Thursday, September 07, 2017

The IPCC on Hurricanes: What It Says

Perhaps just a short note about what the science actually says about hurricanes, as oppose to what many people are assuming it says:

In Oregon

Tuesday, September 05, 2017

It Seems Like Half of Oregon is On Fire

It seems like half of Oregon is on fire right now. From the Oregonian:

Here it's smoky -- you can see it clearly and smell it too. The most prominent fire, the Eagle Creek Fire, is in the (incredibly beautiful) Columbia River Gorge, east of Portland. The only highway through there, I-84, is closed and they've ordered some evacuations near the Bridge of the Gods. About 10,000 acres are on fire, and it's jumped the river into Washington. The fire is 0% contained, as they say. There are lots of trails and waterfalls on both sides, especially the Oregon side -- someone called it "Portland's playground." And it's now all being burned. And it was probably started by a teenager playing with fireworks.

Plus there's ash falling in Portland. Here's a picture of my sister's car early this morning:

Not any in Salem at the moment. There are health advisories all over the place, and Portland schools are letting out early. It's not helping that we're having another heat wave -- highs of 98°F in Salem both last Saturday and Sunday. Normal high for those days is 80°F.

August in Salem was 5.4°F (3.0°C) above the 1981-2010 average.

Monday, September 04, 2017

Richard Muller on Moving From AGW Skeptic to Believer

From an Q&A with Richard Muller in Physics Today (2/10/17; paywalled):
PT: When talking about global warming, you’ve described yourself as a “converted skeptic.” What persuaded you to move from skeptic to believer? Does your experience suggest strategies for talking to current climate skeptics?
MULLER: I was a skeptic because there were five major issues that the Intergovernmental Panel on Climate Change (IPCC) was not adequately addressing. My daughter Elizabeth and I formed the nonprofit Berkeley Earth to examine those, and remarkably, we were able to address all five issues. We enlisted some great team members who were experts at objective analysis of big data, including [Nobel-winning astrophysicist] Saul Perlmutter and [the late Berkeley physicist] Art Rosenfeld.

All of the issues legitimately raised by skeptics were potential biases: data selection, temperature-station siting, data adjustment, and heat island. The fifth was potential bias from the large number of adjusted parameters that were used in the global climate models, and from the instability of those enormous simulations. We came up with a solid analysis of each of the biases and were able to conclude, using our independent work, that global warming was real and caused by humans. We can go farther than the IPCC by attributing 90% of the warming of the past 260 years to humans. We’ve kept our work open and transparent.

I get along very well with skeptics, largely because I respect them. Most of their complaints against climate change are legitimate. Most headlines and most comments made by politicians―and by many scientists!―on this subject are either exaggerated, misleading, or false; that’s why there are so many skeptics. I’ve talked privately to very prominent scientists who admitted to me that they exaggerate on purpose to garner public concern and action. But I think such exaggerations are counterproductive; they lead to a mistrust in science.
All well and good. Separately, I still remember when Muller wrongfully scorned the Michael Mann and the hockey stick, and as far as I know he never corrected himself on that, or apologized. He should.

There's more about this in Wikipedia.

Sunday, September 03, 2017

Trump Picked a Climate Change Denier to Head NASA

On Friday Trump indicated he will nominate Representative James Bridenstine, a Republican from Oklahoma, to be the next administrator of NASA.

But Bridenstine is a climate change denier, pure and simple:


There's some opposition, but only because he's a "politician" and not a space person, not because his views on climate science are completely whacked.

Added 7:24 pm - Amazingly, the New York Times did not mention Bridenstein's climate denial.

Wednesday, August 30, 2017

How Fast Is the Probability of Extreme Temperatures Increasing?

So awhile back I hypothesized that the probability of extreme temperatures increases exponentially when global temperatures increase linearly.

Recently the NY Times posted some data that I think lends some qualitative support to this contention. It's in a graphical form, not numerical, so I can't really analyze it statistically -- only by eyeball. They're the changing probability distributions of summer temperatures in the northern hemisphere:

I don't know -- is the forward tail increasing outward (leftward) faster than the leftward movement of the the distribution peaks? It kind of looks like it, to me....

Monday, August 28, 2017

How Climate Change is Making the Houston Situation Worse

One way climate change is certainly making the Houston flooding is because because sea level is rising. That increases the height of storm surges and brings more water inland.

NY Times:

"Exacerbating the situation, said Hal Needham, a storm surge expert and founder of the private firm Marine Weather & Climate in Galveston, Tex., was that the storm surge elevated Galveston Bay, blocking drainage of the rain that pummeled coastal and inland areas."

Galveston, which is a barrier island, has seen 0.75 meters of sea level rise since 1900. Much of that is due to the island’s subsidence, but sea level rise is making this worse than where the land isn’t sinking. And, with small-slope beaches and relatively flat land, the inland extension of the water is increasing too.

inland extension ~ sea level rise/sin(coastal slope)

And the storm surge of a hurricane is much more dangerous than the winds.

According to a 2013 article in the Houston Chronicle
A 2007 study underwritten by the city of Galveston that anticipated rising sea levels would cover the coastal highway on the west of the island within 60 years appears to have been overly optimistic.

The $50,000 geological hazard report was prepared for the city by geologists from the University of Texas, Rice University and Texas A&M University but then shelved. The report based its calculation on historic sea level rise and failed to include climate change. Sea levels are rising much faster than previous estimates that accounted for climate change, according to reports released in December by U.S. government scientists and in November by the World Bank.
So right there is an example of how political influence in a climate report (which is why I assume the Texas university's report left out climate change) is dangerous.

A 2016 article from the Houston Chronicle about the land subsistence shows that it is large all over the region.
Parts of Harris County have dropped between 10 and 12 feet since the 1920s, according to data from the U.S. Geological Survey.

State and local officials have made various efforts over the past 40 years to stabilize the ground, but some areas continue to sink - by as much as 2 inches per year.
And why is this happening? Humans. People are drawing too much groundwater out of the aquifers, and the land above is sinking.
There is little mystery to why this is happening: The developing region draws an excessive amount of groundwater to keep itself quenched. Over the last century, aquifers here have lost between 300 and 400 feet, leaving the land to collapse.

The science behind this phenomenon is called subsidence.

Houston sits in one of the nation's largest subsidence bowls, so-called because of the crater effect that happens when the ground caves.

Saturday, August 26, 2017

The Sun's Changing Obscuration During the Eclipse

Sorry, but there's one more eclipse-related topic I need to get out of my system.

As we were watching last Monday's eclipse, from the moment the Moon's disk was first noticeable over the Sun, we were trying to figure out how fast the Sun's light was diminishing. First it starts at 0 (0%), of course, and at totality it's 1 (100%).

But how fast does it proceed between the beginning and totality? It's a calculation of how much one disk (the Moon) obscures the other (the Sun).

I had actually tried to calculate this before the eclipse, and while it's just geometry it's a bit tricky, especially for someone who rarely calculates anything anymore. My brother-in-law is a laser physicist, and he said he once had to calculate this once regarding two laser spots (or some such), and only found it after a few hours of work.

Eventually I started hunting around the Web, and found this nice derivation from ​Adrian Jannetta, a math instructor in England. He also built this interactive calculator (at the page's top) to calculate the Sun's obscuration for different radii of the Sun and Moon.

Eclipse astronomers classify how far along the eclipse is by the magnitude M, which is how much of the Sun's diameter is covered up, at any given time, by the Moon. Also, the algebra simplifies considerably if you take the Sun and Moon to have the same radii -- remember, this is the radii as seen in the sky, not in actuality, and the very reason a solar eclipse happens is because the angular diameter of the two is very nearly equal.

(Actually for Monday's eclipse I read the Moon, at totality, obscured 103% of the Sun's area, so its angular radii was just a bit bigger than the Sun's, but I'm going to ignore that here.)

So setting the Sun and Moon radii equal in Janetta's equations gives


where again, M is the magnitude, and α is just an intermediate parameter to make the math look simple.

M is going to be proportional to time, assuming the Moon glides uniformly across the Sun's disk. (Probably not exactly true, but close enough for this example. At our location it took 1 hr 11 m 55 s from beginning to totality.)

Then I get the following for the obscuration as a function of magnitude:

The eclipse banana
This is a lot more boring than I was hoping for. The obscuration starts out relatively slowly. At M=0.5 it's only 39%, and then it proceeds almost linearly to totality. The it reverses as the Moon starts past the Sun.

I guess I thought there might have been a quickening, nonlinear obscuration closer to totality -- when the "banana" shows up, then continually shrinks. But we were all too excited to really judge it objectively.

Anyway, I spent some spare hours working on this because I couldn't get it out of my head. Now's it's gone.