SPARC meets CLIVAR Slides for Tony

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SPARC meets CLIVARSlides for Tony
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Can changes in ENSO activity help to explain
increasing stratospheric water vapor? Adam A.
Scaife, Neal Butchart, David R. Jackson, and
Richard Swinbank, GRL, 2003
Modelled (middle atmosphere model) water vapor
anomalies from January 1981 to December 1990 over
the equator. Units are parts per million and the
contour interval is 0.25ppm up to 4ppm and
logarithmic above that level. The lower panel
shows the Southern Oscillation Index for the same
period (note reversed ordinate).
Conclusion ENSO contributes to stratospheric
water vapor on interannual timescales but
increase of ENSO activity explains only 10 of
trend of stratospheric water vapor
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A Possible Connection of Midlatitude
Mesosphere/Lower Thermosphere Zonal Winds and
the Southern Oscillation Christoph Jacobi and
Dierk Kürschner

r20.54
Time series of summer (JJA, upper part of figure)
and winter (DJF, lower part of figure) zonal
prevailing winds voz near 95 km and SOI.
Conclusion in winter the prevailing wind
is positively correlated with the Southern
Oscillation index (SOI), which qualitatively
fits to the response of the low-latitude
stratosphere on the SO. In summer, however, there
is a negative correlation between
MLT zonal
winds and SOI.
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Analysis of the ENSO Signal in Tropospheric and
Stratospheric Temperatures Observed by MSU,
19792000 Fernández et al. 2004, J. Climate
El Chichon
Pinatubo
QBO
zonal mean stratospheric MSU temperature EOF
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Analysis of the ENSO Signal in Tropospheric and
Stratospheric Temperatures Observed by MSU,
19792000 Fernández et al. 2004, J. Climate
ENSO
deviation from zonal mean (eddy) stratospheric
MSU temperature EOF
Conclusion ENSO modulates the stratospheric
eddy temperature field, synchronously with the
stratospheric field. ENSO does not influence the
zonal mean of stratospheric temperatures
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Extreme climate of the global troposphere and
stratosphere in 194042 related to El Niño S.
BRÖNNIMANN1,2, J. LUTERBACHER3, J. STAEHELIN1,
T. M. SVENDBY4, G. HANSEN5 T. SVENØE, Nature
2004
Using historical observations and reconstruction
techniques, the anomalous state of the
troposphere and stratosphere in the Northern
Hemisphere from 1940 to 1942 is analyzed that
occurred during a strong and long-lasting El Niño
event. There is also observational evidence for
frequent stratospheric warmings and high column
ozone at Arctic and mid-latitude sites. We
conclude that the observed anomalies constitute a
recurring extreme state of the global
tropospherestratosphere system in northern
winter that is related to strong El Niño events.