Zonal index and circulation change in the north Atlantic area, 1873-1972

1982 ◽  
Vol 2 (2) ◽  
pp. 159-169 ◽  
Author(s):  
T. J. Makrogiannis ◽  
A. A. Bloutsos ◽  
B. D. Giles
Keyword(s):  
North Atlantic ◽  
Zonal Index ◽  
The North ◽  
Circulation Change ◽  
The North Atlantic ◽  
North Atlantic Area ◽  
Atlantic Area

Is the Atmospheric Zonal Index Driven by an Eddy Feedback?

1998 ◽  
Vol 55 (19) ◽  
pp. 3077-3086 ◽  
Author(s):  
Steven Feldstein ◽  
Sukyoung Lee
Keyword(s):  
Zonal Index

Analysis of the monthly zonal index values and long-term changes of circulation over the North Atlantic and Europe

2007 ◽  
Vol 11 (5) ◽  
pp. 493-503 ◽  
Author(s):  
T. J. Makrogiannis ◽  
H. S. Sahsamanoglou ◽  
A. A. Flocas ◽  
A. A. Bloutsos
Keyword(s):  
North Atlantic ◽  
Zonal Index ◽  
The North ◽  
Long Term Changes ◽  
The North Atlantic

On the Lower Kimeridgian Ammonite Genera Pictonia, Rasenia, Aulacostephanus and Ataxioceras

1935 ◽  
Vol 72 (6) ◽  
pp. 246-257 ◽  
Author(s):  
W. J. Arkell
Keyword(s):  
Upper Jurassic ◽  
Zonal Index ◽  
The World

The four genera discussed below are mentioned in almost every paper, memoir, and monograph dealing with the Lower Kimeridge Clay in this country and abroad. The first three were given currency in the literature of the Upper Jurassic when species belonging to them were chosen as index-fossils for the three lowest zones of the Kimeridge Clay by Salfeld (1913–14). Ataxioceras, though not comprising any zonal index fossils, is almost as important and has been repeatedly cited for 56 years from all parts of the world.

scholarly journals Diabatic Damping of Zonal Index Variations

2014 ◽  
Vol 71 (8) ◽  
pp. 3090-3105 ◽  
Author(s):  
Xiaoming Xia ◽  
Edmund K. M. Chang
Keyword(s):  
Positive Feedback ◽  
Momentum Flux ◽  
Diabatic Heating ◽  
Mechanistic Model ◽  
Low Frequency ◽  
Dominant Mode ◽  
Precipitation Anomaly ◽  
Model Experiments ◽  
Zonal Index ◽  
The Impact

Abstract Zonal index variations, or north–south shifts of the midlatitude jet, are the dominant mode of zonal wind variability in the Southern Hemisphere. Previous studies have shown that synoptic-time-scale eddy momentum flux provides a positive feedback and acts to increase the persistence and low-frequency variance of the zonal index. However, the impact of diabatic heating due to the precipitation associated with these eddies has not been investigated. In this study, regression analyses have been conducted to demonstrate that a robust precipitation anomaly can be found to accompany the jet and eddy momentum flux anomalies associated with a poleward shift of the jet, with enhanced precipitation on the poleward flank of the jet and reduced precipitation on the equatorward flank. Diabatic heating associated with such a precipitation anomaly is expected to reduce the temperature gradient across the jet anomaly, thus decreasing eddy generation and damping the anomaly. This expectation is confirmed by three sets of mechanistic model experiments, using three different ways to mimic the impact of moist heating in a dry model. Results of this study suggest that diabatic heating provides a negative feedback to zonal index variations, partially offsetting the positive feedback provided by eddy momentum flux. These results could partially explain why zonal index variations have been found to be very persistent in dry mechanistic model experiments since this negative diabatic feedback is absent in dry models. These results suggest that these models may be overly sensitive to climate forcings that produce a jet shift response.

Predictability of the zonal index in a global model

1992 ◽  
Vol 44 (4) ◽  
pp. 331-338 ◽  
Author(s):  
Walter A. Robinson ◽  
Jianchun Qin
Keyword(s):  
Global Model ◽  
Zonal Index

scholarly journals A modified zonal index and its physical sense

2003 ◽  
Vol 30 (12) ◽  
Author(s):  
Jianping Li ◽  
Julian X. L. Wang
Keyword(s):  
Physical Sense ◽  
Zonal Index
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