Application of Equivalent Black Body Temperature in the Forecast of Tropical Cyclone Intensity

Using equivalent black body temperature (TBB) data retrieved from meteorological satellite GMS-5 during 1996-2002, the correlation between the circular symmetric/asymmetric component of TBB and the intensity of tropical cyclone (TC) at various time lags from 0 to 48h is analyzed for the Northwest Pacific(0 -50 N, 120 -155 E), excluding landed and near-coast samples. It is found that the total TBB near southeast of the eyewall, the circular symmetric component, and the sum of the amplitudes of tangential wave numbers 1-10 (SA10) of the TBB between the radii of 0.8°and 1.7°are significantly and negatively correlated with the TC intensity at various time lags from 0 to 48 h. Especially, the maximum 24-h lag correlation coe cients reach -0.52,-0.58, and-0.625, respectively. A statistical prediction scheme for TC intensity is developed based on climatic persistent, synoptic, and TBB factors by stepwise regression technique. It is found that the variance contribution of the averaged TBB over the ring between 1.0°and 1.5°from the TC center ranks the fourth in the equation for 12-h TC intensity prediction, and those of the total TBB near southeast of the eyewall and the difference between maximum and minimum TBB between 1.1°and 1.5°rank the third and fifth respectively in the 24-h forecast equation. It is also shown that, with TBB factors, the following predictions are improved compared to the scheme without TBB factors: 48-h prediction for severe tropical storm (STS), 12-h prediction for TC with a weakening rate greater than 15 m s-1/12 h, 24-h intensity prediction for TC with almost no intensity change, and 48-h prediction for TC intensifying faster than 10 m s-1/48 h.