Editor's specific comments:
1. (abstract, p. 2) Regarding the quote "In the polar regions of the Earth, K(z) is 10-30 times
greater than that in the lower latitudes (Bank and Kocharts, 1973)." -- this statement is incorrect and
misleading! If you go to the relevant pages of B & K (p. 49-53), you'll see that the effect described
is not due to the aurora, but to a seasonal effect. On the Earth, solar UV dominates as a heating
source as compared with the auroral input, and you get large latitudinal variations due to seasonal
effects. There is upwelling over the summer pole ("wind-driven diffusion"), downwelling over the
winter pole, with an interconnecting mean meridional flow. The dynamical response was just being
discovered in the B & K era, and you see hints in this section that dynamics (rather than simple
eddy diffusion) might explain the effect. Later 2-D and 3-D thermospheric and mesospheric
simulations discuss more of the details of this seasonal effect. In any case, the effect described in B
& K (see especially Figure 15.11 on p. 53) causes a difference in an "effective" K_h (and in altitude
of the homopause) at the summer pole vs winter pole, but it's not a low-latitude vs high-latitude
thing, and it has nothing to do with aurora. The B & K reference here (and later in the paper), and
the magnitude quoted, is incorrect.
However, it is likely that aurorae on the Earth *do* affect turbulent mixing -- you're simply using
the wrong reference. Unfortunately, with a quick literature search, I was unable to come up with
very useful references for you, mostly because people were dropping the 1-D eddy diffusion
formulation in favor or 2-D and 3-D models at about the same time the effect was becoming known
and studied. Here are some references that demonstrate that that there is upwelling in the auroral
regions on Earth due to locally enhanced heating due to ion-neutral coupling (ion
drag/frictional/Joule heating). This upwelling can probably emulate K_h enhancements. Note that
you might be able to find some better references out there. Look for TGCM models.
Rees and Fuller-Rowell (1988) Planet. Space Sci. 36, 935-948
Rees and Fuller-Rowell (1990) Adv. Space Res. 10(6), 83-102
Gerard and Deneye (1984) Annales Geophysicae 2, 187-190
Mayr et al. (1978) Rev. Geophysics Space Phys. 16, 539-565
Unfortunately, none of these guys quoted actual K variations in the auroral regions, but you can see
the magnitude of the vertical (and horizontal) winds due to auroral energy input. The seasonal
effect only produces a factor of a few total magnitude enhancement in K_h between equator and
mid-latitude max, and it doesn't look like the auroral effect is as strong as the seasonal effect on the
Earth, except during geomagnetic disturbances. Note also, that the upwelling seems to be confined
to high altitudes. I doubt that the "effective" K profile is much affected outside the altitudes of the
auroral energy input. Also, it seems to be the temperature increase that largely drives the
upwelling, and I'm not sure how that ties in with K. The bottom line is that while it's fair to use an
Earth analogy here, you better get your analogy and references correct, and you might want to
understand the Earth situation before you try and correctly model the Jupiter situation.
It is true that B & K reference is not a good one for our case, so we have removed the
reference. We have decided not to use any earth analogy.
2. (p. 3, introduction) No period before (Clarke...), you might want to put an "e.g." in there before
the references "(e.g., Clarke...)" since this list is not exhaustive and does not contain the discovery
1
papers, and you need to add Clarke et al., 1996 and Grodent et al., 2000 [do you really mean 2001?]
to your reference list. Note also that JGR format requires square brackets rather than parantheses
for references. See the style sheets and examples.
We have removed the references to aurora since they are not relevant to this short paper.
Grodent et al. 2001 appears later, and we have corrected the year.
3. (p. 3-4, introduction) I found it odd that your list of papers that have used various observations
to derive K_h was weighted toward Saturn and Neptune papers rather than Jupiter. Why not just
cite all the relevant Jupiter papers, rather than Saturn and Neptune? For instance, for the UVS
occultation results for the CH4 and other hydrocarbon distributions, the main two Jupiter papers are
Festou et al. (1981, JGR 86, 5715) and Yelle et al. (1996, JGR 101, 2149), neither of which you
cite. For Lyman alpha and its relation to K_h on Jupiter, Hunten (1969, J. Atmos. Sci. 26, 826)
started it all (I think), and there are several other papers you could mention if you wanted to (e.g.,
Broadfoot et al. 1981, Ben Jaffel et al. 1988, Skinner et al. 1988, Emerich et al. 1993, Gladstone et
al. 1996), although a full list is not necessary as long as you quote the most important Jupiter
papers. You've got the two critical ones for He 584 A for Jupiter, although the Gladstone et al.
1996 photochemistry paper also looked at it, and in fact they chose their nominal K profile so that
He 584 A rather than UVS CH4 was reproduced. Did the Gladstone et al. 1995 EUVE paper also
consider 584 A emission and the consequences for the K profile? Note also that there have been
some other observations that provide information about K_h on Jupiter: fluorescence in the nu_3
band of CH4 seen with ISO and Cassini and now from the ground (e.g., Drossart et al. 1998, 2001,
or 2002 DPS abstracts, or 1999 ESA SP-427 paper), and infrared stellar occultations observed from
the Earth (e.g., Drossart et al. 2000 DPS abstract). You might also want to mention that Drossart et
al. (2001, DPS abstract) concluded that K_h was *not* enhanced in the auroral regions, based on
their VLT/ISAAC CH4 observations, which indicated a constant (to within 20%) CH4 mole
fraction in the homopause region across the whole Jovian disk. I'm not sure what spatial resolution
they had, but those observations seem to throw doubt on your theory. You might want to talk with
him about the subject. He's never published these results, so I'm not sure how much to believe him.
We have updated our reference of past observations to derive K profile. For Lyman alpha,
we have included two early ones [Wallace and Hunten, 1973; Yung and Strobel, 1980], and
Gladstone et al. [1996]. Since we only have a partial list for this short paper, we are not
including the observations with CH4 fluorescence 3 band. We looked at Drossart et al.
DPS abstract [2001] but did not find the evidence of non-enhancement of K, and therefore
we are not discussing their result.
4. (p. 4, introduction). You discuss Voyager observations of He 584 A, but you don't mention what
a typical disk-averaged brightness or low-latitude value was (4-5 R?), and you do not mention
EUVE observations at all (typical brightness 1-4 R, disk averaged). You should at least mention
the EUVE observations here, and tell us what the base-level (low latitude) Cassini brightnesses
were for comparison to your "polar" quotes. You also should discuss solar variability and mention
what part of the solar cycle the different observations were taken and how that would affect the
observed brightnesses (here or elsewhere).
2
Chris, please answer this comment.
5. (p. 5, re. helium mole fraction). Your value of 0.136 is probably from the Galileo probe data, not
Voyager IRIS, and you need to provide the reference here.
The reference of He mole fraction is taken from a book, Gautier and Owen [1989], which
we have put in the text.
6. (p. 6, top) The Grodent et al. (2000) reference here and elsewhere should be 2001. I was also a
bit confused here, as the first sentence seems to imply that you took the H2 and He densities from
the Wong et al. 2003 model. That's not really what you say here, but that's how I interpreted it. It
might help to start with the sentence about thermal profiles, and then say that H2 and He densities
were then calculated assuming a hydrostatic equilibrium atmosphere and using the photochemical
model as described in Wong et al. 2003, so it's clear that you model is self-consistent.
Grodent et al. (2001) reference is corrected. It is true that the H2 and He densities and a
few others are taken from the Wong et al. (2003) mode. In the revised text, we have
clarified this point in a similar manner as the editor has suggested:
“The H2 and He densities used in the resonance scattering model are calculated by a onedimensional photochemical model for the polar atmosphere of Jupiter [see Wong et al.,
2003].”
7. (p. 6, middle) The Atreya et al. (1981) K profile was based on a naive view of the temperature
structure of the mesosphere and thermosphere of Jupiter. Their homopause level is at a few times
10^-3 mbar when using their temperature profile -- quite a bit deeper than subsequent analyses
indicate. The He emission from Voyager is not reproduced using their temp and K profile. Oddly,
their K profile actually does better with a more correct temperature profile. In any case, I would
suggest using another K profile as your base model. I know that you are just following the
convention of Wong et al. (2003), but I would suggest switching to the nominal profile of
Gladstone et al. (1996) or one of my profiles (paper in preparation or DPS abstracts – I can send
you information) UNLESS you are sure that your base-level Atreya profile fits the Voyager lowlatitude He 584 A emission data (using a solar flux relevant to the Voyager encounter). If it
doesn't, then your values of 15 times Atreya (or whatever) are meaningless.
We are not using the Atreya (1981) profile directly. Our profile is similar in expression but
different in value to that of Atreya (1981) as well as Gladstone et al. (1996), so that the eddy
diffusion profile is related to the K value at homopause and the density. In the revised text,
we have clarified exactly what profile we are using, and how we test the enhancement:
“Kz is adjustable in this study. For a nominal Kz, we use the expression similar to one
suggested by Atreya et al. [1981] and in Gladstone et al. [1996]:
3
(1.46  106)  (1.4  1013 / nt(z))0.65 above 100 mbar level, and
103
below 100 mbar,
where nt(z) is the total number density at altitude z. We consider four cases of enhanced
eddy diffusion profiles, given by Kz, where  = 1, 3, 10 and 30.”
Kz (cm2 s-1) =
8. (p. 6, middle). The expression you attribute to Atreya et al. (1981) is not correct -- it's
presumably 15 times their expression, but that's not clear, and you should check the original
expression (since I keep coming across errors in Wong et al. 2003, I would no longer assume
they're correct).
See the previous reply.
9. (p. 6) You need to quote the molecular diffusion coefficients you've used for He and CH4 here - those values are critical to your models and conclusions. It's your choice, but it might also be
useful to provide figures or tables of your T-P profiles so that people can reproduce your results.
We include the value of eddy diffusion at the homopause for each case. As mentioned in
the text, the T-P profile is the directly from Grodent et al. [2001], so we are not including
the figure in the paper.
“We consider four cases of enhanced eddy diffusion profiles, given by Kz, where  = 1, 3,
10 and 30. The homopause pressure level and Kh for each  are: (1.2  10-3 mb, 9  105 cm2
s-1), (3.0  10-4 mb, 9  106 cm2 s-1), (2.6  10-5 mb, 2  108 cm2 s-1), and (2.7  10-6 mb, 3 
109 cm2 s-1), respectively.”
10. (Fig. 1 caption) The second sentence is not a sentence (no verb), and I'm not sure what you're
getting at there.
The typo has been corrected.
11. (p. 7, top, re: hydrocarbon emissions). You need to be very careful here. First of all, there is a
whole history of published works of auroral hydrocarbon emissions, so the Romani et al. (2003)
DPS abstract is not the best reference here. Good references to check out include:
Kim et al. 1985, Icarus 64, 233-248
Drossart et al. 1986, Icarus 66, 610-618
Kostiuk et al. 1987, Icarus 72, 394-410
Kostiuk et al. 1989, Infrared Phys. 29, 199-204
Kostiuk et al. 1993, JGR 98, 18823-18830
Livengood et al. 1993, JGR 98, 18813-18822
More importantly, the hydrocarbon emissions from the auroral regions can be highly variable in
location and time, but there is a basic uncertainty as to whether the effects are due to temperature
variations or abundance variations. Because some of the variations are extremely rapid and the
4
photochemical lifetimes of several of the hydrocarbons are long (i.e., longer than horizontal
transport time scales away from the auroral regions), it is clear that at least some, if not all, of the
variation is due to enhanced local temperatures rather than enhanced abundances (see the last two
references above for more details). The prevailing view is that the enhanced C2H2, C2H4, and
C2H6 emission is mostly due to temperature increases, while both enhanced temperatures and
abundances may be affecting C6H6. At best, you could say that the increased hydrocarbon
abundances predicted by the higher K(z) models might *contribute to* (rather than *account for*)
the enhanced hydrocarbon emissions seen in the auroral regions. And even there, you have to be
careful. IR observations are sensitive to the column abundances, and it's not clear to me from your
figures that you get a higher column abundance (above say 10 mbar, a typical depth to which the IR
observations are sensitive) in the high K models than the low K models. Part of the problem is that
you've increased K at all altitudes. An increased K in the lower stratosphere allows the stable
species like C2H6 to be removed to the troposphere more quickly.
What a high K model does do for you is increase the mixing ratio at altitudes where the
temperatures are also enhances, thus increasing the hydrocarbons emission. With high-enough
resolution IR observations, this possiblity might be able to be tested.
In any case, you need to more carefully discuss the hydrocarbon emission observations if you want
to use them as further proof that K(z) is enhanced in the polar regions. I'm not convinced.
12. (p. 7) Eeek! You don't discuss the Cassini UVIS observations at all, but simply quote a DPS
abstract for which there is no written information. Has there been a paper submitted on this
subject? If not, you'll need to flesh out your discussion of these observations. For example, you
tell us that the current best UVIS estimates for the "polar" He 584 brightness lie in the range 3-15
R, but you don't say what the comparable low-latitude values are, whether a large range is quoted
because there is latitudinal or temporal variability or whether it's due to analysis uncertainty.
Presumably, there are images at 584 A, so you should be able to get latitude/longitude variations to
model. Do you really mean "polar", or should that be "auroral-region"? Low-latitude values are
definitely needed for comparison purposes. Again, if your 1 times K(z) profile does not reproduce
the low-latitude emission than you need to come up with a new baseline K(z) profile. If this kind
of information is not available from Cassini UVIS papers yet, you should wait until it is.
We have included a section to discuss the Cassini UVIS observations. Since the
observations are disc averaged, we have no low-latitude values for comparison.
13. (Figure 2). Figure 2 is obscure to me. I assume these are plots of theoretical points and not
observational, right? If so, what is the difference in the different latitude models (i.e., why is the
10*K(z) model so different for 70 deg latitude as compared with 60 deg latitude)? Do the models
use the same temperature profile? The same electron precipitation model? Gravity is not the same,
which affects the altitude grid and maybe the depth of penetration of the electrons, and the solar
angle is different, but this process is not clear and needs to be explained in much more detail. Why
is there such a strong latitude dependence for the 10*K(z) model and not the 3*K(z) model? This
5
figure and your overall model need a much more extensive discussion than two sentences on p. 7. I
have no idea what you're doing.
Chris, after getting new result, please answer this comment.
14. How do the discrete vs diffuse aurora differences come into the picture, and do you ever use
those differences?
This is a typo in the manuscript. We only use the diffuse aurora case from Grodent et al.
(2001), and it is now corrected in the revised text.
15. (p. 7, bottom). The sentence that begins, "Clearly, our modeling seems to suggest..." is not
clear. What do you mean by higher values of K_h are needed "to model the results of Wong et a.
(2003).
Wong et al. (2003) have found that high K values are needed to model heavy hydrocarbons
in the polar atmosphere of Jupiter. Here we want to say:
“These results derived from the present study for He 584 Å airglow are consistent with that
of the previous chemical study for aerosol production [Wong et al., 2003].”
16. (p. 7, bottom). I'm not sure how you derive at the conclusion that there is little correlation
between He 584 A airglow and auroral emissions from the Cassini data? What do you mean by this
statement, and what is your evidence?
17. (p. 8, first sentence) wrong plural/singular "The main uncertainty ... are"
Corrected.
18. Check your references! There are several missing, and some have wrong dates. Please
thoroughly check author list, journal info, date, title, etc.
The references should be complete now.
18. (p. 8, last paragraph) regarding the phrase "more vigorously mixed than previously thought",
you should provide some references and/or discussion here. There are a couple of issues that need
to be mentioned. Although it has long been thought that a higher effective "mixing" coefficient is
possible in the auroral regions, there are some more recent observations that shed doubt on that
theory. The first is the CH4 nu_3 fluorescence observations of Pierre Drossart that I mentioned
earlier. He has interpreted his observations with models that have a CH4 profile that doesn't vary
6
much across the disk (i.e., less than 20% variations in the CH4 homopause level, even in the
auroral regions). He hasn't published this stuff in refereed literature, as far as I can tell, so I
wouldn't require you to discuss it, but it has been discussed at meetings and in my Jupiter book
review chapter, so many people know about it and would wonder how to correlate your conclusions
and his. The second set of observations that pertain to the auroral vs. low-latitude issue is the H2
airglow and auroral-region observations (e.g., Trafton et al. 1994, Liu and Dalgarno 1996, several
others). I don't know much about this kind of modeling, but Liu and Dalgarno (1996) derive only
slightly less CH4 absorption in their non-auroral spectra than Trafton et al. (1994) did in their
auroral spectra, suggesting that there are only minor differences in the homopause levels between
the auroral regions and the rest of the planet. These observations *are* published and should be
discussed. Can they be reconciled with your conclusions? You did not consider He emission due
to electron impact, claiming that such emission must occur above the homopause anyway and so
would require vigorous mixing, but I'm not sure I buy that argument if electron impact can lead to
emissions that are as important or more important than airglow. I would need to see things
quantified better before I would allow this issue to be swept under the rug.
Chris, please work on this reply.
7
Reviewer #1 Evaluations:
Anonymous: No (Jack McConnell)
Comments
Abstract: I am uncomfortable with the use of K(z) (ie B&K reference) in polar regions on Earth in
the mesosphere versus lower latitudes since it is largely circulation driven rather than turbulence
driven.
The B&K reference is discarded in the revised text since it is old and questionable.
"In this paper, we search.." This is a rather awkward sentence, but is sounds backward. It is simply
trying to say "we see 584 and it suggests increased vertical transport. We use neat models to verify
this..."
"Our reference conditions....." Again a pretty awkward sentence and the section "an atmosphere
consistent with the Voyager UVS occultation/Cassini polar observations." I do not know where the
evidence for this comes from, unless it is from the Wong et al (2003) paper. But what is used is a
pretty standard reference modified with a modeled Jovian temperature profile.
This sentence is now removed from the abstract, and we discuss the detail in the paper.
References:There are at least 6 references missing, several not used and a few with the wrong date.
The Porco et al (2003) reference for He 584 is a reference for the Cassini imager. In fact, I cannot
find a reference for the He 584 on Cassini. If there is no reference then there needs to be a lot more
description of the instrument and the observations.
The references are now fixed. We have included a section to describe the Cassini He 584
data, including a figure and a table.
X3-Introduction: Benzene has been observed for quite a long while and not just recently as is
suggested from the wording in the text.
The benzene statement has been removed, since it is less relevant in this work.
X3-line 5 from bottom: “The value of K..”. This sentence is backwards and makes it sound as if Kh
determines molecular diffusion whereas it is Kh and molecular diffusion which define the
homopause.
We agree with the reviewer and this sentence has been removed. The sentence which
defines the homopause now reads:
8
In a one-dimensional model, this mixing is often characterized by the eddy diffusion profile,
Kz. At the homopause, the altitude where the molecular diffusion coefficient of methane
equals the eddy diffusion coefficient, we define Kz = Kh.
X3-l3fb: Extracting Kz from lyman-alpha observations of Jupiter has been notoriously uncertain.
Thus the long list of references for K and H1216 should be caveated by a few sentences outlining
the problems in the past. There has even been a problem with solar Lyman fluxes which appear to
be the main source.
We are not discussing lyman-alpha observations in this paper, so the problems are not
included in the text.
X3-l2. Bishop (1992) -> (1991)?
This reference is removed since it is not relevant to Jupiter.
X5-section 2.1. This first paragraph is very familiar.
Yes. We have only made minor change to this paragraph.
X5-l4fb: The integrated He 584 solar flux. There is no discussion of its variation with solar activity
and solar rotation. A few sentences should address the state of solar activity at the time of Cassini
flyby and observations. From the figures shown a factor of two in solar flux can lead to a factor of
10 in K depending on the temperature and K.
Chris, please reply this comment.
X6-l1: Surely H2 and He densities can be simply calculated from the temperature profile and the
assumption of zero flux? Making reference to the Caltech/JPL model is misleading in that suggests
that a complex model is required (also Wong missing reference) but it is not.
It is true that a simple model can also serve the purpose. We use Wong et al. (2003) model
because it has already incorporated the polar temperature profile and can also generate
heavy hydrocarbons to illustrate their enhancement due to greater mixing. References has
been added.
Also with respect to a question that arises later regarding possible excitation of He 584 with auroral
precipitation, the mention of the self-consistent Jovian model by Grodent (missing ref) leads to the
question why was the excitation rate of He by electrons not calculated as it would be very
straightforward given the type of model.
9
Chris, please reply this comment.
X6 "By analogy, we surmise..." Comparison of Kz at polar and mid-latitudes on Earth and Jupiter
can only be very qualitative and possibly misleading given that the energy going into the Jovian
auroral zone is many time larger than that of Earth. By that analogy K should be much larger at the
polar regions on Jupiter, whereas it is likely circulation limited.
We have removed the comparison with earth.
X6; "From Atreya..." The eddy diffusion profile is not "derived to be.." but "taken to be"
We have re-written the sentence so now it reads:
“Kz is adjustable in this study. For a nominal Kz, we use the expression similar to one
suggested by Atreya et al. [1981] and in Gladstone et al. [1996]:
Kz (cm2 s-1) =
(1.46  106)  (1.4  1013 / nt(z))0.65 above 100 mbar level, and
103
below 100 mbar,
where nt(z) is the total number density at altitude z. We consider four cases of enhanced
eddy diffusion profiles, given by  Kz, where  = 1, 3, 10 and 30.”
X6-The chemistry discussion seems to be a throw away comment as there is very little comment
later.
We have taken out the chemistry discussion here because it is not directly relevant to the
paper.
X6- The results section starts with the presentation of the chemical species but there has been no
discussion of the airglow results yet! If the paper is about the possible variation of chemical species
with K then there should be more presentation of relevant details
And there is no comparison with the measurements that were mentioned earlier.
True. This paper is not about chemical species with K, so we have taken out the part
mentioning the results of chemical model.
X7 : l4 "may account FOR the observations .." missing FOR
Comment taken.
10
X7 - Porco et al (2003) paper and He 584 measurements. This reference does not include the 584
measurements which should be discussed in more detail than they are in this manuscript since they
are critical for the analysis. Unless there is a more detailed journal reference or it will be long in
appearing, there should be a brief instrument description and some discussion of the He 584
measurement results and attendant errors etc.
We have added a section to describe the Cassini He 584 measurement. Porco et al. (2003)
is the wrong reference and has been taken out.
X7- In figure 2. "we can see a clear auroral zone.." I cannot - this needs more explanation and
clarification.
We have clarified this point by the revised text:
“In Figure 3(a), the calculated He 584 Å intensity is plotted as a function of latitude for each
value of . The intensity at 60° is much greater than those at higher latitudes, showing a He
584 Å emission oval zone.”
Also, as mentioned earlier, this section needs more discussion regarding the possible contribution
from auroral precipitation. It seems the tools are readily available and even seem to have been used.
Why not give some estimates of He 584 emission from precipitation with high K. Relying on the
lack of correlation between he584 and other emissions in seems a bit weak. The comments at the
bottom of the page are not convincing. Perhaps even with high Ks there is simply not enough
helium to be excited. That would be enough to convince me but it should be quantitative.
Chris, please reply this comment.
Also why are the Cassini observations given as a simple bar on the side. Do they not have a latitude
and longitude?
The Cassini observations are disc averaged. We added a new section describing the
observations.
Extracting a range of Kz versus latitude seems specious given the presentation of the data.
We are not extracting a range of K versus latitude. We are only presenting the results of
several cases for different latitudes.
"Clearly, our modelling.." There is something wrong with this sentence!
This section has been re-written.
11
X8: l1. The first sentence means to say, I think, that there may be problems with the Cassini UVIS
calibration.
The uncertainty is in the observation. We have included a section describing the
observations in detail.
HC - hydrocarbons, spell out.
Comment taken.
"vigorously mixed than previously thought" . I am not sure that this is true. The notion of more
mixing based on auroral mixing is not new, it is just the evidence for mixing has been weak.
Certainly the He 584 is a much stronger piece of evidence.
We have replaced this statement with a more appropriate one, saying that the polar regions
are more vigorously mixed than in the low latitudes.
12
Reviewer #2 Evaluations:
Anonymous: No (Mike Summers)
As the authors' note, one major uncertainty in their conclusions is the unknown error bars in the
Cassini He 584 A measurements, but that's just something that we just have to live with for the
present. Another major drawback of their approach is that with their 1-dimension
photochemical/eddy mixing model, it is impossible to deduce the relative importance of eddy
mixing and vertical advection in determining the He abundance near and above the homopause.
However, without a 2-dimensional photochemical transport model it's not possible to quantitatively
clarify this issue either. But I would like to see the authors' discuss in at least qualitative terms how
advection in the Jupiters' mesosphere would affect their conclusions.
Chris, please reply this comment, and add something about “how advection in the Jupiter’s
mesosphere would affect our conclusions”.
To motivate their study the authors reference an ancient work on eddy mixing in the terrestrial
mesosphere (Banks and Kockarts, 1973!) that concluded that eddy mixing in the polar regions on
Earth are larger than at lower latitudes. A great deal of research has been done on the Earth's
mesosphere in the past 30 years. For example, we now know that vertical advection dominates
over eddy mixing throughout much the terrestrial mesosphere, and that eddy mixing rates actually
peak significantly south of the pole, whereas vertical advection actually dominates at the poles. I
would encourage the authors to reference more recent research in their introduction, and give a
better motivation.
It is true that B & K reference is not a good one for our case, so we have removed the
reference. We have decided not to use any earth analogy. Chris, please go over this and see
if we need to add some reference and motivation in the introduction.
The paper is very poorly referenced. Many references in the text, including Banks and Kockarts
(1973) and Wong et al (2003), are not even listed in their references. Please proof read the
references more carefully.
All references in the paper have been updated.
Please give a reference for f_He = 0.136.
The reference is: fHe = 0.136 [Gautier and Owen, 1989].
The value of K(z) on p. 6 is confusing, as there appears to be an extra factor of 15 in the equation.
Or am I missing something?
Yes, there was a typo in the equation. The factor of 15 has been taken out.
13
Please clarify how "high hydrocarbons predicted by K(z) models may account the observations of
Romani et al. (2003)"
This reply will be the same as reply 11 for Julie.
Please clarify how "we can see a clear He 584 A auroral oval zone..." It's not clear to me.
The evidence is now added in the text:
“In Figure 3(a), the calculated He 584 Å intensity is plotted as a function of latitude for each
value of . The intensity at 60° is much greater than those at higher latitudes, showing a He
584 Å emission oval zone.”
Please clarify "There is apparently little correlation between He 584 A airglow and auroral
emissions from the Cassini data."
We have included a section describing the observation. To clarify, we add:
“Examining the ratio of He 584 Å airglow to the auroral emission in the UVIS data
(Table 1), we see there is little correlation between these two emissions. Therefore, the He
584 Å emissions are interpreted primarily as airglow and not aurora.”
Figure 1 caption: The sentence which begins "A stratospheric model..." appears to be misplaced.
Figure 1 caption has been changed and the type has been corrected.
Figures 2 & 3: Please clarify "subsolar" and "bandwidth."
Chris.
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