1. Cosmic Rays: Influences on
Climate and Meteorology
Juan J. Taboada
MeteoGalicia

2. Outline of the talk
• First
part: A new arising (and controversial) paradigm:
Cosmoclimatology.
• Second part: Interactions between sun activity (that
modulates cosmic rays) and different patterns that
influences climate and meteorology:
•Modes of low-frequency variability (NAO)
•Weather types
•Artic Oscillation
•Blocking activity.

4. ¿What is the link between climate/meteorology and cosmic
rays?
Solar wind modulates the flux of high energy particles coming from outside the solar system. These
particles, the cosmic rays, are the dominant source of ionization in the troposphere. A more active
sun implies lower tropospheric ionization.

5. ¿How does it work the link between clouds and cosmic
rays?

6. ¿How does it work the link between clouds and cosmic
rays?
Electrons set free in the air by cosmic rays help to assemble molecules of sulfuric acid for cloud
condensaion nuceli on which watervapour condenses to make clouds.

7. ¿Does this mechanism work in the real atmosphere?
Forbush Decreases: Sudden reduction in the influx of GCR as a result of
explosive events on the sun. These events provide a natural experiment for
testing hypothesis about solar influences on the Earth.

8. ¿Does this mechanism work in the real atmosphere?
Decrease of cloud water content over the world’s ocean as a result of the 5
strongest FD over the period 1987-2007. (From Special Sounder Microwave
Imager (SSM/I).
Svensmark H., Bondo T. and Svensmark J. Cosmic ray decreases affect atmospheric aerosols and clouds. GRL, 2009

9. ¿Does this mechanism work in the real atmosphere?
From these data it appears that the answer is yes!!! It works.
Svensmark H., Bondo T. and Svensmark J. Cosmic ray decreases affect atmospheric aerosols and clouds. GRL, 2009

10. Observations
Clouds have been observed from space since the beginning of the 1980's. Using the satellite data,
Henrik Svensmark of the Danish National Space Center in Copenhagen has shown that cloud
cover varies in sync with the variable cosmic ray flux reaching the Earth. More cosmic rays
mean more low level clouds.

11. ¿Is this modulation important for climate? Concept of
radiative forcing

12. ¿Is this modulation important for climate? Concept of
radiative forcing
Great uncertainty on the effects of clouds on
climate

13. Cosmoclimatology: Reconstruction of past climate
changes
The solar system periodically crosses the spiral arms of the Milky Way. Each time it does so, it
should witness an elevated level of cosmic rays. In fact, the cosmic ray flux variations arising from
our galactic journey are ten times larger than the cosmic ray flux variations due to solar activity
modulations, at the energies responsible for the tropospheric ionization (of order 10 GeV).
Shaviv & J. Veizer, "A Celestial driver of Phanerozoic Climate?", GSA Today 13, No. 7, 4, 2003.
N. Shaviv, "Cosmic Ray Diffusion from the Galactic Spiral Arms, Iron Meteorites, and a Possible Climatic Connection", Physical Review Letters 89,
051102, (2002).

14. Interactions betwen solar activity and climate variability

15. Modes of low frequecy variability
NAO EA
EA/WR SCA
15

16. Correlations of different patterns with rainfall (DJF) in Galicia (1980-2006)
Lorenzo and Taboada, JAOS, 2005 16

17. Correlation of different modes of low frequecy variability
with rain
Peinador (1960-2005)
NAO EA EA/WR SCA
DJF -0.45 0.42 -0.51 0.46
MAM -0.30 0.17 0.08 0.13
JJA -0.18 0.02 0.17 0.10
SON -0.22 0.23 0.04 0.66
Coruña – Completa (1960-2005)
NAO EA EA/WR SCA
DJF -0.36 0.39 -0.52 0.36
MAM -0.36 0.15 0.16 0.20
JJA -0.35 0.03 0.05 0.11
SON -0.24 0.35 -0.09 0.66
17

18. Variariability of the correlation over time: Influence of
solar activity
High correlation between the
interaction of NAO with
climate variability in Galicia
and solar activity
Estación Peinador (Vigo)
¿Change of circulation
0.4
regime in North Hemisphere 0.3
at mid 70´s? 0.2
0.1
0
1955
-0.1 1960 1965 1970 1975 1980 1985 1990
-0.2
-0.3
-0.4
-0.5
-0.6
-0.7
18
Media SS 20 años corr. NAO-Lluvia (20 años)

19. Correlation of different modes of low frequecy variability
with temperature
Peinador (1960-2005)
NAO EA EA/WR SCA
DJF 0.15 0.70 0.10 -0.24
MAM 0.17 0.15 0.16 -0.57
JJA 0.04 0.13 -0.37 -0.46
SON -0.08 0.20 0.16 -0.61
Coruña – Completa (1960-2005)
NAO EA EA/WR SCA
DJF 0.25 0.73 0.08 -0.24
MAM 0.12 0.29 0.26 -0.50
JJA 0.03 0.15 -0.27 -0.33
SON -0.31 0.35 0.08 -0.51
19

20. Weather types
• Automatic clasification of weather types
1. Direction of flow was given by tan-1(WF/SF),
180° being added if WF is positive. The
appropriate direction was computed using an
eight-point compass, allowing 45° per sector.
2. If |Z|<F, flow is essentially straight and
considered to be of a pure directional type (eight
different cases, according to the directions of the
compass).
3. If |Z|>2F, the pattern was considered to be of
a pure cyclonic type if Z>0, or of a pure
anticyclonic type if Z<0.
4. If F<|Z|<2F, flow was considered to be of a
hybrid type and is therefore characterized by
SF = 1.350[0.25( p5 + 2 p9 + p13 ) − 0.25( p4 + 2 p8 + p12 )] both direction and circulation (8 x 2 different
WF = [0.5( p12 + p13 ) − 0.5( p4 + p5 )] types).
ZS = 0.85[0.25( p6 + 2 p10 + p14 ) − 0.25( p5 + 2 p9 + p13 ) − 0.25( p4 + 2 p8 + p12 )
+ 0.25( p3 + 2 p 7 + p11 )]
ZW = 1.12[0.5( p15 + p16 ) − 0.5( p8 + p9 )] − 0.91[0.5( p8 + p9 ) − 0.5( p1 + p2 )]
F = ( SF 2 + WF 2 )1 2 20
Z = ZS + ZW

21. 100%
N
80%
NW
W
60% SW
S
SE
40% E
NE
A
20%
C
0%
1 2 3 4 5 6 7 8 9 10 11 12
Frequency of appearance of different weather types in Galicia in different
months.
M.N. Lorenzo, J.J. Taboada and L. Gimeno. “Links between circulation weather types and teleconnection patterns and their
influence on precipitation patterns in Galicia (NW Spain)”. International Journal of Climatology 2008.
21

22. Each weather type explains different quantities of rain
Tipo Annual Winter Spring Summer Autumn
NE 0.91 1.22 0.77 0.87 1.06
E 1.86 3.18 1.94 0.74 1.69
SE 2.36 2.94 1.82 0.33 2.45
S 3.02 5.00 2.70 0.43 2.61
SW 10.31 13.64 9.26 3.48 9.61
W 11.80 14.63 9.79 4.35 14.05
NW 5.37 8.99 4.86 2.43 5.86
N 1.70 3.47 1.57 1.05 2.01
C 13.41 15.34 13.57 6.63 17.22
A 0.21 0.31 0.28 0.08 0.21
22

23. Outlook
•¿Does sun activity correlate with frequency of appearance of different Weather
Types?. Work in progress – Diego Ramos
Preliminary results for other areas of Europe (Huth et al. 2002) shows interesting
results.
• ¿Does the effects on blocking activity (BarrioPedro et al., 2008) has an
influence on Galician climate variability?
• ¿Does the effects on modes of oscillation has an influence on Galician climate
variability?
The whole picture until now shows an enhanced zonality
under solar maxima

25. Thank you very much for your
attention