OLR: Top of the atmosphere outgoing longwave radiative flux (W/m2)
Soil Moisture Degree of saturation within the top 2 cm of the soil (1)
Precip
TPW: Total precipitable water vapor (kg/ m2)
Precip: Model generated precipitation (mm/day)
E-P (Land): Evaporation – Precipitation over land (mm/day)
E-P (Ocean): Evaporation – Precipitation over ocean (mm/day)
3D Fields
U: Zonal Wind (m/s)
V: Meridional Wind (m/s)
T: Temperature (C)
RH: Relative Humidity (%)
Z*: Height Anomaly with respect to Zonal-Mean (m)
Calculations
Fire Weather Index (FWI):
Computed using instantaneous 2 m temperature and relative humidity, sustained wind speed at 10 m, and 24-hour corrected precipitation from MERRA-2, FWI is an index that combines the Initial Spread Index (the ability of a fire to spread after ignition) and the Buildup Index (the amount of fuel available as a function of moisture). Values of FWI exceeding 30 are considered extreme, but the FWI is interpreted differently across fire environments. Interpretation examples for other regions and technical details are provided in Field (2020). Additional details pertaining to the calculation of FWI are available in Field et al. (2015).
References
Fire Weather Index (FWI)
Field, R. D., Spessa, A. C., Aziz, N. A., Camia, A., Cantin, A., Carr, R., de Groot, W. J., Dowdy, A. J., Flannigan, M. D., Manomaiphiboon, K., Pappenberger, F., Tanpipat, V., and Wang, X.: Development of a Global Fire Weather Database, Nat. Hazards Earth Syst. Sci., 15, 1407–1423, https://doi.org/10.5194/nhess-15-1407-2015, 2015.
Field, R. D.: Evaluation of Global Fire Weather Database reanalysis and short-term forecast products, Nat. Hazards Earth Syst. Sci., 20, 1123–1147, https://doi.org/10.5194/nhess-20-1123-2020, 2020.