Daily Archives: June 6, 2013

The Power of The Sea

On June 6th, 1944, some 160,000 soldiers aboard about 5,000 boats of diverse design crossed the English Channel and carried out the Invasion of Normandy, one of the more important events in recent history. Many of the soldiers were so sick from choppy seas that leaving the boats and walking or running into German gunfire seemed like a good idea. The invasion was originally planned for the 45h of June, but a very precise weather forecast told the Supreme Commander, General Eisenhower, to wait until the next day. The forecast for the 6th of June, integrated with the logistical features of the operation, had the landing craft arriving on the German-held beaches just as wave heights were reducing from a level unacceptable for this operation to something that could be managed by most (but not all) vessels.

[a timely repost]

If you’ve seen “The Longest Day” or any of the other classic semi-documentary dramatizations of D-Day, you may recognize the name Captain James Stagg. Stagg was the meteorologist on Eisenhower’s staff, and as such he was the conduit and translator for the information that came from the meteorology group. That, in turn, was a combination of American and British scientists with very different methods and backgrounds, but both using data and analyses that involves a large number of individuals making observations and crunching numbers, from teams at Scripts Institute in California who developed the primary predictive models in use to British Coast Guard observers making observations at sea several times a day.

The Power of the Sea: Tsunamis, Storm Surges, Rogue Waves, and Our Quest to Predict Disasters by Bruce Parker elucidates the science behind this historic moment in great detail in one of several riveting chapters about the ocean, and stuff the ocean does. Parker is a former chief scientist of the National Ocean Service so he knows something about waves, storms, tides, tsunamis, storm surges, and the like. This book is a nice combination of primer on meteorology ala the ocean and weather-related adventure stories. Throughout the book I kept running into things that I had always wanted to know about … like how exactly did that one huge ship I’ve seen so many times off the Cape Peninsula in South Africa sink? (The ocean did it!), what really was the story behind Stagg’s predictions (as discussed) and what is a future with greater storm surges and rising sea going to look like?

I recommend this book for non-experts who need to know all about ocean related science, who need to better understand the effects and dynamics of storms like Sandy, Tsunamis, and similar events. Parker does not hold back on the science and the detail. This is a very enjoyable way to elevate one’s self to the level of armchair oceanic meteorologist in a few evenings of enjoyable reading!

Waste to Energy Plants Are Good

When I was a kid, there was a strange looking garbage can in the back yard. It looked like a regular metal garbage cans (garbage cans were metal back in those days, before plastic was invented) but it was covered with round holes about one inch in diameter. It was also heavily corroded and lived behind the large brick fireplace that was also in the back yard. No one used it for anything but I remember that it had an interesting story that went along with it.

This can was used back in the day, before I was born, by my grandfather (who lived upstairs) to burn garbage. The story was about a can of shaving cream. Apparently, one day my grandfather was burning garbage and there was a discarded shaving cream can in there, which should not have been included in the garbage to burn because such a thing could explode. And it did. A piece of shrapnel from the exploding shaving cream can blew a new hole in the side of the burning garbage can, whizzed past my grandfather but missed him, passed through a hole in a nearby chain link fence and took a chip out of a brick in the apartment building next door. As evidence of this event there was an extra, ragged hole in the garbage can and a piece of brick missing visible on the side of the apartment building.

Yeah, I don’t believe it either. I was the youngest of four siblings and telling me tall tales was a family amusement, since the television had not been invented yet.

Anyway, the idea that burning garbage is good for the environment should strike you as wrong, because garbage is … well, it is garbage … and burning it releases all sorts of horrid toxins into the environment. So, burning garbage to produce energy would also be a bad thing. Better to burn something nice and clean. Like coal. Or uranium. Right?

Well, wrong, actually.

Author and science communicator Shawn Otto (Fool Me Twice: Fighting the Assault on Science in America) has written an interesting piece on burning garbage to make electricity. It turns out that opposition to waste-to-energy technology is an example of science denialism on the left. Modern waste to energy plants are clean, and may be cleaner than many other forms of power plant. Also, when we burn garbage, we are getting “free” energy, to at least some extent, in relation to the problem of burning fossil fuels. While some of the Carbon released into the atmosphere in burning garbage may be Carbon from fossil fuel sources, much of it is carbon from non-fossil fuel sources (like trees).

Today’s waste-to-energy plants are not your granddaddy’s trash burners, and some liberal groups, like the Center for American Progress, are starting to look at the actual science and reevaluate long-held assumptions in light of new information and increasing concern over climate change. When they do, they are finding that today’s WTEs look surprisingly good for the environment and for fighting climate change.

Shawn’s article is detailed and has numerous helpful graphics. Go read it and become much better informed about the science of waste-to-energy production.

I think that one of the plants Shawn visited during his review of this problem may be the power plant not far from my house in Elk River. That power plant is built on the site of one of the earliest commercial nuclear power plants. That little fact has nothing to do with the topic at hand but I find it interesting nonetheless.

The Science of Melting Ice Sheets: New review in Nature

A paper came out in today’s Nature about glacial melting and its contribution to sea level rise. This paper does not present new research, but rather summarizes and evaluates the last several years of research on modeling and measuring contiental glaciers and their dynamics.

From the Abstract:

Since the 2007 Intergovernmental Panel on Climate Change Fourth Assessment Report, new observations of ice-sheet mass balance and improved computer simulations of ice-sheet response to continuing climate change have been published. Whereas Greenland is losing ice mass at an increasing pace, current Antarctic ice loss is likely to be less than some recently published estimates. It remains unclear whether East Antarctica has been gaining or losing ice mass over the past 20 years, and uncertainties in ice-mass change for West Antarctica and the Antarctic Peninsula remain large. We discuss the past six years of progress and examine the key problems that remain

ResearchBlogging.orgThere are many difficulties with measuring and understanding the dynamics of melting of large continental glaciers, the large ice sheets that cover Antarctica and Greenland. As ice melts from these glaciers, they grow lighter and this allows the underlying bedrock to rise up, and conversely, if snow is added to the surface this increases the amount of depression of the underlying bedrock. For this reason you can’t just measure the surface of the ice to estimate how much has been added or removed. When ice melts on the surface, some of it travels down into the glacier and some comes right off the surface. The ice that goes into the glacier may cause deeper ice to melt, or it may provide lubrication to the base of moving streams of ice. As a glacier loses mass at the edge through calving of ice bergs, and the margin retreats away from the sea, the degree of calving, which is an ice-ocean interaction effect probably decreases. Large masses of ice are “grounded” at the outer margin on a “grounding line” beyond which is floating glacier (not sea ice, but large masses of ice undercut by the sea). The grounding line can move towards the sea or away from it, and the dynamics of this movement are complex and difficult to model or measure. Many of the Antarctic grounding lines occur on surfaces that slope downwards in the inland direction, which makes the dynamic a bit more complicated to measure.

Major changes that have improved estimates include adding dimensions to some of the models, such as considering both vertical and horizontal forces along grounding lines. Also, newer models use a finer resolution. However, the increase in resolution is thought to be insufficient; current models are not calculated at fine enough resolution to include numerous smaller ice streams that are narrower than the sampling density of the models.

It appears that the range of uncertainty of ice-melting models has improved significantly over the years so greater confidence in their predictions may be warranted. The best estimates of future contribution to sea level rise of melting glaciers is still highly variable, however.

The current estimates of contributions to sea level rise in mm per year from various studies are between 0.59 and 0.82 from the major ice sheets, between 0.71 and 1.4 for ice caps and glaciers, about 1.1 for thermal expansion, and a negligible but positive amount from changes in terrestrial water storage. These modeled amounts sum to 1.66 mm per year or 3.11 mm per year depending on the set of sources that are used. The observed change in sea level rise over the period from 1993=2008 is 3.22, so there is good agreement though the models are a bit light.

These numbers are small, but they are larger than previous estimates and observations. Still, compared to the potential sea level rise when one considers that the ice in the continental glaciers equals several meters of ocean water, near future sea level rise may be expected to be relatively low if these models are correct and account for everything. Over a century of time, this amounts to about 300 mm, or one foot, of sea level rise. If, however, oceans are warming more than the air at present and a few more episodes of that occur over the next century, this may be considered a minimal estimate. One foot does not sound like a lot of sea level rise, but it is enough to remove extant barrier beaches. Also, flood tides would not be increased by one foot, but rather, more exponentially. This is how a sea level rise of about this order of magnitude over the last century managed to contribute to the flooding of the lower Manhattan subway tunnels when the region was struck by Hurricane Sandy last year.

But there is a problem. Several areas of uncertainty exist in the models that are currently in use, and my impression is that these areas of uncertainty could be associated with dramatic errors in sea level rise estimate. The dynamics of grounding line changes, the role of lubrication at the base of glaciers (which can cause ice streams to speed up on their way to the sea) and the effects of warm currents shifting their position in Antarctic to cause more melt at the boundaries are among those factors that are least known and that have the highest uncertainty. Also, the seaward edge of continental glaciers are not only held in place by their grounding line on the continent, but also by more distal parts of the floating segment of the glaciers being pinned on prominence. As far as I know the effects of pinning being disrupted or lost are not included in any of the models. Also, I’m pretty sure that the effects of sea level rise on grounding and pinning have not been adequately addressed.

That these issues may be a problem is empirically suggested. The paleo-record shows that continental ice melting and associated sea level rise may occur in fits and starts, with steady melting punctuated by brief periods of extreme melting. The current models don’t seem to predict this sort of event, though these events probably happen.

Hanna, E., Navarro, F., Pattyn, F., Domingues, C., Fettweis, X., Ivins, E., Nicholls, R., Ritz, C., Smith, B., Tulaczyk, S., Whitehouse, P., & Zwally, H. (2013). Ice-sheet mass balance and climate change Nature, 498 (7452), 51–59 DOI: 10.1038/nature12238

Photo Credit: christine zenino via Compfight cc


The first named storm of the Atlantic hurricane season has developed. Tropical Storm Andrea formed over the last several hours, and now exhibits winds of 63 knots at 5000 feet, with a surface intensity of about 50 knots, though these winds are only found in the “right hand” side of the storm, now sitting in the northeastern Gulf of Mexico. Most likely, this is all Andrea is going to manage as the storm moves north to make landfall, where it will also interact with upper level winds which will convert the storm to a big rain storm over the next day and a half. However, Andrea will be a very noticeable storm in Florida and later along the east coast. There will be some flooding along the Florida coast and lots of rain in Florida and later to the north. Isolated tornadoes may be formed as well.