Impact of Spatial Resolution on Wind Field Derived Estimates of Air Pressure Depression in the Hurricane Eye

Ruba Amarin,Linwood Jones,Christopher Ruf

doi:10.3390/rs2030665

Abstract

Measurements of the near surface horizontal wind field in a hurricane with spatial resolution of order 1–10 km are possible using airborne microwave radiometer imagers. An assessment is made of the information content of the measured winds as a function of the spatial resolution of the imager. An existing algorithm is used which estimates the maximum surface air pressure depression in the hurricane eye from the maximum wind speed. High resolution numerical model wind fields from Hurricane Frances 2004 are convolved with various HIRAD antenna spatial filters to observe the impact of the antenna design on the central pressure depression in the eye that can be deduced from it.

Highlights

The Hurricane Imaging Radiometer (HIRAD) is a next-generation airborne microwave remote sensor under development by NASA, which will expand the airborne hurricane measuring capabilities of two existing microwave radiometers—the Stepped Frequency Microwave Radiometer (SFMR) [1]and the Lightweight Rainfall Radiometer (LRR) [2]
A simulated hurricane wind field (Figure 1) was used in this study which was derived from observations made of Hurricane Frances on 31 August 2004 using a dynamical numerical model described by Chen [7]
The estimator computes the maximum value of the winds, and the central air pressure depression is derived from the maximum wind speed value

Summary

Introduction

The Hurricane Imaging Radiometer (HIRAD) is a next-generation airborne microwave remote sensor under development by NASA, which will expand the airborne hurricane measuring capabilities of two existing microwave radiometers—the Stepped Frequency Microwave Radiometer (SFMR) [1]. Because of its wide-swath, high resolution imaging capability, HIRAD provides the opportunity to examine the detailed structure of the near surface (10 m height) wind field [3]. Simulated HIRAD retrievals with variable spatial resolution of the surface wind field are derived from the high resolution numerical hurricane model, and the impact of reduced spatial resolution on the ability to accurately estimate the air pressure in the hurricane eye is assessed

Pressure Depression Estimator

Application to a Simulated Hurricane

Findings

Summary