Bibcode
Pallé, E.; Butler, C. J.; O'Brien, K.
Bibliographical reference
Journal of Atmospheric and Solar-Terrestrial Physics, Volume 66, Issue 18, p. 1779-1790.
Advertised on:
12
2004
Citations
48
Refereed citations
47
Description
Recent analysis of monthly mean cloud data from the International
Satellite Cloud Climatology Project uncovered a strong correlation
between low cloud and the cosmic ray flux for extensive regions of the
Earth. Additional data have been recently released covering the period
up to September 2001 with which we have made a new study of the
geographical variation of the correlation between low cloud and
predicted ionization level from cosmic rays at an altitude of 2 km. When
analysed globally, we find that the correlations do not correspond to
the latitude variation of cosmic ray flux and they are not field
significant. Nonetheless they appear to be marginally field significant
over broad latitude and longitude bands with a peak positive correlation
at 50 degrees North and South and a tendency to negative correlation at
lower latitudes. The correlation is strongest over the North and South
Atlantic. Several of these features are consistent with the predictions
of the electroscavenging process. We use a simple model to calculate the
climatic impact should the correlation be confirmed. We show that, under
the most favorable conditions, a reduction in low cloud cover since the
late 19th century, combined with the direct forcing by solar irradiance
can explain a significant part of the global warming over the past
century, but not all. However, this computation assumes that there is no
feedback or changes in cloud at other levels.