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

Variability of North Pacific Sea Ice and East Asia–North Pacific Winter Climate

2007 ◽  
Vol 20 (10) ◽  
pp. 1991-2001 ◽  
Author(s):  
Jiping Liu ◽  
Zhanhai Zhang ◽  
Radley M. Horton ◽  
Chunyi Wang ◽  
Xiaobo Ren
Keyword(s):  
Sea Ice ◽  
East Asia ◽  
North Pacific ◽  
East Asian ◽  
Jet Stream ◽  
Winter Climate ◽  
The North ◽  
Local Warming ◽  
Northern Pacific ◽  
The North Pacific

Abstract Sea ice variability in the North Pacific and its associations with the east Asia–North Pacific winter climate were investigated using observational data. Two dominant modes of sea ice variability in the North Pacific were identified. The first mode features a dipole pattern between the Sea of Okhotsk and the Bering Sea. The second mode is characterized by more uniform ice changes throughout the North Pacific. Using the principal components of the two dominant modes as the indices (PC1 and PC2), analyses show that the positive phases of PC1 feature a local warming (cooling) in the Sea of Okhotsk (the Bering Sea), which is associated with the formation of the anomalous anticyclone extending from the northern Pacific to Siberia, accompanied by a weakening of the east Asian jet stream and trough. The associated anomalous southeasterlies/easterlies reduce the climatological northwesterlies/westerlies, leading to warm and wet conditions in northeast China and central Siberia. The positive phases of PC2 are characterized by a strong local warming in the northern Pacific that coincides with the anomalous cyclone occupying the entire North Pacific, accompanied by a strengthening of the east Asia jet stream and trough. The associated anomalous northerlies intensify the east Asian winter monsoon (EAWM), leading to cold and dry conditions in the east coast of Asia. The intensified EAWM also strengthens the local Hadley cell, which in turn strengthens the east Asian jet stream and leads to a precipitation deficit over subtropical east Asia. The linkages between PC1 and PC2 and large-scale modes of climate variability were also discussed. It is found that PC1 is a better indicator than the Arctic Oscillation of the recent Siberian warming, whereas PC2 may be a valuable predictor of EAWM.

scholarly journals Source-receptor relationships between East Asian sulfur dioxide emissions and Northern Hemisphere sulfate concentrations

2008 ◽  
Vol 8 (2) ◽  
pp. 5537-5561 ◽  
Author(s):  
J. Liu ◽  
D. L. Mauzerall ◽  
L. W. Horowitz
Keyword(s):  
Northern Hemisphere ◽  
North Pacific ◽  
East Asian ◽  
Source Region ◽  
The United States ◽  
So2 Emissions ◽  
Aerosol Model ◽  
The North ◽  
The North Pacific ◽  
Sulfur Emissions

Abstract. We analyze the effect of varying East Asian (EA) sulfur emissions on sulfate concentrations in the Northern Hemisphere, using a global coupled oxidant-aerosol model (MOZART-2). We conduct a base and five sensitivity simulations, in which sulfur emissions from each continent are tagged, to establish the source-receptor (S-R) relationship between EA sulfur emissions and sulfate concentrations over source and downwind regions. We find that from west to east across the North Pacific, EA sulfate contributes approximately 80%–20% of sulfate at the surface, but at least 50% at 500 hPa. In addition, EA SO2 emissions account for approximately 30%–50% and 10%–20% of North American background sulfate over the western and eastern US, respectively. The contribution of EA sulfate to the western US at the surface is highest in MAM and JJA, but is lowest in DJF. Reducing EA SO2 emissions will significantly decrease the spatial extent of the EA sulfate influence over the North Pacific both at the surface and at 500 mb in all seasons, but the extent of influence is insensitive to emission increases, particularly in DJF and JJA. We find that EA sulfate concentrations over most downwind regions respond nearly linearly to changes in EA SO2 emissions, but sulfate concentrations over the EA source region increase more slowly than SO2 emissions, particularly at the surface and in winter, due to limited availability of oxidants (mostly H2O2). We find that similar estimates of the S-R relationship for trans-Pacific transport of EA sulfate would be obtained using either sensitivity or tagging techniques. Our findings suggest that future changes in EA sulfur emissions may cause little change in the sulfate induced health impact over downwind continents but SO2 emission reductions may significantly reduce the sulfate related climate cooling over the North Pacific and the United States.

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

Different Impacts of the East Asian Winter Monsoon on the Surface Air Temperature in North America during ENSO and Neutral ENSO Years

2020 ◽  
Vol 33 (24) ◽  
pp. 10671-10690
Author(s):  
Tianjiao Ma ◽  
Wen Chen ◽  
Hans-F. Graf ◽  
Shuoyi Ding ◽  
Peiqiang Xu ◽  
...  
Keyword(s):  
Wave Packet ◽  
North Pacific ◽  
East Asian Winter Monsoon ◽  
East Asian ◽  
Surface Air Temperature ◽  
Winter Monsoon ◽  
Asian Winter Monsoon ◽  
The North ◽  
The North Pacific ◽  
Central North Pacific

AbstractThe present study investigates different impacts of the East Asian winter monsoon (EAWM) on surface air temperature (Ts) in North America (NA) during ENSO and neutral ENSO episodes. In neutral ENSO years, the EAWM shows a direct impact on the Ts anomalies in NA on an interannual time scale. Two Rossby wave packets appear over the Eurasian–western Pacific (upstream) and North Pacific–NA (downstream) regions associated with a strong EAWM. Further analysis suggests that the downstream wave packet is caused by reflection of the upstream wave packet over the subtropical western Pacific and amplified over the North Pacific. Also, the East Asian subtropical westerly jet stream (EAJS) is intensified in the central and downstream region over the central North Pacific. Hence, increased barotropic kinetic energy conversion and the interaction between transient eddies and the EAJS tend to maintain the circulation anomaly over the North Pacific. Therefore, a strong EAWM tends to result in warm Ts anomalies in northwestern NA via the downstream wave packet emanating from the central North Pacific toward NA. A weak EAWM tends to induce cold Ts anomalies in western-central NA with a smaller magnitude. However, in ENSO years, an anomalous EAJS is mainly confined over East Asia and does not extend into the central North Pacific. The results confirm that the EAWM has an indirect impact on the Ts anomalies in NA via a modulation of the tropical convection anomalies associated with ENSO. Our results indicate that, for seasonal prediction of Ts anomalies in NA, the influence of the EAWM should be taken into account. It produces different responses in neutral ENSO and in ENSO years.

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