The MET Tropical Cyclone (MET-TC) tools were designed to implement the verification logic used at the NOAA National Hurricane Center. They compare forecast hurricane tracks in the Automated Tropical Cyclone Forecasting System (ATCF) format to analysis BEST tracks for those storms. MET-TC consists of 3 tools: TC-DLand which users may run zero or one times, TC-Pairs which users may run once per storm, and TC-Stat which users run many times to compute a variety of analyses and summary statistics.

TC-Dland Functionality

The TC-Dland tool parses land data files and computes distances to land over a regular grid. It writes an output gridded NetCDF file for use by the TC-Pairs tool. A hurricane's location relative to land is an important attribute by which to filter results. Rather than computing these distances on the fly when processing ATCF data, it is more efficient to pre-compute them once for each grid point and look them up later. In fact, the output of the TC-Dland tool is already included in the MET release in the $MET_BASE/tc_data directory. dland_nw_hem_tenth_degree.nc contains distances for the north west hemisphere at 1/10th degree resolution and is sufficient for the Atlantic (AL) and Eastern Pacific (EP) basins. dland_global_tenth_degree.nc contains global 1/10th degree data and works for all basins but is a much larger file and is slower to read. Since hurricane locations are typically reported to 1/10th of a degree, pre-computing distances to land at this resloution is sufficient.

The majority of users will not need actually need to run the TC-Dland tool and can instead use its output included in the release. However, users should consider running it if they would like to:

• Change the definition of land used by NHC. Users may disagree with the inclusion/exculsion of certain islands as counting as a land mass. The land data files are included in the $MET_BASE/tc_data directory and can be modified.
• Change the resolution or spatial extent of pre-computed distances. For example, using 1 degree data is much faster than 1/10th degree.

TC-Dland Usage

View the usage statement for TC-Dland by simply typing the following:

The only required argument is the name of the output NetCDF out_file. The -grid and -land options override the default grid definition and land data files, respectively. TC-Dland does not require a configuration file.