What is a underwater glider?

An underwater glider is an autonomous underwater vehicle (AUV) that uses small changes in buoyancy together with wings to propel itself by converting vertical motion into horizontal motion. Thanks to a very small consumption of energy, underwater gliders have longer ranges when compared to other AUVs, being able to measure several ocean parameters during a period of weeks or months along thousands of kilometers. Gliders use different sensors to measure ocean temperature and salinity profiles. Depending on the instruments installed in the devise, they can also measure ocean currents, chlorophyll fluorescence, optical backscatter, and bottom depth among other parameters. Gliders are commanded remotely via satellite and data transmissions are performed in real-time.

Sustained Ocean Observations with Gliders

AOML/PHOD's scientists are leading a multi-institutional effort that brings together the research and operational components within NOAA and the university community to implement and carry out sustained and targeted ocean observations from gliders in the Caribbean Sea and southwestern tropical North Atlantic Ocean. The upper ocean thermal structure in this region has been linked to rapid intensification of tropical cyclones, and to the seasonal Atlantic hurricane activity. However, there are only few (<300) upper ocean thermal observations carried out per year in this region, and sustained ocean observations are currently not in place or planned.

The work carried-out by this project will provide 3500 to 4500 profile observations per year during the two-year study, starting in 2014. In addition, and for the first time, current velocity profiles will be obtained from the gliders to assist hurricane forecast models to reproduce the key ocean dynamic processes associated with tropical storm-induced surface ocean cooling. The main objectives of this project are to implement upper ocean observations from gliders to evaluate their impact to improve: (1) hurricane intensity forecasts and (2) hurricane seasonal forecasts; using a combination of these new sustained observations, targeted observations, data analysis, and current NOAA operational forecast models. The combined expertise of the investigators involved in this project in carrying out observations, data processing, data distribution, data analysis, and numerical modeling, will be reflected in the implementation and positive outcomes of the proposed work.

This project is a partnership between NOAA, University of Puerto Rico, and Autoridad Nacional de Asuntos Maritimos, Dominican Republic.

The two regions (bounded with red lines) where Seagliders will be deployed. Tracks of Cat. 1-5 cyclones (in grey) in a region of the Atlantic Warm Pool during 1993-2011, with circles indicating the location of their intensifications. The background color is the Tropical Cyclone Heat Potential (proportional to the upper ocean heat content).

The main goal of this project is to deploy a pilot network of Seagliders in the Caribbean Sea and Tropical North Atlantic Ocean and to assess the impact of these observations on the tropical cyclone intensity forecast, and of seasonal forecasts. Sustained ocean observations will be carried-out and assimilated in operational models used for hurricane intensity forecasts and seasonal forecasts, to assess and improve numerical forecast models by comparing their performances with and without the glider observations. Data obtained from this work will be jointly analyzed with other available in situ observations, such as Argo floats, surface drifters, thermistor chains, XBTs, etc; and satellite observations, such as sea surface temperature, sea surface height, ocean color, etc. Of critical importance will be the joint analysis of the data collected through this project with those obtained through targeted observations, such as P3 flights that deploy a suite of marine and atmospheric sensors. The key synergy that will exist between this project and the NOAA/HRD targeted observations will greatly enhance the value of both efforts.

For additional information about this project please contact Dr. Gustavo Goni.