Reply by Dr Rolf Philipona to my web page commenting on his 2005 paper;
Philipona, R., B. Dürr, A. Ohmura, and C. Ruckstuhl (2005),
Anthropogenic greenhouse forcing and strong water vapor feedback
increase temperature in Europe, Geophys. Res. Lett., 32, L19809,
doi:10.1029/2005GL023624.
I emailed Dr Philipona on 13 June to tell him of my web page comments
and he replied as follows and asked that I , "..add these comments to
your Internet page."
I have put my own text in bold italics and have left all Dr
Philipona's comments in normal text. I have also added paragraph
numbering to aid the clarity of subsequent discussion.
Thank you for your interest on our paper.
[1] Your comment: I found it odd that
Philipona et al would use surface T data when many of the atmospheric
processes they were comparing with were operating well above the
surface.
[2] Why would you find this odd? The main focus of our
paper is on radiative fluxes measured at the surface. This is why we
compare the effects of these fluxes to the temperature and humidity
changes at the surface. If the radiation budget at the surface changes
then the temperature at the surface must change. It is true that
atmospheric processes operate far above, but this can not be measured
up there. (I am arguing since a long time with modelers who determine
the radiative forcing at the tropopouse where it can not be measured).
However, we measure the effects of these atmospheric processes in the
radiative fluxes at the surface, and hence compare radiative
fluxes with temperature and humidity at the surface.
[3] Your comment: Panels b and d in Fig 2
below are I think the key evidence for Philipona et al that
the greenhouse effect and strong water vapour feedback are operating
over Europe.
[4] No, the key evidence that an increasing greenhouse
effect is increasing temperature at the surface is shown in our Fig. 3
and this for all the 12 month over the period 1995 to 2002. In Fig. 3 b
we show the net solar radiation (blue), the longwave downward radiation
(green) and the temperature (red). The temperature can also be
understood and expressed as the longwave upward radiation. In Fig. 3 c
we show the total surface absorbed radiation (light blue) and the
temperature (red). [5] You can easily see that whenever the
total surface absorbed radiation increases the temperature increases.
For months with no radiation increases temperature does not change.
That the greenhouse effect increased is proven by the fact that the
solar net radiation decreased on the annual mean but the total surface
absorbed radiation increased. Hence the longwave downward radiation
strongly increased due to an increased greenhouse effect.
[6] Your comment: Panel d shows changes
in Inegrated Water Vapour (IWV) and the effect of these two
panels is clearly to impress readers that they show similar trends,
warming from west to east and increase in IWV from west to east.
[7] We do not try to impress the readers but show what is.
As you can see in our Fig. 1 we show the temperature increase over
Europe from 1980 to 2002 and from 1995 to 2002. Hence, we do not
hide the fact, that the decadal temperature increase from 1995 to 2002
is considerably larger than for the period 1980 to 2002. In your
figures you show that the temperature rise is also less. However, in
all the periods shown in ours and yours temperatur increase is larger
in the east than in the west. The reason why we took the period 1995 to
2002 is because our radiation measurements in the Alpas are availabel
since 1995 and when we wrote the paper we had them analysed until 2002.
It is a fact that over this period temperature and humidity changed a
lot and this allowed us to show nicely how the radiation is driving all
this.
[8] Again, the key message of the paper is shown in Fig. 3.
Fig. 1and 2 show how the temperature and the IWV evolved in Europe over
the period 1995 to 2002.
[9] The reason for showing the evolution over Europe is to
disprove the argument of people who claim that the temperature increase
in Europe would be simply due to NAO activity. Since temperature and
humidity show almost no change in the west and are even negative over
the Iberian peninsula it is very unlikely that warm and humide air
transported from the west or south-west would have increased the
temperature over Europe.
[10] Figure 4 shows how well temperature is related to the
IWV. Also this shows the importance of the water vapor on the
increasing greenhouse effect.
[11] In summary what the paper shows is that the observed
temperature increase in Europe is not due to large scale circulation
but is driven by radiative effects which increases evapotranspiration
at the surface. It further shows that in aereas where sufficiant water
is available the IWV increases and this increases the greenhouse effect
and hence the warming.
For this paper we recently received the Norbert Gerbier - Mumm
International Award from WMO for the year 2007.
http://www.wmo.ch/pages/about/awards/norbert-gerbier-mumm.html (see
Winners)
I would appreciate if you would add this comments to your Internet page.
With kind regards,
Rolf Philipona
Back to my web page commenting on the
Philipona et al 2005 paper