Charly Whisky
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Bienvenue sur Wikipédia, Charly Whisky ! | |
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Pages utiles modifier
- Tout l'indispensable, à lire absolument,
Pour poursuivre, vous pouvez trouver des éclaircissements à partir des pages :
- Aide:Sommaire, plus complet, pour plus tard…
- Aide:Syntaxe, des conventions d'écriture à connaître,
- Aide:Poser une question, si vous vous sentez perdu.
Vous pourrez ajouter par la suite d'autres pages d'aide ou les informations dont vous pensez avoir besoin dans votre espace utilisateur.
Bonnes contributions ! Arria Belli 31 juillet 2008 à 08:22 (CEST)
Bande brillante modifier
Sorry,
I don't follow your thoughts, maybe it is because we both write in our second language. The inverted line is almost the exact duplicate of the lines in Dr. Fabry paper and it is like the reality of weather radar example I've provided : slow increase in snow, sharp peak in the brightband and then decrease in rain but at the end about 1,5 dBZ higher than in snow. As an operational meteorologist, this is what I see anytime a brightband is present.
As for the Mie scattering, it could be a factor in the brightband, as large wet flakes reach closer to the radar wavelenght, but not in the rain, even with larger drops. The examples I've showed you are with a 10 cm weather radar and with a 30 cm wavelength profiler in winter cases, the drops in these occasions won't reach the Mie limit.
As for the philosophy of bright band separate from remote sensing, I don't understand what is your point? The bright band is a remote sensing problem. One cannot separate the two since the brightband is seen on a remote sensing device called a radar by virtue of the radar beam properties!
Finally, thanks for the suggestions about the article and I will think how to improve it. However, the introduction already tell what is the brightband and the rest of the article has to go in more details and one has to understand how radar returns are influence by size and physical properties before explaining the phenomenon. As for the example, you say it is not a brightband but a colored band (?) Since color is related to radar return intensity, they show the increase in the brightband and I fail to see what is your point ?
I've looked at your radar page, good explanation. I did a similar quick and practical explanation in the radar météorologique article. Hoewever, a user created a page on Brightband with only the introduction from your German version. Since an article was the chance to expand on the phenomenon, I added lot more informations. A reader will normally look at the weather radar article and then go to the brightband article for more details.
Pierre cb (d) 2 août 2008 à 13:24 (CEST)
- I think we see this problem on a diffrent point of view, mine is practical interpretation under the aspect for teaching.
- o.k. I don't come from weather radar. My specials are ATC and air defence radar. But i can see and can evaluate a diagram. Sorry, i cannot upload the origin, but you can see it on this external link. The red graph is your inverted attempt, the blue one is the former German version, but turned 4 degrees left, the green graph is the actual diagram from the German version. (Due to your changing of your statement at 15:19, 2. Aug. 2008, i let it without comment :-)
- I learned something other: These graphs of reflectivity depend on the individual radar set. Every radar set has got its own table of reflectivities. The same radar set on a new site needs a new table. I don't come from weather radar. My specials are ATC and air defence radar. But i take part on a course of lectures about weather radar, held from Prof. Richard Doviak and (idolised from me:) Prof. Dušan Zrnič. If i didn't understand some english words on this course, Bey Dušan telled me it in Serbian language - due to the cousinship of Serbian and Bulgarian language, so i understood more than anyone else.
- By the way: All the changes around the diagram are unimportant to establish understanding for the effect of the bright band. All changes are negligibilities.
- o.k. Our diagrams are not dedicated for scietific work. Some inaccuratenesses must be accepted for an easier visibility, i think. --Charly Whisky (d) 2 août 2008 à 16:07 (CEST)
- I've used Prof. Dušan Zrnič book in my univeristy courses on the subject and I'm well aware of his reputation. I met him during radar conference, too. As I said reversing the graph was not perfect but was showing something closer to the reality, a slight increase in dBZ in rain over snow, than the original. Your rotation does a similar thing and it follows more in the snow section. Both are however quick fix. As for the calibration, this increase in rain is not related to radar caracterictics but to the precipitations itself but naturally the form of the graph varies with intensity of precipitations, melting speed, etc. so the graph can have a multitude of path. What is important is the final outcome when one wants to correct for the bright band : one has to use the data either above or below the band, as available, and correct for the difference in the right direction.
- Althought this is irrelevant to the BB itself, the direction of increase/decrease is relevant to the understanding of radar interpretation in melting precipitations. So a corrected graph, yours or mine, that shows that, was needed. I Probably should have said that the difference between rain and snow was inverted instead of saying the graph was inverted.
- This was an interesting conversation. I have made some simplifications and rearrangement to the article because of it.
- Thanks for the correction in Commons ! Pierre cb (d) 7 août 2008 à 04:58 (CEST)
Radartutorial modifier
Hi. I'm flattered that you thought of me for helping you in the translation. I'm away until the end of the month and that is why I answer as and IP on a public computer. I will recontact you after I come back. 75.111.155.246 (d) 21 octobre 2010 à 16:06 (CEST) (for Pierre_cb)
Radartutorial mail modifier
Hi,
I've read your text. Send me an e-mail when radartutorial mail is back on line.