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LOOP CURRENT EFFECTS ON HURRICANES: Hurricane Heat Content

LOOP CURRENT EFFECTS ON HURRICANES: Hurricane Heat Content. Lynn K. Shay, S. D. Jacob, P.G. Black, M. Black. Goal: To understand the role of deep warm ocean mixed layers on heat potential estimates relative to hurricane intensity change. Research support by NSF/NOAA. INTRODUCTION:.

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LOOP CURRENT EFFECTS ON HURRICANES: Hurricane Heat Content

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  1. LOOP CURRENT EFFECTS ON HURRICANES: Hurricane Heat Content Lynn K. Shay, S. D. Jacob, P.G. Black, M. Black Goal: To understand the role of deep warm ocean mixed layers on heat potential estimates relative to hurricane intensity change. Research support by NSF/NOAA.

  2. INTRODUCTION: • Basin-scale gyres advect heat/salt northward from equator. • During strong forcing events, SSTs mix with OML. • Depth of 26oC water deeper in the main ocean features of the gyres. • Heat content relative to 26oC better indicator for possible TC Intensity. • Discussion focuses on Loop Current Warm Core Ring characteristics and impact on hurricanes. • Measurements required to evaluate remote sensors and models.

  3. CARTOON:

  4. APPROACH: • Heat Content:

  5. LOOP CURRENT WARM CORE RING COMPLEX: • Summer 1999;2000: NOAA WP-3D Flights over regime. • Aircraft-based measurements using AXCTD/AXCP/AXBT over synoptic scales. • Radar altimetry better indicator of warm water (positive SHA ~ 35 cm). • Heat Content: 130 KJ cm-2 • d20 > 250 m, d26 >120 m. • Deeper ocean profiling needed to resolve current structures.

  6. AUG 1999: SNAPSHOT

  7. MICOM SIMULATION:

  8. EXPERIMENTATION: To understand the coupled processes, experimental programs must acquire measurements in both fluids: • Surface Wind and Wave Field, • APBL Structure , • Upper Ocean Structure, and • SHA/SST Fields. Fields are required for research and operational models (i.e. to examine parameterization and mixing schemes.

  9. HURRICANES BRET/KEITH:

  10. HURRICANE GORDON AND TS HELENE:

  11. BUOY MEASUREMENTS:

  12. OPERATIONAL IMPROVEMENTS: • TOPEX/ERS-2/ ETC to monitor Hurricane heat content Globally (Build a data base). • Explore different data assimilation schemes to ingest data into oceanic models. • Evaluate estimates of HC from Floats, etc to improve algorithms. • Deploy AXCTDs/AXCPs/AXBTs along satellite tracks (Recon flights). • Relate atmospheric data (GPS) to heat content variability and its change.

  13. TWO-SPEED PROFILERS:

  14. MICOM/HYCOM : • Quiescent, Climatological, Realistic Cases with Eddy Field-Based on OA SAIC CTD data. • OML Parameterizations: KT, PRT, Gaspar, and Deardorff. • Analytical/Real Wind Cases • Comparison to both OML temperatures and Velocities from AXCP/AXBTs. • High Levels of Correlation, Mean Current Differences 10 cm/s. • Deardorff overmixed OML.

  15. TOPEX /ERS-2 ANALYSES: Analyses From Several Storms Over Past Two Years Have Revealed: • Wind Speed Changes Lagged Heat Potential Change By 12-18 Hours. • Annual Climo and Hurricane Climo- High Correlation to heat Content, 20 and 26C isotherm depths from 1999 • Cross-Correlation Indices >0.7 for all cases Wind / Heat Potential Changes. • Related to Air-Sea Fluxes, Theta_e, Over Heat Potential Gradients.

  16. SUMMARY: • Explore/Improve Data Assimilation Techniques for Ocean Models. • Evaluate uncoupled and coupled model performation with data (i.e. ocean mixing schemes under high winds)! • Assess air-sea parameterizations at high winds in presence of a wave field. • Rapid and steady intensifiers: may only happen 5-10% of the time-may cause the most damage (Camille, Opal, Bret, Keith.).

  17. TRANSITIONS: Approach using radar altimetry from satellites is now being transitioned. to improve the product: • Acquire high resolution ocean data-not a technology issue; • Combine 3-D snapshots through Objective Analysis Schemes; • Develop assimilation schemes for models; and. • Require forecasters and researchers to open a dialogue-push the frontier.

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