# Satellite and Ground Based Thermal Observation of the 2014 Effusive Eruption at Stromboli Volcano
## 4 Results
### Field Observations
Temperatures observed with  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Date \& Time**} & \multicolumn{2}{c}{**Maximal T (K) in**} & \multicolumn{1}{c}{**Remarks**} \\ \cline{2-5}  & **TIR** & **MIR** & **SWIR** & **Remarks** \\ \hline
2014/09/10; 17:45 & 699 & / & / & We could observe the area close to the vent with T \textgreater{} 670 K. \\  & & & & Mid-flow was out of sight. The lowest part was visible, but significantly cooler with T \text  
the VarioCam camera (TIR spectrum) are significantly lower than temperatures measured with the ImageIR camera using a narrow band filter centered at 3.9 \(\upmu\)m (Figure 4). The difference between the two datasets can be partially attributed to the differences in the camera resolutions (VarioCam: 1.83 m at a distance of 2200 m), which is coarser than the resolution of the ImageIR (1.32 m). However, of course, the main reason is due to the higher sensitivity of the ImageIR for fresh lava radiating through the cracks in the lava crust. If the temperature data from both cameras (Figure 4) are applied to Stefan-Boltzmann's law to estimate first \(VRP\)[4, 5] and then \(TADR\), we obtain different values (Table 5). In addition, the effective temperature of the lava flow based on the dual band solution provides data for a third version of \(TADR\). We assumed that the temperature of the lava seen in the cracks was 1273 K. The results show that most of the flow was covered by a relatively cool lava crust (400-450 K) which covered the majority of the pixel (95%-97%, in rare pixels less than 85%). For most of the flow pixels the effective temperature was around 600 K, with a maximum value of over 800 K.  
As expected, ImageIR temperatures yield a higher \(TADR\) than VarioCam temperatures for the min \(TADR\) as well as for the max \(TADR\) model. It is interesting that \(TADR\) estimated from the effective temperature is very similar to the ImageIR results. Although we may assume that the observations in the MIR spectrum are better suited for \(TADR\) estimation, the difference between MIR and TIR observations is still significantly smaller (~16%) than the errors between min \(TADR\) and max \(TADR\) models. Thus we may conclude that the most probable \(TADR\) during our observations from a boat was 0.31 m\({}^{3}\)/s. This value was higher than \(TADR\) estimated some hours later by TET-1 (cloudy situation), but the simultaneous field observations at the time of the TET-1 overpass showed that the lava front retreated significantly up the slope. This means that the activity decreased between our observations from the boat (at 19:35-19:55; Table 5) and the TET observations (at 23:25-23:35). Figure 4: A comparison of the TIR and MIR observations from a boat on 20 September 2014 at 19:39:39; VarioCam data were resampled to the resolution of the ImageIR. \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Min TADR (m\({}^{3}\)/s)** & **Max \(TADR\) (m\({}^{3}\)/s)** \\ \hline ImageIR 3.9 \(\upmu\)m & 0.189 & 0.409 \\ VarioCam & 0.190 & 0.343 \\ T\({}_{\mathrm{eff}}\) (dual band) & 0.186 & 0.440 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: \(TADR\) based on the observations with thermal cameras on 20 September 2014 at 7:39:39 p.m.