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Sun-gazing

Geopoetry - Fri, 10/17/2014 - 10:00
 De Pontieu et al., Science 2014

Dopplergrams from the NASA’s space telescope IRIS (Interface Region Imaging Spectrograph) revealing detailed evidence of “twist” between the sun’s surface and outer atmosphere. These phenomena may play a role in driving the temperature difference between the sun’s surface (~6000 K) and the sun’s outer atmosphere (millions of degrees). The reason for this enormous temperature gradient is not fully understood (a puzzle known as the “coronal heating problem”). Image: De Pontieu et al., Science 2014

 

By Galileo’s careful hand, sunspot details are exquisite,

Through eye of forehead, eye of mind beholds what body can not visit.

If only he could see the sights now rendered from Earth’s outer space,

Ultraviolet sunscapes – Oh, to see his raptured face!

High above Earth’s atmosphere, IRIS probes the edges of our star,

A telescope in orbit, through its lenses, we see far.

Six thousand Kelvin screams the surface, roiling plasma, like hellish seas,

Hotter still, the sun’s corona: millions of degrees!

Mysterious, this source of heat that drives the solar wind our way …

High-speed jets, coronal loops and nanoflares may be at play.

What a thrill to gaze through space with spectrographic eyes,

Fueled by human wonder and a zeal to probe the skies.

 

__________________________________________________________

Further reading:

Eyeing the Sun, Science Magazine

This is one in a series of poems written by Katherine Allen, a researcher in geochemistry and paleoclimate at the Lamont-Doherty Earth Observatory and the Institute of Marine and Coastal Sciences at Rutgers University.

Columbia's Burden Room Through Time - Columbia Record

Featured News - Fri, 10/17/2014 - 09:21
Profile of Columbia's Burden Room in Low Library, one of the stops on Lamont scientist Dave Walker's geology tour of campus.

Langseth limericks

The ENAM Seismic Experiment - Fri, 10/17/2014 - 01:19
As we approach the end of the cruise, I think this calls for a round of salty Langseth limericks.  It helps if you imagine a round of hearty “Aye, matey!”  and “Arr!” and such between each verse.

There once was the Langseth, a ship

Over wave and trough did she skip.

Many instruments aboard

To always record

Depth, gravity, mag – every blip.

There once was the Langseth, a vessel

Where in their bunks scientists nestled.

‘Til called to their shifts

Their heads they must lift

For with errors and logs they must wrestle.

There once was the Langseth, a boat

On her airguns the crew they would dote.

Oft while in a turn

Guns were brought up astern

To ensure best acoustical note.

There once was the Langseth, seacraft.

Where we launched XBTs down a shaft.

With each probe descent

To the lab data went

So that temperature-depth could be graphed.

There once was the Langseth, a fine tub!

Where the galley crew made us good grub.

But when seas ran high

Up in knots stomachs tied

And to keep the food down, there’s the rub.

There once was the Langseth, fair barge.

To collect seismic data her charge.

Streamer 8-km long

And four gun strings strong

She’s the fleet’s seismic dreadnaught at large!

-Tanya Blacic, aboard the R/V Marcus. G. Langseth

US Dust Bowl Unrivalled in Past 1,000 years - Scientific American

Featured News - Thu, 10/16/2014 - 11:00
Atmospheric conditions and human actions combined to drive the 1930s mega-drought, according to a new study led by Lamont's Benjamin Cook.

Another Dust Bowl? California Drought Resembles Worst in Millennium - LiveScience

Featured News - Wed, 10/15/2014 - 14:36
The 1934 drought is the worst on record for North America in the past 1,000 years, and had similar conditions to the current California drought, says a new study led by Lamont's Benjamin Cook.

Locked Faults Could Pop Big Earthquake in Bay Area - NBC News

Featured News - Tue, 10/14/2014 - 08:14
Lamont-Doherty seismologist and deputy director Arthur Lerner-Lam comments on a study putting the chance of a big earthquake in the San Francisco Bay Area in the next 30 years at 70 percent.

Extreme High Tides Could Flood Our City's Streets - WNYC

Featured News - Mon, 10/13/2014 - 14:37
Lamont's Klaus Jacob explains what should be done to protect New York City from rising seas.

Lamont-Doherty Open House Highlights - (Rockland/Westchester) Journal News

Featured News - Sun, 10/12/2014 - 11:00
Video of an erupting "trash can" volcano and other highlights from Lamont-Doherty's 2014 Open House.

Last Day of the Cruise!

The ENAM Seismic Experiment - Fri, 10/10/2014 - 10:58

October 10th, 20141158
Three days ago, at approximately 2130, we recovered our final OBS and started our 36-hour transit back to Narragansett, RI. We began docking procedures at Senesco Marine LLC at around 1300 yesterday and were all tied up by 1400. After the lines were clear, both watches performed some preliminary breakdown of the OBS equipment to help stage it for demobilization this morning. It was impressive how fluidly we took and executed directions after a month of working together. It was clear that the trip had bonded us as a team. After everything was done, the group headed out to enjoy our first night on land, which, as anyone whose been on a ship for an extended period will tell you, is just an incredible feeling. One of the eeriest moments, however, was all of a sudden being surrounded by people besides those you’ve been on the trip with. Also, the “dock rock” is an interesting experience.
This morning, after a wonderful, final breakfast made by our steward, Mike Duffy, we packed up the final gear and the crew began lifting it off the boat, staging it on the pier. All that’s left now is to clean up my stateroom, pack up all my stuff, and head on home. This cruise has been both a great scientific and personal learning experience and I am happy to have worked with these crewmembers, techs, researchers, and students. The lab seems so empty now, as I write this post, and there’s a part of me that is sad that this adventure is ending regardless of how excited I am to get back to life on land.
Anyways, time for me to go. For those who are interested in the data we’ve collected on this cruise, look out for information concerning workshops on data access and processing in the near future.
Signing off,Dylan Meyer aboard the R/V Endeavor
Figure 1. Evening recovery of the last OBS, there was much rejoicing!
Figure 2. A crewmember, Charlie Bean, tossing a leading line with a monkey fist to the dock.
Figure 3. The WHOI OBS van and SIO OBSs staged on the pier to be loaded onto trucks.
Figure 4. The WHOI OBS van being loaded onto a truck for transit back to Woods Hole.
Figure 5. The, now empty, lab deck of the R/V Endeavor.

Chemical silence

Geopoetry - Fri, 10/10/2014 - 08:26

 Elkhorn coral colony near Akumal, Mexico. John Bruno (Science).

Photo: Elkhorn coral colony near Akumal, Mexico. John Bruno (Science).

 

What if you couldn’t smell smoke?

Or detect flirty signs from a bloke?

Imagine the cost

Of faculties lost,

Of signals that deafness would cloak …

On reefs, it’s chemical cues

That life-forms will commonly use;

With acid on rise,

A fatal surprise:

What senses might reef-critters lose?

 

__________________________________________________________

Further reading:

Ocean acidification foils chemical signals, Science

 

This is one in a series of poems written by Katherine Allen, a researcher in geochemistry and paleoclimate at the Lamont-Doherty Earth Observatory and the Institute of Marine and Coastal Sciences at Rutgers University.

 

Climate Change Disrupts Arabian Sea with Voracious Plankton - Climate Wire

Featured News - Thu, 10/09/2014 - 14:37
Features plankton study by Lamont's Helga Goes and Joaquim Gomes.

Photographers, Scientists Share Climate Change Pictures - Wall Street Journal

Featured News - Wed, 10/08/2014 - 11:00
Scientists and photographers will post pictures related to climate change in a partnership with the International Center of Photography. Lamont climate scientist Billy D'Andrea featured in one photo.

Is Capturing Carbon from the Air Practical? - MIT Technology Review

Featured News - Wed, 10/08/2014 - 09:23
Profile of former Lamont-Doherty director Peter Eisenberger and his plan to save the world with technology that takes carbon out of the air.

Scripps OBS GoPro

The ENAM Seismic Experiment - Sat, 10/04/2014 - 04:16
I had this idea to attach our GoPro cameras to a Scripps OBS that was being deployed on the shelf nearer the coast.  These underwater housings are rated to 100 feet and we deployed them on three different sites at that depth, recording some of the coolest OBS video I have ever seen.  The stills captured from the video are pretty cool too, but one of the unexpectedly groovy features of the video is the audio.  You can hear the acoustic responses, ship noise in the shallow, ocean background biology, and current noise on the seafloor.


Time series of deployment and recovery. Photo Credit: Ernie Aaron.~ErnieR/V Endeavor

Riding big swells and crossing the Gulf Stream

The ENAM Seismic Experiment - Fri, 10/03/2014 - 14:01

On calm days, you could almost forget that you are in the middle of the ocean.  Its sunny and calm outside, and everything is stable inside.  People get lax and leave cups and other items on table tops unsecured and unattended.  And then some big swells come, and we all remember why chairs are tied to tables, furniture is nailed down to the deck and we use bungie cords and sticky pads to keep computers and other gear in place. Today we are experiencing swells up to 5 m high, in which the ship has rolled up to 25 degrees.  Unsecured items (including people in chairs!) are rolling all over the lab. Meanwhile, we are also crossing the Gulf Steam, which poses it own challenges to our gear. Fishermen are particularly concentrated here, and today we deviated 10 km off of our profile to avoid fishermen and their gear.  The currents are also pushing our seismic streamer around.  In the ideal case, the streamer extends straight behind the vessel and quietly rides 9 meters below the water surface.  The currents today have pushed it to the side by 70 degrees from the ideal track, and the swells generate noise on the hydrophones.  However, even though conditions may not be ideal, it is essential that we collect data here for our science goals. We think that there are thick accumulations of frozen magmas beneath the Earth’s surface here that formed when the supercontinent of Pangea broke apart to form the Atlantic Ocean.  So we shall push ahead!Annotated screen capture from our navigation system showing the ship, the streamer, our intended profile and our deviation.
 Donna Shillington from the R/V Langseth

Greenland Sediment Sheds Light on Sea Level Rise - Climate Central

Featured News - Thu, 10/02/2014 - 08:21
Sediment flowing off Greenland's ice sheet could hold clues about current and future sea level rise; Lamont-Doherty geophysicist Robin Bell comments.

Working hard

The ENAM Seismic Experiment - Tue, 09/30/2014 - 15:07
September 30, 2014

It takes a team of people to get the OBS in the water and back out again. To illustrate the process of deploying a WHOI or SIO OBS, Gary Linkevich has created a time lapse video. The first part of the video captures two WHOI OBS deployments with Peter, Dave, Dylan, Gary, and Kate. The WHOI OBS are the peanut shaped yellow capsules that appear in the background next to the railing. After the WHOI OBS is in the water, we capture an SIO OBS deployment with Mark, Dylan, Gary and Kate. The SIO OBS are the rectangles with a yellow top and white base. Right after we deploy the SIO OBS, we start putting together a new one for deployment. The assembly process involves an instrument test and then attachment of the metal weight, floatation devices, light, and radio together. The deployment of this SIO OBS happened during the midnight crew shift which includes Ernie, Pamela, Afshin and Jenny. Once they pick her up and put her in, they start the assembly process all over again!



Thanks Gary for putting together this time lapse!

See you Later,

Kate Volk aboard the R/V Endeavor

Running the R/V Endeavor

The ENAM Seismic Experiment - Tue, 09/30/2014 - 14:27
September 30, 2014
1527

One of our assistant engineer, Kurt Rethorn, gave us a tour of the engine room. Here's what we learned:

Kurt is an awesome tour guide!

The EngineThe R/V Endeavor is equipped with a two-stroke (providing more power strokes per engine rpm), diesel engine consisting of 16, 350-cubic inch, cylinders with a maximum output of 3050 horsepower. Also, this bad boy is outfitted with a turbo charger which uses the exhaust to increase pressure in the cylinders and improve the power output from the combustion stroke. The engine is kept lubricated by 500 gallons of motor oil, which is changed when the ship is in port based on the number of engine hours. We burn around 1,000 gallons of fuel a day while on station (between the generators and the main engine) and even more when we are in transit between sites. We left port with around 54,000 gallons of fuel stored beneath the berthing decks, but she can hold up to 56,000 gallons of fuel total (the additional space is left to allow for the expansion of fuel due to temperature changes). A fun fact about the R/V Endeavor is that the propeller only spins one direction, meaning that there is no reverse gear. In order to drive the ship in reverse, the pitch of the propeller blades is switched such that the flow of water is reversed. There is also a powerful bow thruster that can be engaged if necessary.

Kurt starting off the tour (Photo credit: Kate Volk)The engine with the exhaust manifold above and access to each of the piston heads underneath the latched doors (Photo credit: Kate Volk)Fuel gauges. Fuel is consumed from both tanks at a relatively similar rate in order to keep the boat properly balanced (Photo credit: Kate Volk) The GeneratorsThe R/V Endeavor has four generators. Three below the water line and one above (for emergencies only). The generators produce all our electricity directly (i.e. they do not charge any batteries). In a power failure, an emergency generator will kick on in less than a minute.
These are two of the generators, aligned along the centerline of the ship (Photo credit: Kate Volk) WaterWe use about 1000 gallons of water a day between showering, cooking, cleaning, and drinking and the ship can only hold approximately 8600 gallons of fresh water. Therefore, we must produce fresh water throughout the cruise and we have two methods of achieving that. We have a reverse osmosis machine, which takes up salt water and pushes it through a long, blue semi-permeable membrane at 800 psi. The high pressure in the membrane causes the salt to drop out of solution producing fresh water. The second way we have of producing water is an evaporator. This brings in salt water under a vacuum at 711 mmHg (13.75 psi). The water is heated up and the condensation is collected, now free of salt. The reverse osmosis machine  and evaporator can produce around 50 and 80 gallons of water per hour, respectively, so that we can theoretically make 3200 gallons of water everyday. However, the evaporative method is dependent upon the engine heat to turn the water into vapor, which means that it runs at a lower efficiency when the engine is cooler. 
Reverse Osmosis machine. You can see the blue membranes that separates the salt and water (Photo credit: Kate Volk)

Water quality (Photo credit: Kate Volk)Sea water temperatures in the Gulf Stream are pretty warm (Photo credit: Kate Volk)
See you later, 
Dylan Meyer and Kate Volk aboard the R/V Endeavor

First Look at OBS Data!

The ENAM Seismic Experiment - Tue, 09/30/2014 - 13:48

September 30th, 2014:1437
We have our first look at data!! Ernie Aaron merged some of the raw data from the Scripps OBSs with navigation files from the R/V Marcus Langseth such that we can start seeing the seismic waves recorded in the in ENAM project.  In Figure 1, the hydrophone record of OBS 209, which was recovered on Sept. 21st, is shown as a function of space and time. To be clear, this is original seismic data. There are still post-processing methods and inversions to apply to the data back on shore that will help extract the seismic velocity structure down to upper mantle boundary along Line 2 or any of the other seismic lines. Until then, however, here is what we learned thus far.
To remind all, the experimental setup for this study is as follows. We on the R/V Endeavorplaced OBSs on the seafloor at a spacing of approximately 15 km along Line 2. The R/V Langseth then cruised along Line 2 from ESE to WNW with airgun shots spaced every 200 meters. The OBSs were then recovered and the hydrophone and geophone data were downloaded.
Figure 1. Traces recorded from OBS 209 (bottom) with various arrivals identified by color. The dashed line shows the multiple of Slope D. Cartoon (top) shows representative raypaths of seismic waves that produced the arrivals indicated in the trace records (Figure Credit: Kate Volk). The acoustic signal was then segmented into separate traces using the GPS-coordinated time of each shot. Ten seconds of each trace were then plotted, by shot number (Figure 1). In this data panel we see the direct wave from the R/V Langseth shots to the instrument (Figure 1; Slope B), seismic reflections and refractions from the Earth below (Figure 1; Slopes A, C, and D), and a later multiple of these seismic refractions (Figure 1; dashed magenta line), after they bounced between the seafloor and sea surface.  
The direct wave travels directly from the seismic source to the OBS, helping us identify the location of the OBS on the seismic line. Using the time it took for the direct arrival to reach the OBS at this location and the acoustic velocity of water (1500 m/s), we can estimate the depth to the OBS. In the case of OBS 209, the R/V Langseth traveled over the device around shot 2200 and it was deployed in approximately 3000 meters of water (Figure 1).
The general slope of the seismic refractions in the space-time diagram gives an indication of the speed at which these seismic waves travelled at large depth.  The data in Figure 1 have been plotted such that waves traveling with a seismic velocity of 7000 m/s, such as those turning near the crust-mantle boundary, will appear as flat events. Slower seismic waves will dip towards larger time away from the OBS, while faster waves will slope towards smaller travel times.  
The OBSs show seismic arrivals that are recorded over a very wide range of source-receiver distances. The seismic waves recorded close to the instrument (< 10 km), are the direct wave from the airguns through the water column to the instrument (Figure 1; Time 2). As you move farther from the instrument (longer offset from source to OBS), the seismic waves move through deeper materials with faster acoustic velocities and those waves reach the instrument before the direct waves (Figure 1; Times 1 and 3). At longer offsets, the primary response comes from seismic waves that travel along deep materials with very fast seismic velocities (Figure 1; Time 4). When combining all the traces together, the slope between similar acoustic responses in traces can be used to infer the seismic velocity of the seismic wave, which can be used to infer the properties of the Earth.
For example, between 60 – 80 km and 100 – 120 km, we identify acoustic responses that are relatively flat (Figure 1; Slope D), indicating that the sound wave is moving through material with an acoustic velocity of 7000 m/s. This is important because it confirms that we are imaging down to the crust-mantle boundary, which will allow us to get a well-constrained seismic velocity profile throughout the crust beneath the margin of the US East Coast.
Until next time,Dylan Meyer aboard the R/V Endeavor
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