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Systematically Merged Atlantic Regional Temperature and Salinity (SMARTS) Oceanic Climatology

SMARTS aims to enhance satellite altimetry products for use in forecasting intensity of tropical cyclones by studying oceanic temperature and salinity. Key questions include the influence of sea surface temperature on tropical cyclones, extending ocean heat content analyses, and improving coupled ocean models to resolve features like Loop Current. A two-layer model is developed to estimate hurricane heat potential and ocean heat content, integrating altimetry data and climatology. This project involves analyzing 25+ years of temperature and salinity profiles to improve accuracy in specific oceanographic regions.

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Systematically Merged Atlantic Regional Temperature and Salinity (SMARTS) Oceanic Climatology

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  1. Systematically Merged Atlantic Regional Temperature and Salinity (SMARTS) Oceanic Climatology Patrick Meyers, Jodi Brewster, and Lynn K. “Nick” Shay NOAAs’ AOML (HRD, PhOD), AOC, NHC/TPC, NCEP, NESDIS

  2. Goals/Questions: Goal: To improve satellite-derived altimetry products for use with SHIPS and dynamical coupled forecast models of intensity. Key Science Questions: Is SST alone a sufficient indicator of ocean’s influence on TCs? Can we extend the OHC analyses to be used for studies during the entire year to capture annual cycles of oceanic variability instead of just hurricane season? Can we improve ocean/coupled models capable of resolving oceanic structure such as Loop Current/Warm Rings/Cold Rings? How would such analyses from SMARTS relate to observed oceanic variability from floats, drifters, XBTs etc?

  3. Introduction: Palmen (48), Fisher (56), Perlroth (62,65) – SST of >26oC on hurricane intensity and air-sea heat and moisture transfers. Perlroth (68) related ocean thermal structure between the surface and 200-foot levels: Stratification (i.e. cooling and vertical mixing) and Currents (i.e. warm current advection) are important. Ship cruises after hurricane Hilda (64), Leipper (67) found: • Warm ocean surface layers were advected from the storm track upwelling from about 60 m; • SST cooling of 5oC (cold wake) and mixing within the strongly forced regime; and • Downwelling to 100 m several Rmax from storm center. O’Brien and Reid (67) developed a 2-layer reduced gravity model to investigate these phenomena. Leipper and Volgenau (72) coined the phrase: Hurricane heat potential to represent integrated vertical structure (pre and post hurricanes) finding the 16 kJ cm-2 threshold.

  4. SMARTS Development • US Navy’s Generalized Digital Environmental Model v3.0 (GDEM) and World Ocean Atlas 2001 (WOA)‏ • Monthly climatology at 1/4° resolution • Objectively analyzed temperature and salinity fields from 25+ years of T-S profiles • Increased resolution better resolves Loop Current and Gulf of Mexico oceanographic features • Satellite altimetry data from objectively analyzed to 1/4° using Mariano and Brown (1992) • TMI SST at 1/4° resolution • Objectively determine each climatology’s performance in various oceanographic regions of interest

  5. Altimetry Availability Since 1992 Jason-10 d GFO- 17 d Envisat- 35 d

  6. Empirical Approach From Altimetry (Shay and Brewster, MWR (In Press) 2010). • Two-layer model. • Blend and objectively map SHA from altimeters. • Infer H20 using mapped SHA and SMARTS climatology with a focus on hurricane season. • Estimate H26 relative to H20 • Estimate OHC relative to 26oC using H26, h, and SST. • Evaluate isotherm depths and OHC

  7. 2-Layer Climatology • 2-Layer model approach • Upper-layer density determined by average density above 20° C isotherm. Lower-layer is 20° C isotherm to bottom • Climatological depths of the 20°C and 26° Cisotherms extracted • 15 day running average to create 'daily' climatology

  8. WOA and GDEM resolve the Loop Current and GOM differently, yielding different OHC in the eddy shedding region. This necessitates a regional study to examine each climatology's performance.

  9. ARGO, XBT, AXBT, Mooring:44,000 Profiles From 98-09‏

  10. Daily Climatology

  11. Hurricane Season Climatology

  12. Lagrangian Framework:Argo Floats

  13. Lagrangian Framework:Argo Floats

  14. Eulerian Framework: Pirata Moorings NOAA’s Pirata Mooring array offers long-term observations (1998-2000) at fixed location, giving insight to changing stratification on daily to yearly timescales.

  15. XBT Cross-SectionAnalysis (04-06)

  16. Progress Summary No perfect climatology or modeling approach. OHC is within 10 to 15% of in situ profiles and approach is sensitive to surface boundary conditions (e.g., SSTs). Updating Atlantic Ocean Basin to 0.25 degree resolution and evaluating using in situ data for transitioning to NOAA NESDIS/STAR Program for an evaluated, operational OHC that incorporates ARGO float data to improve algorithm. Testing revised products by comparing to HYCOM model simulations of the Ivan, Isidore/Lili, Katrina/Rita, Gustav/Ike -JHT project with NCEP (Halliwell et al. , MWR, 08; 10). Extending analyses requires a careful examination of satellite derived values, climatology and available in situ data (Patrick Meyers Thesis). Aircraft measurements during IFEX/GRIP/Predict provide synoptic snapshots to examine the spatial variability of the thermal, momnetum and salinity structure in the Loop Current Complex (Nowlin 72; Shay et al. 92; 98).

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