Response of lake ice breakup in the Northern Hemisphere to the 1976 interdecadal shift in the North Pacific

2000 ◽  
Vol 27 (5) ◽  
pp. 2770-2774 ◽  
Author(s):  
Barbara J. Benson ◽  
John J. Magnuson ◽  
Robert L. Jacob ◽  
Sarah L. Fuenger
Keyword(s):  
Northern Hemisphere ◽  
North Pacific ◽  
Lake Ice ◽  
Ice Breakup ◽  
The North ◽  
Interdecadal Shift ◽  
The North Pacific

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.

scholarly journals Diagnosing the Origin of Extended-Range Forecast Errors

2010 ◽  
Vol 138 (6) ◽  
pp. 2434-2446 ◽  
Author(s):  
T. Jung ◽  
M. J. Miller ◽  
T. N. Palmer
Keyword(s):  
North America ◽  
Northern Hemisphere ◽  
North Pacific ◽  
Forecast Error ◽  
Error Reduction ◽  
Forecast Errors ◽  
The North ◽  
Extended Range ◽  
Ecmwf Model ◽  
The North Pacific

Abstract Experiments with the ECMWF model are carried out to study the influence that a correct representation of the lower boundary conditions, the tropical atmosphere, and the Northern Hemisphere stratosphere would have on extended-range forecast skill of the extratropical Northern Hemisphere troposphere during boreal winter. Generation of forecast errors during the course of the integration is artificially reduced by relaxing the ECMWF model toward the 40-yr ECMWF Re-Analysis (ERA-40) in certain regions. Prescribing rather than persisting sea surface temperature and sea ice fields leads to a modest forecast error reduction in the extended range, especially over the North Pacific and North America; no beneficial influence is found in the medium range. Relaxation of the tropical troposphere leads to reduced extended-range forecast errors especially over the North Pacific, North America, and the North Atlantic. It is shown that a better representation of the Madden–Julian oscillation is of secondary importance for explaining the results of the tropical relaxation experiments. The influence from the tropical stratosphere is negligible. Relaxation of the Northern Hemisphere stratosphere leads to forecast error reduction primarily in high latitudes and over Europe. However, given the strong influence from the troposphere onto the Northern Hemisphere stratosphere it is argued that stratospherically forced experiments are very difficult to interpret in terms of their implications for extended-range predictability of the tropospheric flow. The results are discussed in the context of future forecasting system development.

The progressive intensification of northern hemisphere glaciation as seen from the North Pacific

1996 ◽  
Vol 85 (3) ◽  
pp. 452-465 ◽  
Author(s):  
M. A. Maslin ◽  
G. H. Haug ◽  
M. Sarnthein ◽  
R. Tiedemann
Keyword(s):  
Northern Hemisphere ◽  
North Pacific ◽  
The North ◽  
The North Pacific

scholarly journals The Role of Tropical Mean-State Biases in Modeled Winter Northern Hemisphere El Niño Teleconnections

2020 ◽  
Vol 33 (11) ◽  
pp. 4751-4768 ◽  
Author(s):  
Samantha Ferrett ◽  
Matthew Collins ◽  
Hong-Li Ren ◽  
Bo Wu ◽  
Tianjun Zhou
Keyword(s):  
Northern Hemisphere ◽  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Teleconnection Pattern ◽  
The North ◽  
Precipitation Response ◽  
The North Pacific ◽  
Mean State

AbstractThe role of tropical mean-state biases in El Niño–Southern Oscillation teleconnections in the winter Northern Hemisphere is examined in coupled general circulation models from phase 5 of the Coupled Model Intercomparison Project (CMIP5). The main North Pacific teleconnection pattern, defined here by the strengths of the anomalous Kuroshio anticyclone and North Pacific cyclone, is linked to two anomalous Rossby wave sources that occur during El Niño: a negative source over East Asia and a positive source to the west of the North Pacific. Errors in the teleconnection pattern in models are associated with spatial biases in mean atmospheric ascent and descent and the strength of the corresponding forcing of Rossby waves via suppressed or enhanced El Niño precipitation responses in the tropical western North Pacific (WNP) and the equatorial central Pacific (CP). The WNP El Niño precipitation response is most strongly linked to the strength of the Kuroshio anticyclone and the CP El Niño precipitation response is most strongly linked to the strength of the North Pacific cyclone. The mean state and corresponding El Niño precipitation response can have seemingly distinct biases. A bias in the WNP does not necessarily correspond to a bias in the CP, suggesting that improvement of biases in both tropical WNP and equatorial CP regions should be considered for an accurate teleconnection pattern.

The progressive intensification of northern hemisphere glaciation as seen from the North Pacific

1996 ◽  
Vol 85 (3) ◽  
pp. 452-465 ◽  
Author(s):  
M. A. Maslin ◽  
G. H. Haug ◽  
M. Sarnthein ◽  
R. Tiedemann
Keyword(s):  
Northern Hemisphere ◽  
North Pacific ◽  
The North ◽  
The North Pacific

scholarly journals Evaluation of Northern Hemisphere Blocking Climatology in the Global Environment Multiscale Model

2013 ◽  
Vol 141 (2) ◽  
pp. 707-727 ◽  
Author(s):  
Etienne Dunn-Sigouin ◽  
Seok-Woo Son ◽  
Hai Lin
Keyword(s):  
Northern Hemisphere ◽  
North Atlantic ◽  
North Pacific ◽  
Detection Algorithm ◽  
Late Winter ◽  
Stationary Waves ◽  
The North ◽  
Zonal Wavenumber ◽  
The North Atlantic ◽  
The North Pacific

Abstract The performance of the Global Environmental Multiscale (GEM) model, the Canadian operational numerical model, in reproducing atmospheric low-frequency variability is evaluated in the context of Northern Hemisphere blocking climatology. The validation is conducted by applying a comprehensive but relatively simple blocking detection algorithm to a 20-yr (1987–2006) integration of the GEM model in climate mode. The comparison to reanalysis reveals that, although the model can reproduce Northern Hemisphere blocking climatology reasonably well, the maximum blocking frequency over the North Atlantic and western Europe is generally underestimated and its peak season is delayed from late winter to spring. This contrasts with the blocking frequency over the North Pacific, which is generally overestimated during all seasons. These misrepresentations of blocking climatology are found to be largely associated with the biases in climatological background flow. The modeled stationary waves show a seasonal delay in zonal wavenumber 1 and an eastward extension in zonal wavenumber-2 components consistent with blocking frequency biases. High-frequency eddies are, however, consistently underestimated both in the North Atlantic and Pacific, indicating that the biases in eddy fields might not be the main reason for the blocking biases in the North Pacific.

Sign in / Sign up

Export Citation Format

Share Document