1) The contents of section 2.1 (Background on East Asian Dust) could be included in the introduction, as well as the second paragraph of section 2.2 (i.e., the paragraph about the community effort).
2) Section 2 could be entitled simply: 2. Observations of the April 1998 dust events. Sub-sections or sub-headings are not necessary. Delete the paragraph about modeling of the event.
3) Section 3 could be entitled: 3. Formation of the Dust Clouds.
4) Sections 4 and 5 could be regrouped into a single section, Section 4: 4. Distribution and transport. This section would include 2 sub-sections: 4.1 Horizontal and 4.2 Vertical.
5) Section 6 could become Section 5: 5. Transformation and dissipation.
6) Section 7 would become Section 6: 6. Physical, chemical, and optical characteristics.
7) Sections 8 and 9 could be blended into Section 7: 7. Discussion and recommendations. Describing efects of the dust in that section would be appropriate. Blending the last two sections also would make the last section stronger (right now it's too short and weak).
After arrival over the Pacific Northwest, the elevated dust cloud subsided. Initially the depth was of the order of 4-5 km from the ground. (This was on the weekend. I know this because I was driving up to Pullman to visit my son on Sunday, April 26 and was quite aware of the remarkable whitish haze and wondered what that was all about.) The layer depth remained about 4 km for the next few days (according to pilot reports during landings at Pasco airport), but gradually began diminishing by mid week. On Friday, May 1, when our group did a test flight to check out instruments for an upcoming study in Phoenix, the layer was about 2 km thick. (The size distribution data I gave you is from this flight.) During most of the week, the weather conditions were rather stable and quiet - not much wind. However, late Friday, May 1, a front came through and apparently pushed the dusty airmass to the east. What is not clear is what happened to it after that. It could have been greatly diluted with the clean air moving in from the Pacific or it could have been scavenged by precipitation during passage over the mountain ranges (Cascades, plus those farther east before the main crest of the Rockies). That part I have no information on. What I do remember is that Saturday, May 2, was the remarkably clean air - horizontal visibility was very good, in spite of the general high cloudiness that prevented any good radiometric data on AOD. But like I mentioned above, mostly this is anecdotal without much in the way of hard references. Maybe it is useful to you.
As for my small contribution, I suggest that it be stressed that this data marks the first detection of the leading edge of the dust as it penetrated the western US states. (Thus it should be mentioned before the JPL observations in the text.) The model or satellite results may not show it quite overhead of Utah on 24-25 April, but this is likely because the aerosol layer was still optically thin. Since the figure you now have is only temporary, I want to provide you with an improved version that extends up to 12 km and shows the weak aerosols aloft up to 10 km; the depolarization values are also a bit off, and actually the lidar return is not a log scale. I'll correct these things and send you the figure and a new caption electronically next weak. Small text change for my data discussion- pg 8 line 25, ...particles in the 1-2 um diameter size range "or greater" [Mishchenko and Sassen, 1998].
I have also pointed out to Rudy the work of T. Takemi on understanding the meteorological processes of the China dust storm genesis, recently published in Journal of the Atmospheric Sciences: Vol. 57, No. 11, pp. 1718-1740.
There is also some info which can be "mined" from the original press reports and weather observer reports in China which can shed some light on the initial meteor- ological processes and meteorological evolution of the dust cloud. Some of this info is in the CNN video, which I believe is archived on the Asia/Fareast web page under "resources" or "reports" at http://capita.wustl.edu/ASIA-FAREAST/reports/CNNTranscript.TXT The actual video (which I think is still archived somewhere) shows a black haboob- like cloud advecting in, with dust probably entrained up into the atmosphere by convective processes (the "arid region squall lines" researched by Takemi et al.)
(2) I agree that it is no problem to remove "modeling" as a separate heading, but to instead subsume any modeling comments within the overall body of the paper elsewhere. I agree with Dan Jaffe that those sentences should stay in, just not as a separate section, add them elsewhere.
(3) I also agree that a lot of the required changes were a result of editorial/organizational minor "glitches" that were a result of the haste of making sure something was submitted on time.
(4) With regards to the sections on Dust Processes, Dust Characteristics and Effects it is fine to retain them as is since they are not part of the chronological evolution, however, I do suggest that each of those sections (processes, characteristics, effects) be organized chronologically where feasible within each of those three sections. -i.e. it would be good for each section to have a parallel and chronological structure.
-Tom Gill
"Modeling of the dust event.
The April 1998 Asian dust event was simulated by at least four modeling groups. The dust models have provided valuable insights into the emissions, transport and removal process that governed the life cycle of such events [Westphal, 2000]. Also, the data from field observations were used to "test and validate" the performance of dynamic global scale aerosol models [Nickovic et al., this issue; Uno et al., this issue). The details of the dust subsidence over British Columbia were further investigated with the aid of a mesoscale transport model [McKendry et al., this issue]. "
I should add that our paper has undergone minor revisions after positive reviews (I sent it away yesterday). The main change is that the modelling has been reworked and looks much better (i.e. the hotspot in central Washington is captured). The meteorological mechanisms are also nailed down a bit better.
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