Dan's Wild Wild Science Journal

I saw an interesting press release about a paper this past week.  The headline was along the lines of “Climate Change Increasing Space Junk”.

Say what? I can predict the comments now that this will get. “You blame everything on global warming!”

Well, let’s look at what the paper really says and why they reached the conclusions they did.

I know one of the authors of this paper. Judith Lean is a solar physicist at the U.S. Naval Observatory. Dr. Lean is one of the scientists who has shown very conclusively that the sun is NOT responsible for more than a small part of the warming temps. over the last 50 years (in spite of numerous political web sites online that claim otherwise).

She quickly responded and the story behind this is really fascinating.

The Atmospheres layers- NASA/U. Cal. (Living With a Star)

First some basics.

The atmosphere has 5 main layers.

Most weather happens in the bottom 10km called the troposphere. From around 10km to 50km is the Stratosphere, and above that is the mesosphere and thermosphere.

The thermosphere extends several hundred miles above the surface into what most people think of as “space”.Temperatures in this layer of the atmosphere are several thousand degrees, but there is so little air that if you were to stick a hand out of a spacecraft, it would feel very cold. (Just before the blood in your hand boiled).

The Stratosphere is getting colder.

It’s common knowledge that the planet’s temperature is rising. The troposphere is warming. What is not commonly known is that the stratosphere is cooling for the same reason. Greenhouse gases warm the troposphere and cool the stratosphere.

Image courtesy Dr. Ben Santer LLNL. (personal comm.) Santer has done research into the fingerprints of climate change. Santer is an expert on climate fingerpints. His research is actually quite famous if you follow climate science. Click to get a larger size.

The reasons for cooling aloft are rather complex but John Cook of Skeptical Science has an understandable explanation of it here. Gavin Schmidt of NASA GISS has a more detailed and more complicated explanation here.

The sun is responsible for very little of the observed warming over the past century.

The Solar Cycle.

The big player here is the sun. It goes through an 11 year cycle of sunspots. When the sun is producing a lot of spots it puts our quite a bit more energy in the extreme ultraviolet portion of the electromagnetic spectrum. This causes the thermosphere to heat up and increases the density at any given altitude. When the sun is at the quiet end of the cycle, just the opposite occurs and satellites in orbit run into fewer molecules (mainly oxygen).

Since we just had a very long lasting solar minimum, you would expect the thermosphere to have cooled and so it did!

So what you ask?

Satellites and space junk are running into fewer molecules, so they will stay in orbit longer. In most cases this is bad, since there is a HUGE amount of junk up there. If you are on the ISS, it is good news. You do not need a boost back to your preferred orbital altitude by the space shuttle as often.

What the authors of the paper ”Record‐low thermospheric density during the 2008 solar minimum

J. T. Emmert,1 J. L. Lean,1 and J. M. Picone2

(Geophysical Research Letters- published 19 June 2010)

discovered was this. The thermosphere density hit a record low during the recent solar minimum. Besides that, the drop in extreme ultraviolet radiation (EUV) does not seem to be enough to account for all of the drop.

Density of the Thermosphere at 400 km over the last 4 solar cycles. from the paper referenced in the text and ctsy Judith Lean. F10.7 is the solar flux at a wavelength of 10.7cm. this is a good proxy for Extreme Ultraviolet Radiation (EUV) from the sun.

The big discrepancy.

This last solar cycle saw a 29% drop in thermosphere density. Only about 10% of this drop can be blamed on less EUV radiation from a quiet sun. It’s estimated that about 3-6% can be added for extra co2 from humans in the atmosphere. (remember that co2 causes warming near the surface but cooling in the upper atmosphere.)

So what about the 13-16% of the density drop that is not accounted for.

Here is what the authors say about it:

Internal MLT(mesosphere and lower thermosphere) processes

possibly in combination with longer‐term anthropogenic

changes are therefore appealing candidates for explaining

the density changes. In addition to enhanced radiative

cooling by CO2 and CH4 (CH4 is Methane, another greenhouse gas, that is increasing), changes in two other MLT minor

species, O3 (O3 is Ozone) and H2O, also influence thermospheric densities, but trends in these latter species were

small during cycle 23 . Prior work has established that greenhouse‐gas

cooling of the thermosphere is enhanced during solar

minima, a relationship that the prolonged (by more than a

year) 2008 minimum may have amplified. If changes in the

radiative properties of the MLT are responsible for the

temperature and composition changes of the upper thermosphere,

then the density anomalies may signify that an as yet

unidentified climatological tipping point, involving energy

balance and chemistry feedbacks, has been reached.

There is a LOT of space junk up there. ctsy. ESA.

So the short of it all is this- Climate change AND a quiet sun are causing space junk to stay in orbit longer. The data also indicates that some fundamental changes might be underway in the atmosphere.

You might wonder how the density of the thermosphere is estimated. Simply by how quickly satellite orbits decay. How is the sun’s EUV radiation measured? Directly since 2002 but before that the noise of the sun at a frequency of 10.7 cm is used. The data indicates that this proxy itself may be starting to change for unknown reasons.

I wanted to tell this story because it’s a nice example of how scientist use data to discover new things. You would not think at first that there would be any connection to how fast satellites fall out of orbit to climate change, but now you know there very likely is.

Remember in your junior high science book where it says that scientists make observations and then formulate a hypothesis. This is true, but it rarely works in the exact order or as neatly as your book implied!

In the same week that Dr. Michael Mann was completely cleared of charges that he was conducting science outside of normal standards comes this:

Click to read the Guardian story from 5 July.

Mann was the last one- every other person accused by those who poured through the stolen emails have already been completely cleared. The Guardian story pretty much explains the type of people that made the charges.

Nutters.

Dan

Standing at the Pole Jan. 11, 2010. Picture taken by Chaz Firestone.

On the 11th of January I was lucky enough to join a rather small club. Those who have stood at the very bottom of the world.

WAIS DIVIDE

While I saw a lot of the science underway in Antarctica, there was one site in Antarctica I didn’t get to see, WAIS Divide. The Western Antarctic Ice Shelf is the site of one of the most important science projects in the world right now.

Researchers there are drilling through the ice to obtain an ice core that will tell us about the past climate of Earth. It will not be the first ice core, but this one will give detail that has never been seen before.

WAIS Divide drill site- courtesy of the Nat. Science Foundation (Who took me to Antarctica)

WAIS Divide is more remote than the South Pole and the weather was too bad to get in there.  The text books will someday have a lot about these cores. They may very well ask how the nations of the world could ignore the warnings they gave (while burning fossil fuels at an ever increasing rate) as the planet warmed.

NEEM IN GREENLAND

There is another ice core being drilled at the opposite end of the world and in a place just as remote. The site is called NEEM. That stands for Northwest Greenland Eemian ice core.

The site is on top of the Greenland ice cap at over 8,000 feet. In summer, the top of the icecap is the coldest place in the Northern Hemisphere )with  the exception perhaps of the top of Mt. Mckinley in Alaska).

The NEEM site was chosen because it may very well be possible to obtain ice with year to year countable layers that extend all the way back through the last ice age to the warm period before it!

The Eemian

The last ice age started about 115,000 years ago. The warm period before is called the Eemian (115,000 to 130,000 ybp). Temperatures in Greenland were likely 3-5C warmer then than they are today in the present interglacial. (The last ice age ended about 11,000 years ago)

Midnight July 1,2010 at NEEM on the Greenland Ice cap. Photo: NEEM ice core drilling project, www.neem.ku.dk.

Having two cores from opposite ends of the world will give paleoclimate researchers the best understanding of how are planets climate has changed over the last 130,000 years. They may very well confirm the estimates of what is called the climate sensitivity.

The climate sensitivity sounds complicated but like most things in science, if you take the time to understand it, it is really pretty simple.

Here are the basics and the big question all in one:

If you double the carbon dioxide in the atmosphere, how much does the Earth warm?

Climate models and ice cores obtained over the last 25 years all seem to indicate a sensitivity of about 3-4 degrees C. Most research shows it is not likely less than 2C but it could be higher than 4C.

If this is indeed true, then you don’t need a climate model to forecast the weather at the end of this century. The CO2 levels are rising rapidly and will reach the doubling point long before 2100. The CO2 is actually rising faster than predicted by the IPCC and will soon hit 400 parts per million. When Thomas Jefferson signed the Declaration of Independence it was about 280 ppm.

Ice core at NEEM in 2009. Photo: NEEM ice core drilling project, www.neem.ku.dk.

Rewriting The Text Books

Previous ice cores have already rewritten the climate text books. I was taught back in the late 1970′s that climate changes very slowly. Not enough to be perceptible in one life time. The Greenland cores have shown that the climate there changed many times, to much warmer conditions in just a couple of decades!

This was stunning information.

It’s why climate experts like James Hansen worry about so called tipping points.

Now that we are controlling the CO2 (not mother nature), could something like that happen again? Hansen thinks so and believes that we are already at a level of CO2 where it could. (A world 4C warmer than today would be dramatically different with likely catastrophic consequences)

NEEM is on top of 2500 meters of ancient ice. Image ctsy. NEEM

Ancient Ice

The ice cap at NEEM is over 2,500 meters thick and at the bottom is ice from snow that fell 130,000 years ago! If all goes well, researchers in late July will be handling the most ancient Greenland  ice humans have seen. (Antarctic cores have gone back even further).

Embedded in it will be a record of the temperature, and a host of other variables. That ice has locked in it the story of what that world was like when those soft snow flakes drifted down onto the icecap so incredibly long ago.

So now that you know why these ice cores are so important, I can tell you my disappointment at not reaching WAIS Divide was short lived.

ctsy. NEEM

Would You Believe??

I’ve been invited to visit NEEM in about three weeks!

Not many people get to stand at the bottom and the top of the planet inside of one year. If ever!

If all goes well the same New York air guard unit that flew us to the South Pole will land me on top of the Greenland Ice cap, well north of the Arctic Circle, in a few weeks. A land of 24 hour daylight at the top of the world.

More coming soon about NEEM and details about the ice cores and what modern science can tell about the past by analysing them.

If all goes well, I will see history first hand in a few weeks, and yes, I am bringing cameras.

Hurricane Alex IR image (Courtesy if CIMMS U Wisc.)

Hurricane Alex is already producing flooding along the South Texas Coast as it nears landfall. Winds are at 90 mph in the eye wall near the center. The amount of storm surge is VERY dependent on the shape of ocean bottom and the angle the storm comes into the coast. So don’t assume that a category one storm will not produce serious flooding. It can.

Meteorologist Alan Raymond of our staff spent last night flying into Alex with the Hurricane Hunter aircraft based at Keesler AFB in Mississippi.

Alex is the first June hurricane since 1995. Most tropical storms develop after August 1st each year.

Dan

Update 6pm CDT- Alex is now a Cat Two storm with 100 mph winds.

Tropical Storm Alex is looking quite healthy this afternoon and has finally started moving. There seems to be a growing consensus among the models that Alex will come ashore in Mexico, well south of Brownsville, Texas. The latest movement, along with the new guidance, is a bit left of the last NHC track.  Look for a shift the forecast a little southward in the next advisory.

Click for full resolution- Courtesy USNRL.

It is not out of the question that Alex could reach Category two strength before landfall, and the swells from the storm will likely impact the oil slick operations well across the Gulf.

Update: The NOAA 18 Polar orbiter has a a sensor called the Advanced Microwave Sounding Unit. This allows a radar type image of the storm and can be very helpful in determining storm structure. Looking at the latest pass, it does not show an eye yet.

The rest of the tropics seem quiet right now.

Meteorologist Alan Raymond from our office will be on board the Air Force recon. aircraft for the overnight fixes. He may very well be flying into a hurricane. Alex is very close now…