Development and Assessment of the Systematically Merged Pacific Ocean Regional Temperature and Salinity (SPORTS) Climatology for Ocean Heat Content Estimations

Abstract

A Systematically Merged Pacific Ocean Regional Temperature and Salinity (SPORTS) climatology was created to estimate ocean heat content (OHC) for tropical cyclone (TC) intensity forecasting and other applications. A technique similar to the creation of the Systematically Merged Atlantic Regional Temperature and Salinity (SMARTS) climatology was used to blend temperature and salinity fields from the Generalized Digital Environment Model and World Ocean Atlas 2001 at a 0.25° resolution. The weights for the blending of these two climatologies were estimated by minimizing residual covariances across the basin. Drift velocities associated with eddy variability were accounted for using a series of 3-yr sea surface height anomalies (SSHA) to ensure continuity between the periods of different altimeters. In addition to producing daily estimates of the 20° and 26°C isotherm depths, mixed-layer depth, and OHC, the model produces mapping errors from the optimal interpolation of the SSHA due to gaps in altimeter track coverage and sensor uncertainties. Using SPORTS with satellite-derived sea surface temperature (SST) and SSHA fields from radar altimetry, daily OHC was estimated from 2000 to 2011 using a 2.5-layer model approach. Argo profiling floats, expendable probes from ships and aircraft, long-term Tropical Atmosphere Ocean (TAO) moorings, and drifters provide more than 267 000 quality controlled in situ thermal profiles to assess uncertainty in estimates from SPORTS. This carefully constructed climatology creates an accurate estimation of OHC from satellite-based measurements, which can then be used in TC intensity forecasts in the North Pacific Ocean and analysis of ocean thermodynamics. The SPORTS time and space series extends from 1998 to 2016, forming a 19-yr dataset by the end of 2016.

Sea Surface Temperature and Ocean Heat Content during Tropical Cyclones Pam (2015) and Winston (2016) in the Southwest Pacific Region

“…It is difficult to monitor Q H uniformly due to the distribution of ocean profilers and so Q H is usually estimated from satellite altimetry using sea surface height anomalies (e.g., Goni et al 2009;Nagamani et al 2012). Recently, significant improvements to satellitebased estimates of Q H have been achieved by considering climatology from hundreds of thousands of in situ measurements of temperature (e.g., Meyers et al 2014;McCaskill et al 2016).…”

More Than 50 Years of Successful Continuous Temperature Section Measurements by the Global Expendable Bathythermograph Network, Its Integrability, Societal Benefits, and Future

“…A potential application for XBTs is to improve seasonal hurricane outlooks. In the Pacific Ocean, PX09 (Honolulu to Suva)/PX31 (Los Angeles to Suva) and PX40 data are used to derive OHC estimates to improve tropical cyclone intensity forecasts (Shay and Brewster, 2010;McCaskill et al, 2016). The AX08 transect crosses the development region for Atlantic hurricanes, a region where coupled models generally present a cold bias and where cyclone development is affected by eddy, interannual, and decadal upper OHC variability via turbulent heat fluxes.…”