impacts of El Niño and La Niña on interannual snow accumulation in the Andes: results from a high-resolution 31 year reanalysis

Snowpacks in the Andes are vital water sources for rivers in South America. It impacts the atmospheric circulation and downstream water availability of the entire South American continent. For downstream water resources management, it is important to quantify snow water volumes and characterize the space-time variability of the Andes snowpack. 

The Andes Snow Reanalysis (Andes-SR) dataset contains the daily reanalysis snow water equivalent (SWE) from the year 1984 to 2015, along with the static DEM data, and the glacier mask associated with the dataset. The SWE estimates were originally generated by integrating observed snow depletion data from Landsat together with a snow model forced by the Modern-era Retrospective Analysis for Research and Applications as described in Cortes and Margulis (2017). 

The dataset is stored in HDF5 format (*.h5 files) on a regular latitude/longitude grid at a 0.001-degree resolution (i.e. ~100 m), which is regridded from the raw resolution 180 m resolution on a UTM grid.

Methods
The HDF5 files are a regridded form of the raw reanalysis results described in Cortes and Margulis (2017). The raw data was 180 m resolution on a UTM grid for each watershed over the domain. In the HDF5 files the grid is a regular lat/lon grid at a 0.001 degree resolution (i.e. ~100 m). For the SWE data, the data is provided as daily maps over the full water year. Within each HDF5 file, data is stored in “chunks” where each daily (or static) map represents a chunk. This allows for a single day’s worth of data be loaded if loading the full year is not needed. Maps are stored in row (lat) vs. column (lon) format. Time-varying map data are generally stored as integers to reduce file size with a no-data value (i.e. outside of the domain) of -32768. Latitude and longitude vectors are stored in each file.