# planetwater

ground- water, geo- statistics, environmental- engineering, earth- science

## Geologist on “Gipskeuper” / Anhydrite – Stuttgart 21

via Amphibol

update Saturday; September 4, 2010 The paper “Nürnberger Nachrichten” published an article today pointing out the geological risks of Stuttgart 21.

Written by Claus

August 31st, 2010 at 9:27 pm

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## Where is it?

What has happened to the oil in the gulf?

Has it disappeared? Is it still there? Lots of people, lots of thought. And those bacteria sure must have been hungry!

## Identi.ca Weekly Updates for 2010-08-25

Written by Claus

August 25th, 2010 at 11:11 am

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## Water Cycle Hip Hop

Jo! Listen to the “soundtrack of science”! Rain! Rain! (via WaterWired)

Written by Claus

August 24th, 2010 at 4:57 pm

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## Estimate the Distribution of an Underlying Process Based on Samples

Say you have many sets of samples (measurements). What do you do if you wanted to estimate the distribution of the underlying population? Ok, if all your samples are well behaving, you throw them in one pot, and estimate the distribution based on all the samples. Ok.

Now, what if you wanted, for whatever reason, to estimate the underlying distribution based on the individual sets of your samples? What you could do is estimate a distribution based on each sample. Then you would have to somehow average the distributions. How would you do that? By multiplication? Turns out – no. In fact, the average of the density functions of each sample seems to be a pretty good estimator of the underlying density function.

using 10 sets of samples with 10 samples each

using 25 sets of samples with 100 samples each

Written by Claus

August 19th, 2010 at 1:49 pm

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## Classic Books on Statistics and Hydrogeology – in German

The book-recommendations on this book are among the most popular posts on this blog:

These recommendations so far have all been for books written in english. They are not all purely technical books or particularly textbooks. However, they are all related to the theme of “water”, despite my hands-on quantitative-statistical take on that theme.

Two things happened in the recent past: I realized that I use wikipedia for surprisingly many tasks. I realized that I haven’t used a book in ages for example to look up a distribution function. The other thing that happened, just the other day, was that I took a fairly old programming book, because I wanted to re-read on a certain topic. And I knew it was covered in that (old) book well.

That’s when I thought, that I really like well written books, despite the wickedness of the internet (despite the fact that it recently was claimed to be dead – or not). Then I wondered, what are the best German written books related to the subject I am working in and which also is the topic of this blog? Of course, this is a tough question. And the two books I am going to name in a second are most likely not the only ones. However, they are the two that came to my mind immediately:

The statistics book appears a bit daunting at first with its 1145 pages. I don’t believe it is possible to read the entire book and neither it is recommended by the authors. However, it has happened to me many times that I was looking for a certain topic, like “How does the Wilcoxon Rank Test work?”, and sure enough I found theory for the test as well as an example in the book.

In contrast to statistics, hydrogeology is not as clearly defined. It’s much harder to distinguish a given topic to be or not to be “a hydrogeology topic”. Hence it would seem much harder to write a book on “hydrogeology”, because it would have to cover many topics. However, Hölting and Coldewey have done an excellent job to explain in short and precise language the basics of hydrogeology, from geology, well hydraulic to chemical aspects. It deserves special mentioning that there is a nice chapter on practical aspects, for example on how to get water out of the ground or groundwater protection.

Written by Claus

August 18th, 2010 at 4:54 pm

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## Identi.ca Weekly Updates for 2010-08-18

Written by Claus

August 18th, 2010 at 11:11 am

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## Identi.ca Weekly Updates for 2010-08-04

Written by Claus

August 4th, 2010 at 12:11 pm

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## Floods in Pakistan

Various newsoutlets report on floods in Pakistan (NYT 1, NYT2, globeandmail. About 800 people or more reportedly died. From a european perspective that seems quite a lot.

Nobody writes about why so many people died, or what the causes were: are there reservoirs? What was the estimated return period?

update Wednesday; August 4, 2010: There are reports that in Pakistan’s northwest, precipitation intensities were as high as 312mm within 36 hours.

update Saturday; August 14, 2010 NPR titles: “China, Pakistan Floods: Preventable Disasters?”

update Sunday; August 15, 2010 The Google Earth Blog has satellite images to be looked at in Google Earth showing the extent of the flood in Pakistan

update Tuesday; August 17, 2010:

• Steven Solomon’s view as written in the NY Times. He points out that the crazy thing is that Pakistan actually has a fresh water shortage.
• here’s a pretty impressive image from NASA (link to article; via Anne Jefferson @highlyanne )

Extent of flood in Pakistan on August 17, 2010

update Friday; August 20, 2010:

Over at howbigreally.com, there is an awesome tool where you can center the overlay of the current extent of the floods in Pakistan over any other area in the world.

Extent of current pakistan flood over central Europe

The CBC has a new article, stating that 4 million people are left homeless

updata Friday; November 19, 2010 … and Clinton says it’s climate change! Other people disagree Also the longer-term consequences are starting to emerge. I think especially worrisome is the question of what might happen to the food-situation next year?

Written by Claus

August 1st, 2010 at 8:56 am

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