Role of the western hemisphere warm pool in climate variability over the western North Pacific

2019 ◽  
Vol 53 (5-6) ◽  
pp. 2743-2755 ◽  
Author(s):  
Jae-Heung Park ◽  
Jong-Seong Kug ◽  
Soon-Il An ◽  
Tim Li
Keyword(s):  
Climate Variability ◽  
North Pacific ◽  
Western North Pacific ◽  
Warm Pool ◽  
Western Hemisphere

scholarly journals The Role of Latent Heat Flux in Tropical Cyclogenesis over the Western North Pacific: Comparison of Developing versus Non-Developing Disturbances

2019 ◽  
Vol 7 (2) ◽  
pp. 28 ◽  
Author(s):  
Si Gao ◽  
Shengbin Jia ◽  
Yanyu Wan ◽  
Tim Li ◽  
Shunan Zhai ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
North Pacific ◽  
Western North Pacific ◽  
Specific Humidity ◽  
Near Surface ◽  
Tangential Wind

The possible role of air–sea latent heat flux (LHF) in tropical cyclone (TC) genesis over the western North Pacific (WNP) is investigated using state-of-the-art satellite and analysis datasets. The authors conducted composite analyses of several meteorological variables after identifying developing and non-developing tropical disturbances from June to October of the period 2000 to 2009. Compared to the non-developing disturbances, increased LHF underlying the developing disturbances enhances boundary–layer specific humidity. The secondary circulation then transports more boundary–layer moisture inward and upward and, thus, induces a stronger moist core in the middle troposphere. Accordingly, the air in the core region ascends following a warmer moist adiabat than that in the environment and results in a stronger upper-level warm core, which is associated with a stronger near-surface tangential wind based on the thermal wind balance. This enlarges the magnitude and negative radial gradient of LHF and, thereby, further increases boundary–layer specific humidity. A tropical depression forms when the near-surface tangential wind increases to a certain extent as a result of the continuing positive feedback between near-surface wind and LHF. The results suggest an important role of wind-driven LHF in TC genesis over the WNP.

Dominant Role of Atlantic Multidecadal Oscillation in the Recent Decadal Changes in Western North Pacific Tropical Cyclone Activity

2018 ◽  
Vol 45 (1) ◽  
pp. 354-362 ◽  
Author(s):  
Wei Zhang ◽  
Gabriel A. Vecchi ◽  
Hiroyuki Murakami ◽  
Gabriele Villarini ◽  
Thomas L. Delworth ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
North Pacific ◽  
Western North Pacific ◽  
Dominant Role ◽  
Atlantic Multidecadal Oscillation ◽  
Tropical Cyclone Activity ◽  
Cyclone Activity

scholarly journals The Heat Balance of the Western Hemisphere Warm Pool

2005 ◽  
Vol 18 (14) ◽  
pp. 2662-2681 ◽  
Author(s):  
David B. Enfield ◽  
Sang-ki Lee
Keyword(s):  
Heat Flux ◽  
Gulf Of Mexico ◽  
Heat Balance ◽  
North Pacific ◽  
Mixed Layer Depth ◽  
Warm Pool ◽  
Western Hemisphere ◽  
Flux Divergence ◽  
Pacific Warm Pool ◽  
The Heat Balance

Abstract The thermodynamic development of the Western Hemisphere warm pool and its four geographic subregions are analyzed. The subregional warm pools of the eastern North Pacific and equatorial Atlantic are best developed in the boreal spring, while in the Gulf of Mexico and Caribbean, the highest temperatures prevail during the early and late summer, respectively. For the defining isotherms chosen (≥27.5°, ≥28.0°, ≥28.5°C) the warm pool depths are similar to the mixed-layer depth (20–40 m) but are considerably less than the Indo–Pacific warm pool depth (50–60 m). The heat balance of the WHWP subregions is examined through two successive types of analysis: first by considering a changing volume (“bubble”) bounded by constant temperature wherein advective fluxes disappear and diffusive fluxes can be estimated as a residual, and second by considering a slab layer of constant dimensions with the bubble diffusion estimates as an additional input and the advective heat flux divergence as a residual output. From this sequential procedure it is possible to disqualify as being physically inconsistent four of seven surface heat flux climatologies: the NCEP–NCAR reanalysis (NCEP1) and the ECMWF 15-yr global reanalysis (ERA-15) because they yield a nonphysical diffusion of heat into the warm pools from their cooler surroundings, and the unconstrained da Silva and Southampton datasets because their estimated diffusion rates are inconsistent with the smaller rates of the better understood Indo–Pacific warm pool when the bubble analysis is applied to both regions. The remaining surface flux datasets of da Silva and Southampton (constrained) and Oberhuber have a much narrower range of slab surface warming (+25 ± 5 W m−2) associated with bubble residual estimates of total diffusion of –5 to –20 W m−2 (±5 W m−2) and total advective heat flux divergence of –2 to –14 W m−2 (±5 W m−2). The latter are independently confirmed by direct estimates using wind stress data and drifters for the Gulf of Mexico and eastern North Pacific subregions.

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