GOES-16 Observations of Rapidly Intensifying Tropical Cyclones: Hurricanes Harvey, Irma, and Maria (2017)

With the launch of the next-generation of high-resolution geostationary satellites (e.g. NOAA/NASA’s GOES-16), the substantial advancement in both the spatial and temporal frequency of observations allow for a more in-depth examination of tropical cyclone (TC) intensification processes through remotely-sensed observations. This study utilizes brightness temperatures observed by the IR longwave window band (Ch 14; 11.2 μm) from the Advanced Baseline Imager (on GOES-16) to examine the structure of Hurricanes Harvey, Irma, and Maria (2017) throughout many phases of the TCs lifetimes. Detailed two-dimensional inner-core structural evolutions in the times leading up to their rapid intensification (RI) events are examined to analyze the strength and location of the developing convection, while azimuthally-averaged brightness temperature evolutions illustrate the development of the eye/eyewall and variability of the radial extent of the central dense overcast (CDO) associated with the diurnal cycle.

In addition, Hovmoller diagrams constructed by extracting data at constant radii (50-km and 100-km from the TC surface centers) reveal areas of cold brightness temperatures, likely associated with convective bursts, propagating around the TC on timescales of 2–3 h. The examination of these brightness temperatures in a deep-layer shear-relative sense reveals that convective bursts initiate primarily in the downshear-left quadrant of the TC, and begin to advect cyclonically. As RI-onset is approached, the areas of the coldest brightness temperatures are able to propagate into the upshear-left quadrant of the TC, promoting enhanced diabatic heating near the TC center, which helps facilitate the onset of more significant intensification. Despite differences in track, intensity, and structure throughout the lifetimes of Harvey, Irma, and Maria, the evolutions of the IR longwave brightness temperatures of all three TCs demonstrate similarities in the structure of the developing convection prior to RI-onset.