Climatology of Passive Microwave Brightness Temperatures in Tropical Cyclones and their Relations to Storm Intensities as Seen by FY-3B/MWRI

Bo Qian,Ying Wu,Fuzhong Weng,Haiyan Jiang

doi:10.3390/rs12010147

Abstract

A new database, the tropical cyclones passive microwave brightness temperature (TCsBT) database including 6273 overpasses of 503 tropical cyclones (TC) was established from 6-year (2011–2016) Fengyun-3B (FY-3B) Microwave Radiation Imager (MWRI) Level-1 brightness temperature (TB) data and TC best-track data. An algorithm to estimate the TC intensity is developed using MWRI TB’s from the database. The relationship between microwave TB and the maximum sustained surface wind (Vmax) of TCs is derived from the TCsBT database. A high correlation coefficient between MWRI channel TB and Vmax is found at the radial distance 50–100 km near the TC inner core. Brightness temperatures at 10.65, 18.70, 23.8, and 36.5 GHz increase but 89 GHz TB’s and polarization corrected TB at 36.5 GHz (PCT36.50) and PCT89 decrease with increasing TC intensity. The TCsBT database is further separated into the 5063 dependent samples (2010–2015) for the development of the TC intensity estimation algorithm and 1210 independent samples (2016) for algorithm verification. The stepwise regression method is used to select the optimal combination of storm intensity estimation variables from 12 candidate variables and four parameters (10.65h, 23.80v, 89.00v and PCT36.50) were selected for multiple regression models development. Among the four predictors, PCT36.50 contributes the most in estimating TC intensity. In addition, the errors are lower for estimating 6-h and 12-h future Vmax than estimating the current Vmax.

Highlights

Meteorological satellites have become an indispensable tool for tropical cyclone monitoring, early warning, and forecasting
A global tropical cyclones passive microwave brightness temperature (TCsBT) database based on the 6-year FY-3B/Microwave Radiation Imager (MWRI) TB data and corresponding best-track data was developed, and TB distribution related to tropical cyclones (TC) Vmax was presented over the TC center to 250 km radial distance annular regions
Mean TB parameters of 10.65 and 18.70 GHz have a high correlation with TC Vmax and the 50–100 km annular region is a good representative area for TC intensity estimation

Summary

Introduction

Meteorological satellites have become an indispensable tool for tropical cyclone monitoring, early warning, and forecasting. The center channel frequencies of the PMW imagers available on meteorological satellites typically include 10, 19, 23, 37, 85, and 91 GHz. Many hurricane intensity estimation studies have been conducted using these PMW sensors. Jiang et al (2019) [12] developed a multi-linear regression algorithm to estimate TC intensity using predictors derived from 85 GHz PCT and microwave retrieved rain rate from TRMM TMI data. The detailed error statistics of different TC intensity estimation techniques, including the Dvorak techniques, were summarized in Table 9 of Jiang et al (2019) [12]. It is optimal to us3eotfh15e retrieved rain rate to estimate TC intensity, the PMW retrieval algorithms could have many uncertainties, especially for the newly launched FY-3/MWRI program. F2Y. -F3YB-/3MB/WMRWI-RbIa-sbeadsetrdotpriocpaliccaylccloyncleosnpeasspsiavsesimveicmroiwcraovweabvreigbhrtingehstsnetesms tpeemrapteurraetu(TreCs(TBCT)sBT) database construction flowchardt.atabase construction flowchart

Selection of MWRI Overpasses

Relations between PMW TB and TC Intensities

Regression Analysis

Results

Summary and Conclusions