## 4 Discussion
Plot-to-plot equity was also not well captured by the L3 dataset in these schemes, which is identified by the plot clusters of similar values (Figure 5). However, the L3 and L2 datasets may be used to compare scheme plots or divisions. Equity was also assessed on dekadal scale. All datasets captured some level of seasonal variability in each scheme. The L3 dataset captured the magnitude of variability better than the L1 and L2 datasets. The difference in CV, or equity, between resolutions decreased with increasing plot size, this is with the expectation of the Wonji, the scheme with the largest plots. The Wonji has the least inconsistentdifference in CV of ETIa between spatial resolutions over space (e.g., adequacy in Figure 3) and time (e.g., equity in Figure 6). This is likely due to the introduction of Proba-V in March 2013, where the 100 m data is no longer resampled from the 250 m NDVI (or L1) data. In terms of ETIa, this only has a large effect in the Wonji. The other schemes only see a light deviation in results from the introduction of Proba-V. However, the L3 dataset did not capture the dekad-to-dekad changes as well, which was identified by a sometimes smoother L3 trendline. This may be a result of the revisit time of the L1 and L2 satellite data input of one or two days, compared to the L3 dataset of 16 days, providing less NDVI inputs and smoothing the results. This may become particularly influential during raining seasons, where cloud cover reduces the satellite data availability further for satellites with lower return periods and for users wishing to look beyond a seasonal scale. This affect may be being reduced by the daily meteorological data used to interpolate image gaps. Inter-annual scheme CWP was captured by all levels for all schemes irrelevant of dataset and therefore suggested that all resolutions are suitable for scheme-scale inter-annual comparison. This is compared to another study which showed that at a regional scale, the L3 resolution provided little extra value in determining agricultural boundaries or NDVI trends [32]. The three levels are derived from different sensors and therefore have different nominal band wavelengths, Landsat being the most dissimilar to the other levels. The primary use of optical bands in WaPOR is to estimate various vegetation indices (primarily NDVI). Studies in marshes and agricultural lands have shown that nominal band wavelengths limit differences between MODIS and Landsat do not greatly impact vegetation indices such as the enhanced vegetation index (EVI) or NDVI [59; 60]. However, the WaPOR products are not currently inter-calibrated, and the impacts of varying nominal wavelengths in WaPOR is not well known. The product producer (WaPOR) is currently undertaking inter-calibration to improve dataset consistency, which is suggested for best practice quality assessment [61; 62]. Though it has been suggested that Landsat 30 m data is a valuable asset to water management, which may be true, it still may not be of high enough resolution for monitoring and evaluating small-scale agriculture [63]. Pixel purity represents the relative contribution of the surface of interest to the signal detected by the remote sensing instrument [21]. For smaller plots, the signal will be mixed by varying crops or non-agricultural area. Therefore, when the plot size it smaller than the pixel size, pixel mixing will arise. We found that at the scheme level, for absolute indicators, such as productivity or adequacy, the lower resolution products are still suitable to assess scheme-level performance over time. However, for relative indicators (i.e., equity), the spatial variation is integral, and the higher resolution product is required. Therefore, while accuracy is lower and variation is not as well captured at the plot level, at the scheme level, L1 and L2 resolutions appear suitable and save time and processing costs. However, for higher-level inter-plot comparison, the L3 data provided value in all schemes for all indicators at both a dekadal and an annual scale.