## 3 Results
### Buoy SWH Observational Validation  
To validate our new SWH and aid in comparisons to models and alternate data presented in Section 3.4, we source all readily available wave buoy data within the satellite data domain. We find all satellite data records within 100 km of each buoy and take all the buoy wave height measurements within 3 hours of each passing satellite track. Due to the limited number of wave buoys in the Arctic we take a wider spatial area to [18] (100 km vs. 50 km). We found that reducing the spatial area for correlation to 50 km, the data correlation showed little improvement for a reduced number of coincident measurements. The pairs of measurements were used to calculate the Person correlation coefficient for each buoy record. The majority of buoy data accessed was from the 6 year time series of the Met Office Buoy K7 at \(-4.5^{\circ}\)E, 60.7\({}^{\circ}\)N. This buoy was within the SAR mode of operation for the whole time series. The top line of Figure 6 shows the comparison between the buoy record and our and RADS retrieved SWH from CS2 data coincident to the buoy location over the period 2014-2019. Our new SWH has an improved correlation compared to the RADS (0.88 to 0.86) and reduced bias, with our new SWH at +11% and RADS at +17%. Additionally SAMOSA data were also gathered for the whole 2018 for further comparison. The new SWH and RADS perform better for this year with correlations of 0.96 (0.97 for SAMOSA). The bias for 2018 is less than for the whole 2014-2019 time period with our new SWH at +7%, RADS at +12% and additionally SAMOSA data at +7%.  
Figure 5: Comparisons between our new SWH data product and existing CS2 derived data sets and models. Comparisons are performed after binning the individual tack data onto a 100 km grid. The first column is for SWH from the RADS data. Column 2 is for the WaveWatch 3 model data. Column 3 is for the SAMOSA data. Column 4 is the ECMWF model data. The top row shows scatters comparing our data and the comparison data for both LRM (blue) and SAR (green) modes (SAR mode only processed by SAMOSA). The second row shows the Normalised Bias (NBIAS) (new SWH as a percentage of the comparison SWH) and the bottom row shows the correlation between our new SWH and the comparison data for daily averaged data for the time series listed above.  
For the central Arctic two data sources were available. First is from the NOAA NDBC archive with records from fixed oil and gas platforms. These data are available for a few summers, with 2014 presented here in row three of Figure 6. This data source has times of good correlation (2014-08-3 to 2014-08-24), but also times where there is little match (2014-09-07 to 2014-09-21). Due to this both our new SWH and RADS have a correlation of around 0.5. The bottom row shows the buoy data collected as part of the MIZ project in the summer of 2014. These buoys are floating with regular contact with the ice edge (for example between 2014 and 09-07 and 2014-09-18), which presents a challenge for co-locating CS2 paths. The comparisons used here were made using our 100 km gridded SWH. The buoy presented here, shows good correlation with our new SWH (correlation of 0.77) while the RADS data at this location has no identifiable correlation.