TITLE: NOAA Post Storm Surface Wind Analysis System Gridded Data [AOML/HRD]

This documentation is compiled from information downloaded from http://www.aoml.noaa.gov/hrd/Storm_pages/surf_background.html and http://www.aoml.noaa.gov/hrd/Storm_pages/grid.html You can find graphs showing the coordinate spage on the second link.


The Hurricane Research Division (HRD) is a part of the Atlantic Oceanographic and Meteorological Laboratory (AOML). HRD is engaged in advancing the basic physical understanding and improving the forecasts of hurricanes and tropical meteorological systems. This dataset contains Wind Analysis data downloaded from http://www.aoml.noaa.gov/hrd/data_sub/hurr2005.html by clicking on H*Wind for the storm of interest.


The Wind Analyses in this dataset are for research purposes only. These are experimental products created by NOAA's Hurricane Research Division. For official National Weather Service products go to The National Hurricane Center website. Any use of these data are subject to the provisions of HRD's Data Policy and by using these data the user agrees to this policy.

Background on the HRD Surface Wind Analysis System

Tropical cyclones are monitored globally by space-, aircraft-, land- and marine-based observing systems. Advances in computing and communications have made it possible to obtain these observations in near real-time. However, scientists involved in operational forecasting and basic and applied research on hurricanes have few tools that enable real-time interaction with, and analysis of, observations gathered in tropical cyclones. In the Atlantic, Eastern Pacific, and Central Pacific Ocean basins, hurricane wind fields are determined subjectively based on the specialist's interpretation of flight-level reconnaissance data, satellite observations, pressure-wind relationships and available surface data. These fields are represented by text portions of the official forecast product as radii (from the storm center) of 34 kt, 50 kt, and hurricane force winds in four compass quadrants relative to north. Until recently, no operational objective method has been available for assimilating and synthesizing disparate observations into a consistent wind field. The HRD Surface Wind Analysis System is a research tool designed to fill this need.

The HRD approach to hurricane wind analysis evolved from a series of peer-reviewed, scientific publications analyzing landfalls of major hurricanes including Frederic of 1979, Alicia of 1983, Hugo of 1989, and Andrew of 1992 (Powell et al., 1991, Powell and Houston, 1996, 1998, Powell et al., 1998). In our paper describing Hurricane Hugo's landfall, we developed the concept of a system for conducting real-time analysis of hurricane wind fields. We were in the process of constructing this system when Hurricane Andrew struck. The system was first used in real-time during Hurricane Emily in 1993 (Burpee et al., 1994). Since 1994, HRD wind analyses have been conducted on an experimental basis to create real time hurricane wind field guidance for forecasters at the National Hurricane Center. During Hurricane landfall episodes, HRD scientists work side by side hurricane specialists at NHC analyzing wind observations on a regular 3 or 6 hour schedule consistent with NHC's warning and forecast cycle.

An HRD wind analysis requires the input of all available surface weather observations (e.g., ships, buoys, coastal platforms, surface aviation reports, reconnaissance aircraft data adjusted to the surface, etc.). Observational data are downloaded on a regular schedule and then processed to fit the analysis framework. This includes the data sent by NOAA P3 and G4 research aircraft during the HRD hurricane field program, including the Step Frequency Microwave Radiometer measurements of surface winds, as well as U.S. Air Force Reserves (AFRES) C-130 reconnaissance aircraft, remotely sensed winds from the polar orbiting SSM/I and ERS, the QuikScat platform and TRMM microwave imager satellites, and GOES cloud drift winds derive from tracking low level near-infrared cloud imagery from these geostationary satellites. These data are composited relative to the storm over a 4-6 hour period. All data are quality controlled and processed to conform to a common framework for height (10 m or 33 feet), exposure (marine or open terrain over land), and averaging period (maximum sustained 1 minute wind speed) using accepted methods from micrometeorology and wind engineering (Powell et al., 1996, Powell and Houston, 1996). This framework is consistent with that used by the National Hurricane Center (NHC), and is readily converted to wind load frameworks used in building codes.

2.0 Gridded Data Format

Each file is about 3 megabytes in size, uncompressed. Below is a description on how the read the file.

The gridded files of cyclone wind components have the following structure:

  1. A few lines giving the grid spacing in meters and the latitude and longitude of the storm center. In mercator cartesian coordinates the storm center is at (x,y)=(0,0)
  2. Cartesian coordinates (meters) are then given for the grid boundaries. First listed are the WEST TO EAST mercator X coordinates which pass through the storm center at x=0. They are listed in increasing order from WEST to EAST. The total number of entries is given before the coordinate listing so that the entire set of MERCATOR X COORDINATES can be read in at once.
  3. Next the SOUTH TO NORTH mercator Y coordinates (meters) which pass through the storm center at y=0 are listed. They are listed in increasing order from SOUTH to NORTH. The total number of entries is given before the coordinate listing so that the entire set of MERCATOR Y COORDINATES can be read in at once.
  4. The next listing is the EAST LONGITUDE COORDINATES of the grid boundary followed by a listing of the NORTH LATITUDE COORDINATES of the other two grid boundaries. Again, before the actual coordinates are listed. an integer specifying how many coordinate entries follow is given to facilitate reading them in as a single array all at once.
  5. Finally, the SURFACE WIND COMPONENTS (M/S) are listed as a listing of complex numbers of the form (u,v). They should be read in as a SINGLE COMPLEX ARRAY of two dimensions. The dimensions of the array are given on a line preceeding the actual component listing again so that the entire array can be read in at once.

Further details on the HRD wind analysis methods may be found in the papers listed below.


Burpee, R. W., S. D. Aberson, P. G. Black, M. DeMaria, J. L. Franklin, J. S. Griffin, S. H. Houston, J. Kaplan, S. J. Lord, F. D. Marks, Jr., M. D. Powell, and H. E. Willoughby, 1994: Real-time guidance provided by NOAA's Hurricane Research Division to forecasters during Emily of 1993. Bull. Amer. Meteor. Soc., 75, 1765-1783.

Powell, M. D. , P. P. Dodge, and M. L. Black, 1991: The landfall of Hurricane Hugo in the Carolinas. Weather Forecast., 6, 379-399.

Powell, M. D., S. H. Houston, and I. Ares, 1995: Real-time damage assessment in hurricanes. 21st AMS Conference on hurricanes and tropical meteorology, Miami, FL., April 24-28, 1995, p 500-502.

Powell, M. D., S. H.Houston, and T. A. Reinhold, 1996: Hurricane Andrew's Landfall in South Florida. Part I: Standardizing measurements for documentation of surface wind fields. Weather Forecast., 11, 304-328.

Powell, M. D., and S. H. Houston, 1996: Hurricane Andrew's Landfall in South Florida. Part II: Surface Wind Fields and Potential Real-time Applications. Weather. Forecast., 11, 329-349.

Powell, M. D., S. H. Houston, L. R. Amat, N. Morisseau-Leroy, 1998: The HRD real-time hurricane wind analysis system. J. Wind Engineer. Ind. Aerody., 77&78, 53-64.

Powell, M. D., and S. H. Houston, 1998: Surface wind fields of 1995 Hurricanes Erin, Opal, Luis, Marilyn, and Roxanne at landfall. Mon Wea. Rev., 126, 1259-1273.

Powell, M. D., and S. H. Houston, 1999: Comments on "A Multiscale Numerical Study of Hurricane Andrew (1992). Part I: Explicit Simulation and Verification". Mon. Wea. Rev., 127, 1706-1710.