Gina Henderson: Samples Aplenty, August 23, 2012

NOAA Teacher at Sea
Prof. Gina Henderson
Aboard NOAA Ship Ronald H. Brown
August 19 – 27, 2012

Mission: Western Atlantic Climate Study (WACS)
Geographical area of cruise: Northwest Atlantic Ocean
Date: Thursday, August 23, 2012
Weather conditions: calm conditions overnight leading to widespread radiation fog immediately following sunset. Ship had to make use of foghorn for a couple of hours overnight. Today, cloudy with possible rain showers. Winds SW from 10-15 kts, with gust up to 20 in rain showers. Seas from the SW at 3-5 ft.

Science and Technology Log

WACS Field Campaign Update:

This morning we reached the 3-day mark for sampling at station 1, which was in the high chlorophyll concentration off of Georges Bank. During these 3 days, we have been continuously sampling aerosols using both the Sea Sweep and the Bubble Generator (see last post for descriptions of each of these methods).

Some issues that have cropped up throughout this time are linked to our extremely calm and settled weather. Although the calm winds have made for minimal seas, ideal conditions for the Sea Sweep, those scientists sampling ambient air have been picking up ship exhaust in their measurements, despite the bridge keeping our bow head-to-wind. However, during our transit this complication should not be an issue and ambient sampling can take place continuously.

Conductivity, Temperature and Depth:

CTD rosette

Conductivity, temperature, and depth (CTD) rosette after deployment. Niskin bottles can be tripped at different depths for seawater sampling at various levels.

We also took a Conductivity, Temperature and Depth (CTD) profile using the CTD rosette on the 21st, collecting water near the bottom at 55m and other levels on the way to the surface.  These water samples were utilized by numerous scientists on board for experiments such as, testing for surface tension, biological testing and chlorophyll measurement.

The science plan for today involved one final CTD cast while at station 1, with all Niskin bottles being tripped at 5m. This large volume is necessary for a Bubble Generator experiment that will be run with this CTD water during the transit to station 2.

After the CTD cast was completed, the Sea Sweep was recovered and other necessary preparations for the transition to our new station. While underway for approximately 24 hours, intake hoses were switched to enable sampling of ambient aerosols along the way.

How to sample aerosols?

One of the tasks that I have been helping out with is the changing of aerosol impactors that are used to collect aerosol samples. These impactors consist of metal cylinders with various “stages” or levels (upper left photo below). Each level has different sizes of small holes, over which a filter is laid. During sampling, these impactors are hooked up to intake hoses where airflow is pumped through them and as the air is forced through the different “stages” or levels, the aerosols are “impacted” on the filters.

Filters being changed inside aerosol impactors (upper left). Picture of me unhooking impactors from inlet hoses for filter switching (upper right). Kristen just finished changing filters in a clean box (bottom).

This all seems simple enough…. However can be a little more cumbersome as the impactors are heavy, climbing up ship ladders with heavy things can be tricky depending on current sea state, and 2 of our impactor changes happen routinely in the dark, making things a little interesting at times!

Seawater sampling for chlorophyll:

Megan filtering raw seawater for chlorophyll extraction and measurement.

Another type of sampling I have helped out with involves the filtration of raw seawater to extract chlorophyll. This is done in the seawater van where we have a continuous flow of in situ water that is taken in at the bow at a depth of approximately 5m. This is done with two different types of filters, a couple of times a day. The photo below shows Megan running a sample through one type of filter, which will later be prepared with an acetone solution and after a resting period, be measured for chlorophyll concentration using a fluorometer.

Lots of sightings during transit:

As we headed south during our transit to station 2, we had an afternoon full of sightings! An announcement from the bridge informing us that we were now in “shark infested waters” sent an air of excitement around the ship as we all raced to the bridge for better viewing. Some loggerhead turtles were also spotted. Our final sighting of the day was a huge pod of porpoises riding the wake from our bow.

Pod of porpoises riding the bow wave during our transit south to station 2.

Everyone races to the bridge after an announcement about “shark infested waters!”

Gina Henderson: 30 Days of Science in 9 Days… August 21, 2012

NOAA Teacher at Sea
Prof. Gina Henderson
Aboard NOAA Ship Ronald H. Brown
August 19 – 27, 2012

Mission: Western Atlantic Climate Study (WACS)
Geographical area of cruise: Northwest Atlantic Ocean
Date: Tuesday, August 21, 2012

Weather Data: Winds light and variable less than 10 kts. Combined seas from the SW 3-5 ft, lowering to 2-4 ft overnight. Into Wednesday 22nd, winds continue to be light and variable, becoming NE overnight less than 10 kts. 

Science and Technology Log

WACS Field Campaign Update

Greetings from Georges Bank off the coast of New England! This is our first of 2 sampling stations during the Western Atlantic Climate Survey (WACS) field campaign, over the next 9 days. Our current location was chosen due to its high chlorophyll values, indicating productive waters. Shortly after our arrival here approximately 0700 on the 20th, the Sea Sweep instrument was deployed, and aerosol collection began (see picture below). However, for many of the scientists onboard, data collection began almost immediately after disembarking Boston, on the 19th.

The Sea Sweep

Photographs showing the Sea Sweep (top left), deployment of the Sea Sweep (bottom left), and Sea Sweep underway with bubble generation and aerosol collection taking place (right).

Upon my arrival to the ship in Boston, I quickly learned that this field campaign is a little unusual due to the sheer volume of equipment being utilized, and the short nature of the cruise itself. As we disembarked the Coast Guard pier in Boston, a running joke being echoed around the ship was, “30 days of science in 9 days…. ready, set, and GO!”

Science vans on deck

Looking from the bow towards the bridge, not visible in this photograph due to the mobile lab vans that have been installed on the deck for this cruise.

Over 9 mobile research vans were loaded onto the Ron Brown in preparation for this campaign making for a “low-riding ship”, joked our captain at our welcome meeting on the 19th. Each van contains multiple instruments, computers, ancillary equipment and supplies, and they also serve as research labs for the science teams to work in.

During the past two days, I have been making the rounds to each of these lab vans to hear more about the science taking place in each. With the help of the Chief Bosun, Bruce Cowden, I have also been able to shoot some video of these visits. With the assistance of Bruce, I am learning how to stitch these clips together into some fun short video pieces, so stay tuned for more to come!

A Little about the Sea Sweep

The Sea Sweep instrument consists of floating pontoons that hold a metal hood. The hood is mounted on a frame that protrudes below the water line when deployed, with two “frizzles” or “bubble maker” nozzles that air is pumped through to produce freshly emitted sea spray particles. These particles are then collected through two intake pipes attached to the hood, and are piped into the AeroPhys van. From there, samples are collected and also the intake is drawn into other vans for additional measurements.

Comparison of Sea Sweep Data with “the Bubbler”

Aerosol generator

Scientist Bill Keene from University of Virginia talking to me about “the bubbler”.

Sea spray particles are also being produced and collected via another method onboard, allowing for comparison with the Sea Sweep data. The picture below shows bubbles being generated in seawater that is fed into a large glass tower. This is an aerosol generator (a.k.a. “the bubbler”) brought on board by the University of Virginia. Through sampling with both the Sea Sweep and the bubbler, a greater size range and variety of aerosols can be sampled throughout the cruise.

Personal Log

After waiting a day or so for things to settle down and instruments to get up and running, I was eager to dive right in and be put to work on board. After an announcement made by the chief scientist, Trish Quinn, during our first evening meeting I was quickly solicited by a few different people to help with a range of tasks. So far these have included helping change impactor filters necessary for aerosol sampling 3 times a day (1 of these switches has been happening at 0500, making for some early mornings but pretty sunrises), getting raw sea water samples every 2 hours from different sampling points on board, preparing sea water samples for different analysis such as surface tension, and measuring samples for chlorophyll, dissolved organic carbon and particulate organic carbon.

Amongst all the sampling taking place however, it has been nice to take a break every once in a while to enjoy the extremely calm and settled weather we are having. A very memorable moment yesterday occurred when an announcement over the ship’s intercom alerted all aboard to a pod of whales off the port bow. It was nice to see the excitement spread, with both crew and science team members racing to the bow in unison with cameras in tow!

fun pics aboard

Early morning sky after an impactor filter change (left). All hands rush to the bow after whale sighting is announced (right).

Gina Henderson: Introduction, August 15, 2012

NOAA Teacher at Sea
Prof. Gina Henderson
Soon to be aboard NOAA Ship Ronald H. Brown
August 19 – 27, 2012

Mission: Western Atlantic Climate Study (WACS)
Geographical area of cruise: Northwest Atlantic Ocean
Date: Wednesday, August 15, 2012

Introduction: Purpose of the Cruise

Gina Henderson, NOAA Teacher at Sea 2012

Hello from Annapolis, MD! My name is Gina Henderson and I am very excited about my imminent departure to Boston this coming Saturday as part of the NOAA Teacher at Sea program. In Boston  I will rendezvous with the Ronald H. Brown NOAA ship and join the science team to conduct experiments aimed at collecting in situ measurements of ocean-derived aerosols. The purpose of this experiment is to characterize the cloud-nucleating abilities of these aerosols. We also aim to sample atmospheric particles, gases, and surface sea water to assess the impact of ocean emissions on atmospheric composition.

A Little about Me

I am an Assistant Professor in the Oceanography Department at the United States Naval Academy. Here, I teach courses in climate science, physical geography and weather. My research to date has focused on land-atmosphere interactions using computer climate models, understanding the role of snow cover in the hydrologic and global climate system, and the influence of such elements on atmospheric circulation and climate change.

Growing up on the east coast of Ireland, my interest in climatology was awakened from an early age having been exposed to the elements through outdoor pursuits including sailing, travel, and hiking. I have found that sharing my enthusiasm and passion for these sciences, focusing on the application of how they relate to our day-to-day lives and the environment in which we live, is an excellent platform to foster student interest and participation.

Having worked as a sail racing coach in Ireland, and captaining boats in the Caribbean during my undergraduate summers, I was eager to get back to the sport after relocating to Annapolis. Since my arrival at the Academy, I have also been volunteering as a coach for the Varsity Offshore Sailing Team which has been a great experience so far and helped me learn more about my students outside of the classroom.

Midshipman measuring sea surface temperature with a bucket thermometer.

Going into my second year teaching at the Naval Academy, I am excited to get this opportunity to participate in this NOAA field work campaign. Having spent the last few weeks as the science officer for a Yard Patrol cruise, where we took a group of 17 midshipmen and introduced them to various oceanographic and meteorologic instrumentation on board the Oceanography Department’s dedicated Yard Patrol training vessel, I hope to acquire new fieldwork skills and experiences while aboard the Ron Brown and to use such experiences back in Annapolis.

Prof. Henderson giving some history about sea surface temperature measurement throughout the past 200 years.

The timing of this research cruise coincides with the start of the semester back at the Naval Academy. This semester, I am teaching two sections of the upper level major elective course, Global Climate Change. While it will be challenging to be absent from the classroom for the first two weeks of class, I plan on engaging with my students virtually and as close to real-time as communications allow  through this blog.

With this in mind, after a colleague introduces the course policy statement and syllabus next Monday 20 August, I am asking all students to take 10-20 minutes to google the underlined terms in the “Introduction: purpose of this cruise” section above, beginning with the NOAA Teacher at Sea Program. Students should write a brief summary (2-3 sentences) of what they find, focusing on the program goal(s). Students should then research the other underlined terms and write a brief summary (1-2 sentences) of what they should know about these terms from their previous course, SO244: Basic Atmospheric Processes. This assignment will be submitted via email to Prof. Henderson before the beginning of class on Tuesday August 21.

Midshipmen visit the Fleet Weather Center in Norfolk with Prof. Henderson during summer Yard Patrol cruise 2012.