For offshore turbines, such as those found off coasts in Europe, this approximation is valid. However, Hu explained, even seemingly flat land, like in Iowa, can make an appreciable impact on wind energy production.
Hu and his team are using wind tunnels, miniature generators and scale models of wind turbines to see how rolling hills, ravines and ridges can affect energy output. "Recently, we found that if you have a hill [near a wind farm], the distance between the wind turbines can be reduced significantly. Energy can be recovered faster," said Hu. "We can quantify how that decay will interact with the next row of wind turbines."
The researchers observed flow fields and vortices created by spinning blades and published some of their findings online in the Journal of Visualization last November. In addition, Hu is investigating how turbine operators can compensate for weather effects like icing on turbine blades.
With this information, energy developers can plan wind farms better, but also extract more energy from their existing turbines while minimizing wear and tear on their hardware.
What's going on at the hub?
However, over a turbine's operating life, the climate becomes a larger factor. "If we take the intermediate term, a five-year basis, there have been some studies that show there have been some periods where wind speeds are significantly above or below the long-term average," explained Eugene Takle, a professor of agricultural meteorology at Iowa State.
"That's the scale that's relevant for people that are investing in wind power," he said. Long-term predictions can also help utilities plan new generators to meet future demand.
According to Takle, predicting wind speeds that are relevant for wind turbines is still an emerging process. "One of the challenges we have is that most of the models we use don't have a long history of application and validation for forecasting wind at the hub height of these turbines. We've used these forecasts for years to forecast winds near the surface of the Earth," he said.
The reason that's important, particularly in places in the central United States, he explains, is that winds at the height of the hub of a wind turbine, roughly 260 feet, are different from the winds at the surface.
Like Kamath, Takle did acknowledge that the simulations need to be validated with field studies, measuring how accurate their predictions are in the real world. He said that using tools like weather balloons, airplane-mounted instruments and laser radar, scientists can test their simulations.
Eventually, the scientists hope to reduce the uncertainty in wind forecasting, lowering its overall costs and increasing its reliability.
Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500
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18 Comments
Add CommentIt'll be something for us climate change scientists to move on to, I suppose. I've been concerned that I'll be out of a job for some time.
Reply | Report Abuse | Link to thisYou're joking. There are no "climate change" scientists and anybody calling themselves that is not being entirely honest. Why would "you" be out of a job? Humans show no sign of even slowing the growth of CO2 emissions and many climate models have UNDERSTATED the rate of environmental change those emissions have caused. If anything, we'll need more CLIMATE SCIENTISTS in the future to help plan adaptation measures to the climate change that's already baked into the cake!
Reply | Report Abuse | Link to thisUnfortunately, I've been caught editing temperature data again. I blame the pressures of work. The problem's been building up since 1998 when the skeptics have been pointing out that my model which predicts an increase in global mean temperature of 3.5C (IPCC AR4) by 2100 doesn't stack up. I've been coming up with a number of elaborate strategies such as claiming that it's due to lower solar activity. Unfortunately, the solar activity started increasing in 2009. Luckily 2010 was a very warm year, so my grant was ok for a while. Then 2011 the pressure's began to build up again, as it's only the 11th warmest year when my model predicted that manmade greenhouse gases and an increase in solar activity should have made it much warmer than 2010. I've been praying that a volcano could explode or something but no such luck. I've joined the ENSO bandwagon. It wasn't much as it only has a small effect on global mean temperatures for just a few months but by exaggerating the effect of ENSO and calling it a La Nina year, I covered my tracks up until now.
Reply | Report Abuse | Link to thisMy new problem is that it's been pointed out that parts of the planet haven't warmed up in particular seasons for more than 100 years. I'm stumped how to explain this as it's essentially inexplicable, apart from the "climate noise" explanation which is stretching it over such a long period.
Can you help me sault? I don't want to become a wind scientist. I'm much bigger than weather, I'm a climate guy.
You worry too much jdey123. Based or your current concern, you must have thought your job was in jeopardy a dozen times or more in the last 50 years or so; yet the heat content of the planet continues to rise despite the short-term noise you are so worried about. Don't worry; no one has proven the basic physics of CO2 and radiative energy wrong for the last 150 years. I'm sure your job is safe a little longer.
Reply | Report Abuse | Link to thisI tried that, but then a schoolkid embarassed me by looking up "carbon cycle" on Wikipedia. Although CO2 only accounting for 0.036% of the atmosphere seemed to be a bit of a stretch even to me to account for the predicted 3.5C rise in global mean temperature, by applying appropriate weighting factors, I could produce a model that made CO2 look like a likely candidate. Embarassingly, I'd forgotten that CO2 actually gets breathed in by plants & trees and is dissolved in rainwater, and this process called the carbon cycle, apparantly, has been going on for millions of years. CO2 has historically been pumped in to the air via volcanic eruptions and forest fires. I'm now trying to think if there's something special about carbon that we've dug out of the ground compared to the carbon that volcanoes dig out of the ground. I intend to write a peer-reviewed paper shortly and present to IPCC. If I'm lazy I might just get the schoolkid to help me out, as the IPCC 4th report based some of their more startling predictions on student papers they found on the internet, I think scientific practise is settled. I hope you're right about my job, pray to God 2012 is going to be a hot one.
Reply | Report Abuse | Link to thisDenialists like this guy should be imprisoned, publishing satellite data nonsense. Everybody knows that weather stations located mainly in populated areas and on board ships is far more accurate than satellites. He even get's his data out within a few days, because he doesn't bother tweaking it. Amateur, or what.
Reply | Report Abuse | Link to thishttp://www.drroyspencer.com/latest-global-temperatures/
A La Nina's developed again starting September 2011. Do you think I can put a spin on this natural phenomenon that cools 1 part of the Pacific ocean and warms the other part, as something that could affect the global climate? I've felt discomfortable about this in the past. Maybe, I could produce some science about the gulf stream not being as warm due to the ice melting? I'm not really sure where I'm going on this, unfortunately. 97% of peer-reviewed scientists agree that global warming is very likely down to mankind. That's all the science I need.
Reply | Report Abuse | Link to thisI hope that was a bad attempt at humor...
Reply | Report Abuse | Link to this1 thing that has been disappointing me a bit seeing as I'm an expert in this field, is that I actually own a greenhouse and in winter it's not been trapping heat as well as I'd like. So what I've been doing lately is to add about double the percentage of CO2 to the Greenhouse and making sure its all nicely sealed. I figured the temperature would dramatically rise and I'd be able to sell on my idea to gardeners. You don't need anything sophisticated. Shaking a bottle of lemonade in my small greenhouse is a good approximation to man made CO2 pollution. Sadly my dreams of lounging in my birthday suit in January haven't panned out. My greenhouse temperature is practically the same as usual.
Reply | Report Abuse | Link to thisYou mean THIS Dr. Roy Spencer?
Reply | Report Abuse | Link to thishttp://www.skepticalscience.com/skeptic_Roy_Spencer.htm
What about if we made you breathe air that was %0.039 Cyanide or you had to dring water that was %0.039 Arsenic?
Reply | Report Abuse | Link to this%0.039 seems small, but when OVER %99 of the gas in the atmosphere is TRANSPARENT to the longwave radiation that the Earth sends out, that %0.039 makes a BIG difference!
I don't know how you can say we aren't affecting the balance of CO2 in the air when its concentration starts rising EXACTLY when we begin pumping it into the atmosphere (1850) on an industrial scale. How come CO2 is relatively constant for 10,000 years and then magically starts to increase in the Industrial Revolution? The ONLY way to explain it (and not deny reality) is that the extra CO2 from humanity's carbon emissions is building up in the atmosphere. We've taken a system that was in balance with all those plants "breathing in" CO2 and volcanoes pumping it into the air and made it steadily accumulate CO2 a ppm or two (now three!) per year. We've also degraded land plants' and the oceans ability to absorb CO2 through land use changes, pollution and the initial warming of the ocean.
CO2 from fossil fuels has a distinct isotope signature from biological and volcanic carbon. The %40 increase in CO2 in the air is almost entirely due to fossil carbon.
Finally, do you think it's wise to double the CO2 in the atmosphere 1000 TIMES FASTER than the greatest volcanic eruption in the geologic record?
http://en.wikipedia.org/wiki/Permian-Triassic_extinction_event#Volcanism
skepticalscience.com. Lol. I post on here, because unlike skepticalscience.com, the moderators don't label anybody who disagrees with the anthropogenic global warming theory as skeptics, denialists, trolls or other abusive terms, nor do they delete posts which prove the theory to be incorrect.
Reply | Report Abuse | Link to thisI don't have a problem with reducing CO2 emissions, although not sure how we're going to achieve this given that the world economy is dependent on power and alternative energy is currently prohibitively expensive.
Reply | Report Abuse | Link to thisI do have a problem with suggesting that extra CO2 is warming the planet, when it obviously isn't. If CO2 is causing global warming, and CO2 has increased from 365ppm in 1997 to 392ppm in 2011, that's a greater than 7% increase in the CO2 in the air, yet 2011 was colder than 1997. This can't be explained away by saying that something unscientifically described as "climate noise" has suppressed the temperature for 14 years.
CO2 levels have gone up and down throughout history.
What is climate noise other than stuff that climate scientists don't understand? If I sold you an MP3 player in which you could hear nothing but white noise, and when you complain I told you well save all the sound for 30 years, then play it back at 100 times speed, and you'll hear the song, you'd say I was having a laugh. Electronics engineers have spent years steadily improving the quality of recorded sound, but have never had the audacity to sell something that was totally inaudible other than to peer-reviewed scientists. Yet, whenever anybody complains about climate science, we're told that we're denialists, skeptics and other abusive terms and that the "science is settled" suggesting that it's as good as we should ever expect things to be.
The 1st thing that climate scientists need to do to get any credibility is to agree that any published information should cover the period from 1850 onwards (this being the first date that we have global temperature records) and pick a fixed baseline period (1940-1980), say.
Anybody can make anything look significant by varying the time period and baselines.
Let's take the examples from the 3 websites which provide global mean land and ocean temperature information
Reply | Report Abuse | Link to thishttp://www.ncdc.noaa.gov/sotc/service/global/glob/201101-201111.gif
http://data.giss.nasa.gov/gistemp/graphs_v3/Fig.A2.gif
http://www.cru.uea.ac.uk/cru/data/temperature/nhshgl.gif
NOAA's graph looks like the warming trend from 1978 wasn't that dramatic and the flattening trend in the last decade is obvious.
NASA's GISS graph looks like the warming trend from 1978 was very dramatic and you can hardly spot the flattening trend in the last decade.
CRU graph shows a quite dramatic warming trend from 1978 but the flattening trend in the last decade is obvious.
NOAA and CRU use the same baseline period - 1961 to 1990, whereas GISS use 1951-80.
The main reason why the GISS graph looks the most dramatic is because the temperature scale is unbalanced, and covers only the temperature when it was at the coolest to the temperature when it was a warmest, so temperature changes are distorted.
The CRU graph looks more dramatic than the NOAA graph, because the timescale has been compressed, which has the effect of making longer term trends look more significant.
Of the 3, warmists obviously favour GISS's presentation of the climate data. As you can see, without using consistent temperature scales, time scales & periods and baselines, you can present a very different picture of reality.
The most compelling evidence against the anthropogenic global warming theory is that provided by the warmists themselves. Global warming hit the headlines in 1988 when James E Hansen, Professor of the Goddard Institute of Space Studies (part of NASA) delivered a presentation to Congress stating that the earth was warming and that it could be demonstrated that it was down to mankind's production of greenhouse gases. The presentation was based on his paper of the same year:-
Reply | Report Abuse | Link to thishttp://pubs.giss.nasa.gov/docs/1988/1988_Hansen_etal.pdf
In the paper, he presents 3 different scenarios:-
A) CO2 emissions grow exponentially
B) CO2 emissions grow linearly
C) CO2 emissions are curtailed completely by 2000 i.e. we stop burning any fossil fuels (oil, coal, gas) by that date.
Of the 3 scenarios, Hansen says that scenario B is the most likely, and from CO2 measurements since, it's correct that CO2 has grown linearly.
Hansen's model was produced by using variables (known as forcing agents) and applying weighting factors and algorithms to them to fit known historical data.
So, how has Hansen's model, panned out. In 2012, are we still on course to experience global warming as predicted by scenario B?
Reply | Report Abuse | Link to thisWell, Hansen hasn't updated his graph since 2007, but we can take a look at it here:-
http://pubs.giss.nasa.gov/docs/2006/2006_Hansen_etal_1.pdf
The 3 scenarios are present in the graph produced in that paper, the black line showing global mean land and ocean temperatures mirrors what was presented in the 1988 paper. As it was already looking at that point that we were more likely to be on the Scenario C than B path, Hansen introduces another measure based purely on land mean temperatures and suggests the true temperature should be between these, conveniently making it look like we were still on course for scenario B. So the 2007 paper only includes data up until 2005. Looking at the dataset behind the graph, the global mean temperature in 2005 was 0.55C. The graph in the 2007 paper appears to show it as more like 0.62C which is somewhat curious. http://data.giss.nasa.gov/gistemp/graphs_v3/Fig.A2.txt
Ok, so given that Hansen hasn't updated us since, then how are we doing in 2012? Well, GISS haven't produced the figure for 2011 yet, so we'll have to go to 2010. Scenario B predicts an anomaly of 0.87C for 2010 from the baseline period for 1951-1980, which is the one Hansen & GISS use. Scenario C predicts an anomaly of 0.64C. What was the temperature anomaly for 2010? According to the GISS dataset, it was 0.63C, which is slightly less than the scenario had we cut all fossil fuel emissions by 2000, which clearly we haven't.
As Hansen's 1988 model on which global warming theory hit the headlines clearly doesn't work, the theory doesn't hold. We can't have had linear increases in CO2 and yet no global warming.
In case, I'm accused of cherry picking just 1 year, if you look at the GISS dataset, 2006, 2007,2008 and 2009 are also at or below the temperature anomalies predicted for scenario C (no CO2 emissions) and miles away from those predicted by scenario B.
Finally, in case you think that 2011 may get us back on target, although GISS has yet to be updated, the other 2 main datasets computed are CRU
http://www.cru.uea.ac.uk/cru/data/temperature/hadcrut3gl.txt
and NOAA
http://www.ncdc.noaa.gov/sotc/global/
which rank 2011 as the 12th and 11th warmest year on record. Unfortunately, as they use different baseline periods, they have lower anomalies than GISS. However, once the GISS dataset is updated in the next week or so, it will be clear that 2011 is well below 2010's temperature and scenario C.
Interesting article from a guy whose followed the same line of inquiry as me, previously in 2009. i.e. why is Hansen's 1988 model so out, and yet the global warming hypothesis not been retracted? The divergence from Hansen's prediction and the real data is even more glaring now.
Reply | Report Abuse | Link to thishttp://climateaudit.org/2008/01/16/thoughts-on-hansen-et-al-1988/
The carbon cycle will continue to shift out of balance while more of it is easily extracted from below and added to the atmosphere. Then, when we will be forced to depopulate, we may already know how to better forecast wind conditions. Overcoming the short-term nuisances associated with wind irregularities will help us master long term survival challenges beyond using assets that our earth provides for us for free.
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