Toward an Integrated Air-Sea Real-Time Airborne Observing System for Landfalling Hurricanes
Peter G. Black (firstname.lastname@example.org) John Gamache (email@example.com) Eric Uhlhorn (firstname.lastname@example.org) www.aoml.noaa.gov/hrd/ NOAA-AOML Hurricane Research Division Miami, FL
Edward Walsh (email@example.com) www.esrl.noaa.gov/psd/
James Carswell (firstname.lastname@example.org) www.rmss.us
Paul Chang (Paul.S.Chang@noaa.gov) www.orbit.nesdis.noaa.gov/star/osb_index.php
Allan Goldstein (Alan.S.Goldstein@noaa.gov) www.aoc.noaa.gov
Ivan Popstefanija (email@example.com) www.prosensing.com
Rick Lumpkin (Rick.Lumpkin@noaa.gov) www.aoml.noaa.gov/phod/index.php
Efforts have been ongoing for a number of years to develop a suite of airborne sensors that will describe the surface, boundary layer and subsurface conditions in hurricanes in real time during their life cycle, especially as they evolve and approach populated areas. This observational effort is maturing at a time when increasingly sophisticated coupled hurricane prediction models such as HWRF are becoming operational. At the same time, improvements in satellite communications are allowing increasing amounts of data to be relayed from aircraft platforms to forecast offices where real time analysis tools such as HRD’s H*WIND program synthesize the data into real time maps of critical parameters such as surface wind. A review of the impact of the Stepped Frequency Microwave Radiometer (SFMR) since its operational introduction in 2004 on board the two NOAA WP-3D aircraft has shown real benefit for short term forecasts and warnings and helped reduce the uncertainty in surface wind field estimation. It is anticipated that additional benefit will be shown with the phased introduction of SFMR systems on the AFRC WC- 130J aircraft beginning in 2007 and culminating with a fully operational fleet in 2008. The use of the SFMR system in conjunction with the NOAA Doppler radar and GPS dropsondes is anticipated to enhance initial and validation wind fields for operational storm prediction using HWRF. It is anticipated that in addition, an SFMR system will begin initial flights on the NOAA G-IV in 2008 in conjunction with the new G-IV Doppler radar system.
In order to validate wave models in the coupled HWRF system, an operational Scanning Radar Altimeter for significant wave height measurement will begin test flights in 2007 and is expected to be operational by 2008. These data are anticipated to be useful for forecast and warnings related to the extent of critical wave heights within hurricanes. Algorithm development and initial testing is underway for a scanning SFMR system referred to as the Hurricane Imaging Radiometer (HIRad) to produce a swath of surface winds along the aircraft track to further complement the multilevel wind swath provided by the airborne Doppler radar, and further reduce surface wind field uncertainty and enhance the probability of detecting the true maximum surface winds.
Subsurface ocean thermal features have been shown to have a significant impact on hurricane intensity change, especially in the Gulf of Mexico offshore from vulnerable Gulf Coast communities such as New Orleans. Recent communication advances will allow real time transmission of Airborne Expendable Bathythermograph (AXBT) data that will follow the evolution of ocean features along the hurricane path. The capability to accomplish this has been available for years on the NOAA WP-3D aircraft, and is being investigated as an additional low-cost addition to the AFRC WC-130J capability. Impacts on HWRF initialization are expected to be significant.
For storms approaching landfall, a program has been developed to augment the over-ocean observing system by deployment from WC-130J aircraft of drifting buoy and float arrays ahead of hurricanes to gather time series of subsurface ocean thermal and current conditions as well as surface winds and wave heights. It is expected that these platforms will be deployed up to two days ahead of a potential landfalling hurricane to provide addition atmosphere- ocean-wave inputs to that supplied by aircraft reconnaissance- primarily for initialization of the improved coupled air-sea hurricane prediction models. Examples of these advances will be illustrated.