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

By: Dr. Jeff Masters , 2:11 PM GMT on March 18, 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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Quoting WatchingThisOne:


Scheduled for today (Saturday) in Paris. I hope they don't linger over dessert.



He knows he is going down, he is going to fight till they get to him.
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airwaves silent concerning Libya....
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Robots to the Rescue? MSNBC (photo from iRobot)



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Quoting WatchingThisOne:


Meanwhile, back at the ranch ...

"It's the heaviest bombardment I have seen so far. We believe they (Gadhafi's forces) want to enter the city at any cost before the international community starts implementing the U.N. resolution," said Saadoun, a rebel fighter.

"On behalf of all the people of Misrata, the women, the children and the elderly, we call on the international community to do something before it's too late. They must act now," he said. "They already failed us before and were late in taking a decision, they should not repeat the same mistake."

(from msnbc.msn.com)



German foreign minister rejects Libyan call to send cease-fire monitors, says it is job for UN


Gadhafi is operating on his own, he has 0 support.
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Quoting WatchingThisOne:
from bbc.co.uk

"Leaders from Britain, the US, France and allied Arab countries are set to meet in Paris to discuss military action in Libya under a UN resolution."

Discuss. I see.


Meanwhile, back at the ranch ...

"It's the heaviest bombardment I have seen so far. We believe they (Gadhafi's forces) want to enter the city at any cost before the international community starts implementing the U.N. resolution," said Saadoun, a rebel fighter.

"On behalf of all the people of Misrata, the women, the children and the elderly, we call on the international community to do something before it's too late. They must act now," he said. "They already failed us before and were late in taking a decision, they should not repeat the same mistake."

(from msnbc.msn.com)

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Here is a BBC report on power efforts at Fukushima 1 - sounds optimistic. We'll know within a couple of days. There is hooking the pumps up and then there is getting them operational.
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milliSieverts
"...400 millisieverts per hour inside the boundaries of the Fukushima plant...is still the highest..."

"Two days ago, the Japanese government raised the legal limit...to 100 millisieverts (mSv) an hour, and 250 millisieverts a year. This new limit is more than 12 times what is legal for nuclear workers to be exposed to in Britain.
The highest level of radiation recorded at Fukushima so far is around 400 mSv. According to the World Nuclear Association: "Above about 100 mSv, the probability of cancer (rather than the severity of illness) increases with dose. 50 mSv is, conservatively, the lowest dose at which there is any evidence of cancer being caused in adults."
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from bbc.co.uk

"Leaders from Britain, the US, France and allied Arab countries are set to meet in Paris to discuss military action in Libya under a UN resolution."

Discuss. I see.
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707. xcool


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Ive heard from some very credible sources, as in physicists, that dangerous radiation is not a threat to the west coast of the U.S.

I think I'll trust the physicists...


The amount of radiation reaching the West Coast is probably lower than those dangerous life threatening radioactive bananas we eat.



:) lol
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Quoting Ossqss:


Ha, I have never been so insulated (spelled correctly) in my whole life. I am not nearly the vintage of those you reference :)








Not to mention.. no living witnesses.
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Now, good night Grothar and DAM!
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Quoting kellnerp:
Pumps now working in units 5 and 6 on diesel backup power.


For real? Hope it holds.
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Quoting kellnerp:
Pumps now working in units 5 and 6 on diesel backup power.


Yay! I'll take some good news for a change.
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Quoting caneswatch:


Good God man. THANK YOU!!!!!!!!!!!!!!!


Nite, Canes
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Quoting Grothar:


I've been giving you lines from the movie each time. You haven't gotten it yet. PLATOON, OK



Good God man, THANK YOU!!!!!!!!!!!!!!! I wanted the movie name, not the lines from the movie LOL.
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Quoting caneswatch:


The movie, so I can go to bed LOL


I've been giving you lines from the movie each time. You haven't gotten it yet. PLATOON, OK
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Quoting caneswatch:


The movie, so I can go to bed LOL


'Night, canes ;-)
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Quoting caneswatch:


The movie, so I can go to bed LOL


I know, but had to google it. Tired enough for me to tell?
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Quoting caneswatch:


Nope


If you don't stop, I'll get a whole platoon after you.
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Quoting Grothar:


You are going to cause a "crisis" if you don't stop.


The movie, so I can go to bed LOL
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Quoting caneswatch:


"He says they had no choice... says the NVA killed their old honcho when he said no, and I say all the rice is theirs. "

This one. What movie?


You are going to cause a "crysis" if you don't stop.
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Quoting Terradad:
Apocalypse Now?


Nope
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Pumps now working in units 5 and 6 on diesel backup power.
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Quoting sunlinepr:


The question is: Are we capable of fighting in so many war fronts? Do we have the resourses? What about our internal problems?


No, no, and who knows. We have spread ourselves out too thinly. Wars are very costly. The US doesn have the capability of enormous resources and, not to be arrogant, we are very resourceful as well. We were not really prepared in World War II, but found our way. This situation is quite different though. It may seem odd to say, but in other wars there existed a certain clarity. There were rules of engagement, and clear sides. Here, we are facing an entirely new situation. Perhaps never before seen. It must be done with caution and clear thinking. Not just jumping in an start fighting.
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Apocalypse Now?
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Quoting EYEStoSEA:
Well, I'm out for the night guys....always sleep better after a-lot-of-laughter....and beware the Supermoon...:)


I'm also into bed.... Gnite
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Quoting Grothar:


The Merry Mailman, now get to bed.


"He says they had no choice... says the NVA killed their old honcho when he said no, and I say all the rice is theirs. "

This one. What movie?
Member Since: October 8, 2008 Posts: 14 Comments: 4553

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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.