DOI: 10.5061/dryad.ngf1vhj0s
title: Data from: impacts of El Niño and La Niña on interannual snow accumulation in the Andes: results from a high-resolution 31 year reanalysis

description: 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.
description: 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.
description: # Andes UCLA Daily Snow Reanalysis, Version 1 The Andes Snow Reanalysis
 Dataset (Andes-SR) contains snow water equivalent (SWE) and static
 information including DEM and glacier mask. The files in this dataset are
 regridded to 0.001 degree of spatial resolution from a raw resolution of
 180 m. ## Description of the data and file structure The data is stored in
 HDF5 format (\*.h5 files), which is a self-describing data format that can
 be loaded by many software packages. The directory structure of the
 dataset is: ANDES\_SWE\_WYyyyy.h5 ANDES\_static\_data\_new.h5
 ANDES\_static\_data\_glacier\_new.h5 which respectively contain the
 reanalysis snow water equivalent, the static DEM data (and implicit mask,
 projection info., etc.) associated with the dataset, glacier mask. The
 placeholder "yyyy" shown above represents a particular water
 year, where the water year extends from April 1st though March 30th of the
 following year. For example, WY1985 corresponds to April 1st, 1985 through
 March 31st, 1986. ## Sharing/Access information Links to other publicly
 accessible locations of the data:
 https://ucla.app.box.com/v/ANDES-SWE-REANALYSIS Data was derived from the
 following sources: Margulis, S., M. Girotto, G. Cortes, and M. Durand,
 2015: A Particle Batch Smoother Approach to Snow Water Equivalent
 Estimation, Journal of Hydrometeorology, doi:10.1175/JHM-D-14-0177.1, 16,
 1752-1772. Margulis, S., G. Cortes, M. Girotto, and M. Durand, 2016: A
 Landsat-era Sierra Nevada (USA) Snow Reanalysis (1985-2015). J.
 Hydrometeor., doi:10.1175/JHMD-15-0177.1, 17, 1203-1221. Cortes, G., and
 S. Margulis (2017), Impacts of El Nino and La Nina on interannual snow
 accumulation in the Andes: Results from a high-resolution 31 year
 reanalysis, Geophys. Res. Lett., 44, 68596867, doi:10.1002/2017GL073826.