Global Change Abstracts The Swiss Contribution - SCNAT
Global Change Abstracts The Swiss Contribution - SCNAT
Global Change Abstracts The Swiss Contribution - SCNAT
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42<br />
08.1-17<br />
Atmospheric blocking: space-time links to the<br />
NAO and PNA<br />
Croci Maspoli M, Schwierz C, Davies H C<br />
Switzerland<br />
Meteorology & Atmospheric Sciences ,<br />
Oceanography<br />
In the Northern hemisphere, regions characterized<br />
by an enhanced frequency of atmospheric<br />
blocking overlap significantly with those associated<br />
with the major extra-tropical patterns of largescale<br />
climate variability-namely the North Atlantic<br />
Oscillation (NAO) and the Pacific North American<br />
(PNA) pattern. <strong>The</strong>re is likewise an overlap in the<br />
temporal band-width of blocks and these-climate<br />
patterns. Here the nature of the linkage between<br />
blocks and the climate patterns is explored by using<br />
the ERA-40 re-analysis data set to examine (1)<br />
their temporal and spatial correlation and (2) the<br />
interrelationship between blocks and the NAO/<br />
PNA. It is shown that a strong anti-correlation exists<br />
between blocking occurrence and the phase<br />
of the NAO (PNA) in the North Atlantic (western<br />
North Pacific), and that there are distinctive interbasin<br />
differences with a clear geographical (over<br />
North Atlantic) and quantitative (over North Pacific)<br />
separation of typical blocking genesis/lysis<br />
regions during the opposing phases of the climate<br />
patterns. An Empirical Orthogonal Function (EOF)<br />
analysis points to a significant influence of blocking<br />
upon the NAO pattern (identifiable as the<br />
leading EOF in the Euro- Atlantic), and a temporal<br />
analysis indicates that long-lasting blocks are associated<br />
with the development of negative NAO/<br />
PNA index values throughout their life-time. In<br />
addition an indication of a cause-and effect relationship<br />
is set-out for the North Atlantic linkage.<br />
Climate Dynamics, 2007, V29, N7-8, DEC, pp<br />
713-725.<br />
08.1-18<br />
FinROSE - middle atmospheric chemistry transport<br />
model<br />
Damski J, Thlix L, Backman L, Taalas P, Kulmala M<br />
Finland, Switzerland<br />
Meteorology & Atmospheric Sciences , Modelling<br />
In this paper we describe the development and<br />
performance of a three- dimensional global middle<br />
atmospheric chemistry transport model Fin<br />
ROSE. <strong>The</strong> FinROSE chemistry transport model<br />
includes a numerical scheme for stratospheric<br />
chemistry with parameterizations for heterogeneous<br />
processing on polar stratospheric clouds<br />
(PSC) and on liquid binary aerosols together with<br />
a parameterisation of large nitric acid trihydrate<br />
<strong>Global</strong> <strong>Change</strong> <strong>Abstracts</strong> – <strong>The</strong> <strong>Swiss</strong> <strong>Contribution</strong> | Atmosphere<br />
particles (i.e. NAT-rocks) and PSC sedimentation.<br />
<strong>The</strong> total number of trace species in the model is<br />
34 and the total number of gas-phase reactions,<br />
photodissociation processes and heterogeneous<br />
reactions is about 150. <strong>The</strong> model is forced by external<br />
wind and temperature fields. <strong>The</strong> simulations<br />
are normally performed in a 5 degrees x 10<br />
degrees (lat. x long.) grid from the surface up to<br />
around 0.1 hPa, with a vertical resolution of ca.<br />
1.5 km in the stratosphere. Long-term simulations<br />
(40 to 50 years) have been done using winds and<br />
temperatures from ECMWF ERA40 analyses. <strong>The</strong><br />
performance of the model in describing the stratospheric<br />
composition and chemistry is shown and<br />
evaluated in this paper. In general, the FinROSE<br />
results show a good comparison with measured<br />
total ozone. Also the timing, the depth and the<br />
deepening of the Antarctic ozone hole, and the<br />
responsible processes are captured well in the<br />
model simulations.<br />
Boreal Environment Research, 2007, V12, N5, OCT<br />
24, pp 535-550.<br />
08.1-19<br />
Doubled length of western European summer<br />
heat waves since 1880<br />
Della Marta P M, Haylock M R, Luterbacher J,<br />
Wanner H<br />
Switzerland, Australia, England<br />
Meteorology & Atmospheric Sciences<br />
(1) We analyzed a new data set of 54 high-quality<br />
homogenized daily maximum temperature series<br />
from western Europe (Austria, Belgium, Croatia,<br />
Czech Republic, Denmark, Finland, France, Germany,<br />
Ireland, Netherlands, Portugal, Spain, Sweden,<br />
Switzerland, United Kingdom) to define more<br />
accurately the change in extreme warm Daily<br />
Summer Maximum Temperature (DSMT). Results<br />
from the daily temperature homogeneity analysis<br />
suggest that many instrumental measurements in<br />
the late 19th and early 20th centuries were warm-<br />
biased. Correcting for these biases, over the period<br />
1880 to 2005 the length of summer heat waves over<br />
western Europe has doubled and the frequency of<br />
hot days has almost tripled. <strong>The</strong> DSMT Probability<br />
Density Function (PDF) shows significant changes<br />
in the mean (+ 1.6 +/- 0.4 degrees C) and variance<br />
(+ 6 +/- 2%). <strong>The</strong>se conclusions help further the evidence<br />
that western Europe’s climate has become<br />
more extreme than previously thought and that<br />
the hypothesized increase in variance of future<br />
summer temperature has indeed been a reality<br />
over the last 126 years.<br />
Journal of Geophysical Research Atmospheres,<br />
2007, V112, ND15, AUG 3 ARTN: D15103.