Disclaimer for Data from
Marsh Landing, Sapelo Island National Estuarine Research Reserve

The description of the data from Marsh Landing is described here.
Adpating Data for NFDRS (National Fire Danger Rating System) Calculation
To calculate NFDRS indices, 10-hour fuel mositure information is needed. It can be obtained by
  • 1. Manually weighting a 10-hour fuel stick
  • 2. By electronic fuel stick manufactured by Forestry Technology Systems (FTS). Georgia Forestry Commission uses this method for all our stations.
  • 3. By (Ralph) Nelson's formula when Solar Radiation is available. All stations from US Forestry Service uses this method in WIMS to derive 10-hour fuel moisture. Although solar radiation is measured at Marsh Landing, it is in photons/m2. Watts/m2 is needed for Nelson's formula. Prof. Gerrit Hooganboom of Unvisersity of Georgia at Griffin advises us that there is no direct conversion between photons/m2 and Watts/m2. Therefore, this method will not work.
  • 4. Georgia Forestry Commission still uses the Fire Weather Pro 3 from Remsoft to generate Fire Danger Ratings. Fire Weather Pro 3 can calculate 10-hour fuel moisture if temperature and relative humidity are available. However, NFDRS codes require "State-of-Weather" (essentially cloudiness) as an additional input for 10-hour fuel moisture calculation. When "State-of-Weather" is not available, like in this case, it will assume a "State-of-Weather" of 2 (i.e. mostly cloudy, with 0-clear and 3-overcast). In the current NFDRS code, 10-hour fuel moisture will take into account of 100-hour fuel moisture, but that piece of code was not updated in Fire Weather Pro 3. Since Remsoft has already discontinued any further development of Fire Weather Pro 3, we cannot correct this.

    Manning Class Determination Points
    GFC uses 1988 version of NFDRS. For details on how GFC runs 1988 version of NFDRS, please refer to this and that page. Fuel Model D is selected for Sapelo Island station, as the adjacent stations were using Fuel Model D. However, analysis of BI (Burning index) based on 2004-2007 data from this station showed that its range is different from other stations. Table 1. below showed the differences of the determination points for Fuel Model D and Sapelo Island. Therefore, the Class Day reported on this and that page are based the determination points for the Sapelo Island in Table 1.

    Table 1: Manning Class Determination Points for other Fuel Model D stations and Sapelo Island.
    Class Description BI Percentiles Fuel Model D Sapelo Island
    5 Extreme 97th + 90+ 129+
    4 Very High 90th - 97th 76-89 113-128
    3+ High to Very High 81st - 90th 65-75 99-112
    3 High 61st - 80th 52-64 83-98
    3- Low to Moderate 46th - 60th 44-51 72-82
    2 Moderate 21st - 45th 13-43 47-71
    1 Low 0th - 20th 12 or less 46 or less