Tropical Cyclone Diurnal Cycle Property From Satellite Passive Microwave Observations

The Tropical cyclone (TC) database created at the Naval Research Laboratory in Monterey includes measurements from the conical scan passive microwave sensors onboard all available satellites during 1987-2012. These observed brightness temperatures (TBs) are inter-sensor calibrated for the frequency differences at 85-89-91 GHz from different sensors so that the calibrated TBs are in the 89 GHz. For a better diagnostic analysis of the TC structure and intensity, a Backus-Gilbert interpolation scheme is applied to generate a very high spatial resolution TC TB datasets. In addition, an advanced TC center fixing algorithm called the automated rotational center hurricane eye retrieval (ARCHER) in locating the accurate TC centers and a polar coordinate framework are utilized for a better presentation of the TC characteristics. Preliminary results show clear diurnal cycle features for both the TC maximum wind speed (Vmax) and minimum seal level pressure (MSLP), although their diurnal magnitudes are not very large. The TC TBs show a clear diurnal cycle at horizontal distributions. These TC diurnal cycle properties present strongly oceanic basin-dependent characteristics. A detailed discussion will be presented at the conference.