Effects of Central American Mountains on the Eastern Pacific Winter ITCZ and Moisture Transport*

2005 ◽  
Vol 18 (18) ◽  
pp. 3856-3873 ◽  
Author(s):  
Haiming Xu ◽  
Shang-Ping Xie ◽  
Yuqing Wang ◽  
R. Justin Small
Keyword(s):  
Central America ◽  
Climate Model ◽  
Warm Pool ◽  
Central American ◽  
Eastern Pacific ◽  
Global Ocean ◽  
Boreal Winter ◽  
The Pacific ◽  
Pacific Warm Pool ◽  
Eastern Pacific Warm Pool

Abstract The intertropical convergence zone (ITCZ) is displaced to the south edge of the eastern Pacific warm pool in boreal winter, instead of being collocated. A high-resolution regional climate model is used to investigate the mechanism for this displaced ITCZ. Under the observed sea surface temperature (SST) and lateral boundary forcing, the model reproduces the salient features of eastern Pacific climate in winter, including the southward displaced ITCZ and gap wind jets off the Central American coast. As the northeast trades impinge on the mountains of Central America, subsidence prevails off the Pacific coast, pushing the ITCZ southward. Cold SST patches induced by three gap wind jets have additional effects of keeping the ITCZ away from the coast. In an experiment in which both the Central American mountains and their effect on SST are removed, the ITCZ shifts considerably northward to cover much of the eastern Pacific warm pool. The Central American mountains are considered important to freshwater transport from the Atlantic to the Pacific Ocean, which in turn plays a key role in global ocean thermohaline circulation. The results of this study show that this transport across Central America is not very sensitive to the fine structure of the orography because the increased flow in the mountain gaps in a detailed topography run tends to be compensated for by broader flow in a smoothed topography run. Implications for global climate modeling are discussed.

scholarly journals Human-caused Indo-Pacific warm pool expansion

2016 ◽  
Vol 2 (7) ◽  
pp. e1501719 ◽  
Author(s):  
Evan Weller ◽  
Seung-Ki Min ◽  
Wenju Cai ◽  
Francis W. Zwiers ◽  
Yeon-Hee Kim ◽  
...  
Keyword(s):  
Climate Model ◽  
Hydrological Cycle ◽  
Heat Content ◽  
Warm Pool ◽  
Small Island ◽  
Past Century ◽  
The Pacific ◽  
Pacific Warm Pool ◽  
Basin Scale ◽  
Climate Model Simulations

The Indo-Pacific warm pool (IPWP) has warmed and grown substantially during the past century. The IPWP is Earth’s largest region of warm sea surface temperatures (SSTs), has the highest rainfall, and is fundamental to global atmospheric circulation and hydrological cycle. The region has also experienced the world’s highest rates of sea-level rise in recent decades, indicating large increases in ocean heat content and leading to substantial impacts on small island states in the region. Previous studies have considered mechanisms for the basin-scale ocean warming, but not the causes of the observed IPWP expansion, where expansion in the Indian Ocean has far exceeded that in the Pacific Ocean. We identify human and natural contributions to the observed IPWP changes since the 1950s by comparing observations with climate model simulations using an optimal fingerprinting technique. Greenhouse gas forcing is found to be the dominant cause of the observed increases in IPWP intensity and size, whereas natural fluctuations associated with the Pacific Decadal Oscillation have played a smaller yet significant role. Further, we show that the shape and impact of human-induced IPWP growth could be asymmetric between the Indian and Pacific basins, the causes of which remain uncertain. Human-induced changes in the IPWP have important implications for understanding and projecting related changes in monsoonal rainfall, and frequency or intensity of tropical storms, which have profound socioeconomic consequences.

scholarly journals Eastern Pacific Warm Pool paleosalinity and climate variability: 0-30 kyr

2006 ◽  
Vol 21 (3) ◽  
Author(s):  
H. M. Benway ◽  
A. C. Mix ◽  
B. A. Haley ◽  
G. P. Klinkhammer
Keyword(s):  
Climate Variability ◽  
Warm Pool ◽  
Eastern Pacific ◽  
Pacific Warm Pool ◽  
Eastern Pacific Warm Pool

Nutricline shoaling in the eastern Pacific warm pool during the last two glacial maxima

2013 ◽  
Vol 70 (1) ◽  
pp. 25-34 ◽  
Author(s):  
Hasrizal Bin Shaari ◽  
Masanobu Yamamoto ◽  
Tomohisa Irino ◽  
Tadamichi Oba
Keyword(s):  
Warm Pool ◽  
Eastern Pacific ◽  
Pacific Warm Pool ◽  
Eastern Pacific Warm Pool

scholarly journals Explicit Convection over the Western Pacific Warm Pool in the Community Atmospheric Model

2005 ◽  
Vol 18 (10) ◽  
pp. 1482-1502 ◽  
Author(s):  
MichałZ. Ziemiański ◽  
Wojciech W. Grabowski ◽  
Mitchell W. Moncrieff
Keyword(s):  
Large Scale ◽  
Climate Model ◽  
Atmospheric Model ◽  
Warm Pool ◽  
Western Pacific ◽  
Boreal Winter ◽  
Western Pacific Warm Pool ◽  
Climate System Model ◽  
Pacific Warm Pool ◽  
Standard Configuration

Abstract This paper reports on the application of the cloud-resolving convection parameterization (CRCP) to the Community Atmospheric Model (CAM), the atmospheric component of the Community Climate System Model (CCSM). The cornerstone of CRCP is the use of a two-dimensional zonally oriented cloud-system-resolving model to represent processes on mesoscales at the subgrid scale of a climate model. Herein, CRCP is applied at each climate model column over the tropical western Pacific warm pool, in a domain spanning 10°S–10°N, 150°–170°E. Results from the CRCP simulation are compared with CAM in its standard configuration. The CRCP simulation shows significant improvements of the warm pool climate. The cloud condensate distribution is much improved as well as the bias of the tropopause height. More realistic structure of the intertropical convergence zone (ITCZ) during the boreal winter and better representation of the variability of convection are evident. In particular, the diurnal cycle of precipitation has phase and amplitude in good agreement with observations. Also improved is the large-scale organization of the tropical convection, especially superclusters associated with Madden–Julian oscillation (MJO)-like systems. Location and propagation characteristics, as well as lower-tropospheric cyclonic and upper-tropospheric anticyclonic gyres, are more realistic than in the standard CAM. Finally, the simulations support an analytic theory of dynamical coupling between organized convection and equatorial beta-plane vorticity dynamics associated with MJO-like systems.

Convection and Easterly Wave Structures Observed in the Eastern Pacific Warm Pool during EPIC-2001

2003 ◽  
Vol 60 (15) ◽  
pp. 1754-1773 ◽  
Author(s):  
Walter A. Petersen ◽  
Robert Cifelli ◽  
Dennis J. Boccippio ◽  
Steven A. Rutledge ◽  
Chris Fairall
Keyword(s):  
Warm Pool ◽  
Eastern Pacific ◽  
Easterly Wave ◽  
Pacific Warm Pool ◽  
Eastern Pacific Warm Pool

scholarly journals Air–Sea Interaction over the Eastern Pacific Warm Pool: Gap Winds, Thermocline Dome, and Atmospheric Convection*

2005 ◽  
Vol 18 (1) ◽  
pp. 5-20 ◽  
Author(s):  
Shang-Ping Xie ◽  
Haiming Xu ◽  
William S. Kessler ◽  
Masami Nonaka
Keyword(s):  
High Resolution ◽  
Warm Pool ◽  
The Other ◽  
Eastern Pacific ◽  
Cold Spot ◽  
Turbulent Heat ◽  
Strong Wind ◽  
Atmospheric Convection ◽  
Pacific Warm Pool ◽  
Eastern Pacific Warm Pool

Abstract High-resolution satellite observations are used to investigate air–sea interaction over the eastern Pacific warm pool. In winter, strong wind jets develop over the Gulfs of Tehuantepec, Papagayo, and Panama, accelerated by the pressure gradients between the Atlantic and Pacific across narrow passes of Central American cordillera. Patches of cold sea surface temperatures (SSTs) and high chlorophyll develop under these wind jets as a result of increased turbulent heat flux from the ocean and enhanced mixing across the base of the ocean mixed layer. Despite a large decrease in SST (exceeding 3°C in seasonal means), the cold patches associated with the Tehuantepec and Papagayo jets do not have an obvious effect on local atmospheric convection in winter since the intertropical convergence zone (ITCZ) is located farther south. The cold patch of the Panama jet to the south, on the other hand, cuts through the winter ITCZ and breaks it into two parts. A pronounced thermocline dome develops west of the Gulf of Papagayo, with the 20°C isotherm only 30 m deep throughout the year. In summer when the Panama jet disappears and the other two wind jets weaken, SST is 0.5°C lower over this Costa Rica Dome than the background. This cold spot reduces local precipitation by half, punching a hole of 500 km in diameter in the summer ITCZ. The dome underlies a patch of open-ocean high chlorophyll. This thermocline dome is an ocean dynamic response to the positive wind curls south of the Papagayo jet, which is optimally oriented to excite ocean Rossby waves that remotely affect the ocean to the west. The meridionally oriented Tehuantepec and Panama jets, by contrast, only influence the local thermocline depth with few remote effects on SST and the atmosphere. The orographical-triggered air–sea interaction described here is a good benchmark for testing high-resolution climate models now under development.

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