Community Access to MODIS Satellite Reprojection and Reduction
Pipeline and Data Sets
Moderate Resolution Imaging Spectroradiometer (MODIS), the key
instrument aboard NASA's Terra and Aqua satellites, continuously
generates data as the satellites cover the entire surface of earth
every one to two days. This data is important to many scientific
analyses, however, data procurement and processing can be challenging
and cumbersome for user communities. Our current work is focused on
enabling calculations using a combination of land and atmosphere
products over land. Before performing the calculation the data must be
downloaded and transformed, from a swath space and time system to a
sinusoidal tiling system.
Downloading data for a single product for an entire year can take
several days and involves downloading via FTP many small files (on
average ~83,000 files) in hierarchical data format (HDF4). The data
processing, a swath-to-sinusoidal reprojection, is computationally
intensive. Currently available community tools only work for single
sinusoidal tiles. We have developed a data-processing pipeline that
downloads the MODIS products and reprojects them on HPC systems. HPC
systems do not traditionally run these high-throughput data-intensive
jobs and hence we need to address unique challenges for our
pipeline.
The resulting reprojected data is being widely made available to the
community through this front-end web portal. The portal will allow
users to download reprojected data (~1TB/year) for the following land
and atmosphere products: MODO4_L2 (Aerosol), MOD05_L2 (Water Vapor),
MOD06_L2 (Cloud), MOD07_L2 (Atmosphere Profile) and MOD11_L2 (Land
Surface Temperature Emissivity).