Trace radioactivity from Japan likely over the Western U.S. today

By: Dr. Jeff Masters , 14:11 GMT le 18 Mars 2011

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Traces of radioactive substances emitted by Japan's damaged Fukushima nuclear power plant will likely arrive over the Western U.S. today, carried by the prevailing west to east winds that have blown over the Pacific Ocean during the past week. Rainfall is expected over California this weekend, and it is likely that the rain will wash radioactive particles out of the air to the surface in quantities that will be detectable at several locations. I want to strongly emphasize that the radioactivity from Japan arriving over the U.S. over the next few days poses absolutely no threat to human health, and is present in only miniscule quantities. The radioactive plumes from Japan have had seven days to dilute over a 5000+ mile journey, and have been subject to deposition to the ocean due to gravity and rainfall along the way. Natural radiation is present in our environment every day, and the extra radiation from the Fukushima nuclear plant will cause much less than a 1% increase this background radiation. Radioactive particles from the Chernobyl disaster in 1986 were detected in North America ten days after that event, and caused no harmful effects. The radiation from Japan over U.S. during the next week should be at levels even lower than the Chernobyl fallout.


Figure 1. Backward trajectories for the air arriving at the surface (red line) and 300 meters altitude (blue line) in San Francisco, California on Saturday, March 19, at 11am PDT. According to the latest run of the GFS model, the air arriving in San Franciso tomorrow will have originated near the surface in northern Japan last Saturday, when radioactive emissions from the Fukushima nuclear plant began. The radioactive particles arriving in California will be in trace quantities, and will have no harmful effects on human health. Images created using NOAA's HYSPLIT trajectory model.

Radioactive plumes emitted from Japan's troubled Fukushima nuclear power plant continue to move offshore to the east over the Pacific Ocean today, thanks to predominantly west winds blowing at 5 - 15 mph. These winds are being driven by the clockwise flow of air around a surface high pressure system centered just southeast of Tokyo. As this high pressure system moves northeastwards, parallel to the Japanese coast, today through Saturday, winds will gradually shift to the southwest, keeping the radiation from the Fukushima plant blowing out to sea. As the winds shift to southwesterly, the sinking air over Japan will be replaced by rising air, and radioactive emissions will begin being lifted high in the atmosphere. Since there is less friction aloft, and the high speed winds of jet stream increase as the air moves higher in the atmosphere, this radiation will undergo long-range transport. Latest trajectory runs using NOAA's HYSPLIT model (Figures 2 - 4) show that radioactivity emitted today could wind up over Alaska after five days, and radioactive particles emitted on Saturday could make it to California by late next week. I've made trajectory plots for the next three days assuming two possible release altitudes--a surface-based release near 10 meters, which should be the predominant altitude in the current situation, and a higher release altitude of 300 meters, which might occur if there is an explosion and major fire. However, the 5-day trek to Hawaii and California is 4000 - 5000 miles, and a tremendous amount of dispersion and dilution of the radioactive plume will occur. Given the current levels of radiation being emitted, any radioactivity reaching Hawaii or the U.S. may be difficult to detect, and will not be a threat to human health. Keep in mind also that the most dangerous radionuclide to human health in the radioactive plume--Iodine-131--has a half life of eight days, so will be reduced by at least 30% after 5 days of travel time.

Of much greater concern is the possibility of dangerous level of radiation over Japan. The next period of onshore winds that will blow radioactivity inland over Japan may occur beginning on Saturday night (U.S. time), continuing through Sunday, according to the latest run of the GFS model. The latest HYSPLIT trajectories show winds on Sunday may carry radiation from the disaster site southwards over Tokyo. A low pressure system is expected to bring considerable rain to Japan on Sunday, and this rain is likely to remove most of the radioactivity from the air where rain and radioactivity are both present. The winds associated with this low are difficult to predict at this time, since the winds will be light and variable.


Figure 2. Five-day forecast movement of plumes of radioactive air emitted at 10 meters altitude (red line) and 300 meters (blue line) at 18 UTC (2pm EDT) Friday, March 18, 2011 from the Fukushima Daiichi nuclear plant. The plumes get caught in a southwesterly flow of air in advance of an approaching low pressure system. The plume emitted near the surface (red line) stays trapped near the surface for 4 days then lifted to 4 km, but the plume emitted at 300 meters is lifted to 5 km altitude after 2 1/2 days by the rising air associated with the approaching low pressure system. Images created using NOAA's HYSPLIT trajectory model.


Figure 3. Five-day forecast movement of plumes of radioactive air emitted at 10 meters altitude (red line) and 300 meters (blue line) at 18 UTC (2pm EDT) Saturday, March 19, 2011 from the Fukushima Daiichi nuclear plant. The plumes get caught in a southwesterly flow of air in advance of an approaching low pressure system and lifted to 4 - 5 km altitude. The plumes are predicted to move over California and Mexico at high altitude. Images created using NOAA's HYSPLIT trajectory model.


Figure 4. One-day forecast movement of plumes of radioactive air emitted at 10 meters altitude (red line) and 100 meters (blue line) at 18 UTC (2pm EDT) Sunday, March 20, 2011 from the Fukushima Daiichi nuclear plant. The plumes get caught northerly winds, and the two lower altitude plumes move over Tokyo by 6 UTC on Monday, March 21. This is a low confidence forecast, as winds are expected to be light and somewhat variable on Sunday over Japan. Images created using NOAA's HYSPLIT trajectory model.

Resources
Seven-day weather forecast for Sendai near the Fukushima nuclear plant

The Austrian Weather Service is running trajectory models for Japan.

Current radar loops from the Japan Meteorological Agency

Jeff Masters

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885. BahaHurican
21:15 GMT le 20 Mars 2011
Quoting HaloReachFan:
Quoting seflagamma:
Hello everyone,

Happy Saturday to you all!

Yes, it is finally getting warmer here in Florida but March is suppose to be in 80's..

and we are still getting down to 59/60 at night here in Ft Lauderdale area.. at 6am it was 60 degrees this morning..
that is very cool for night time.

I am loving the sunshine and warmth.. I don't consider temps in the 80's as "hot" :o)

But as much as I love the sunshine we need rain so badly here in South Florida.

North and Central Fla have gotten rain all winter and it all fades away before getting to us down here...

my rain barrel is dry and our canals and ponds are at very low water levels and we are in deep
red fire hazards.




Hey, gamma.... I'm with u on the temps. It's still fairly moderate here compared with March temps for the last few years. Today felt like mid-Feb more than mid-March. Mind u, I'm not complaining.... lol. Also we've had a bit more rain with passing fronts than in the past while... maybe u guys got our dry zone :o). Anyway, April is just a couple weeks off, and I'm sure rain will arrive then....
Member Since: 25 octobre 2005 Posts: 19 Comments: 21887
884. AussieStorm
11:19 GMT le 20 Mars 2011
Quoting Patrap:
Financial News, Plate Tectonics and Orbital Celestial Mechanics all in one setting.


phascinating


Is this guy serious. The Christchurch quake was only a 6.3, the reason it was so deadly was it's depth and location to a big city. September 4 2010 Christchurch had a 7.1 quake yet it was deeper and further away from Christchurch, hence there was very little damage compared to 3 weeks ago.
Member Since: 30 septembre 2007 Posts: 9 Comments: 15935
883. AussieStorm
08:59 GMT le 20 Mars 2011
Anyone here?
There has been 2 quakes in the last hour moving away from Japan.

6.0 2011/03/20 08:26:11 19.008 121.261 36.6 BABUYAN ISLANDS REGION, PHILIPPINES

5.5 2011/03/20 08:00:51 22.396 121.421 17.3 TAIWAN REGION


Could there be any relation between these quakes and the major Quake and aftershocks?

Another interesting link between the Japan megaquake.
Member Since: 30 septembre 2007 Posts: 9 Comments: 15935
882. Floodman
21:22 GMT le 19 Mars 2011
Quoting auburn:
Anyone know anything about Equatorial Refractor Telescopes...I have one that has no manual...and I want to use it tonight for the Super Moon...
I can post some picks of the unit if it will help!


What brand is it?
Member Since: 2 août 2006 Posts: 10 Comments: 9922
881. auburn (Mod)
21:06 GMT le 19 Mars 2011
Anyone know anything about Equatorial Refractor Telescopes...I have one that has no manual...and I want to use it tonight for the Super Moon...
I can post some picks of the unit if it will help!
Member Since: 27 août 2006 Posts: 546 Comments: 50594
880. Floodman
21:02 GMT le 19 Mars 2011
Quoting Shroomduke:
What is this, high school?

Remember what Mom said, if you don't have anything nice to say, don't say anything at all...

BTW there is an "ignore user" option...

I think this illistrates how and why America is in trouble, no conflict resolution skills. Divided we are weak, vulenerable, and easily looted and "privatized". The boot-licking Sycophants want to defund NOAA and the rest of our government and privatize everything from regulatory agencies, to education, police and military. from Ca. to Ny. they are looting pensions, defunding government, and outsourcing jobs by the thousands while we bicker over... what?

They Thought They Were Free
http://www.press.uchicago.edu/Misc/Chicago/511928 .html
Good citizens set aside their differences in time of crisis and work togather. ...This may be off on a tangent but if we don't stand togather we are all screwed!


The url you posted results in a 404 error
Member Since: 2 août 2006 Posts: 10 Comments: 9922
878. emcf30
20:50 GMT le 19 Mars 2011
Could you immagine 112 of these coming at you ?
Member Since: 7 août 2010 Posts: 0 Comments: 1933
877. Shroomduke
20:38 GMT le 19 Mars 2011
What is this, high school?

Remember what Mom said, if you don't have anything nice to say, don't say anything at all...

BTW there is an "ignore user" option...

I think this illistrates how and why America is in trouble, no conflict resolution skills. Divided we are weak, vulenerable, and easily looted and "privatized". The boot-licking Sycophants want to defund NOAA and the rest of our government and privatize everything from regulatory agencies, to education, police and military. from Ca. to Ny. they are looting pensions, defunding government, and outsourcing jobs by the thousands while we bicker over... what?

They Thought They Were Free
http://www.press.uchicago.edu/Misc/Chicago/511928 .html
Good citizens set aside their differences in time of crisis and work togather. ...This may be off on a tangent but if we don't stand togather we are all screwed!
Member Since: 18 février 2011 Posts: 0 Comments: 2
876. beell
20:31 GMT le 19 Mars 2011
But it probably only needs to be stated once.
Member Since: 11 septembre 2007 Posts: 142 Comments: 16478
875. beell
20:29 GMT le 19 Mars 2011
I certainly appreciate The Women's Movement. Poetry in motion.
Member Since: 11 septembre 2007 Posts: 142 Comments: 16478
873. KEEPEROFTHEGATE (Mod)
20:03 GMT le 19 Mars 2011
Quoting emcf30:
The US missles hit near Tripoli, What a supprise.





like i said
that murdering bastard and he's goons gonna get a just reward they hold that country hostage alot want to speak out but are afraid its time
Member Since: 15 juillet 2006 Posts: 170 Comments: 53536
872. caneswatch
20:02 GMT le 19 Mars 2011
Quoting PalmBeachWeather:

ecmf...I am anti violence , but this needs to be done.I salute Obama on this decision


Seconded. All of what has been going on over there must be stopped, bar none.
Member Since: 8 octobre 2008 Posts: 14 Comments: 4553
870. emcf30
19:53 GMT le 19 Mars 2011
Palmbech, totally agree
Member Since: 7 août 2010 Posts: 0 Comments: 1933
869. PalmBeachWeather
19:52 GMT le 19 Mars 2011
Quoting emcf30:
The US missles hit near Tripoli, What a supprise.

ecmf...I am anti violence , but this needs to be done.I salute Obama on this decision
Member Since: 3 octobre 2008 Posts: 0 Comments: 5842
868. atmoaggie
19:51 GMT le 19 Mars 2011
Quoting JohnTucker:



lol yea.

Youve posted a link to WUWT for common radiation readings and come in this blog and Dr Roods to harass in every other instance. Including supporting a fake credentialed blogger posting misinformation which I dont even understand.

Its no surprise you show up now.
Okay. don't take good advice. Your grave.

But, WTH are you talking about?
fake credentialed blogger posting misinformation which I dont even understand
And I posted no link to WUWT. Not even an image hosted there.
Member Since: 16 août 2007 Posts: 6 Comments: 12461
866. emcf30
19:50 GMT le 19 Mars 2011
The US missles hit near Tripoli, What a supprise.
Member Since: 7 août 2010 Posts: 0 Comments: 1933
864. Shroomduke
19:45 GMT le 19 Mars 2011
Quoting MagicFan:
DR. Masters is wrong as all indications are radioactive levels are none existant in California. Doc somestimes tries to scare people on here with somem of these bogus blogs. No is going to die in the US as a result of radioactive activity and our vegies will be fine as none of these particales are making it to the US. so PEOPLE CALM DOWN!

We should all agree that level heads are always best in any situation.

My Complaint is that I am not hearing any numbers or facts that make sense, except above where 1% is stated. I would like to know a baseline of the different types of normal radiation, what kinds and how much are reaching california and real world examples of short and long term radiation exposure.

Part of the problem is that Americans have lost faith in the integrity of Regulatory Agencies, our Government, and the Nuclear Industry. Most feel that they have betrayed our good faith and trust far too often in the past. This could be an opportunity for them to regain credibility.
Member Since: 18 février 2011 Posts: 0 Comments: 2
863. Patrap
19:45 GMT le 19 Mars 2011
US Warship's launch Cruise Missile attack on Libya's Air Defences,,

Breaking News
Member Since: 3 juillet 2005 Posts: 423 Comments: 127807
862. atmoaggie
19:44 GMT le 19 Mars 2011
Quoting JohnTucker:


You know you show up only to support people like record season and this - then harass Nepo and other technical posters when they call them out.

All the social bloggers harass the technical bloggers then cry about not posting videos at the worst time during a crisis.

I would like to see some posts on a technical aspect of weather and climate from you. If that is possible.
I'm supporting a non-child blog. Period. Your prepubescent middle school back and forth is terrible to read and, frankly, embarrassing to the entire community. Both of you have to power to end it. Feel free to do so at any time.

Read back if that's all you think I've posted today.

And I cannot image why you would respond to that other one, unless you enjoy the attention, or something.

Weather and climate? Like you've ever believed anything I've posted in that subject matter, even if referenced with peer-reviewed publication...I can post when I like and anything I like that's reasonably on topic.

It was nicer in here before you arrived. And her. And you felt the need to respond. Maybe getting back on topic would help your image.
Member Since: 16 août 2007 Posts: 6 Comments: 12461
861. emcf30
19:44 GMT le 19 Mars 2011
US Warships Lauch cruise missiles towards Libya's air defences.
Member Since: 7 août 2010 Posts: 0 Comments: 1933
860. ShenValleyFlyFish
19:44 GMT le 19 Mars 2011
Every now and then I like tto come on the site without logging in. Gives me a perspective as to who's who and what's what. Makes me more willing to let some things just slide by. ;)
Member Since: 9 septembre 2007 Posts: 36 Comments: 4687
859. Floodman
19:43 GMT le 19 Mars 2011
Quoting TomTaylor:

says a lot haha


No picking on the aged (because I could be next)...
Member Since: 2 août 2006 Posts: 10 Comments: 9922
853. TomTaylor
19:31 GMT le 19 Mars 2011
Quoting Grothar:


Actually, I was thinking of Cheers, before Frasier. What does that say.

says a lot haha
Member Since: 24 août 2010 Posts: 19 Comments: 4357
852. PalmBeachWeather
19:31 GMT le 19 Mars 2011
Quoting Grothar:


Actually, I was thinking of Cheers, before Frasier. What does that say.

Grother.....Loved Cheers, Norm, Carla, And even Kristie Allie
Member Since: 3 octobre 2008 Posts: 0 Comments: 5842
851. atmoaggie
19:29 GMT le 19 Mars 2011
Quoting QuiltingQueen:
Let us all practice this familiar phrase: "Just be nice."
That would be nice. Was so very much nicer in here earlier.
Member Since: 16 août 2007 Posts: 6 Comments: 12461
850. caneswatch
19:29 GMT le 19 Mars 2011
Quoting PalmBeachWeather:

Buckeyes sure looked good last night


Didn't see it. I watch the UNC game last night, looked pretty good.
Member Since: 8 octobre 2008 Posts: 14 Comments: 4553
849. Grothar
19:29 GMT le 19 Mars 2011
Quoting TomTaylor:

He's well before my time



Jk my parents used to watch Frasier all the time when they were still making new shows


Actually, I was thinking of Cheers, before Frasier. What does that say.
Member Since: 17 juillet 2009 Posts: 71 Comments: 25996
848. PalmBeachWeather
19:27 GMT le 19 Mars 2011
Quoting caneswatch:
Since someone's gotta do it.....

GO CANES!!!!!

Buckeyes sure looked good last night
Member Since: 3 octobre 2008 Posts: 0 Comments: 5842
847. PalmBeachWeather
19:22 GMT le 19 Mars 2011
Quoting TomTaylor:

He's well before my time



Jk my parents used to watch Frasier all the time when they were still making new shows

..............NORM........
Member Since: 3 octobre 2008 Posts: 0 Comments: 5842
846. caneswatch
19:21 GMT le 19 Mars 2011
Since someone's gotta do it.....

GO CANES!!!!!
Member Since: 8 octobre 2008 Posts: 14 Comments: 4553
845. TomTaylor
19:20 GMT le 19 Mars 2011
Quoting Grothar:


Could have been talking about Kelsey Grammer!!!

He's well before my time



Jk my parents used to watch Frasier all the time when they were still making new shows
Member Since: 24 août 2010 Posts: 19 Comments: 4357
844. seflagamma
19:20 GMT le 19 Mars 2011
so on a happier note..

tonight will we all be out
"Dancing in the Moonlight" and then

"Howling at the Super Full Moon?"

wolf howl Pictures, Images and Photos

enjoy your weekend,

Gams
Member Since: 29 août 2005 Posts: 298 Comments: 40891
843. seflagamma
19:19 GMT le 19 Mars 2011
Hello everyone,

Happy Saturday to you all!

Yes, it is finally getting warmer here in Florida but March is suppose to be in 80's..

and we are still getting down to 59/60 at night here in Ft Lauderdale area.. at 6am it was 60 degrees this morning..
that is very cool for night time.

I am loving the sunshine and warmth.. I don't consider temps in the 80's as "hot" :o)

But as much as I love the sunshine we need rain so badly here in South Florida.

North and Central Fla have gotten rain all winter and it all fades away before getting to us down here...

my rain barrel is dry and our canals and ponds are at very low water levels and we are in deep
red fire hazards.




Member Since: 29 août 2005 Posts: 298 Comments: 40891
842. QuiltingQueen
19:19 GMT le 19 Mars 2011
Let us all practice this familiar phrase: "Just be nice."
Member Since: 17 Mars 2011 Posts: 2 Comments: 33
841. caneswatch
19:18 GMT le 19 Mars 2011
Quoting MagicFan:
Go Noles!


I take offense to that good sir.......
Member Since: 8 octobre 2008 Posts: 14 Comments: 4553
840. HaloReachFan
19:18 GMT le 19 Mars 2011
Quoting PalmBeachWeather:
John Tucker= JFLORIDA
Member Since: 15 septembre 2010 Posts: 1 Comments: 563
838. Xyrus2000
19:17 GMT le 19 Mars 2011
Quoting alfabob:
So basically if a worker was near the 400 mSv radiation for more then 2.5 hours it would be equivalent to the lower range of exposure during Chernobyl. All I know is that #3 under went a meltdown; and because MOX rods were used, there was most likely a coolant/fuel reaction. I also know that the spent rod pool was cracked from the explosion, while the core materials were mostly ejected upwards. So it's possible that a lot of the initial material was blown offshore; it is also possible that the smoke was initially the rods being on fire, and now it's a mixture between a fire and steam.


No, you don't know that. You are speculating and making assumptions. There are no measurements to back up claims of a significant release of nuclear material in the atmosphere, least of all any amounts that could raise concern in the US.

You are also not being clear by stating "the lower end of Chernobyl". Is that 400 mSv per hour? Per day? For example, shortly after the initial explosion at Chernobyl radiation levels near the reactor core were 300 mSv/hr Link. You'll need to cite where that 800 mSv number comes from if that is supposed to be per hour.
Member Since: 31 octobre 2009 Posts: 0 Comments: 1473
836. QuiltingQueen
19:15 GMT le 19 Mars 2011
Quoting MagicFan:


It seems as we are in summer very early here in FL. The 10 day forecast for orlando shows highs anywhere from 83 to 89 for the next 10 days. Very early to see temps this warm in mid March. I can only imagine the rise in SST going on in Gulf over the next week.


The Gulf will be warm earlier than normal if these temperatures stay this high. Today the best place to be is in the shade by the pool with a little bit of breeze. I made some fresh squeezed lemonade and that is most helpful in this weather. I have been reading a wonderful book about the science behind climate change. I don't need a book most days, I just look out the window.
Member Since: 17 Mars 2011 Posts: 2 Comments: 33
835. HadesGodWyvern (Mod)
19:15 GMT le 19 Mars 2011
Mauritius Meteorological Services
Tropical Disturbance Advisory #19
DEPRESSION TROPICALE, FORMER CHERONO (07-20102011)
22:00 PM RET March 19 2011
==========================================

At 18:00 PM UTC, Tropical Depression, Former Cherono (997 hPa) located at 19.9S 64.2E has 10 minute sustained winds of 30 knots with gusts of 45 knots. The cyclone is reported as moving west southwest at 13 knots.

Near Gale Force Winds
=======================
180 NM from the center in southern semi-circle

Dvorak Intensity: T2.0/2.5/W0.5/24 HRS

Forecast and Intensity
======================
12 HRS: 21.0S 61.1E - 30 knots (DEPRESSION Tropicale)
24 HRS: 22.1S 58.6E - 30 knots (DEPRESSION Tropicale)
48 HRS: 24.0S 54.4E - 30 knots (DEPRESSION Tropicale)
72 HRS: 26.9S 53.8E - 25 knots (PERTURBATION Tropicale)

Additional Information
=====================

The system still show a shear pattern with an estimated low level circulation center located at more than 75 NM to the northwest of main convection which still show some fluctuation . Wind structure remains very asymmetric with all the strongest wind (likely up to gale force winds) located in the southern semi-circle. Ex-Cherono is now racing west southwest at 13 knots and is now located about 80 km to the east southeast of Rodrigues Island. It should pass within the next hours close to the south of this island and this high likely scenario is the most favorable for the island as the strongest wind should remain offshore.

According to CIMSS analysis and Numerical Weather Prediction models, vertical wind shear is expected to strengthen gradually aloft as the system is approaching an upper level trough. Environmental conditions are not favorable for a regeneration, however strong near gale force to locally gale force winds should exist in the southern semi-circle due to the gradient effect with the subtropical high pressure until Monday. Available Numerical Weather PRediction models are in fair good agreement for a track towards the west southwest on the northern edge of the low to mid tropospheric subtropical high pressure up to J+2/J+3. The more realistic forecast beyond is a recurve of the track southeastward in relation with a gap in the subtropical high pressure and dissipation of the system.

The next tropical cyclone advisory from Mauritius Meteorological Services will be issued at 0:30 AM UTC..
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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