Seagoing experiments
explore a wide range of physical processes having a wide range of length scales from basinwide ocean currents to centimeter-scale turbulent mixing. Experimental sites range from the open ocean over marginal and coastal seas to estuaries and the extremely shallow Florida Bay. Oceanographic instrumentation used include current meter moorings, MPO's Ocean Technology Group having the experience to deploy long-term moorings in any environment in the deep sea as well as in coastal waters. Further major observational tools include CTD / LADCP sondes that profile the abyss to measure temperature, salinity, dissolved oygen and ocean currents. MPO researchers also have experience in quantitatively observing small-scale processes including turbulent mixing. Looking at the web pages of some specific experiments will probably provide a better idea of the seagoing work done at MPO. The analysis of data gained during research cruises often employs satellite-based remote sensing and often has a component of numerical circulation modeling. Ship-based work has been done in conjunction with aircraft observations and land-based surface current measurements.

Expert support provided by the Ocean Technology Group.

Airborne Experiments
Scientists in the division utilize aircraft such as NOAA WP-3Ds and NCAR WC-130J to synoptically sample the upper ocean using current, temperature, and salinity profiles in real time using airborne expendable profilers. Aircraft has the capability to adapatively sample mesoscale processes as a result of changing atmospheric and oceanic conditions. In addition to sampling the upper ocean, wind, temperature and humidity profiles from atmospheric sondes simultaneously sample the atmospheric structure. Thus, aircraft measurements provide spatial context for mooring and ship-based measurement systems during light winds (i.e. Eastern Pacific Investigation of Climate), and provide important upper-ocean data during strong winds such as hurricanes (i.e. NOAA Hurricane Field Program - Lili) in assessing the role of the upper ocean's role on hurricane intensity and structure change. Given uncertainities in the scales and location of atmospheric disturbances (i.e. easterly waves, hurricanes), the aircraft plays an integral role in the acquisition of three-dimensional synoptic snapshots of oceanic and atmospheric variability. As aircraft measurements are acquired in a grid, these data are valuable for ground truthing satellite-based remote sensing, and for process-oriented model studies aimed at improving parameterizations for both oceanic (mixing) and coupled (air-sea fluxes) responses. This research effort at the University of Miami is supported by NSF and NOAA.

Surface Current Radar
Briefly, the concept of Doppler radar is used to measure the two-dimensional surface velocity fields.  The approach is similar to that of a policemen measuring the speed of a car. In our case, an array of receive antennae are placed along the beach along with a transmit antennae. The transmitter sends out radio waves at a particular frequency, that bounces off ocean surface waves of one-half the radar wavelength (known as Bragg wave).  The backscattered signals from the Bragg waves are received by the array of antennae from which a radial current is determined from a Doppler spectrum.  To measure the 2-dimensional surface flows, two stations are required usually over a baseline distance of approximately 25-50 km depending on the transmitter frequency.  The radial current from each is combined based on the geometric configuration of the grid and the intersection angles between the two stations.

Over the past decade, the University of Miami used the Ocean Surface Current Radar (OSCR) under several venues from the Florida Keys to the New York Harbor. Recently, a "Wellen Radar" (WERA) system has been installed with stations on Key Largo, Key Biscayne, and at Dania Beach.  The WERA, designed by University of Hamburg scientists, offers a longer range of 80 to 100 km, sufficient to cover the width of the Strait of Florida across to the Bahamas.  The WERA also offers a variable time and space resolution depending on the approved bandwidth by the Federal Communications Commission.  The current SE Florida WERA system has been operating since late 2004.  Surface current maps are available on the web in near-real time.  ---> Click here for the current Florida Strait currents. <---

Over the next few years, we envision a network of WERA deployments from Key West to as far north as Jacksonville to map large-scale surface velocity field in support of the Coastal Ocean Observing Systems.  In addition to surface currents, the technology allows one to map significant wave height, wind direction and the 2-dimensional direction wave spectra in real time.  Such grided data will also be useful to assimilate into ocean models.  This research is currently supported by ONR through the SEA-COOS grant at the University of North Carolina.

For further information and for specific experiments see Dr. Lynn "Nick" Shay's personal web page.