Hurricane Research Division Achievements
Tropical cyclone wind radii estimation using an empirical inland wind decay model
A method for estimating the maximum wind, and 34,50, and 64 kt wind radii of landfalling tropical cyclones utilizing the operational NHC storm structure and track forecasts and a revised version of the Kaplan/DeMaria decay model was developed as part of the NOAA Joint Hurricane Testbed (JHT). This technique was declared operational by the NHC for use in both the Atlantic and East Pacific basins prior to the 2008 Hurricane Season.
A revised tropical cyclone rapid intensity index for the Atlantic and East Pacific basins
A revised version of the original SHIPS rapid intensity index (RII) was developed for the Atlantic and East Pacific basins as part of the NOAA Joint Hurricane Testbed (JHT). The revised RII uses predictors from the Statistical Hurricane Intensity Prediction Scheme (SHIPS) to estimate the probability of rapid intensification (RI) for 3 different RI thresholds (25,30, and 35 kt) utilizing linear discriminant analysis. The RII was declared operational by the NHC prior to the 2008 Hurricane Season.
Validation of Hurricane Surface Winds Measured by the HRD SFMR
The HRD Stepped-Frequency Microwave Radiometer (SFMR) that is carried aboard NOAA Hurricane Hunter aircraft has been determined to be the most accurate and reliable remote sensing device available for measuring hurricane force winds at the sea surface. Results of a study show that surface winds measured by the SFMR are comparable to the Global Positioning Systems (GPS) dropwindsonde measurements that are the current standard. The benefit of the SFMR is that winds are continuously measured during flights, allowing for more complete mapping of hurricane surface wind structure.Press Release
Scientific paper available through Eric Uhlhorn's webpage
Distributed Real-Time Hurricane Wind Analysis System
The H*Wind program integrates information from a variety of platforms in and around a hurricane and creates a real-time wind field analyses, for use by the hurricane specialists.
Designed a satellite-based modem method for transmitting data from the NOAA WP-3 aircraft
Designed a system that allows satellite communication with the computers onboard the NOAA WP-3 hurricane aircraft to fascilitate the real-time transfer of data.
Rapid Intensification Index
A technique for estimating the probability of tropical cyclone rapid intensification (RI) using the operational SHIPS model output was developed for the Atlantic basin. This product was provided to NHC hurricane forecasters in real-time in support of Joint Hurricane Testbed (JHT).
Atlantic hurricane data (HURDAT) re-analysis project
This project has extended the Atlantic hurricane database back 35 additional years so that it now covers the period of 1851 to date. It includes the estimated tracks and intensities for all tropical storms and hurricanes every six hours, the "raw" observations from ships and coastal stations from which the HURDAT was derived, specific U.S. landfall data, basin-wide track maps of all tropical storms and hurricanes, and comments from/replies to the OAR's Best Track Change Committee.
First (only) real-time hurricane ensemble forecasting system
A 41-member daily hurricane track ensemble forecasting system using the VICBAR shallow water model has been run during the 1998 and 1999 hurricane seasons and will be run in realtime during the 2000 hurricane season. These forecasts will provide, for the first time, estimates of the reliability of individual forecasts and probabilistic landfall forecasts based on numerical guidance.
Improvements in track forecasts / targeting of observations
By finding locations in which the atmosphere is unstable to small perturbations, and by sampling in and around these targets with dropwindsondes, improvements of up to 35% can be achieved in forecasts through four days.
Transmission of airborne surface wind speed and rainrate measurements
The airborne Step Frequency Microwave Radiometer (SFMR) measures microwave emissions from the ocean surface at six frequencies. These are transformed with radiative transfer equations to obtain measurements of surface wind speed and rain rate below the aircraft. These data are transmitted in real time.
Ground-based hurricane wind fields from single Doppler Radar
Doppler wind data from a single land-based radar can be used to deduce the tropical cyclone windfield in much the same manner as data from a single airborne Doppler Radar. These wind fields can provide continuous monitoring of tropical cyclones as they approach landfall along the U. S. coast for the first time.
Surface wave measurements from aircraft in tropical cyclones
An airborne scanning radar altimeter (SRA) generates a topographic map of the sea surface in hurricanes over open ocean. Wave heights, their variation around the tropical cyclone, and their direction of motion are all measured, and can provide realtime estimates of wave height and storm surge at landfall.
First (only) skillful realtime hurricane intensity forecast model
The Statistical Hurricane Intensity Prediction (SHIPS) model provides the first and only consistently skillful guidance for tropical cyclone intensity prediction.
Warm oceanic features and hurricane intensity change
Regular satellite-based oceanic topographic information provides information on the underlying ocean structure, such as warm rings and boundaries. Passage of hurricanes over such features affects their intensity, allowing for improvements in intensity forecasting especially in cases of rapid intensification.
First high-resolution measurements of vertical wind and thermodynamic structure in hurricanes
Newly-developed dropwindsondes based upon Global Positioning System technology can measure winds every half second during descent in the eyewall of tropical cyclones. These measurements have become the standard by which studies of the reduction of flight-level winds to surface winds are made, and is now standard operational procedure on all reconnaissance flights.
Empirical Hurricane Inland Intensity Model
An empirical model for predicting the winds in landfalling hurricanes has been developed for the Gulf and east coasts of the U.S. This model predicting the two-dimensional field of maximum surface winds (wind swath) for storms after landfall. As of the 2000 hurricane season this model is included in the operational SHIPS model, to make possible over land predictions of intensity.
Shift to climatologically active Atlantic hurricane seasons
In the 70's and 80's, the overall hurricane activity in the Atlantic basin was much lower than the previous several decades, especially the stronger ("major") hurricanes. Several long-term climatic signals have been found to have shifted, first in 1988, and again in 1995, leading to the conclusion that the Atlantic had shifted back into a more active and destructive phase that might last for at least the next 10-20 years.
Cover article SCIENCE 20 July 2001
Vertically Scanning Doppler Radar
A Vertically Scanning Doppler Radar (VSDR) has been developed for use on the NOAA aircraft. This instrument directly measures wind velocity beneath the aircraft, and can provide wind profiles through the boundary layer.
Global Positioning System Dropwindsonde
The GPS dropwindsonde was developed for use with NOAA and Air Force aircraft to take measurements in the environment and inner core of hurricanes to improve their analysis and forecast.
Real-time hurricane surface wind analyses
A real-time system for objectively analyzing meteorological observations in hurricanes using a common framework for wind exposure, measurement height, and averaging time, has been developed. These analyses are presented to NHC hurricane specialists as often as eight times per day and have become the standard for assessing winds from new remote sensing platforms. They are used to initialize numerical forecast models, to provide forcing for storm surge models, and in disaster management.
Transmission of airborne radar reflectivity images and Doppler windfields from within the hurricane
Radar images of hurricanes, and analyses of windfields from Doppler rada, previously only available from coastal radars when the hurricane was near landfall, are now regularly available from the NOAA research aircraft. This enables specialists to see convective features in hurricanes generally obscured from satellites by high clouds and windfield structure inside the storm. Features such as eyewall replacement cycles and asymmetries that can help in forecasting of intensity are now regularly seen before landfall.
National Hurricane Research Laboratory Achievements
The Mesoscale and Covective Structure of hurricane Rainbands
Data from research flights into Hurricane Floyd (1981) were used to map out
the structure of hurricane rainbands.
Hurricane Allen's interaction with islands
The fluctuations in Hurricane Allen are related to its interactions with Caribbean islands.
Doppler radar onboard NOAA P3s implemented
A vertically scanning Doppler radar in mounted in the tail radome of the NOAA P3 aircraft and tests are run comparing results with ground-based radar, demonstrating the feasability of using it to map the winds of the inner core of a hurricane.
Hurricane Frederic's boundary-layer wind field mapped
The transformation of Hurricane Frederic's boundary-layer wind field as it makes landfall are described.
Hurricane Frederic's rainfall pattern is documented
The pattern of Hurricane Frederic's rainfall was recorded from ground based radar and related to airborne observations. Its transition due to landfall is documented.
Polygonal eyewalls and rainbands
The existence of polygonal eyewalls and angular rainbands is documented.
Objective wind center tracks created
An objective method of determening the wind center of hurricanes from airborne observations is created and storm track are created from these centers by use of spline curves.
Hurricane climatology patterns delimited
The historical records of Atlantic hurricane activity were subjected to mathimatical analysis to reveal patterns and cycles. The influence of ENSO and other large-scale oceanic oscillations were quantified.
Hurricane rainfall and radar values defined
The relationship between airborne radar return and observed rainfall rates were derived from aircraft measurements made during hurricane flights.
Hurricane interaction with upper-level features
Hurricane Gertrude (1974) offers an example of a hurricane dissipating due to negative interation with an upper-level trough.
Atmospheric turbulence measured during GATE
Tropical atmospheric measurements of turbulence during the GATE experiment were accomplished using hot-film anemometers.
The structure of a small, intense hurricane
Aircraft observations of Hurricane Inez (1966) are used to delimit the structure of a small but intense hurricane.
The boundary layer of mature hurricanes values estimated
The values of various meteorological parameters in the boundary layer of mature hurricanes are estimated from aircraft observations.
A barotropic track model for tropical storms is developed
SANBAR is a barotropic model used to forecast the movement of tropical cyclones.
African easterly waves described
The structure and characteristics of African Easterly Waves are determined from synoptic-scale analyses of the tropical Atlantic.
Data assimilation methods for computer model simulations of hurricanes are developed
Methods for initializing computer simulations of hurricanes with real observations are developed.
STORMFURY experiments on Hurricane Debbie (1969) are examined
Hurricane modification experiments carried out in 1969 are described and the results evaluated.
A multilevel primitive-equation model is developed to forecast hurricane tracks
Experiments with monomolecular films on the ocean surface carried out
Experiments with monomolecular films are carried out over the open ocean east of Miami as a possible method to modify hurricanes.
Three-dimensional tropical cyclone model developed
A three-dimensional tropical cyclone model is developed to examine asymmetries and the effects of seeding experiments.
Saharan Air Layer movements tracked
The large-scale moitions of Saharan air outbreaks are tracked over the Atlantic and their interactions with African easterly waves are examined.
Two-dimensional tropical cyclone model used to simulate seeding
A two-dimensional tropical cyclone model is used to simulate the effects of cloud seeding.
Hurricane Debbie seeded
The most extensive STORMFURY experiments are carried out on Hurricane Debbie, creating the definative dataset on seeding tropical cyclones.
NHC-67 hurricane tracking model developed
NHC-64, a statistical tracking model for tropical cyclone movement, is improved with new data.
Cold low structure described
The steady-state structure of upper-level cold lows over the Tropics are descrived as well as their cloud and moisture patterns.
Sea-surface temperature wake of hurricane measured
The sea-surface temperature wake of Hurricane Betsy (1965) is measured over a five-day period.
NHC-64 hurricane tracking model developed
NHC-64, a statistical tracking model for tropical cyclone movement, is created from hurricane database.
National Hurricane Research Project Achievements
Tropical cyclone development simulated
Numerical models are developed to simulate the formation of tropical cyclones and the results lead to insights about tropical cyclogenesis.
First hurricane flown throughout its life cycle.
NHRP follows a disturbance in the western Carribbean until it makes landfall in Texas as Hurricane Carla 1961. They were able to fly fourteen scientific missions into the growing storm over six days, the first time a tropical cyclone had been followed from its formation at sea to landfall as a major hurricane.
First successful deployment of a beacon balloon in a hurricane
Air Force Hurricane Hunters deploy a constant pressure balloon-borne radio beacon into the eye of Hurricane Helene 1958 in coordination with the NHRP aircraft. Balloon remains in th eye's center of circulation and is tracked remotely for two hours. Bob Simpson wins a steak dinner from Herb Riehl in a bet over whether such a balloon would stay in the eye or be carried out.
September 26, 1958
Mean Tropical Sounding calculated
An averaged sounding from tropical stations is developed to represent background conditions in the West Indies.
First three plane scientific mission into a hurricane
Both NHRP's dedicated Air Force B-50 aircraft fly a scientific investigation into Hurricane Carrie 1957 in coordination with the B-47 high altitude jet, the first such planned coordinated flights between three planes.
September 15, 1957
First two plane scientific mission into a hurricane
One of NHRP's dedicated Air Force B-50 aircraft flies a scientific investigation into Hurricane Greta 1956 in coordination with the NHRP B-47 high altitude jet, the first such planned coordinated flights.
November 2, 1956
First flight into a hurricane where data is automatically recorded
Noel LaSeur flies aboard one of NHRP's dedicated Air Force B-50 aircraft into Hurricane Betsy 1956, the second flight of the Project's field program and the first such flight where the automatic data recording system works. The punch card deck of data is accidently dropped and scattered on the tarmac. Several years of dedicated graduate student work is needed to recover the information in proper order.
August 14, 1956