OverviewSWOT will revolutionize oceanography by detecting ocean features with 10 times better resolution than present technologies. The higher resolution of SWOT is required to distinguish structures that occur on scales of 100 kilometers (62.1 miles) or shorter, where most of the ocean's energy is mixed and transported. Such small-scale ocean features contribute to the ocean-atmosphere exchange of heat and carbon, major components in global climate change. Moreover, SWOT's detailed information on ocean circulation will improve understanding of the ocean environment including motion of life-sustaining nutrients and harmful pollutants.
Characterize the ocean mesoscale and sub-mesoscale circulation (15 – 200 km or about 9 – 124 mi, overall) at spatial resolutions of 15 km (~9 mi) and greater.
Fine-Scale Transport of Heat & CarbonCurrently, there is a poor understanding of fine-scale circulation where most of the ocean's motion-related energy is stored and lost. For example, SWOT will unveil unprecedented details about sub-mesoscale eddies. These ubiquitous, relatively short-lived, swirling currents are often "spun off" of major currents such as the Gulf Stream, whose larger (i.e., mesoscale) eddies have been revealed in satellite sea surface height and temperature maps for decades.
Circulation at sub-mesoscales is thought to be responsible for transporting half of the heat and carbon from the upper ocean to deeper layers. Such downward ocean motion has helped to mitigate the decades-long rise in global air temperatures by absorbing and storing heat and carbon away from the atmosphere. Knowing more about this process is critical for understanding global climate change.
Predicting the Ocean EnvironmentNot only will SWOT's global measurements of small ocean features help to improve climate prediction models, these data will also reveal new details about the transport of many important substances. Some nutrients suspended in seawater are "essential ingredients" for microscopic plants and algae known as phytoplankton, which fuel the entire marine food web. Thus the distribution and transport of nutrients by currents and eddies is tied to the productivity of marine fisheries and the health of our living ocean.
Fine-scale ocean motion is also responsible for transporting pollutants such as crude oil, harmful river discharge, and debris (e.g., from tsunamis). Precisely tracking the location, speed and direction of potentially harmful materials will aid in natural hazard assessment, prediction, and response. In addition to modelling the dispersal of substances entrained in seawater, understanding the motion of water itself will be valuable. SWOT data will be used to improve ocean circulation forecasts, benefiting ship and offshore commercial operations, along with coastal planning activities such as flood prediction and sea level rise.
Featured Science Investigations
Assimilation and Interpretation of High-Wavenumber Variability in the Ocean for SWOT PI: Sarah Gille
The objective of our research in support of SWOT is to develop 4-dimensional variational assimilation (4d-var) methods that include both quasi-geostrophic and tidal motions in order to build the capabilities to map, evaluate, and interpret SWOT observations, with a specific focus on the California Current region, which has been identified as one of the target regions for calibration and validation of SWOT (Wang et al., 2016). Our aim is to distinguish balanced, geostrophic motions from the myriad other processes that influence SSH variability at the ocean surface.
Calibration and Validation of SWOT Oceanographic Products Using the Permanent Facility for Altimetry Calibration in West Crete, Greece PI: Stelios Mertikas
The main goal of this research is to answer these questions and carry out absolute calibration and validation (Cal/Val) of the SWOT products using the Permanent Facility for Altimetry Calibration (PFAC) in west Crete, Greece.