Monthly Archives: April 2013

Boston

Tony Bennett left his heart in San Francisco. I left mine in Boston.

Worth More than a Thousand Words

This is what Lawrence Solomon, writing in the Financial Post, considers “analysis.”

Perhaps everyone who reads this should inform the Financial Post what they think of his “analysis.”

Not Just the Facts — the Wrong Conclusions Too

A WUWT contributor who calls himself “justthefacts” has written a post which attempts to tout the so-called “pause” in global warming. It’s pretty well summed up by the title of this post.

Once More

Let’s take a signal which everybody agrees is broadband. It’s called the sinc function, and I’ll choose the form

$x = {\sin(\pi t) \over \pi t}$.

Its Fourier transform is a rectangle function, equal to 1 for frequency between -0.5 and +0.5, equal to zero otherwise.

Sampling Rate, part 2

“Suppose we have a signal which is band-limited, say it’s limited to the frequency band from 0 to 0.5 cycles per day,” says the engineering professor to the class in digital signal processing. “If we observe this signal at regular intervals with a sampling rate which is at least twice the bandwidth — in this case, at least once per day — then we can use Fourier analysis to reconstruct the signal. We can even interpolate it to fill in the gaps. This is one of the most common applications of Fourier analysis in the real world — we observe a signal, then use its Fourier transform either to reconstruct the signal or simply to identify its Fourier components (and therefore its physical nature).”

I don’t know what to say

about the latest from James Delingpole at the U.K. Telegraph:

Who You Gonna Believe?

It seems that Anthony Watts politely disagrees with my post about the connection between oil and gas production and earthquake activity. Actually that’s not a fair portrayal of his post. It’s a hatchet job against me personally. What a nice guy.

Sampling Rate

T, from my mechanical engineering world we have strict rules on sampling rates vs. signal frequency rates. Ie you cannot reliably measure a 60hz ac sine wave with a 5hz analog sampling device. The result ends up being strange results that donâ€™t show spikes well and also might not show averages well either. Can you help me understand how 120 year sampling proxies can resolve relatively high frequency temperature spikes?

This objection comes up so often from those who are accustomed to data which are evenly sampled in the time domain, and the misconception is so firmly imprinted on so many people, that it’s worth illustrating how uneven time sampling overcomes such limitations.

Does Fracking Cause Earthquakes?

Mother Jones reports on recent earthquakes in regions not accustomed to much seismic activity, Oklahoma, Arkansas, and Ohio. Much of their story consists of anecdotal evidence, particularly the strongest earthquake in Oklahoma history at magnitude 5.6 in November 2011, which happened along a fault which a Univ. of Oklahoma geophysics professor referred to as “a dead fault that nobody ever worried about.” Since this quake “injured two people, destroyed 14 homes, toppled headstones, closed schools, and was felt in 17 states,” people are starting to worry.