Extended Abstract (1.1M)15A.5
Daily hurricane variability inferred from GOES infrared imagery
James P. Kossin, CIRA/Colorado State Univ., Fort Collins, CO
Using the NESDIS/CIRA tropical cyclone infrared (IR) imagery archive, combined with best track storm center fix information, a coherent depiction of the temporal and azimuthally averaged spatial structure of hurricane cloudiness is demonstrated. The diurnal oscillation of areal extent of the hurricane cirrus canopy, as documented in a number of previous studies, is clearly identified but often found to vanish near the convective region of the hurricane eyewall. While a significant diurnal oscillation is generally absent near the storm center, a powerful and highly significant semidiurnal oscillation is sometimes revealed in that region. This result intimates that convection near the center of tropical storms and hurricanes may not be diurnally forced, but might, at times, be semidiurnally forced. A highly significant semidiurnal oscillation is also often found in the near environment beyond the edge of the hurricane cirrus canopy. The phase of the semidiurnal oscillations in both the central convective region and the region beyond the canopy is robust and congruous with the phase of the solar semidiurnal atmospheric tide.
Session 15A, Tropical Cyclone Observations and Structure IV (Parallel with Sessions 15B and 15D)
Thursday, 2 May 2002, 4:00 PM-5:30 PM
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