TABLE K-1 Tropical Cyclone Center Fixes in 2004 (up to December 9)

Location

Number of Fixes

Southern Hemisphere

202

Western Pacific Ocean

296

Atlantic Ocean

58

East Pacific Ocean

88

Indian Ocean

25

Total

669

NOTE: The number of fixes is a function of (1) the number of tropical cyclones within each basin, (2) frequency of TMI overpasses while a storm is alive, and (3) diligence of satellite fixing agencies in gathering TMI data in near real time for fixes.

of TMI data (5 km at 85 GHz), these fixes are typically assigned very high quality when compared with all other satellite location datasets (e.g., visible, infrared, and microwave sensors such as SSM/I and AMSU-B). Thus, the TMI fixes drive both the near-real-time warning positions and typically the best track created when all data is compiled after a storm has completed its life.

The National Hurricane Center and the Joint Typhoon Warning Center include TMI in their storm discussions that outline how the data have affected their warning positions or provided insight on storm structure that directly influences storm intensity estimates and/or short-term intensity trends. This appendix provides examples of how TMI data are used for intensity estimates and fixing storm locations.

SPECIFIC IMPACTS OF TRMM DATA

Tropical Cyclone Maximum Intensity: Kenna

“Now that Kenna [Figure K-1] has developed a vertically deep eye feature in the TRMM data and the center is embedded in the middle of the CDO [Central Dense Overcast] … a 24-hour period of rapid intensification is being forecast.” (From Tropical Storm Kenna Discussion Number 6 at 2 am PDT October 23, 2002.)

Impact of TRMM data: TRMM data led the Tropical Prediction Center to correctly change its forecast from “intensification” to “rapid intensification.”



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