (AWP) is a big body of warm water with SST greater or equal to 28.5◦ C, that appears in the Gulf of Mexico, the Caribbean and the western tropical North Atlantic and it is a key element of the climate system. Previous studies have focused on climate variability within the AWP, but did not take into account the distinctive properties of AWP sub-regions. In other cases, obtained results had not been tested against selected databases. This work will try to deal systematically with these limitations. Ocean reanalysis databases have been used in order to detect AWP climate variability, mechanisms through which thermal component of ocean-atmosphere interactions operates and the effect of remote phenomena such as El Niño-Southern Oscillation (ENSO) and North Atlantic Oscillation (NAO).  Empirical Orthogonal Functions, spectral analysis, linear correlation and composites analysis techniques have been used. A large portion of AWP variability comes from Caribbean Sea and Gulf of Mexico while North tropical Atlantic contains a large internal variability. The thermal component of ocean-atmosphere interactions appears partitioned in Gulf of Mexico and Atlantic from Caribbean Sea. SST/latent heat feedback mechanism operates not globally in the AWP but stronger in the open Atlantic sub-region. ENSO+ enhances AWP development, while ENSO- is opposite to both development and decay of AWP. NAO effect is stronger in its negative phase by enhancing the AWP decay.</p>

A Further Study of the Tropical Western Hemisphere Warm Pool

2003 ◽  
Vol 16 (10) ◽  
pp. 1476-1493 ◽  
Author(s):  
Chunzai Wang ◽  
David B. Enfield
Keyword(s):  
North Atlantic ◽  
El Niño ◽  
El Nino ◽  
Longwave Radiation ◽  
South Pacific ◽  
Warm Pool ◽  
Western Hemisphere ◽  
Hadley Cell ◽  
Trade Winds ◽  
Sst Anomalies

Abstract Variability of the tropical Western Hemisphere warm pool (WHWP) of water warmer than 28.5°C, which extends seasonally over parts of the eastern North Pacific, the Gulf of Mexico, the Caribbean, and the western tropical North Atlantic (TNA), was previously studied by Wang and Enfield using the da Silva data from 1945–93. Using additional datasets of the NCEP–NCAR reanalysis field and the NCEP SST from 1950–99, and the Levitus climatological subsurface temperature, the present paper confirms and extends the previous study of Wang and Enfield. The WHWP alternates with northern South America as the seasonal heating source for the Walker and Hadley circulations in the Western Hemisphere. During the boreal winter a strong Hadley cell emanates northward from the Amazon heat source with subsidence over the subtropical North Atlantic north of 20°N, sustaining a strong North Atlantic anticyclone and associated northeast (NE) trade winds over its southern limb in the TNA. This circulation, including the NE trades, is weakened during Pacific El Niño winters and results in a spring warming of the TNA, which in turn induces the development of an unusually large summer warm pool and a wetter Caribbean rainy season. As the WHWP develops in the late boreal spring, the center of tropospheric heating and convection shifts to the WHWP region, whence the summer Hadley circulation emanates from the WHWP and forks into the subsidence regions of the subtropical South Atlantic and South Pacific. During the summers following El Niño, when the warm pool is larger than normal, the increased Hadley flow into the subtropical South Pacific reinforces the South Pacific anticyclone and trade winds, probably playing a role in the transition back to the cool phase of ENSO. Seasonally, surface heat fluxes seem to be primarily responsible for warming of the WHWP. Interannually, all of the datasets suggest that a positive ocean–atmosphere feedback through longwave radiation and associated cloudiness seems to operate in the WHWP. During the winter preceding a large warm pool, there is a strong weakening of the Hadley cell that serves as a “tropospheric bridge” for transferring El Niño effects to the Atlantic sector and inducing warming of the warm pool. Associated with the warm SST anomalies is a decrease in sea level pressure anomalies and an anomalous increase in atmospheric convection and cloudiness. The increase in convective activity and cloudiness results in less longwave radiation loss from the sea surface, which then reinforces SST anomalies. This data-inferred hypothesis of the longwave radiation feedback process needs to be further investigated for its validation in the WHWP.

scholarly journals An Analysis of Low- and High-Frequency Summer Climate Variability around the Caribbean Antilles

2012 ◽  
Vol 25 (11) ◽  
pp. 3942-3952 ◽  
Author(s):  
Isabelle Gouirand ◽  
Mark R. Jury ◽  
Bernd Sing
Keyword(s):  
Climate Variability ◽  
North Atlantic ◽  
High Frequency ◽  
Low Frequency ◽  
Late Summer ◽  
Summer Climate ◽  
The North ◽  
Tropical North Atlantic ◽  
Low Pass ◽  
The Caribbean

This study contrasts the pattern of low-frequency (LF) and high-frequency (HF) climate variability in the eastern Caribbean. A low-pass Butterworth filter is used to study oscillations in rainfall and regional SST on time scales of greater and less than 8 yr in the period 1901–2002. The results show that the southern and northern Antilles are dominated by HF variability, whereas rainfall fluctuations in the eastern Antilles oscillate at quasi-decadal periods over the 102-yr record. In the southern Antilles, the HF rainfall signal derives from a late-summer response to the ENSO phase: warm and dry versus cool and wet. In the northern Antilles, the HF signal relates to a combination of an ENSO and North Atlantic Oscillation (NAO) phase: a warm ENSO and a negative NAO bring wetter conditions, while a cool ENSO and a positive NAO bring drier conditions. The early rainfall LF signal in SST is characterized by a dipole between the North Atlantic and South Atlantic and is associated with cross-equatorial winds that promote convection in the Caribbean. The study analyzes the upper-ocean structure—in particular, a low (high) salinity signal in the tropical North Atlantic (North Pacific) that relates to LF (HF) climate variability.

Non-linearity in the pathway of El Niño-Southern Oscillation to the tropical North Atlantic

2021 ◽  
Author(s):  
Jake W. Casselman ◽  
Andréa S. Taschetto ◽  
Daniela I.V. Domeisen
Keyword(s):  
North Atlantic ◽  
Southern Oscillation ◽  
Static Stability ◽  
Reanalysis Data ◽  
Trade Winds ◽  
The North ◽  
The Pacific ◽  
Tropical North Atlantic ◽  
Sst Anomaly ◽  
The North Atlantic Oscillation

<p>El Niño-Southern Oscillation can influence the Tropical North Atlantic (TNA), leading to anomalous sea surface temperatures (SST) at a lag of several months. Several mechanisms have been proposed to explain this teleconnection. These mechanisms include both tropical and extratropical pathways, contributing to anomalous trade winds and static stability over the TNA region. The TNA SST response to ENSO has been suggested to be nonlinear. Yet the overall linearity of the ENSO-TNA teleconnection via the two pathways remains unclear. Here we use reanalysis data to confirm that the SST anomaly (SSTA) in the TNA is nonlinear with respect to the strength of the SST forcing in the tropical Pacific, as further increases in El Niño magnitudes cease to create further increases of the TNA SSTA. We further show that the tropical pathway is more linear than the extratropical pathway by sub-dividing the inter-basin connection into extratropical and tropical pathways. The extratropical pathway is modulated by the North Atlantic Oscillation (NAO) and the location of the SSTA in the Pacific, but this modulation insufficiently explains the nonlinearity in TNA SSTA. As neither extratropical nor tropical pathways can explain the nonlinearity, this suggests that external factors are at play. Further analysis shows that the TNA SSTA is highly influenced by the preconditioning of the tropical Atlantic SST. This preconditioning is found to be associated with the NAO through SST-tripole patterns.</p>

scholarly journals Nonlinear analysis of the occurrence of hurricanes in the Gulf of Mexico and the Caribbean Sea

2017 ◽  
Author(s):  
Berenice Rojo-Garibaldi ◽  
David Alberto Salas-de-León ◽  
María Adela Monreal-Gómez ◽  
Norma Leticia Sánchez-Santillán ◽  
David Salas-Monreal
Keyword(s):  
Time Series ◽  
Gulf Of Mexico ◽  
Nonlinear Analysis ◽  
North Atlantic ◽  
Chaotic Dynamics ◽  
Chaotic Behavior ◽  
Caribbean Sea ◽  
The North ◽  
The Caribbean ◽  
The Individual

Abstract. Hurricanes are complex systems that carry large amounts of energy. Their impact produces, the majority of the time, natural disasters involving the loss of human lives and of materials and infrastructure in billions of US dollars. However, not everything is negative, as hurricanes are the main source of rainwater for the regions where they develop. In this study, we perform a nonlinear analysis of the time series obtained from 1749 to 2012 of the occurrence of hurricanes in the Gulf of Mexico and the Caribbean Sea. The construction of the hurricane time series was carried out based on the hurricane database of The North Atlantic-basin Hurricane Database (HURDAT), and the published historical information. The Lyapunov exponent indicated that the system presented chaotic dynamics, and the time-series’ spectral analysis along with the nonlinear analysis of the hurricanes time series showed chaotic edge behavior. One possible explanation for this edge is the individual chaotic behavior of hurricanes, either by category or individually, regardless of their category, and their behavior on a regular basis.

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