scholarly journals Connections between wintertime jet stream variability, oceanic surface heating, and transient eddy activity in the North Pacific

2008 ◽  
Vol 113 (D21) ◽  
Author(s):  
Xuejuan Ren ◽  
Yaocun Zhang ◽  
Yang Xiang
Keyword(s):  
North Pacific ◽  
Surface Heating ◽  
Jet Stream ◽  
Transient Eddy ◽  
Eddy Activity ◽  
The North ◽  
Oceanic Surface ◽  
The North Pacific

scholarly journals Interdecadal changes in synoptic transient eddy activity over the Northeast Pacific and their role in tropospheric Arctic amplification

2021 ◽  
Author(s):  
Dong Xiao ◽  
Hongli Ren
Keyword(s):  
Heat Flux ◽  
North Pacific ◽  
The Arctic ◽  
Transient Eddy ◽  
Arctic Amplification ◽  
Eddy Activity ◽  
The North ◽  
Eddy Heat Flux ◽  
Subtropical Jet ◽  
The North Pacific

AbstractArctic amplification refers to the greater surface warming of the Arctic than of other regions during recent decades. A similar phenomenon occurs in the troposphere and is termed “tropospheric Arctic amplification” (TAA). The poleward eddy heat flux and eddy moisture flux are critical to Arctic warming. In this study, we investigate the synoptic transient eddy activity over the North Pacific associated with TAA and its relationship with the subtropical jet stream, and propose the following mechanism. A poleward shift of the subtropical jet axis results in anomalies of the meridional gradient of zonal wind over the North Pacific, which drive a meridional dipole pattern of synoptic transient wave intensity over the North Pacific, referred to as the North Pacific Synoptic Transient wave intensity Dipole (NPSTD). The NPSTD index underwent an interdecadal shift in the late 1990s accompanying that of the subtropical jet stream. During the positive phase of the NPSTD index, synoptic eddy heat flux transports more heat to the Arctic Circle, and the eddy heat flux diverges, increasing Arctic temperature. This mechanism highlights the need to consider synoptic transient eddy activity over the North Pacific as the link between the mean state of the North Pacific subtropical upper jet and TAA.

BREAKING GRAVITY WAVES ON A JET STREAM OVER THE NORTH PACIFIC

Weather ◽  
1971 ◽  
Vol 26 (7) ◽  
pp. 306-307 ◽  
Author(s):  
J. R. C. Young
Keyword(s):  
Gravity Waves ◽  
North Pacific ◽  
Jet Stream ◽  
The North ◽  
The North Pacific

scholarly journals Development and Maintenance Mechanism for the Semiannual Oscillation of the North Pacific Upper-Level Circulation

2014 ◽  
Vol 27 (10) ◽  
pp. 3767-3783 ◽  
Author(s):  
Tsing-Chang Chen ◽  
Jenq-Dar Tsay
Keyword(s):  
North Pacific ◽  
Function Analysis ◽  
Dynamic Processes ◽  
Jet Stream ◽  
The North ◽  
Transient Activity ◽  
Vorticity Flux ◽  
The North Pacific ◽  
Maximum Minimum ◽  
Semiannual Oscillation

Abstract The north–south semiannual oscillation (SAO) of the North Pacific jet stream, part of the atmospheric SAO in the Northern Hemisphere, can be well depicted by the semiannual component of the monthly-mean eddy streamfunction. Expressed by the semiannual eddy streamfunction budget, the dynamic processes develop and maintain the SAO, including the adjustment between vorticity advection and convergence of vorticity flux of the monthly-mean mode and the convergence of transient vorticity flux. An empirical orthogonal function analysis of these dynamic processes shows an east–west elongated cyclonic (anticyclonic) cell of the semiannual eddy streamfunction anomaly, which appears in January and July (October and April) south of the Siberia–Alaska landmass. The maximum (minimum) adjustment processes by the monthly-mean mode and the maximum (minimum) feedback impact of transient activity on the SAO occur in December and June (September and March), a month ahead of the maximum (minimum) north–south SAO of the North Pacific jet stream. Because vorticity is supplied by the convergence of vorticity flux associated with divergent flow, the SAO for the rotational flow is established by diabatic heat and heat transport through the divergent circulation over the North Pacific Ocean, and by precipitation maintained by convergence of water vapor flux along the oceanic storm track. Additionally, the feedback impact of the modulated transient activity affects the SAO development of the atmospheric rotational and divergent circulations, and the hydrological cycle.

Hawaiian Regional Climate Variability during Two Types of El Niño

2020 ◽  
Vol 33 (22) ◽  
pp. 9929-9943
Author(s):  
Bo-Yi Lu ◽  
Pao-Shin Chu ◽  
Sung-Hun Kim ◽  
Christina Karamperidou
Keyword(s):  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Moisture Flux ◽  
Jet Stream ◽  
Flux Divergence ◽  
The North ◽  
The Impact ◽  
The North Pacific ◽  
Moisture Flux Divergence

AbstractThe large-scale atmospheric circulation of the North Pacific associated with two types of El Niño—the eastern Pacific (EP) and central Pacific (CP)—is studied in relation to Hawaiian winter (December–February) rainfall and temperature. The eastern and central equatorial Pacific undergo active convective heating during EP El Niño winters. The local Hadley circulation is enhanced and an upper-level westerly jet stream of the North Pacific is elongated eastward. Due to the impact of both phenomena, stronger anomalous descending motion, moisture flux divergence anomalies near Hawaii, and reduction of easterly trade winds, which are characteristic of EP winters, are unfavorable for winter rainfall in Hawaii. As a result of this robust signal, dry conditions prevail in Hawaii and the standard deviation of rainfall during EP winters is smaller than the climatology. For CP winters, the maximum equatorial ocean warming is weaker and shifted westward to near the date line. The subtropical jet stream retreats westward relative to EP winters and the anomalously sinking motion near Hawaii is variable and generally weaker. Although the anomalous moisture flux divergence still exists over the subtropical North Pacific, its magnitude is weaker relative to EP winters. Without strong external forcing, rainfall in the Hawaiian Islands during CP winters is close to the long-term mean. The spread of rainfall from one CP event to another is also larger. The near-surface minimum temperature from three stations in Hawaii reveals cooling during EP winters and slight warming during CP winters.

Responses of the East Asian jet stream to the North Pacific subtropical front in spring

2017 ◽  
Vol 34 (2) ◽  
pp. 144-156 ◽  
Author(s):  
Leying Zhang ◽  
Haiming Xu ◽  
Ning Shi ◽  
Jiechun Deng
Keyword(s):  
North Pacific ◽  
East Asian ◽  
Jet Stream ◽  
Subtropical Front ◽  
The North ◽  
East Asian Jet Stream ◽  
The North Pacific
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