Tuesday, July 28, 2015

Sikuliaq (“Si-COOL-i-ak” - Emphasis on the COOL!)

R/V Sikuliaq breaking ice in July 2015
Let me tell you a little bit about our home for the next few weeks, the R/V Sikuliaq.  Sikuliaq is actually an Inupiaq word meaning “young sea ice,” which is fitting because the Sikuliaq is not technically an icebreaker, but it is ice capable, which means that it can break some thin or “young” ice, but not thick multi-year ice.  It can break 3 feet of ice, and we are definitely testing that today as we are crunching our way to the site where we are going to deploy an array of hydrophones.

The Sikuliaq is operated by the University of Alaska Fairbanks on behalf of the National Science Foundation, and her home port is Seward, Alaska. The Sikuliaq is a brand new ship that just left the shipyard last year, so it has all new state-of-the-art equipment.

At 261 feet long, the Sikuliaq is a pretty big ship as far as research vessels go. The main level of the ship is mostly outdoor deck space, which is great for doing moorings and storing big equipment.  There is also a main lab, a wet lab, a computer lab, an analytical lab (for chemists and biologists) and a Baltic room, which is kind of like a big garage.  They have a great heater set-up in there for when you’re cold on deck and need to warm up quick! 

On the next deck up are the galley (kitchen), mess (dining room) and the lounge, as well as the science berthing. There is berthing space for 24 scientists, and since there are only 12 of us in the science party on this cruise, it is nice and roomy.  The next two floors are berthing spaces for the crew, and then the bridge is up top.  The bridge is where the captain and the mates drive the ship, and it has the best view for watching the ice break.

Also, because the Sikuliaq operates primarily in the icy Arctic, it even has a sauna!  I haven’t tested it out yet, but I will.  Oh yes I will.

Monday, July 27, 2015

Feeling HARPy

 The main event of this research cruise is putting out an array of hydrophone (underwater microphone) receivers and transmitting sound to them from a ship-based source, which we will get to in a few days, but there are a lot of other things going on as well!  Today we are steaming to the location of a HARP, which stands for High-frequency Acoustic Recording Package.  This instrument package has been out here for a year recording the sounds of the Arctic, also called the Arctic soundscape.


Bruce Thayre
Bruce Thayre from John Hildebrand’s lab at the Scripps Institution of Oceanography is here to recover the HARP, grab the data, make sure it is still in good operating condition, put new batteries in it, and redeploy it so that it will continue listening for another year.  Bruce has also been preparing another HARP (see photo), so there will be two HARPs measuring the soundscape for the coming year. 

The HARP is on a small mooring with an anchor at the bottom, then 4 meters of chain, then acoustic releases, then another 4 meters and then the HARP package, which consists of 3 tubes containing the recording electronics, the disks, and the batteries.  The hydrophone itself is attached by a rope and sits above the recording package.

The HARP records at a rate of 200,000 samples per second (200 kHz).  The HARP could record for 10 months continuously at this rate, but scientists are really interested in knowing how the soundscape changes through the cycle of an entire year, so the HARP is programmed to record at a duty cycle of 2/3, which means it samples 2/3 of the time, and lasts for the entire year.

HARPs have been deployed up here in the Arctic since 2006 and have recorded sounds from bowhead whales, beluga whales, ringed seals, bearded seals, ribbon seals, and once even a walrus.  They also record passing ships, wind and rain sounds, and lots and lots of ice breaking. 

Friday, July 24, 2015

Back for More Adventures in Acoustic (and Arctic!) Oceanography

 
This time we are heading waaaaay up North to the Arctic Ocean.  A lot of melting has been going on in the Arctic in recent years and scientists are interested in finding out how fast the ice is melting and how this melting affects the physical oceanography of the region, as well as the rest of the globe. On this expedition, we will be exploring how sound travels underwater and under ice and how acoustic data can help us learn about the changing Arctic.

R/V Sikuliaq
Able Sea Chick (ASC) Kathleen is back in Virginia, working with graduate students and getting ready to teach fall courses at George Mason University, and I (ASC Lora) am heading out to sea from Nome, Alaska on the R/V Sikuliaq. 









For those of you who have never been to Nome (not many people have!), it is a city in Alaska with a population of about 3800 people.  It is located at approximate latitude 64.5 degrees North and longitude165.4 degrees West, and is actually closer to Siberia than it is to the mainland United States.  Because it is so far north, and because it is summertime right now, it is light outside almost all day and all night.  The sun doesn’t even set until after midnight!  July is actually the warmest month in Nome, and the average high temperature is 58 degrees F (break out your swim suits!). Nome is a gold rush town (any fans of the reality series Bering Sea Gold out there?) and is also the end-point of the famous Iditarod dog sled race.  

ASC Lora in Nome!



Today, however, we are saying goodbye to Nome and starting our voyage north, though the Bering Strait (where we can see the US and Russia at the same time!), to the Beaufort Sea. 

Tuesday, April 5, 2011

We caught a mooring.....and a fish!




Some rough weather at the start of the cruise slowed us down a bit, but over the last week our crew has been busy recovering moorings. So far we have picked up 3 of the source moorings and the vertical receiver array mooring.

We've had some exciting moments during these recoveries! On Monday, we discovered that the mooring wire had become entangled with fishing line and our mooring had caught a rather large fish! The pictures (taken by the Able Sea Chicks good friend Mr. Lloyd Green) show the fish coming out of the water and on deck, just before it was cut off the line and fell back into the water. You should be grateful that these pictures can't convey smell! This tuna had been dead a long time and had quite a strong aroma.

There was quite a lot of line wrapped up in the mooring. The third picture shows three of our science crew (Meghan, Matt, and Jim) cleaning up the tangled wire.

Saturday, April 2, 2011

Roomba's seagoing sister


Seagliders are underwater robots made by the company iRobot, the same company that makes the Roomba (you know, that vacuum cleaner that zooms around your house all by itself while you aren’t home)! Well, the company may be the same, but these gliders are not out there cleaning up the Pacific Garbage patch or anything. (That would be cool, though wouldn’t it?!) Instead of cleaning, these gliders are actually out there taking oceanographic measurements. They dive down to about 1000 meters and then back up to the surface, measuring temperature and salinity along the way. Gliders dive for about 8 hours at a time. When they come to the surface they stick their tail up in the air (the tail is an antenna) to communicate with a satellite. They get their latitude and longitude position from GPS and then they send back the temperature and salinity data that they collected during the dive. While they are at the surface the Seaglider pilots can also tell them where to go on the next dive.

The University of Hawaii put out four Seagliders in November and now Lora is here to pick them all up and bring them back to Hawaii. We have just one more to pick up, Seaglider 513. We are tracking it while we are out here at sea, so we know exactly where it is. When we take a break from recovering moorings, we will go out and grab it! You can follow it too, if you’d like. Check out the glider web page at: http://hahana.soest.hawaii.edu/seagliders/history513.html

Friday, March 25, 2011

Overview

We were eager to start recovering our moorings, but the sea is pretty choppy today, so we are going to wait until tomorrow. While we’re waiting, we thought we’d give you a little refresher as to what we are doing out here so that you know what to expect in the coming weeks.

As you may recall, last year we deployed six acoustic sources and a Distributed Vertical Line Array (DVLA) in the Philippine Sea. The map shows the locations of the 6 sources and the DVLA. Right now we are at he location of Source 5. The DVLA consists of approximately 5km of wire with 150 hydrophones (underwater microphones) attached to it. Each of the six source moorings also has a smaller array with four hydrophones on it. All of the moorings are anchored to the bottom and held vertical by a subsurface buoy. The basic idea is to transmit sound back and forth between the different sources to map out the temperature and currents of the ocean in between the moorings. Check out our earlier post “An ocean acoustic tomography experiment” for more info.

The sources have been out here transmitting and collecting data for almost a year now, so we are going to go pick up the moorings one by one and start downloading the data. We are also going to be making some of the same types of measurements we made during our last cruise. For example, we plan to make more maps of the ocean floor between our moorings (see our post Sounding Out the Ocean’s Depths) and we will be doing some more CTDs (see our post Good Morning CTD). In addition we have a couple other exciting side projects that are going on during this cruise as well. We will be recovering a couple acoustic seagliders, which are underwater robots that have been listening to the sources and measuring temperature and salinity in the upper ocean. We'll also be sampling some mud from the bottom of the ocean!

Thursday, March 24, 2011

Back, by popular demand

The able sea chicks are back! Remember all those moorings we deployed last year? Well, the time has come for us to head back out into the Philippine Sea to recover them and download all the data that has been collected over the past year.

We are experiencing a little deja vu as we sail out of the harbor in Kaohsiung, Taiwan on the R/V Roger Revelle, but a lot has happened since we set out on our deployment cruise a year ago.

Able Sea Chick Kathleen finished up her sabbatical at the Scripps Institution of Oceanography in San Diego and is back teaching at George Mason University. Lucky for us, she could take a few weeks off and join us for another oceanographic expedition.

Able Sea Chick Lora finished up her postdoc at Scripps, and has started a research position at the University of Hawaii (Aloha!). She was out on the Revelle here in the Philippine Sea last November to deploy acoustic Seagliders, which have been swimming around the moorings making measurements since that time. We will be recovering two of these gliders during this cruise and will tell you all about them in later posts.

Welcome aboard for another cruise, and feel free to spy on us on the ship's webcam.