Alaska Lake and Pond Occurrence Dataset

The Alaska Lake and Pond Occurrence Dataset (ALPOD) is a spatially explicit map of seasonal fluctuations in lake and pond extent across Alaska. ALPOD is constructed from Sentinel-2 imagery and its lake occurrence raster has a 10 m resolution, with each pixel recording the percentage of observations classified as open water during the 2016-2021 ice-free seasons at near-daily temporal resolution. The number of water bodies depends on the occurrence threshold, but a conservative estimate is that ALPOD maps over 800,000 lakes and ponds larger than 0.001 square km. The data format includes lake occurrence rasters tiled by UTM zone and latitude, as well as a vector product defined based on a 25% occurrence threshold. ALPOD was created using a U-Net lake identification model and manual inspection to produce a maximum possible lake extent mask. This mask serves as the region of interest for an adaptive NDWI threshold water classification algorithm written in Google Earth Engine, which was used to classify open water within the maximum lake mask in every available cloud and ice free Sentinel-2 image during the study period. The resulting dataset is suitable for investigations of individual water bodies as well as lake and pond patterns across Alaska.

Geotiffs included here are 10 m resolution lake occurrence rasters with each pixel recording the percentage of observations classified as open water during the 2016-2021 ice-free seasons. They are tiled by UTM zone above 60 degrees north. Regions below 60 degrees north are separated into two geotiffs.