River / channel transmission losses

Benefits

• RapidEye offers daily imagery with 5m spatial resolution.

• Frequent coverage provides a better chance to capture imagery without clouds.

• Remote sensed data allow for a rapid and rough estimation of channel transmission losses in ungauged dryland rivers.

Limitations

• Cloud cover.

• Need to purchase high resolution imagery.

Applicability for Northland

Yes, possibly depending on rivers' characteristics.

Yet, an important limitation would come from the need to acquire high-resolution imagery, which at the moment is not available freely, and would therefore induce monitoring costs.

Techniques applying optical data will be limited in coverage and temporal granularity by the persistent cloud cover in the region, particularly during the winter months. Mature cloud-masking techniques are directly available for open access multispectral data (e.g. Landsat and Sentinel-2). When using commercial data, care must be taken to ensure that there is sufficiently cloud free imagery available, as cloud masking is not as mature, and ordering a large volume of imagery to ensure complete cloud free coverage between multiple observations can become cost prohibitive.