Precipitation, Convective Clouds, and Their Connections With Tropical Cyclone Intensity and Intensity Change. Geophysical Research Letters
In this paper, satellite-based precipitation, clouds with infrared (IR) brightness temperature (BT), and tropical cyclone (TC) data from 2000-2015 are used to explore the relationship between precipitation, convective cloud, and TC intensity change in the Western North Pacific Ocean. An IR BT of 208 K was chosen as a threshold for deep convection based on different diurnal cycles of IR BT. More precipitation and colder clouds with 208 K <IR BT< 240 K are found as storms intensify, while TC 24-h future intensity change is closely connected with very deep convective clouds with IR BT<208 K. Intensifying TCs follow the occurrence of colder clouds with IR BT<208 K with greater areal extents. As an indicator of very deep convective clouds, IR BT< 208 K is suggested to be a good predictor of TC intensity change. Bases upon the 16-year analysis in the western North Pacific, TCs under the conditions that the mean temperature of very deep convective clouds is less than 201 K, and the coverage of this type of clouds is more than 27.4% within a radius of 300 km of the TC center, will more likely undergo rapid intensification after 24 h.
Ruan, Z. and Q. Wu. Precipitation, Convective Clouds, and Their Connections With Tropical Cyclone Intensity and Intensity Change. Geophysical Research Letters, 2017,doi: 10.1002/2017GL076611.
Figure 1: Shear-relative composites of precipitation and BT of very deep convective clouds and high clouds according to different TC intensity categories in the western North Pacific. Black circles represent 100-, 200-, 300- km radii from the TC center. The arrow represents the direction of wind shear. The sample sizes are shown at the bottom right-hand corner of each panel.