Satellite-derived ocean heat content variability: implications for weather and climate studies

Lynn Shay (University of Miami/RSMAS, United States)

CoAuthors

Jodi Brewster (University Of Miami/RSMAS, United States); Eileen Maturi (NOAA/NESDIS, United States); David Donahue (NOAA/NESDIS, United States); Eric Leuliette (NOAA/NESDIS, United States); Benjamin Jaimes (University of Miami/RSMAS, United States); Jun Zhang (NOAA/HRD, United States)

Event: 2017 Ocean Surface Topography Science Team Meeting

Session: Science Keynotes Session

Presentation type: Type Keynote/invited

A 20-year time series of satellite-derived oceanic heat content (OHC) estimates relative to 26C has been generated from quality controlled sea surface height anomaly (SSHA) fields from various missions (e.g., TOPEX, Jason 1-3, Envisat, SARAL, Cryosat-2, Sentinel-3A) cast into a reduced-gravity ocean model and a daily ocean climatology of mean isotherm depths and reduced gravities. Over this time/space series, two or more satellites have been operational at any given time to resolve mesoscale ocean variability. Sea surface temperatures (SST) from the NESDIS Geopolar Blended product and Remote Sensing System’s Optimally Interpolated product represent the surface boundary condition to produce isotherm depths of the 20 and 26C (D20, D26), mixed layer depth, and OHC for use in weather (tropical cyclone) and climate (ENSO) studies. For the operational product suite, SSHA data from 10 days before the date in question are used. By contrast, the reprocessed data uses SSHA data from 5 days before and 5 days after the date of interest for more detailed research product including those with longer repeat tracks so mesoscale oceanic features were not unnaturally stretched out. The resulting data products date back to 1998 for three basins. As part of the product generation and updating the climatologies, satellite-derived estimates have been compared to over a million in-situ thermal measurements from multiple platforms (e.g., Argo and APEX Floats, ship transects, moorings) to assess biases and uncertainties in spaced-based estimates and to adjust climatologies. Central to this assessment is the need for sustained moorings in the tropics that provide the evolving isotherm depths and OHC variations for weather and climate studies.

Implications of OHC variations on hurricane passage will be discussed using historical cases such as Earl over the western Atlantic Ocean basin in 2010 (during NASA GRIP), Patricia over the eastern Pacific Ocean basin (2015) and more recently Harvey (2017) over the Gulf of Mexico. Prior to Patricia, the strong El Nino conditions increased the SSHA by more than 12 cm as satellite-derived OHC values were nearly twice those under non El Nino conditions consistent with Argo float data. More recently, Harvey (2017) rapidly intensified over a warm eddy that was separated from the Loop Current in the eastern Gulf of Mexico. Space-based OHC estimates were consistent with those determined from airborne expendable bathythermographs deployed from NOAA research aircraft and APEX-EM profiling floats.
 

Keynote/invited presentation show times:

RoomStart DateEnd Date
Symphony Ballroom IV Mon, Oct 23 2017,14:50 Mon, Oct 23 2017,15:15
Lynn Shay
University of Miami/RSMAS
United States
nshay@rsmas.miami.edu