NOAA HURRICANE RESEARCHERS GEARED UP FOR ANOTHER BUSY SEASON

August 1, 2005 — With the impacts of the 2004 hurricane season still evident in many communities, the coastal populations of the United States should prepare for what is expected be another very active hurricane season. The destructive winds, storm surge and heavy rains that produced flooding last year now serve as staunch reminders that hurricanes are one of nature's most extreme hazards. In fact, it is estimated that hurricanes Charley, Frances, Jeanne and Ivan caused a combined estimated $43 billion in damage in 2004 (surpassing the $34.9 billion caused in 1992 by Hurricane Andrew, the nation’s most costly single storm).

Although it is impossible to prevent hurricanes, advances by the NOAA Hurricane Research Division (part of the NOAA Atlantic Oceanographic and Meteorological Laboratory in Miami, Fla.) and its partners at the Tropical Prediction Center and the Environmental Modeling Center of the NOAA National Centers for Environmental Prediction are making it easier for coastal residents to properly prepare for and survive the annual Atlantic hurricane season. Using a combination of computer models, theories and observations (collected from both the Earth’s surface and by NOAA hurricane hunting aircraft and satellites high in the sky) NOAA has improved the two-day (48 hour) track forecasts for hurricanes by an average of 43 percent since 1990. Those improvements have greatly decreased the total miles coastline placed under a hurricane warning when a storm approaches the United States, saving millions in costly preparations and local community closures. In contrast, the forecasts of hurricane intensity have only improved by 17 percent, leaving uncertainty in the actual hurricane wind speeds as the storms make landfall.

“Despite the highly destructive nature of the 2004 hurricane season, NOAA researchers gained valuable insight into further understanding and predicting hurricanes and other tropical weather. As a result, NOAA fine tuned its hurricane track forecasts through new model improvements and is focused on doing the same for hurricane intensity and precipitation forecasts over the next few years,” said Frank Marks, director of the Hurricane Research Division. “Given the steady improvement in NOAA hurricane track forecasts, the next thing coastal residents want to know is how strong these storms will be once they reach the coast and travel inland.”

Will 2005 be Another Active Hurricane Season?
Unfortunately, the devastating 2004 hurricane season was not an aberration. In fact, such active seasons are likely to be the norm for the next 15 to 30 years. While the total number of storms making landfall may vary, the total number of major hurricanes that develop is expected to remain above average during the 2005 season. Major hurricanes tend to occur in cycles of relatively low activity and relatively high activity that can last for decades. These long, slow cycles can be attributed to natural fluctuations in atmospheric conditions and water temperatures (also known as the Atlantic Multi-decadal Oscillation). Historical data suggests that around 1995, a 25-year inactive phase marked by fewer major hurricanes ended and an active period began. If this trend continues as predicted, warmer sea surface temperatures and minimal wind shear are expected to generate more of the most damaging hurricanes — categories three, four and five on the Saffir-Simpson scale — well into 2020 and perhaps beyond. Although it is important to remember that it only takes one storm to devastate a community, as Andrew (the only major hurricane of 1992) did in south Florida.

Hurricane Research Priorities for 2005
In addition to supporting their operational partners within NOAA and other federal agencies, NOAA HRD researchers will also be focusing on a number of research projects this hurricane season. HRD’s most important goal this hurricane season will be advancing the physical understanding of hurricane intensity change, which will ultimately contribute to more accurate hurricane intensity forecasts. NOAA researchers will also study “rapid intensification,” a phenomenon that can transform a hurricane from a relatively minor category one or two hurricane to a highly destructive category four or five hurricane in less than a day. An equally important research effort will be the analysis of hurricane surface winds (the effort to improve hurricane track forecasts through the use of hurricane hunting aircraft and targeted observations will continue, but with somewhat fewer resources than in the past). Quantitative estimation and prediction of tropical cyclone rainfall is also becoming an increasingly vital part of NOAA’s hurricane research program because drowning from hurricane-induced inland flooding is another significant cause of hurricane related mortality in the United States.

NOAA HRD researchers are also working to transition a number of new observation technologies into operational tools, e.g., the stepped frequency microwave radiometer, airborne Doppler radar, airborne expendable ocean probes, and an remotely operated aircraft (i.e., aerosonde). These efforts are coordinated with NOAA and other agency partners. These new observations will be useful to the new model development, as well as the forecasters.

The NOAA HRD will also continue to conduct modest, but sustained, research aimed at better understanding the climatology of hurricane occurrence. This research is key to preparing the human and natural environment for the rare, but extreme, events that dominate hurricane impacts.

Hurricane Intensity Research will be a High Priority this Hurricane Season
NOAA's Hurricane Research Division will begin working with the NOAA Aircraft Operations Center on a new multi-year experiment this summer called the Intensity Forecasting Experiment. Developed in partnership with the NOAA Environmental Modeling Center and the NOAA National Hurricane Center, IFEX is intended to improve our understanding and prediction of hurricane intensity change by collecting observations that will aid in the improvement of current operational models and the development of the next-generation operational hurricane model, the Hurricane Weather Research and Forecasting model. Unlike in the past, this seasons emphasis will be on collecting observations in tropical cyclones at all stages in their lifecycle, from formation and early organization to peak intensity and subsequent landfall or decay over open water.

There are several unique aspects of IFEX in 2005 that will help improve our understanding and prediction of hurricane intensity change, including the following:

• Hurricane Genesis Experiment:This experiment, flown with the two NOAA P-3 aircraft in conjunction with a high-altitude ER2 NASA aircraft, is intended to improve our understanding of how a tropical disturbance becomes a hurricane. Very few aircraft measurements have been made in tropical disturbances over the past 25 years, largely because it is so difficult to collect data in these systems. The eastern Pacific Ocean is an ideal location for genesis studies, since that region has the highest frequency of developing hurricanes per unit area in the world. Because most eastern Pacific storms originate close to Central America and Mexico, NOAA and NASA aircraft will base operations out of San Jose, Costa Rica in an attempt to observe developing hurricanes. This experiment ran from July 3 to July 23.
• Mature-Storms Experiment: Developed jointly between EMC and HRD, this experiment is designed to provide data sets that improve our understanding of intensity and structure change in mature storms. Data sets will be collected suitable for the initiation and evaluation of the Hurricane Weather Research and Forecasting (HWRF) model. This experiment is repeated every 12-24 hours to provide the maximum possible temporal resolution over the lifetime of the storm. The experiment also takes advantage of the NESDIS Ocean Winds and Rain Experiment (Ocean Winds) and the NSF sponsored rainband experiment (also known as RAINEX). The Ocean Winds experiment is designed to improve understanding of microwave remote sensing of the ocean surface wind field from satellite scatterometers in high-wind and heavy rain using the Integrated Wind and Rain Airborne Profiler (IWRAP) on the NOAA WP-3D. RAINEX is designed to collect airborne Doppler data sets in the eyewall and rainband from the Naval Research Laboratory (NRL) and the two NOAA WP-3D aircraft simultaneously. These data sets will be used to document the dynamic interaction between the eyewall and rainbands, and the role this interaction has on the evolution of the structure and intensity of the storm.
• Hurricane Decay Experiment: Developed jointly between NHC and HRD, this experiment will examine the decay of hurricanes in the eastern North Pacific. Direct observations are rarely, if ever, available in eastern North Pacific hurricanes decaying over cooler waters. The purpose of this experiment is to obtain direct observations of decaying hurricanes to better calibrate existing satellite based methods of estimating hurricane intensity over cold water.
• Impact of Saharan air on intensity forecast models: Recent research has shown that a large mass of very dry air originating from the African continent, called the Saharan Air Layer may be an important factor in hurricane intensity change in the North Atlantic and Caribbean Sea. Further research is needed to understand how the SAL affects tropical cyclone intensity, however, analysis shows that the SAL’s dusty, dry air and strong winds may weaken hurricanes in the Atlantic. The lack of an accurate representation of the SAL feature in operational models may impede them from accurately predicting hurricane intensity. To address this, the NOAA G-IV jet will deploy GPS dropsondes to gather high quality moisture data, which will provide observations to better prescribe the initial conditions in the operational global model. It is hoped that this data will help the models better "see" the SAL and therefore improve intensity forecasts for Atlantic hurricanes that are ingesting the SAL's dry, dusty air.
• SFMR Validation: The Stepped-Frequency Microwave Radiometer is a unique airborne tool that enables the remote measurement of surface wind speeds and rain rates over the water. The SFMR has provided NHC with a valuable means of determining the maximum surface wind speed, as well as the extent of hurricane (>73 mph) and gale-force (39-54 mph) winds. This information enables more accurate timing and location of hurricane and tropical storm watches and warnings. Work will continue during IFEX to validate the operational SFMR by comparing it with direct measurements from GPS dropsondes, packaged sensors deployed from aircraft, in these environments.
• Mapping Of The Eyewall Wind Field From Airborne Tail Doppler Radar And Its Transmission To EMC And NHC In Real-Time: Scientists onboard the NOAA P-3's will test a method for sending radar-derived wind measurements of a hurricane's inner-core to EMC in real-time. These measurements will ultimately be used in the development of techniques for incorporating data into models that can be applied to storms at all stages of their lifecycle. These measurements will also be sent to NHC, where they will be evaluated for the potential of being routinely provided to the hurricane specialists during the hurricane season.
• Real-Time Transmission Of Lower Fuselage Radar: For the first time ever, a NOAA WP-3D will be transmitting lower fuselage radar imagery in real-time to another aircraft, the Naval Research Laboratory P-3. The NRL P-3 will be flying outside of a hurricane's rainbands, while the NOAA P-3 will be flying along the more turbulent inner edge of the rainbands. This capability, developed by the NESDIS Ocean Winds Experiment and the Aircraft Operations Center, will enable the safe operation of the NRL P-3 in an environment it has never flown in before.
• Aerosonde Project: While the capabilities and utilization of the WP-3D Orion and Gulfstream IV aircraft have made NOAA a global leader in hurricane aircraft surveillance and reconnaissance, detailed observations of the near-surface hurricane environment (sea level to 500 meters) have been elusive due to the severe safety risks associated with low level manned flights. A successful deployment of these unique low flying unmanned aerosondes will accurately document and improve our understanding of the rarely-observed near surface hurricane environment. An important (and immediate) additional benefit would be the real-time transmission of hurricane surface conditions directly to the NHC. In addition, detailed comparisons between in-situ and satellite-derived observations will also be possible.
• NOAA G-IV Doppler Evaluation Missions: In 2005, the high-altitude NOAA G-IV jet will penetrate the inner core of hurricanes (previously the G-IV flew primarily in the environment around the hurricane - monitoring the steering currents around the storm). This capability will be vital once a Doppler radar is installed on the G-IV, enabling the three-dimensional mapping of wind fields from nearly top to bottom of hurricanes. These wind measurements will prove invaluable in improving the forecasts of hurricane intensity with the next-generation HWRF model. To date, the NOAA G-IV crew has already successfully completed a Doppler evaluation mission in Hurricane Emily and Tropical Storm Franklin’s Central Dense Overcast, the cirrus cloud shield that results from the thunderstorms in the eye wall of a tropical cyclone and its rainbands. These missions are a joint effort between HRD, AOC, and NWS.

In 2005, IFEX will be operating in partnership with several other experiments:

• NASA Tropical Cloud Systems and Processes Experiment
• NSF Hurricane Rainband and Intensity Change Experiment
• NOAA Ocean Winds Experiment

Although NOAA will never be able to prevent hurricanes from making landfall along the coastal United States, advances made by the NOAA HRD will yield more improved hurricane forecasts and give America's coastal residents the time needed to safely evacuate the predicted landfall area, thus minimizing false alarms and the lose of life and property.

Relevant Web Sites
NOAA Hurricanes Page

Aircraft Operations Center

NOAA Commissioned Corps Officers

Hurricane Research Division: Frequently Asked Questions

NOAA Historical Hurricane Tracks

HIGHLIGHTS OF NOAA’S 2004 HURRICANE RESEARCH

O'DARK THIRTY
Observations of NOAA Aircraft Production Controller/WP-3D Flight Engineer Greg Bast

NOAA's HURRICANE RESEARCH

NOAA ISSUES 2005 ATLANTIC HURRICANE SEASON OUTLOOK
Another Above Normal Season Expected

NOAA RESEARCHER SAYS SAHARAN AIR LAYER CONNECTED TO ATLANTIC HURRICANE SUPPRESSION AND INTENSITY CHANGE

SCIENTISTS GATHER DATA DURING FRANCES TO SAVE LIVES, PROPERTY BUT ALSO TO ADVANCE RESEARCH

NOAA HURRICANE HUNTER REMOTE SENSING DEVICE GETS HIGH MARKS FOR MEASURING HURRICANE SEA SURFACE WIND

Media Contact:
Jana Goldman, NOAA Research, (301) 713-2483 x 181