Model coupling is the connection of several separate numerical models so that output from each model becomes input for the other models. Models exchange information at specified intervals, so that, for example, predictions about the weather affect and are affected by ocean surface temperature, sea surface roughness, heat flux, etc. This allows a more complete and realistic description of ocean conditions than that available from uncoupled, stand-alone models.
Some of the sub-models that can be coupled include models of ocean conditions, weather, sea ice, waves, plankton, and biogeochemistry.
Models of ocean conditions are numerical predictions of what the ocean is like at a given time, based on inputs and known physics. The inputs are observations from satellites, moorings, tidal gauges, high-frequency radar stations, and buoys, among other sources. This information is collected daily and fed into the model. The model takes this new data, along with model estimates from the previous calculation, and applies equations of fluid physics to calculate how the conditions at a site will change over a given time period. To describe the conditions of a body of water, the model fills that three-dimensional body with millions of points arrayed in a 3-D grid. It calculates the conditions at each point, based on the point’s previous conditions, observations near that point, and the amount of time from the last calculation. All these point calculations are the model output, and are often visualized in a 3-D map of the water body.
A research cruise in the Gulf of Mexico to support the project Three-Dimensional Gulf Circulation and Biogeochemical Processes Unveiled by State-of-the-Art Profiling Float Technology and Data Assimilative Ocean Models will take place May 1-10, 2017. University of Miami’s Rosenstiel School of Marine and Atmospheric Science (RSMAS) is leading the expedition, aboard the R/V F. G. Walton Smith. UMiami Principal Investigator (PI) Nick Shay, NC State University PI Roy He, Dalhousie University PI Katja Fennel, and Peter Furze of Teledyne Webb Research are collaborating on this project to build a rapid response capability that can be deployed in the event of an oil spill.
Jodi Brewster of RSMAS has posted a blog of cruise preparation, which will continue as a log book as the cruise gets underway. Follow along to learn about how scientists prepare for the intense 24-hour-a-day schedule of research activities onboard the ship.
NCSU’s College of Science set up tables of information and activities throughout Hunt Library on April 21. The Ocean Observing and Modeling Group was represented by Nabi Allahdadi, Shun Mao, Laura McGee, and Jennifer Warrillow. Hundreds of people toured the Library to learn about the science conducted at the university. Nabi, Shun, Laura, and Jennifer had the opportunity to explain ocean modeling in general and the CNAPS model specifically to people of all ages. Surfers, fishers, meteorologists, and others enjoyed learning about the features of ocean models.
Onboard the R/V Neil Armstrong, OOMG’s Joe Zambon and NCSU Marine Science undergrad Lauren Ball have been assisting with the NSF-funded Processes investigating Exchange Around Cape Hatteras (NSF-PEACH) project. A crucial component of the ongoing cruise is to utilize real-time in situ, satellite, and model data to assist Chief Scientist Magdalena Andres position the ship for crucial measurements while at sea. Joe designed a data pipeline to provide this imagery in a timely manner, with limited internet connection at sea. 24/7 operations means that the work never stops as Joe and Lauren has been working the overnight shift to sample and prepare important data for cruise planning meetings in the early morning. In addition, a concerning forecast for the next few days has extended this analysis to include weather and wave models. Over the next few hours, the crew will be deciding where to head next as a gale is expected to blow through the study region Monday night into Tuesday.
Valerie Winzenried, a retired gifted-education teacher and an education consultant for Eastman, boarded the R/V Neil Armstrong last week. During her time at sea, she has been participating in hands-on research and data analysis along with onboard scientists. In addition, she has been interviewing researchers in order to construct lesson plans in geosciences to educate the next generation of oceanographers. She sat down with OOMG’s Joe Zambon on Thursday night to discuss ocean models, remote observations, cruise planning, and the various methods that have been used to sample the ocean’s physical parameters. It was a great experience for both as their discussion covered a wide-range of possible topics for high school education and opened the door for future communication.
Last Saturday (22-April) marked the halfway point of the NSF-PEACH R/V Neil Armstrong cruise with OOMG’s Joe Zambon and NCSU Marine Science undergrad Lauren Ball. While underway at sea, both researchers have participated in research exploring the waters along the continental shelf from Cape Cod, MA to Cape Hatteras, NC. So far, the team has taken advantage of the prevailing calm seas and have deployed meteorological buoys, Acoustic Doppler Current Profilers (ADCPs), Pressure-Inverted Echo Sounders (PIES), eXpendible BathyThermographs (XBTs), Conductivity-Temperature-Depth (CTD) profilers, hydrophones, Argo floats, autonomous gliders, and have collected and filtered hundreds of liters of sea water from the surface to the sea floor for analysis.
Throughout the NSF-PEACH research cruise, OOMG’s Joe Zambon has been providing data to PIs and Chief Scientist Magdalena Andres for cruise planning. Several study sites were pre-determined months in advance, but this data has been instrumental in determining supplementary surveys of the Gulf Stream. In addition, short-duration features such as eddies have been sampled by determining their location while at sea. One significant challenge of this has been to balance data from satellites and models. While satellite data provides a high-resolution (~1 km) daily picture, there are gaps where they cannot see through clouds – a big problem in coastal environments. To fill the gaps, OOMG’s numerical models are employed with lower resolution (~7 km). The two products, working in tandem, allow research scientists to deploy instrumentation and direct transects with more confidence than any one product alone. Below is a short animation of the PEACH domain with Satellite and CNAPS model-resolved Sea Surface Temperature (SST).
One cruise objective for the April 2017 NSF-PEACH research cruise is to conduct a bathymetric survey of the shelf break approximately 20 nautical miles east-southeast of Cape Hatteras, NC. UNC’s Sara Haines explains that existing bathymetry in this area is of questionable quality possibly owing to the stitching of hand-drawn bathymetric maps in along the line of latitude at 35ºN. Over 2 evenings, R/V Neil Armstrong will drive several lines over the area while using shipboard multibeam sonar in order to survey the seafloor. This data will be extremely important for OOMG’s numerical models resolving the area in future studies of the Gulf Stream and shelf water exchange.
The cruise progresses, and the scientists have used calm weather days to work on instruments on moored buoys. Some deployed instruments are already returning data, showing the velocity of the Gulf Stream.
Read details of the instruments being used at the UNC Coastal Studies Institute’s site here.
Read the research project overview here.
By Lauren Ball, a senior in the Dept. of Marine, Earth, and Atmospheric Sciences at NC State University. Lauren is part of the science crew on the R/V Neil Armstrong, collecting data off of Cape Hatteras, NC.
One thing I was not expecting about this research cruise was the lack of a personal schedule. I am on watch from midnight to noon, meaning anything scheduled within that time period I am partly responsible for executing, but depending on the day there may not be anything that needs my attention. Other times, there are experiments scheduled for outside my shift time and I adjust accordingly to be able to work on those. While on a research cruise, you have a limited amount of time to get your list of tasks done, which means everyone works hard to accomplish the cruise goals.
As a student who has worked full or part time throughout my degree, lack of a daily schedule is a foreign concept to me. So I sleep when I can, and try to jump on any part of the itinerary that is possible for me to participate in. Dr. Zambon was right when he told me that I’d learn more on this cruise than I would if I had sat in a classroom the rest of the semester!
By Lauren Ball, a senior in the Dept. of Marine, Earth, and Atmospheric Sciences at NC State University.
As a graduating senior in Biological Oceanography, I am very fortunate to have the opportunity to participate in the PEACH Cruise on the R/V Neil Armstrong. I ended up only having one class this semester, Observational Methods and Data Analysis in Marine Physics, and Professor Ruoying He announced the cruise opportunity during one of the first meetings. Although my concentration is biological, I jumped at the chance to get my first research cruise under my belt, and, since I am in the middle of job searching, to be able to add this to my resume. My primary assignments are assisting Dr. Joe Zambon on the marine physics aspects of the cruise, and helping Marco Valera collect planktonic specimens for later analysis in Dr. Astrid Schnetzer’s lab.
As cliché as it sounds, some of my favorite parts of the cruise have been seeing the instruments that were described in class actually used or deployed. So far I have been participating in expendable bathythermograph (XBT) and conductivity, temperature, and depth recorder (CTD) deployments and preparing plankton samples at each site, and watching the Acoustic Doppler Current Profile (ADCP) and Pressure Inverted Echo Sounder (PIES) launches. We will also be utilizing a glider, met moorings, and Argo floats later in the cruise. No matter how much you study a subject, you can’t fully learn until you gain the experience. This is why I chose my major: to be by the sea, have adventures, and become a part of a research team on a subject I find very interesting. I thought my education was coming to an end, but now I can see it’s just starting.
MEAS technician Marco Valera from Dr. Astrid Schnetzer’s Plankton Ecology Lab has been collecting plankton samples by filtering hundreds of liters of water from various depths of CTD casts. Marco’s water samples are time-sensitive and need to be filtered immediately after arriving on the ship. OOMG’s Joe Zambon and NCSU Marine Science undergrad Lauren Ball have been happy to help out. After attending a few training sessions on-shore, they have spent some night shifts in the wet-lab filtering out hundreds of liters of sea water. These filtered samples will then be analyzed for DNA and chlorophyll to determine plankton concentrations at different depths along the east coast. The typical toolbox of the physical oceanographer does not include graduated cylinders, glass-fiber filters, test tubes, hydrochloric acid and syringes. However with any research cruise, everyone’s science is a priority and Joe, Lauren, and Marco have all had a hand in each other’s research.
The research cruise to study processes affecting exchange across the continental shelf at Cape Hatteras, NC got underway on 13 April 2017. The R/V Neil Armstrong set out from its home port of Woods Hole, MA carrying scientists including OOMG’s Joe Zambon and NCSU Marine Science undergrad Lauren Ball. Researchers have been deploying eXpendable BathyThermographs (XBTs), which transmit temperature as they sink through the depths. Plans also include deployment of an underwater glider, pressure inverted echo sounders (PIES), and acoustic Doppler current profilers (ADCPs).
Stand by for more posts from this cruise!
Track the Armstrong’s position here.
Thanks to the National Science Foundation for funding this research!
Ocean Observing and Modeling Group postdoctoral research associate Jeff Willison delivered a lecture to the Southeast Climate Communicators Network (SCCN) at a workshop hosted at the North Carolina Museum of Natural Sciences.
Willison’s lecture covered the nuances of climate modeling and explained how climate scientists try to determine which physical processes are important for understanding how the Earth’s climate will change under the influence of increasing concentrations of greenhouse gasses.
SCCN is comprised of professionals such as teachers, zookeepers and museum docents. Workshops such as this one allow SCCN members to educate themselves so they can effectively teach the general public about how we know what we know about climate. SCCN members hail from Virginia and the Carolinas.
The North Carolina Museum of Natural Sciences is the most popular museum in the Southeast with over one million visitors per year.