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Dataset
Open Access
Creative Commons Attribution 4.0 International License
HAMSTER: Hyperspectral Albedo Maps dataset with high Spatial and TEmporal Resolution
Giulia Roccetti1, 2 , Luca Bugliaro3, Felix Gödde2, Claudia Emde3, 2, Ulrich Hamann4, Mihail Grigorov Manev2, Michael Fritz Sterzik1, and Cedric Pascal Wehrum2
1European Southern Observatory
2Ludwig-Maximilians-Universität München
3German Aerospace Center
4Federal Office of Meteorology and Climatology MeteoSwiss
First published:
July 8, 2024
DOI: 10.57970/04zd8-7et52
Keywords:
albedo
MODIS
energy budget
radiative transfer
seasonal variability
Earth System Models

Roccetti, G., Bugliaro, L., Gödde, F., Emde, C., Hamann, U., Manev, M., G., Sterzik, M., F., and Wehrum, C., P. (2024): HAMSTER: Hyperspectral Albedo Maps dataset with high Spatial and TEmporal Resolution. LMU Munich, Faculty of Physics. (Dataset). DOI: 10.57970/04zd8-7et52

wget and curl are the two standard tools that are available on most Linux and macOS computers. wget contains a feature for downloading a list of files: 
wget -x -nH -i 'https://opendata.physik.lmu.de/04zd8-7et52/?list'
curl is missing a feature like that, but the same functionality can be created by combining curl and xargs: 
curl 'https://opendata.physik.lmu.de/04zd8-7et52/?list' | xargs -I URL -n1 bash -c 'curl --create-dirs -o ${1:31} ${1}' -- URL
Abstract
This dataset contains 365 hyperspectral albedo maps of Earth, one for each day of the year. The hyperspectral albedo maps are built from a 10-year average of the MODIS Surface Reflectance dataset (MCD43D 42-48, version 6.1). Using a Principal Component Analysis (PCA) regression algorithm we combine different hyperspectral laboratory and in-situ measurements spectra of various dry soils, vegetation surfaces and mixure of both to reconstruct the albedo maps in the entire wavelength range from 400 to 2500 nm, with a spectral resolution of 10 nm. The hyperspectral albedo maps have a spatial resolution of 0.05° in latitude and longitude. Additional hyperspectral albedo maps with a coarser spatial or spectral resolution are available upon request.
README.md

Authors: Giulia Roccetti, Luca Bugliaro, Felix Gödde, Claudia Emde, Ulrich Hamann, Mihail Manev, Michael Fritz Sterzik, Cedric Wehrum

Contact: giulia.roccetti@eso.org giuli.roccetti@gmail.com

Related publication: HAMSTER: Hyperspectral Albedo Maps dataset with high Spatial and TEmporal Resolution, Roccetti et al., 2024, https://doi.org/10.5194/egusphere-2024-167

The dataset has 365 files, each corresponding to a day of the year (DOY). The wavelength range starts at 400 nm (wvl = 0) and ends at 2500 nm (wvl = 211), in steps of 10 nm.

Description of the variables in the netCDF4 files:

variable name            dimension      resolution                      
Latitude (lat) 3600 0.05°
Longitude (lon) 7200 0.05°
Wavelength (wvl) 211 10 nm
Black_Sky_Albedo      lat, lon, wvl 0.05° x 0.05° x 10 nm

Spectral evolution of Earth's albedo for DOY 265.

Download_movie

Seasonal variablity of the spectral albedo of different regions of the world derived from HAMSTER
Seasonal variablity of the spectral albedo of different regions of the world derived from HAMSTER.

Example to read and plot the data with python and netCDF4:

import netCDF4 as nc
import matplotlib.pyplot as plt
data = nc.Dataset("DOY001.nc", "r", format='NETCDF4')
albedo = data.variables["Black_Sky_Albedo"]
plt.imshow(albedo[500:1500,3300:4300,40], vmin=0, vmax=1, cmap='YlGnBu_r')
plt.colorbar()
Europe and Northern Africa black-sky albedo at 800 nm
Europe and Northern Africa black-sky albedo at 800 nm

Acknowledgements

We acknowledge NASA LAADS DAAC for providing the MCD43D42-48 data products.

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