Monthly Archives: August 2010

You're Getting Warmer

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Have you noticed all the hot – and erratic – weather this summer?

So has NASA GISS climatologist Jim Hansen. He’s out with the draft of a new paper and popular summary that explores July’s anomalous weather. His main point:

The global average July 2010 temperature was 0.55°C warmer than climatology in the GISS analysis, which puts 2010 in practically a three way tie for third warmest July. July 1998 was the warmest in the GISS analysis, at 0.68°C.

Here’s his prediction on whether 2010 will shape up as the warmest in the GISS record:

2010 is likely, but not certain, to be the warmest year in the GISS record. However, because of the cooling effect of La Niña in the remainder of the year, there is a strong possibility that the 2005 and 2010 global temperatures will be sufficiently close that they will be practically indistinguishable.

And his take on whether the extreme weather events – such as the brutal heat wave that’s hammered Moscow – are connected to global climate change:

The location of extreme events in any particular month depends on specific weather patterns, which are unpredictable except on short time scales. The weather patterns next summer will be different than this year. It could be a cooler than average summer in Moscow in 2011…What we can say is that global warming has an effect on the probability and intensity of extreme events.

This points to the distinction that scientists are always making between weather and climate. Solar activity, El Nino or even volcanic eruptions can affect the weather and temperature over a short term. But when it comes to classifying what is happening to the climate, the trend must be clear and free of these influences. The climate “signal” must emerge from the data over the course of at least a decade.

What’s happening with the global surface temperature record fits this bill, Hansen said in the draft paper. Despite El Ninos, La Ninas, changes in the Arctic Oscillation, fluctuations in the sun’s radiance, snowy winters and cool summers, hot summers and warm winters, the continued trend of the average global surface temperature remains on an upward climb.

To learn more about NASA’s surface temperature record, visit this temperature update from earlier this year. Also, you can visit GISS’s technical page for detailed information about GISS’s surface temperature record.

— By Patrick Lynch and Adam Voiland, NASA’s Earth Science News Team

–The map at top was created by NASA’s Earth Observatory using data from MODIS 

NASA Earth Buzz: Steamy July, Shakedown in the Gulf, and Look How Good We All Look

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Degrees of Change
New data from GISS puts July 2010 in a three-way tie with 1998 and 2005 for warmest July on record. (Earth Observatory)

“Shakedown” in the Gulf
NASA’s DC-8, which is in Florida preparing to hunt for hurricanes, took to the air this week for a practice flight as part of GRIP. (NASA.gov)

Fingerprints of Fire
A massive plume of carbon monoxide made its way across Asia, unleashed by Russian wildfires. (JPL)

A Bit of Elegance for Your Day
A visual artist at the Earth Observatory has a new blog on the development of science imagery; the first post offers fascinating details about imaging Eyjafjallajökull. (Elegant Figures)

Gray Marble
See Earth in its grayest and gloomiest glory. (My Big Fat Planet)

Straight to the Source
Tired of the filter? Get closer to the data with this new Twitter feed from the Data Information and Services Center at Goddard, one of eight core data dissemination groups across NASA. (NASA_GESDISC)

Tweet of the Week
We look good, don’t we? http://bit.ly/bPIAL4 (NASA_GoddardPix)

Reading the Sky

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Recently, a colleague and I caught a glimpse of an odd-looking contrail stretching across the sky. As we stood there and studied it, my colleague made in interesting observation.

“That’s the trail from a rocket launch,” he said. He was referring to a launch from NASA’s Wallops Flight Facility, which is about 70 miles northeast of our location at NASA Langley in Hampton, Va.

A contrail is formed when hot, humid air from exhaust mixes with cold, dryer air at high altitudes. The condensation trail forms a cloud that shows the passage of the aircraft (or, in this case, a spacecraft). Contrails can change and move easily, and by studying them we can determine how they affect Earth’s energy budget.

It can be hard to read the sky correctly because the curvature of the Earth produces some confusing optical effects. In this case, our ground perspective about 70 miles from the launch made the trail appear at first as a regular contrail crossing the sky horizontally.

But as I continued to watch, it became clear that this was no ordinary contrail. Rather than continuing across the sky, the trail clearly became higher and higher until it vanished entirely as the rocket left the bulk of the atmosphere behind.

Aside from that high arc, this trail had some other odd features. Unlike a typical contrail, which is usually pretty smooth, this one looked narrow and wiggly. Those wiggles, I discovered, were the result of adjustments in the pointing of the rocket as it zoomed through the atmosphere. This is apparent in the video of the launch.

The winds were relatively light that evening, so about 45 minutes later the trail was still clearly visible overhead. However, there was just enough wind to twist the contrail into something that could have been left behind by a crazed aerobatic pilot.

I searched the web and found the picture on the left from a Shuttle launch, which gives you some idea of what we saw.

From my point of view on the ground, there was nothing to tell me that those loops weren’t a horizontal set of circles made by a plane flying at a constant altitude. But since I knew that a rocket had left the trail, I could correctly interpret them as a spiral up to higher levels of the atmosphere.

While this experience is an extreme example, it points out the perspective problems at work whenever we look up at the sky.

Nonetheless, our Earthly perspective is valuable to learning more about clouds’ behavior, and with the help of satellites, we can get a little closer to understanding how clouds affect our climate system.

— By Dr. Lin Chambers, NASA Langley Research Center

— Top photo courtesy of Allen Kilgore, NASA Langley Research Center

What On Earth is That? #3

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(Please post your answers and your name in the comments, and we’ll give the answer next week….)

Here at What on Earth, we’re constantly stumbling across interesting photos, videos, and audio clips from NASA’s exploration of our planet (be it from space, the field, or the lab.). We’ve started posting snippets of them every now and then, usually on Fridays. What we post will change, but the question to you all will always be the same: “What on Earth is that?”

We’ll give you a week to mull it over and guess (use the comments), and we’ll post the answer the following Friday. Our only hints:

1) Our picks will always be related to Earth science in one way or another, and…

2) They’ll have some relation to what we do here at NASA.