CloudSat and MODIS Data Merging: The First Step toward the Implementation of the NASA A-Train Data Depot

The A-Train is a succession of six U.S. and international sun-synchronous orbit satellites seconds to minutes apart across the 1:30 p.m. local afternoon equator crossing time according to the sequence: Orbiting Carbon Observatory (OCO), EOS Aqua, CloudSat, Polarization & Anisotropy of Reflectances for Atmospheric Sciences coupled with Observations from a Lidar (PARASOL), CALIPSO, and EOS Aura. Flying in such a formation increases the number of observations and enables coordination between science observations, resulting in a more complete “virtual science platform.” The A-Train formation will allow for synergistic measurements where data from several different satellites can be used together to obtain comprehensive information about various key atmospheric components or processes. This combined information from several sources will give a more complete answer to many questions than would be possible from any single satellite. .. In order to take advantage of this unique opportunity, the NASA Goddard Space Flight Center (GSFC) Earth Sciences (GES), Data and Information Services Center (DISC) is building an A-Train Data Depot (ATDD) to process, archive, access, visualize, analyze and correlate distributed atmosphere measurements from various instruments along A-Train tracks. The ATDD will enable the seamless access to remotely located A-Train data, so that they can be combined to create a consolidated vertical view of the Earth's Atmosphere along the flying tracks. Once the infrastructure of the ATDD is in place, it can be easily evolved to serve data from all A-Train data measurements as a one-stop shopping that will save time and improve efficiency. Users interest in Atmospheric Chemistry, and Water and Energy Science will have a clear connection with their data of interest by being able to access the specific subset (parameter, spatial, and temporal) of interest. .. This presentation will describe the initial efforts at the GES/DISC in the development of the ATDD portal beginning with the CloudSat products and subsetting services from the CloudSat data processing facility at the Cooperative Institute for Research in the Atmosphere (CIRA). The project combines data from the AQUA MODIS instrument with the CloudSat 94 GHz cloud imaging radar and serves as a benchmark to the challenges facing the full development and implementation of the ATDD. The main issues to be discussed include ground track matching to determine the MODIS pixel closest to the CloudSat ground track, management of pixel resolution differences, compensation for orbital variations, etc.