Then decided to comment. Notice the accusations against me from an amature scientist. This is why they will forever lose the argument
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DJ FergalR • an hour ago
Models are used for several things. One is to help us understand and challenge observations. It's true in bridge engineering, disease epidemiology, soil hydrology and - would you believe it - in climate science. If it's crap explain why.
The difference in the aforementioned models such as Bridge building and hydrology models are repeatable and testable, climate change models are not. For example TR-55 Hydrology modeling has been tested with repeatable results, climate change models have not.
DJ Equus Pallidus • an hour ago
Actually, no. Numerical soil hydrological models tend to be based on semi-empirical models using transfer functions. In other words they are statistical with an underpinning in theory - like aggregate climate models.
Equus Pallidus DJ • an hour ago
Actually yes, TR-55 was based on scientific experiments involving soil type, vegetation, channel length, drainage area, slope/ground contour. Tested and retested with measurable accurate results with +/- margins of error, climate models have not because of the time/experiment factor. They are not comparable and to say that they are either shows you don't know what you are talking about are you are fudging.
DJ Equus Pallidus • an hour ago
No Equus. But your Googling is impressive.
Equus Pallidus DJ • 40 minutes ago
No, it was my professional experience (24 years) of the engineering and design of waterways, dams, diversions and soil conservation. What are your credentials?
foxoles Equus Pallidus • an hour ago
Or, judging by his other replies, probably both.
Why don't you put my replies in google and search where I copied and pasted anything. It is you who has been exposed. You ran across the wrong guy today. So continue with your lies about me
DJ Equus Pallidus • 30 minutes ago
Shot the wrong guy - Google skills rather better than your aim.
Equus Pallidus DJ • 26 minutes ago
Take up my challenge, and put my replies in Google, you won't find them. Now again what are your credentials? I told you mine.
DJ Equus Pallidus • 16 minutes ago
You seem to be arguing from authority. I thought that was taboo? Or is it the expertise of climate scientists (you know - the people who passed exams and stuff) which can be so casually dismiss?
Equus Pallidus DJ • 11 minutes ago
In other words you have no credentials or experience or fail to show them. I am arguing from experience as in engineering, running Hydrology models. There is no argument among scientists that hydrology modeling works because it has been tested, there is much arguing on the accuracy of climate modeling among scientist.
DJ • 3 minutes ago
Yes, you are right. I have no credentials or experience or I fail to show them.
I repeat - Numerical soil hydrological models tend to be based on semi-empirical models using transfer functions. In other words they are statistical with an underpinning in theory - like aggregate climate models.
The difference between debates about soil hydrological models and climate models is not so great. In both cases certain approaches have adherents but the general intention to model more accurately (within the limits of computing power) is the same across the disciplines and improvements are adopted.
Hydrology modeling is not based on semi-empirical models. It is based on actual experiment and observation.
Clearly, you missed something in the nuance of DJ's explanation.
ReplyDeleteI used to do hydrology compliance work for a big gas production operation. I was a doing field/tech work not design/engineering, although the one time I designed a filtration system it worked and save the company some big bucks. Anyway the hydrology models are tested out and used over and over again. They are repeatable. If we do x y and z we get abc result. In those cases where that doesn't happen we discover that some variable was off.
ReplyDeleteI lost a dam on a 4 acre holding pond when a large spring runoff washed out a earthen dam. We discovered that there wasn't adequate spillway and that the top half of the soil wasn't compacted at all during construction. The pond had never been more than 1/4 full due to two years of drought. The model would have worked if the roustabouts had done the job as designed. We still had to pay the fine.
I've done some stormwater engineering. Mostly it is a mathematical model. The probabilities are calculated from past rainfall records.
ReplyDeleteI don't know if we really have a handle on the probabilities. There are lakes here that are 20 feet deep with trees sticking out. For the life of that tree, the lake was either dry or much much smaller. Now the water is 20 feet deep. A little investigation has found old shorelines even higher up. We have no idea what normal is. Take a look at the Missouri river flood from a couple years back. They had to release 125,000 cfs for over a month. previous record I think was 75,000 cfs. Was that a freak event, or is it more common?
I tend to cut the corp of engineers some slack, as it was a large snowpack that was thawed by a mega-huge rain event. People were complaining but if those dams weren't there it would have been huge.
I've done some stormwater engineering. Mostly it is a mathematical model. The probabilities are calculated from past rainfall records.
ReplyDelete1,2,5,10,25,50.100 year storm events. Most structures I designed to handle 25 year storm events. There are type I, IA, II, III storm events type "I" being the most extreme. But we do have a good handle on the storm events we prepare for and they are extremely accurate. There is always an exception but they are very rare.
I don't know about the accuracy. Our intensities were just revised upwards a few years ago.
ReplyDeleteWe are not just having problems with storms, but climate. We have areas that the roads had to be built up 10 feet because the wetlands became lakes. This is happening all over the region. My dad and uncles grew up hunting and trapping in sloughs that you could go all over in with waders. They were dry some years. Now these are 15-20 foot deep lakes and have been for a decade. My favorite route to work went under water 4 years ago and the road is still under water.
I don't know about the accuracy. Our intensities were just revised upwards a few years ago.
ReplyDeleteI know, the structures I designed are still functioning within their limits. The only change I have seen is a slight shift in the geographical location of storm type which is to be expected as we get more data. But for the most part not much has changed. Climate may change gradually over time or it may change suddenly with cycles or catastrophic events, but there is no reason to panic or pay taxes for natural occurrences we have no control over.