This visualization consists of a Parallel Coordinates display of Atlantic Hurricane Season data from 1851 to 2011. A parallel coordinates display works by displaying n-dimensional data as a series of lines crossing n axes. Put simply, the visualization consists of a number of horizontal lines, one for each data point, and vertical lines (called "axes", or singular "axis") representing each variable. Each horizontal line represents one row in the input data table and crosses each axis at the value of the data row for that column of the data. For definitions of each variable in the visualization, see the section labeled "About the Data" below.
| Year | Named Storms | Named Storm Days | Hurricanes | Hurricane Days | Intense Hurricanes | Intense Hurricane Days | Accumulated Cyclonic Energy | Hurricane Destruction Potential | Power Dissipation Index | Net Tropical Cyclone | Tropical Storms | Category 1 | Category 2 | Category 3 | Category 4 | Category 5 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No data selected | ||||||||||||||||
| Variable | Definition |
|---|---|
| Year | The year the rest of the data represents |
| Named Storms | The number of named storms in that season. This excludes tropical depressions and subtropical storms that are not named. |
| Named Storm Days | Total number of days each storm that season was active. A named storm day consists of four six-hour periods that a storm is active. |
| Hurricanes | Total number of named storms that reached hurricane status in that season. A hurricane is a tropical cyclone with sustained winds of at least 74 miles per hour (MPH) |
| Hurricane Days | Similar to Named Storm Days, however only for days when a storm is classified a hurricane. |
| Intense Hurricanes | Total number of intense hurricanes in a season. An intense hurricane (also called a major hurricane) is classified as a hurricane that is Category 3 or greater (sustained winds of greater than 111 MPH). |
| ACE | Accumulated Cyclone Energy, a sum of the approximation of the energy of each storm in a season over its lifetime. Calculated by summing the estimated wind speed every six hours, squared, for the lifetime of the storm. Often divided by 10,000 to make values more manageable.[1] |
| HDP | Hurricane Destructive Potential, similar to ACE except only calculated during periods a storm is classified a hurricane.[2] |
| PDI | Power Dissipation Index, similar to ACE, except wind speed values are cubed instead of squared.[3] |
| NTC | Net Tropical Cyclone activity, compares a given season's statistics to the 1950-2000 average. [4] |
| Tropical Storms | Number of cyclones that peaked at tropical storm force in a season. A tropical storm is defined as a tropical cyclone with winds greater than 39 MPH. |
| Category 1 | Number of cyclones that peaked at Category 1 in a season. Defined as a hurricane with winds between 74 and 95 MPH. |
| Category 2 | Number of cyclones that peaked at Category 2 in a season. Defined as a hurricane with winds between 96 and 110 MPH. |
| Category 3 | Number of cyclones that peaked at Category 3 in a season. Defined as a hurricane with winds between 111 and 129 MPH. |
| Category 4 | Number of cyclones that peaked at Category 4 in a season. Defined as a hurricane with winds between 130 and 156 MPH. |
| Category 5 | Number of cyclones that peaked at Category 5 in a season. Defined as a hurricane with winds greater than 157 MPH. |
Data from 1851 to 2007 was compiled by Dr. Chad Steed and provided by Dr. T. J. Jankun-Kelly. Data from 2007 to 2011 was compiled by Richard Sween from National Hurricane Center annual reports. [5] The data can be viewed in tab-separated value format here. Note that years 2007-2011 do not contain HDP or PDI values.
[1] http://en.wikipedia.org/wiki/Accumulated_cyclone_energy
[2] http://en.wikipedia.org/wiki/Accumulated_cyclone_energy#Calculation
[3] http://en.wikipedia.org/wiki/Tropical_cyclone_scales#Alternative_scales
[4] http://einstein.atmos.colostate.edu/~mcnoldy/tropics/NTC.html