Net longwave irradiance LW_net

The difference between the downward LW_d and upward LW_u long-wave radiation in the 4-100 µm wavelength range. Values are expressed in [Wm^-2]. The SatBałtyk system provides maps (spatial resolution 1 km) of mean daily effective radiation as a component of the radiation budget. Negative values signify that the sea emits more energy in the form of long-wave radiation than the atmosphere. Positive values indicate the reverse condition.

Methodology

The effective radiation is calculated on the basis of mean daily maps of the downward and upward long-wave radiation as determined within the SatBałtyk System (SBRS model [1]).

Validation

The statistical error, expressed as the standard deviation of the differences between net longwave irradiance measured in situ and those determined using the model for daily average values, was  σ=12.2 Wm^-2. The systematic error (the mean difference between measured and calculated values) was estimated at -1.1 Wm^-2. The empirical measurements used for validating the model were obtained from Baltic Beta drilling rig localted on the Baltic Sea (φ=55°28’50.9’’N, λ=18°10’44.7’’E).

Fig. Comparison of mean daily values of measured effective radiation LW_NET,real and calculated LW_NET,model on the basis of the SBRS model.

[1]SBRS - Surface Radiation Budget for SatBałtyk