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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835. HadesGodWyvern (Mod)
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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03/18/2011
MEDICAL ASSISTANCE

A U.S. Air Force search and rescue airman, right, assists a Japanese disaster medical assistance team to off-load an earthquake victim from an HH-60G Pave Hawk helicopter in Sendai, Japan, March 14, 2011.. U.S. Air Force photo by Airman 1st Class Katrina R. Menchaca

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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.


Magic.....Been debating all day if I need to close up the house and turn the air on.Very warm, but it cools off nicely...Can't wait to see the "BIG" moon
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Quoting TomTaylor:

spelling correction :)


Could have been talking about Kelsey Grammer!!!
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Quoting MagicFan:
LOOK at the heat here in FL. WOW! first 90 degree readings so far this year around my area.

http://www.srh.noaa.gov/images/rtimages/mlb/adas/ temp_sfc.gif


It is very warm in Florida today. I tried to go out and work in my garden a bit but I didn't last long. I am seeing more ants this year than I have in many. I also have something eating up my leafier plants. I just hate spraying any chemicals in my garden and it looks like the bugs will win this year.
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Maybe blog about it in a entry of yer own.

Doing it here will get one all the time off they need, very soon.


Food for thought.

Ciao,..
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..Go Gators..
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Quoting KEEPEROFTHEGATE:


Awesome, Awesome video !!!! Thats a keeper, Keeper! Found it, saved it...TY
Member Since: September 16, 2010 Posts: 0 Comments: 1496
John Tucker= JFLORIDA
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x
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This isn't a weather blog anymore.It's turned into a......gulp.....FoxNews blog.
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Operation TOMADACHI Imagery
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Quoting PalmBeachWeather:

"Grammar correction"

spelling correction :)
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Quoting JohnTucker:
Im thinking a particular poster is not even a female as they cant post something without a derogatory gender reference.

Especially as they make it a point to stalk other posters and have narratives that sure seem similar to others.
Seems your on to something....I remember when serval bloggers thought I was an under cover Admin.It was hilarious.
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Quoting Xyrus2000:


War will exits for as long as there are people who will profit from it.

wars will exist as long as there are people to fight them
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Quoting QuiltingQueen:


A Department of Peace is desperately needed in these turbulent times. Please, no more war!


War will exits for as long as there are people who will profit from it.
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Pottery, It was stated that anti Gaddafi forces shot this down. This was before the Fench places becave active over Libya. This is a video from a diffent area which is closer to the crash site which I posted this morning. Wounder what happen to the pilot who is seen ejecting in the video
Member Since: August 7, 2010 Posts: 0 Comments: 1957
Quoting pottery:
and bolts.
And in the meantime the French Airforce has been in action.
I wonder if they shot it down? Would not surprize me.
No way to down one of those from the ground, using a rifle....
lol

yea, idk what took it down, but it sounded like gun fire in the background
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Quoting TomTaylor:


That's nuts
and bolts.
And in the meantime the French Airforce has been in action.
I wonder if they shot it down? Would not surprize me.
No way to down one of those from the ground, using a rifle....
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Quoting Patrap:
Financial News, Plate Tectonics and Orbital Celestial Mechanics all in one setting.


phascinating


well I hope he's wrong
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Quoting Patrap:
Libyan jet shot down over Benghazi



That's nuts
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re: post 792

my understanding is that the holes were drilled to vent hydrogen gas - not to relieve pressure. we certainly don't need any more hydrogen explosions there.

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Latest earthquakes list....world

Link
Member Since: September 16, 2010 Posts: 0 Comments: 1496
Quoting Patrap:

"Its a Marvelous time for a Moondance"...


Hiya BFOTR


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Latest from IAEA....Japan

Link
Member Since: September 16, 2010 Posts: 0 Comments: 1496
Looks like the French planes are engauging in ground troups in Libya. On another note, does anyone have any information on the holes that were reportly drilled into two of the reactors to releave pressure at the Fukushima Plant by CNN ?
Member Since: August 7, 2010 Posts: 0 Comments: 1957
Quoting muddertracker:
The moon will be closest to the earth tonight than it has been in twenty years? Is this correct? My "conspiracy nut" neighbor just went on a tyrade about how the moon is responsible for the Japanese tsunami, earthquake, etc. etc. Nutcase.



Do you realise how many mad people we've had mascarading as world leaders?
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>the moon has everything to do with plate tectonics
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omg...so maybe my neighbor is not so crazy with his moon-quake theory...at least peanut butter or the commies is not involved with this one...lol
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Financial News, Plate Tectonics and Orbital Celestial Mechanics all in one setting.


phascinating

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"Its a Marvelous time for a Moondance"...


Hiya BFOTR
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786. beell
Hey, bf, guygee, & nrt. Actually have a shortage of computers here this AM so I must bail. Who would have thought my kids would want to do homework on a Saturday. Thx for the comments.
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Oh, gosh. Now we got the Moon involved.
:)

Thanks, nrt.

Thanks, Pat.

All this=way beyond my brain.
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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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