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Hurricanes in T511 Nature run Oreste Reale

Hurricanes in T511 Nature run Oreste Reale. Period: September-November; 1 degree fields Collaborators: Joe Terry, Juan Carlos Jusem. Longitude bands in which recurving of disturbances out of AEWs occur: September. 700hPa u,v wind. Latitude Upward, Time horizontal.

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Hurricanes in T511 Nature run Oreste Reale

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  1. Hurricanes in T511 Nature run Oreste Reale Period: September-November; 1 degree fields Collaborators: Joe Terry, Juan Carlos Jusem

  2. Longitude bands in which recurving of disturbances out of AEWs occur: September 700hPa u,v wind Latitude Upward, Time horizontal In both months (Sep and Oct) the model manifests a tendency to create several early recurvers (around or east of 45W) or system that remain in the Eastern Atlantic

  3. Longitude bands in which recurving of disturbances occur: October 700hPa u,v wind Latitude Upward, Time horizontal However, the most intense systems occur in the western Atlantic. The number of early recurvers is higher than climatology (about 50% against observed less than 20%).

  4. However, early recurvers do occur in packs Example of a number of early recurving systems in an active season, 2004.

  5. At least 9 `major’ tropical cyclone-like systems Only TCLs having a center pressure of less than 1000 hPa in the 1x1 fields and 900 hPa vorticity greater than 3x10-4 s-1 are considered

  6. HL vortices: horizontal structure The 1 degree fields do not allow a full evaluation of HL vortices. Pressure center and low-level wind are realistic, but no evidence of bands is seen, neither in the low-level vorticity or in the specific humidity fields. Full-resolution fields need to be analyzed.

  7. HL vortices: vertical structure Vertical structure of a HL vortex shows, even at the degraded resolution of 1 deg, a distinct eye-like feature and a very prominent warm core.

  8. More HL vortices: horizontal structure As observed in July and August, the 1 degree fields do not allow a full evaluation of HL vortices structure, since little evidence of bands is seen. However, pressure center and 850hPa wind are very realistic (970 hPa and 50 m/s) in the major 20 October 2005 Gulf of Mexico `Hurricane’

  9. `Major’ hurricane over the Gulf: vertical structure Wind speed (m/s) Temp (oC) Vertical structure of a HL vortex shows, even at the degraded resolution of 1 deg, a distinct eye-like feature and a very prominent warm core. Structure even more impressive than the system observed in August. Low-level wind speed exceeds 55 m/s

  10. Realistic Variability of TCL system tracks in the Atlantic Looping and Binary vortex interaction 4 systems: Looping, Binary vortex Interaction, Extratropical Transitions and Extra-tropical Re-intensification Singuarities, binary vortex Interactions, Intensity fluctuations Due to large-scale forcing fluctuations

  11. Multiple simultaneous tropical cyclones in the Atlantic 500 hPa geop (m) and 900 hPa rel vort (s-1)

  12. Remarkable days in which almost all possible processes related to Tropical Cyclones happen together:21-24 September Although weaker systems than at other times, the period 21-24Sep is extremely interesting. Multiple tropical cyclogenesis, cyclolysis, subtropical cyclogenesis extratropical transition, looping, binary vortex interaction, center jump, rejuvenation, extratropical reintensification. Up to four tropical or at least partially tropical systems simultaneously present. Tropical-Extratropical interaction is very evident Given the resolution limitations, this is an extraordinary realistic representation of a very active period 500 hPa geop (m) and 900 hPa rel vort (s-1)

  13. Preliminary concluding remarks on the African Monson region and tropical Atlantic • A synoptic assessment of the NR over the AM region and the tropical Atlantic shows an overall very realistic African Monsoon, AEJ and wave activity • In addition to the 2 `major’ systems with a full hurricane-like development up to Aug 31st , at least other 9 `strong’ systems (for 1x1 res.) develop during September and October • Several weaker tropical and sub-tropical systems are also present • In spite of a tendency of creating several early recurvers, it can be stated that the NR, given the resolution limitation, does have a good representativeness of tropical cyclone track variability in the Atlantic, as it would occur in an active season • This Nature Run seems to represent a very promising tool to perform OSSEs over the tropical Atlantic

  14. CURRENT and FUTURE WORK at NASA GSFC (GLA and SIVO) on the NR validation • Comprehensive statistics on midlatitude cyclone activity have been performed (J. Terry) • Comprehensive statistics on precipitation (J.C. Jusem) are in progress and will be presented in the next meeting together with an assessment of the South American monsoon • Analysis of tropical weather over Indian Ocean and Asian Monsoon regions with emphasis on the Somali Jet, monsoon onset and breaks, tropical depressions, is being completed • An assessment of the Eastern Pacific tropical cyclone season is also being completed • Southern Hemisphere and Western Pacific tropical weather systems will be investigated in the near future

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