Question About Wind as it relates to fallout.

[kato13]

I am currently adding fallout to my nuclear effects map. The source for a portion of my code recently unexpectedly added fallout to the effects display

http://www.carloslabs.com/node/20

Unfortunately this has surprised me from a data perspective. I had not thought about wind direction when I did the data model. The carloslabs page solves this question by making the wind direction random but adjustable. Adjustable is not feasable on my system due to the number of strikes.

At first I thought random would be ridiculous as in the US winds primarily move from West to East i always expected fallout to follow that pattern. Thinking about it I wondered if the thermal effects of such a bomb screw things up so much that random wind might be possible.

I still think I will go with a fixed wind direction for each strike using the following basis:

USA. West to East with variation from northerly to southerly, southerly slightly emphasized.

Canada. West to East with variation from northerly to southerly, southerly strongly emphasized.

USSR. Generally radiating out from the center or the country, but significant variation.

UK. Generally North to South with easterly to westerly variation, easterly slightly emphasized.


Anyone have any opinions on this. This kinda came at me from left field and is the only thing holding me back from finishing up the strikes portion of my system.

[Legbreaker]

As the US prevailing winds are west to east, perhaps somehow working a bit of randomness into it might not be a bad idea. Would need to skew the possible results towards the prevailing winds of course, but like you say, thermal effects, and normal storm fronts etc will certainly have an impact.
These variations are likely to be relatively short lived I'd think though - perhaps hours, maybe a few days to a week in duration.

Wind speed is another variable you might want to consider, perhaps humidity (especially heavy rain or snow) could contribute also.

I wonder how much a Cyclone/Hurricane or tornados would screw things up?

[Grimace]

I used to room with a guy in the Air Force that worked in some of those missile silos. He had a book that I got to look at (it had been declassified) that showed maps of what the Air Force thought would happen as far as radioactive fallout after a nuclear war. Needless to say, it wasn't a pretty thing for the East Coast of the U.S.

So I think you've generally got the right idea. The thing to do is get a picture showing the jet stream. Then you can base your wind drift patterns based on that. Also...and I'm not sure if you're taking this into account, but ground bursts created substantially more fallout and much bigger affected area downwind from the impact zone than that of an airburst.

[Legbreaker]

Once particles reach the jet stream, my understanding is that they're likely to stay up there a VERY long time. It's this dust that's supposed to cause the nuclear winter and we all know how long some estimates say that'll last.....

The biggest, or at least more immediate threat from fallout will probably be in the first few weeks. After that time, most of the airborne particles are likely to be coating the ground and just about every other surface only causing significant immediate problems if it's stirred up (which normal winds are certain to do, not to mention people walking through it).

Fallout (ie particles falling from the sky) is likely to remain a danger for as long as there's dust in the upper atmosphere. Without rain to flush it clear (it's WELL above cloud level), this could be generations. Fortunately the amount of dust isn't going to be anything like directly after the initial bursts.

[kato13]

Originally Posted by Legbreaker

As the US prevailing winds are west to east, perhaps somehow working a bit of randomness into it might not be a bad idea. Would need to skew the possible results towards the prevailing winds of course, but like you say, thermal effects, and normal storm fronts etc will certainly have an impact.
These variations are likely to be relatively short lived I'd think though - perhaps hours, maybe a few days to a week in duration.

Wind speed is another variable you might want to consider, perhaps humidity (especially heavy rain or snow) could contribute also.

I wonder how much a Cyclone/Hurricane or tornados would screw things up?

There is certainly going to be a random factor. If the few hours I have had to think about this I have been daunted by the math. Even the best minds can't figure out the weather so I don't feel too bad.

Since I want my maps to appear the same every time you come back to them, I have to set the wind direction in the database. Which means deciding on wind direction for 3000 or so data points. I want it automated, but I also want points close together to have a similar, but not identical wind direction. Fallout from 10 strikes from a closely clustered MIRV are unlikely to produce fallout in all directions. Of course other close strikes might happen on different days. As someone who over thinks everything this is a nasty curve to be thrown so close to completion.

I think once I finalize all the other strike issues I will put this on hold while I do units and resources. I appreciate the comments they help keep my mind open.

Oh here is my first test using T2k Canon strikes.

[kato13]

Originally Posted by Grimace

I used to room with a guy in the Air Force that worked in some of those missile silos. He had a book that I got to look at (it had been declassified) that showed maps of what the Air Force thought would happen as far as radioactive fallout after a nuclear war. Needless to say, it wasn't a pretty thing for the East Coast of the U.S.

So I think you've generally got the right idea. The thing to do is get a picture showing the jet stream. Then you can base your wind drift patterns based on that. Also...and I'm not sure if you're taking this into account, but ground bursts created substantially more fallout and much bigger affected area downwind from the impact zone than that of an airburst.

I think this focuses on near term fallout as long term fallout is too hard to model (and to be honest way too depressing).

[Legbreaker]

Just to make the task even more "interesting" some of the resources state which direction fallout from particular strikes fell. The information is usually hidden away in descriptions of small towns, etc.
Looks like you've got a bit of reading ahead of you....

[kato13]

Originally Posted by Legbreaker

Just to make the task even more "interesting" some of the resources state which direction fallout from particular strikes fell. The information is usually hidden away in descriptions of small towns, etc.
Looks like you've got a bit of reading ahead of you....

I am going to do some digging before I launch. I want as many European strikes as I can find, Unit strengths, Strike miss distance and direction, etc. I guess I will add "wind/fallout" related words to my search term list.

I think I will investigate converting all the pdfs I have to txt to make searching multiple files at the same time easier. I am a lazy programmer there is no way I am reading everything

One good thing though is that everything within my system is databased so over the long run errors and inaccuracies can be changed by a few keystrokes.

[Fusilier]

There's also the possibility if you want to consider that many of the strikes may be high air bursts (usually depending on the nature of the target) so there would be little fallout to worry about.

Also the strikes occurred in November and beyond. You often get a lot of N / S wind patterns (at least in the areas I'm familiar with) due to cold fronts pushing down from northern Canada.

[Graebarde]

Life After Doomsday has a windrose table in the appendix that shows the wind speed and direction for locations all across the US.

Also remember that radiation starts to degrade at a factor 7/10 ( ten fold drop for every seven fold time) from time of detonation. The longer they are in the atmosphere the less lethal they are when they fall.

[kato13]

Originally Posted by Graebarde

Life After Doomsday has a windrose table in the appendix that shows the wind speed and direction for locations all across the US.

Also remember that radiation starts to degrade at a factor 7/10 ( ten fold drop for every seven fold time) from time of detonation. The longer they are in the atmosphere the less lethal they are when they fall.

I actually have found the average wind direction for November 1997 for 313 locations through out the US. I think I am going to determine the closest location to a strike and use a slightly randomized wind based on that location's average wind direction.

[kato13]

Here are the results.



I had never considered that during winter, winds would primarily come from the direction of water bodies as they would be the major thermal reservoirs. I still may tweak the results later but the data I have now I am comfortable with.

This actually changed my perspective about post TDM Chicago a bit as I had always assumed the fallout would go the other way.

[Cdnwolf]

As someone who lives in Southwestern Ontario and get hit from the weather coming from Detroit I can tell you that winds 80% or the time come from the southwest and flows generally to the northeast. The second most common direction that the winds come from is the northwest heading southeast ... during winter it accounts for all those damn snowsqualls that hits my city.

Then you add in the common weather systems like Alberta Clippers and Colorado lows - both fast moving storm systems that hit fast, dumps tons of snow and rain ... and leaves just as fast.

And of course those weather systems that hit Detroit... come from Chicago...

Also a great source for watching weather patterns is the NOAA ..... It you watch the loop of the weather systems you can see the patterns.

http://www.srh.noaa.gov/ridge/Conus/index_loop.php

[kato13]

The average wind direction for Detroit for November from 1930-1996 was WSW at 11 knots according to the pdf attached. It surprised me as well. I even thought that it might be the direction the wind came from (as winds are often reported) but the pdf does seem to support it is the direction.

I may throw in some Canadian weather station reports, for greater accuracy, if I can dig them up.

[Cdnwolf]

Ahhh I see what you did wrong... the wind directions listed are for what direction the wind is COMING from ... not blowing to... thats why your fallout pattern in the second map is a bit off.

[kato13]

That might be the case and I have considered it. However the PDF does say

prevailing wind directions (DIR) are given in compass points;

It has always bugged me that wind is sometimes referred to by the source direction not the travel direction. I am 90% confident that this is travel direction however all my preconceptions support your conclusions. I will look at a little more data before I launch with the final wind directions. I can flip the wind direction 180 degrees with 2 commands if I determine that is necessary.

[kato13]

From reading definitions I guess a "Westerly" wind could mean ether from the west or towards the west. As a logical person this annoys me to no end.

Overall I agree with you that the wind should be flipped 180 degrees. Thanks for pointing that out.

I actually like this better as it bodes well for a more prosperous city in my future potential Chicago source book. Well to those who are to the east of me enjoy the extra fallout

[Cdnwolf]

The important question should be...

Should I let the Chicago Blackhawks win the Stanley Cup... before I wipe Chicago from the face of the Earth?

(We all know the Toronto Maple Leafs will NEVER win the cup...lol)

[kato13]

All I have to say to that is thank goodness the Red Wings are gone in all my nuclear scenarios. I may adjust the strike near Detroit to be placed over their stadium, just to make sure.

[Graebarde]

Originally Posted by kato13

The average wind direction for Detroit for November from 1930-1996 was WSW at 11 knots according to the pdf attached. It surprised me as well. I even thought that it might be the direction the wind came from (as winds are often reported) but the pdf does seem to support it is the direction.

I may throw in some Canadian weather station reports, for greater accuracy, if I can dig them up.

A thing to remember about these reported winds is they are "surface" winds. While they affect the fallout, the higher altitude winds above about 20K feet will be a real determining factor I think, since lower level particles will fall out more rapidly and be localized while those thrown into the higher winds will travel further. (does this make sense )

[Graebarde]

Originally Posted by kato13

That might be the case and I have considered it. However the PDF does say
It has always bugged me that wind is sometimes referred to by the source direction not the travel direction. I am 90% confident that this is travel direction however all my preconceptions support your conclusions. I will look at a little more data before I launch with the final wind directions. I can flip the wind direction 180 degrees with 2 commands if I determine that is necessary.

NWS reports winds as direction which they come, hence Westerly comes from the west. At least in all the reports I've dealt with and submitted.

[kato13]

Originally Posted by Graebarde

A thing to remember about these reported winds is they are "surface" winds. While they affect the fallout, the higher altitude winds above about 20K feet will be a real determining factor I think, since lower level particles will fall out more rapidly and be localized while those thrown into the higher winds will travel further. (does this make sense )

I does make sense but currently the math involved has to be capable to be run on a clients PC via their browser. That means I have to keep things kinda simple. Right now when I run the math for my ~2600 morrow strikes it ties up my pc for about 200 seconds. To solve this I will restrict display to a selectable 4/25(and maybe 50) of the nearest strikes to the center point of the map. This runs in under a second. More complex math would of course take more time.

Even if I don't model it perfectly, trust me you guys are going to think it is cool. Eventually I may do more complex models and store them, but that is out of scope for Version 1.0

[kato13]

Originally Posted by Graebarde

NWS reports winds as direction which they come, hence Westerly comes from the west. At least in all the reports I've dealt with and submitted.

Yeah I've been aware of (and annoyed by) that fact since I was a kid. I guess when I saw direction = W, I just assumed it meant the direction of the wind is west. No biggie, it literally took me 25 seconds to fix it in the database. That is why I prefer building my site off a database as it makes recovering from an error like that almost painless.