The kinetic energy of mesoscale variability scales of tens to hundreds of KM and tens to hundreds of days is more than an order of magnitude greater than the mean kinetic energy over most of the…

This federal contract award, with ID NNX16AH59G, was granted by the National Aeronautics and Space Administration (NASA) Shared Services Center to the University of Washington (UW) to support research on intrathermocline eddies. The $252,713 grant aims to analyze the global distribution and evolution of these eddies, and evaluate their impact on air-sea interaction and near-surface chlorophyll. The research will leverage satellite data, Argo float profiles, and eddy-resolving ocean models. UW, a leading public research university, has a track record of securing prime federal contracts and grants across various disciplines. This award does not have a set-aside designation. UW often serves as the prime contractor on such federal research projects, drawing on its extensive expertise in fields like oceanography, climate science, and data analysis.

The kinetic energy of mesoscale variability scales of tens to hundreds of KM and tens to hundreds of days is more than an order of magnitude greater than the mean kinetic energy over most of the ocean. On average, 25 of the oceans surface is within the interiors of mesoscale eddies. The vertical structure of these eddies is generally characterized by isopycnals that are domed upwards in cyclonic eddies and displaced downwards in anticyclonic eddies, characteristic of the first baroclinic mode. Some anticyclones contain an intrathermocline lens of water within their cores, resulting in shoaled isopycnals above the lens and depressed isopycnals below, characteristic of a mode 2 vertical structure. Similarly, some cyclones have downward displaced isopycnals in the upper ocean and upward displacement of isopycnals at depth, resulting in a thinning of the intrathermocline lens. Eddies with intrathermocline lenses intrathermocline eddies are known to influence air sea interaction, the distribution of water masses in the ocean, and biogeochemical cycling, in fundamentally different way when compared to standard mode 1 eddies. Intrathermocline eddies can be formed by local process, such as the entrainment of an intrathermocline lens during formation, or by remote processes, like eddy induced vertical velocities. Eddy induced ekman pumping, which results in upwelling in anticyclones and downwelling in cyclones, was recently shown to enable the formation of intrathermocline eddies that originated with common mode 1 vertical structure. The main focus of this project is the analysis of the the global distribution and abundance of intrathermocline eddies and their evolution in space and time. Using this information, the effect of intrathermocline eddies on air sea interaction and near surface chlorophyll will be evaluated. To identify intrathermocline eddies, satellite derived measurements of sea surface height, sea surface temperature and near surface chlorophyll will be combined with profiles of temperature and salinity made by argo floats in an eddy centric frame of reference. These observations will be compared to a series of eddy resolving ocean models that are run in two configuration with and without eddy induced ekman pumping. Comparisons of these simulations will allow the role of eddy induced ekman pumping the formation of intrathermocline eddies to be assessed. The specific objectives of the proposed research are to 1 develop an automated detection method to identify intrathermocline eddies from argo float profiles collocated to the interiors of eddies identified and tracked in satellite observations of sea level anomalies. Construct and make publicly available a global atlas of the geographic distribution of intrathermocline eddies. 2 determine the characteristic surface expression of intrathermocline eddies from satellite observations and an eddy resolving ocean circulation model their impact on sea surface temperature, wind speed and chlorophyll. 3 develop observational criteria that allow for the identification of eddies with intrathermocline lenses from satellite observations alone. 4 identify long lived eddies that originate with vertical structure characteristic of the first baroclinic mode that undergo transition into intrathermocline eddies. Examine the relative importance of eddy induced ekman pumping in the generation of intrathermocline eddies. 5 develop a parameterization of the influence of eddies with intrathermocline lens on air sea and physical biological interaction to be included in coarse resolution ocean models.