Southern hemisphere cyclones and anticyclones: recent trends and links with decadal variability in the Pacific Ocean

2007 ◽  
Vol 27 (11) ◽  
pp. 1403-1419 ◽  
Author(s):  
Alexandre Bernardes Pezza ◽  
Ian Simmonds ◽  
James A. Renwick
Keyword(s):  
Pacific Ocean ◽  
Southern Hemisphere ◽  
Decadal Variability ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Recent Trends

scholarly journals A global climatology of tropospheric and stratospheric ozone derived from Aura OMI and MLS measurements

2011 ◽  
Vol 11 (6) ◽  
pp. 17879-17911 ◽  
Author(s):  
J. R. Ziemke ◽  
S. Chandra ◽  
G. Labow ◽  
P. K. Bhartia ◽  
L. Froidevaux ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Tropospheric Ozone ◽  
Stratospheric Ozone ◽  
Ozone Monitoring Instrument ◽  
Mean Values ◽  
Latitude Range ◽  
The Pacific ◽  
The Pacific Ocean

Abstract. A global climatology of tropospheric and stratospheric column ozone is derived by combining six years of Aura Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) ozone measurements for the period October 2004 through December 2010. The OMI/MLS tropospheric ozone climatology exhibits large temporal and spatial variability which includes ozone accumulation zones in the tropical south Atlantic year-round and in the subtropical Mediterranean/Asia region in summer months. High levels of tropospheric ozone in the Northern Hemisphere also persist in mid-latitudes over the Eastern North American and Asian continents extending eastward over the Pacific Ocean. For stratospheric ozone climatology from MLS, largest ozone abundance lies in the Northern Hemisphere in the latitude range 70° N–80° N in February–April and in the Southern Hemisphere around 40° S–50° S during months August–October. The largest stratospheric ozone abundances in the Northern Hemisphere lie over North America and Eastern Asia extending eastward across the Pacific Ocean and in the Southern Hemisphere south of Australia extending eastward across the dateline. With the advent of many newly developing 3-D chemistry and transport models it is advantageous to have such a dataset for evaluating the performance of the models in relation to dynamical and photochemical processes controlling the ozone distributions in the troposphere and stratosphere. The OMI/MLS ozone gridded climatology data, both calculated mean values and RMS uncertainties are made available to the science community via the NASA total ozone mapping spectrometer (TOMS) website http://toms.gsfc.nasa.gov.

scholarly journals Roles of Low- and High-Frequency Eddies in the Transitional Process of the Southern Hemisphere Annular Mode

2005 ◽  
Vol 18 (6) ◽  
pp. 782-794 ◽  
Author(s):  
Hideo Shiogama ◽  
Toru Terao ◽  
Hideji Kida ◽  
Tatsuya Iwashima
Keyword(s):  
Pacific Ocean ◽  
Southern Hemisphere ◽  
High Frequency ◽  
Momentum Flux ◽  
Rossby Waves ◽  
Low Frequency ◽  
Wave Activity ◽  
Transitional Process ◽  
The Pacific ◽  
The Pacific Ocean

Abstract The effects of low- and high-frequency eddies (time scales longer and shorter than 10 days, respectively) on the transitional processes of the Southern Hemisphere “Annular Mode” are investigated, based on NCEP–NCAR daily reanalysis data for the period 1979–2001. Special attention is focused on the zonal symmetry/asymmetry and the temporal evolution of the eddy forcing. For the poleward transitional process, the effects of low-frequency eddies precede those of high-frequency eddies in driving the jet transition. Quasi-stationary Rossby waves propagating along the polar jet with wavelengths of 7000 km play an important role. The waves, originally come from the Indian Ocean through the waveguide associated with the polar jet, dissipate equatorward over the eastern Pacific Ocean. This anomalous equatorward dissipation of wave activity induces an anomalous poleward momentum flux, which is responsible for changes in the polar jet over the Pacific Ocean during the beginning stage. Following the low-frequency eddy forcing, momentum forcing anomalies due to the high-frequency eddies rapidly appear. This forcing continues to drive the polar jet poleward over the whole of longitude, while the low-frequency eddies have completed their role of inducing the anomalous poleward momentum flux during the earlier stage. For the equatorward transitional events, the roles of the low-frequency eddy forcing differ from that in the poleward ones. Anomalous equatorward momentum fluxes due to low-frequency eddies appear simultaneously with that due to high-frequency eddies. Quasi-stationary Rossby waves with wavelengths of 7000 km propagate southeastward through the waveguide over the Pacific Ocean. The convergence of their wave activity results in the deceleration of the westerlies over the higher latitudes of the Pacific Ocean. On the other hand, the high-frequency eddy forcing contributes to the equatorward jet drift longitudinally over the whole of the hemisphere.

On the Pacific Ocean regime shift

2001 ◽  
Vol 28 (19) ◽  
pp. 3721-3724
Author(s):  
Cathy Stephens
Keyword(s):  
Pacific Ocean ◽  
Regime Shift ◽  
The Pacific ◽  
The Pacific Ocean
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