## 3 Results and Discussion
\(T_{min}\) for \(b_{d}\) decreases about 20% from 24.6 \({}^{\circ}\)C to 19.1 \({}^{\circ}\)C for salinity varying from 0 to 40 psu, whereas over the same salinity range \(T_{min}\) for \(b_{c}\) increases slightly by \(\sim\)3%, from 32.2 \({}^{\circ}\)C to 33.2 \({}^{\circ}\)C. In terms of absolute magnitude, \(b_{d}\) is about 2-10 times greater than \(b_{c}\) (Figure 2a), but in terms of change with respect to salinity, \(b_{c}\) is about 10 times greater than \(b_{d}\) (Figure 2b). As a result, the change of \(T_{min}\) for the total  
Figure 1: The temperature variations of light scattering by pure water, calculated using the [PERSON] and [PERSON] [9] model (i.e., Equation (2)) at 436 and 546 nm and normalized by their respective values at 25 \({}^{\circ}\)C, are compared with the estimates using the [PERSON], et al. [7] model and with the measurements by [PERSON] and [PERSON] [6]. Note that the normalized variations estimated by the [PERSON] and [PERSON] model overlap with each other at the two wavelengths. scattering coefficient, \(b\) is dominated by \(b_{c}\), and increases from 24.6 \({}^{\circ}\)C to 27.5 \({}^{\circ}\)C for \(S\) from 0-40 psu (Figure 3). It is well known that \(T_{max}\) for density [26] and \(T_{min}\) for isothermal compressibility [27] decrease with the salinity. Here, we show for the first time that \(T_{min}\) for light scattering increases with salinity, which is largely due to the temperature variation of scattering introduced by sea salts. Table 1 lists the variations of \(T_{min}\) for \(b_{d}\), \(b_{c}\), and \(b\) at different salinities. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \(S\) (psu) & **0** & **5** & **10** & **15** & **20** & **25** & **30** & **35** & **40** \\ \hline \(b_{d}\) (\(\mathbf{m^{-1}}\)) & 24.6 & 24.0 & 23.4 & 22.7 & 22.0 & 21.2 & 20.5 & 19.8 & 19.1 \\ \(b_{c}\) (\(\mathbf{m^{-1}}\)) & 32.2 & 32.3 & 32.5 & 32.7 & 32.8 & 33.0 & 33.1 & 33.2 \\ \(b\) (\(\mathbf{m^{-1}}\)) & 24.6 & 25.3 & 25.9 & 26.3 & 26.6 & 26.9 & 27.2 & 27.3 & 27.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Temperatures (\(T_{min}\) in \({}^{\circ}\)C) at which the scattering of light at 546 nm by pure seawater due to density fluctuations (\(b_{d}\)), concentration fluctuations (\(b_{c}\)), and their total (\(b\)) reach the minimum for various salinities (\(S\)). Figure 3: Total scattering coefficient by pure seawater at 546 nm as a function of temperature and salinity. Lines of progressive colors from blue to red correspond to different salinities from 0 to 40 psu at 5 psu increments. The dotted line connects \(T_{min}\) at different salinities. Figure 2: Light scattering by pure seawater at 546 nm as a function of temperature and salinity. (**a**) \(b_{d}\), the scattering due to density fluctuation; and (**b**) \(b_{c}\), the scattering due to concentration fluctuation. Lines of progressive colors from blue to red correspond to different salinities from 0 to 40 psu, at 5 psu increments. The dotted line in each plot connects \(T_{min}\) at different salinities. In conclusion, using the latest scattering models for water and seawater, we find that water exhibits an anomalous light scattering behavior, with a minimum occurring at 24.6 \({}^{\circ}\)C for pure water, and that this minimum increases with the salinity, reaching 27.5 \({}^{\circ}\)C at 40 psu. This temperature behavior changes little spectrally. Caution should be exercised when using the [PERSON], et al. [7] model, which predicts a temperature behavior of scattering that is inconsistent with the measurements [6] or the results of this study. [PERSON] and [PERSON] conceived and designed the experiments; [PERSON] wrote the paper. National Aeronautics and Space Administration (NASA) (NNX13 AN72G, NNX15 AC85G) and National Science Foundation (NSF) (1355466, 1459168). We thank three anonymous reviewers and [PERSON] for their comments, which have improved the manuscript. The authors declare no conflict of interest.