Snow from a Nuclear Plant
I don't discuss climate change and anthropogenic global warming very often. For me, the science is settled; it's a done deal. The issue of global warming, like the problems associated with the ozone hole, DDT, leaded gasoline, or second-hand cigarette smoke, has many angles and complexities. Obviously, it stimulates many opinions. Whenever I discuss this issue, I always try my best to separate the science from policy.
There is common ground on which most scientists agree: Burning fossil fuels releases carbon dioxide (CO2) into the atmosphere; we burn a lot of fossil fuels, and atmospheric concentrations of CO2 are increasing. More importantly, there's strong consensus that human activity has changed the atmospheric composition of carbon dioxide.
Even the most hardened scientists who remain skeptics about global warming agree that CO2 has a warming effect. For the record, the warming effects from CO2 dates back more than a century (military research conducted during, and just after, World War II got the physics exactly right). Attributing the recent warming to human activity is more of a hurdle when it comes to scientific consensus, but even most of the hardened skeptics and, essentially all of the mainline climate scientists, agree that warming has occurred over the last century and that human activity was expected to cause warming.
The 0043Z base reflectivity from KPBZ (Pittsburgh). At the time, the radar was in clear-air mode. Larger image. Courtesy of NCDC and NOAA.
In addition to anthropogenic climate change, there are palpable examples that illustrate how human activity impacts our atmosphere. The examples I have in mind are perceptible changes in daily weather. Just the other day (the late afternoon and early evening of January 22), the effluent from a nuclear power plant located in Shippingport, PA (near Pittsburgh in western Pennsylvania) caused a plume of snow that spread eastward with westerly winds in the lower half of the troposphere. I'll add here that there's also a coal power plant nearby that might have also contributed to the snow plume.
To see the radar footprint of the snow, check out the 0043Z image of base reflectivity (above; larger image) from KPBZ (Pittsburgh). I note that the radar was in clear-air mode (and not precipitation mode) at the time, allowing the radar to better detect and display snow.
For a more complete view, check out the animated gif (radar loop) from 23Z to 01Z (6 P.M. to 8 P.M.). This animated gif comes courtesy of the National Weather Service at Pittsburgh.
To get a better sense for the eastward evolution of the snow plume, check out the vertical profile of westerly winds on the 00Z GDAS skew-T at Wexford, PA (see Wexford's 00Z GDAS skew-T below; refer to my previous blog about skew-Ts). I chose Wexford because the radar loops indicate that the plume moved over this town (revisit the animated gif from 23Z to 01Z). In case you're wondering, GDAS is the Global Data Assimilation System used by the GFS model for initial conditions. Specifically, GDAS uses variational and statistical methods to blend all types of weather observations into the model background (usually based in the previous run's forecast cycle). In this way, the effects of weather observations can propagate forward in time.
The 00Z GDAS temperature and dew-point soundings at Wexford, Pennsylvania, on January 23, 2013 (7 P.M. EST on January 22).
At any rate, note that the precipitating layer over Wexford at 00Z (7 P.M. local time), which spanned from roughly 900 mb to 800 mb. I can infer precipitation was present because the troposphere was saturated in this layer. Also note the stable layer just above 800 mb (roughly isothermal), which was likely caused by subsidence above 800 mb (check out the 00Z Rapid Refresh model analysis of vertical motion, expressed in microbars per second; positive values indicate downward motion).
Any way you slice it, that's a relatively shallow precipitating layer. Although it snowed for approximately four to six hours hours, accumulations were only about one inch (yet there were reports that the snow caused traffic to back up on I-79 near Wexford). For the record, visibility under this plume was less than a one-half mile. In general, snow was light, but that doesn't diminish my point that human activity has perceptible impacts on the atmosphere.
The precipitating cloud associated with the plume of snow was a mixing cloud (the same cloud you observe when you see "your breath" on a cold day. In this case, hot water vapor in the effluent belching from the cooling towers of the nuclear plant (and possibly the nearby coal power plant) mixed with Arctic air (cold and dry), producing a mixing cloud. In turn, ice nuclei in the effluent served as sites for ice crystals to grow, setting the stage for an anthropogenic snow band. Yes, human activity has perceptible impacts on the atmosphere.
For the record, ice nuclei in ordinary clouds are not as ubiquitous as condensation nuclei. In this case, it's difficult to say exactly what kind of ice nuclei were present in the effluent from the power plants.
I should also point out that the National Weather Service referred to the effluent as "steam blowing from the stacks" on their Facebook page. For the record, steam is invisible water vapor at the boiling point. Indeed, almost everyone uses the word, "steam," incorrectly. I don't have any problem with a "steam cloud," but steam is invisible, by definition.
No big deal, but I thought I'd mention it. You know me.
Lee
Reader Comments
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Nuclear winter: Shippingport's plants send snow downwind
11:59 AM GMT on January 28, 2013
Many thanks for the pictures!
Apparently, there's a coal-power plant close by. Do you think the effluent from the coal-power plant might have also contributed? I did a little more research and I think this plant probably contributed (I added this possibility to the text).
Again, many thanks for your contribution.
By the way, I was born in Butler, Pa. Do you live in western Pennsylvania?
I was wondering the same thing. When I lived in Germany, I would notice clouds and (I suspected) light precipitation from cooling tower vapor of power plants. Living in W. Berlin before the fall of the wall, I was pretty certain these were coal-fired plants. I think E. Germany only had one nuclear power plant. Anyway, the cloud streaks always amazed me... they were very easy to see from a plane and to the track from the ground, given the flat, flat landscape around Berlin.
This reminds me of the understated and disappointingly short weather forecasts I would get from the staid, respectable Berlin newspaper, Der Tagesspiegel. It made me laugh to see the "weiter aussicht" or extended forecast was nearly always "wenige aenderungen" or few changes. I wondered how the seasons ever got around to changing. Only gradually, I guess. Then there was the classic cop out for today's forecast "heiter bis wolkig" meaning clear to cloudy. Then again, in Berlin, it could be cloudy, then clear, then cloudy again several times in one day.
1:22 PM GMT on January 28, 2013
That reminds me of the film, L.A. Story, with Steve Martin playing Harris K. Telemacher, a weather guy at a TV station in Los Angeles.
I can't remember exactly, but didn't Harris "phone in" a forecast for generic L.A. weather (fog in the morning then sunny)? And then it rained hard??? Or is my memory failing me?
As I recall, it was an entertaining movie.
The effluent probably provided CCN which were maybe more hygroscopic but I'm skating on the thin ragged edge of my knowledge.
The sounding shows the shallow precipitating layer was between -20 and -25C and most CCN are very effective freezing nuclei at that temperature.
5:46 PM GMT on January 28, 2013
Excellent point, George!!!! You're right on the money.
The efficacy of particles at nucleating the transformation of liquid to ice does indeed increase markedly with decreasing temperature. What one finds in the cloud physics books are plots of the number of ice nuclei versus temperature.
It certainly makes sense that the lower the temperature, the more effective the nucleus.
Very good science, my friend. Very good.
I live in East Central Florida. The pics come from the sourced link below them.
I think you are right about the coal plant. The pictures struck me a little odd the three in a row with a fourth tower in the distance & that long skinny stack like you would see at an old coal plant. There is one at Clemson where I schooled. Those aren't so common at nuclear plants, especially those old brick ones like pictured. So I did a little more digging on the event...
Steam was pumped into the air from two cooling towers at the Beaver Valley Nuclear Power Station and three similar towers at the coal-fired Bruce Mansfield Station next to it created the snow.
So I think what we are seeing in these pics is the 2 stacks are the nuclear power plant & the three in a row, plus tall skinny stack are the coal plant, all producing snow.
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When I went to VPI (SW VA mountains) in 1976-77 the area experienced an extremely cold fall and winter. In December I started noticing that the stratocumulus produced snow under a much wider range of dynamics and with less sky coverage.. indeed there were often at least a few flakes in the air many hours of most days. I also noticed this at Penn State during cold outbreaks but when I read about ice nucleation I think I found out why. Boundary layer temperatures sufficient to glaciate stratocumulus are rare in the DC area and the ceilings are higher so any flakes that do fall with the marginal glaciation that happens at -15C, don't make it to the surface. But at VPI ( 700 meters) and UNV (350 meters)
more flakes reach the ground and these locations are also colder. The 1977 situation at VPI was extreme (It's in southwest VA near ROA) but it happened in 1979, 1980 and 1981 when I was at PSU so I think it's common and expected there a few times a winter.
When it gets really cold in the boundary layer, clouds glaciate almost as soon as they form and instead of cloud I see a milky haze producing snowflakes. I've only seen this a few times. One time on January 10, 1982 in DC, when 850mb temperatures were near -28C, I saw what looked like a very large very fast moving cirrus cloud in an otherwise clear sky and then
realized it was in the boundary layer. Despite the cold, the precipitation did not reach the surface in one of the most intense arctic outbreaks of the 20'th century. (The 80s produced a disproportionate number of intense arctic outbreaks.. I don't know why)
9:17 PM GMT on January 28, 2013
Many thanks for the confirmation.
9:26 PM GMT on January 28, 2013
I have observed something very similar regarding flakes in the air from stratocu.
In the early 1980's, I was a graduate student at McGill in Montreal. Man, was it cold! But I'm telling you, George, I chased some of the best snow squalls ever downwind of Lake Ontario (I would drive from Montreal into western New York). In 1983, I chased squalls so intense that I could not see to drive (I could not see the front of the hood on my car). It was both exhilarating and scary.
9:40 PM GMT on January 28, 2013
Here's an example of "slaughter plant" snow.
The radar loop from Dodge City, KS (below), on that day captured a moving train!!!! Do you see it???
And some of those stationary echoes on the right are radar returns from wind farms (a more modern-day radar problem).
Wow, I do see it. Now I'm going to have to watch radar downwind of the power plant. There is also a big wind farm up there, so it could be interesting to watch.
I doubt this would occur in winter in Beijing (or DC)
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