ASTER Data Collection Categories
better manage ASTER observing resources, three data collection categories for science data
have been defined. These categories are based on data-set size and science objectives.
|Local Observations||Images of limited areas, as requested by authorized ASTER Users|
|Regional Monitoring data||Multi-temporal images and/or images of large areas, in support of EOS science objectives|
|Global Map||Images in all ASTER wavelengths (and stereo) of the Earths entire land surface and a portion of the oceans, acquired once during the EOS-AM1 mission|
Local Observations will be made in response to data acquisition requests from authorized ASTER Users. Local Observations might include, for example, scenes for analyzing land use, surface energy balance, or local geologic features.
One subset of Local Observations consists of images of such ephemeral events as volcanoes, floods, or fires. Requests for "urgent observations" of such phenomena must be fulfilled in short time periods (of a few days). These requests receive special handling.
Regional Monitoring Data:
Regional data sets contain the data necessary for analysis of a large region (often many regions scattered around the Earth) or a region requiring multi-temporal analysis. A "Local Observation" data set and a "Regional Monitoring" data set are distinguished by the amount of viewing resources required to satisfy the request, where smaller requirements are defined as Local Observations and larger requirements are defined as Regional Monitoring.
The ASTER Science Team has already selected a number of Regional Monitoring tasks. Among the most significant are three which involve repetitive imaging of a class of surface targets:
As these and other tasks are defined further, more information will be provided here.
The Global data set will be used by investigators of every discipline to support their research. The high spatial resolution of the ASTER Global Map will complement lower resolution data acquired more frequently by other EOS instruments. This data set will include images of the entire Earths land surface, in all ASTER spectral bands and stereo.
Each region of the Earth has been prioritized by the ASTER Science Team for observation as part of the Global Map.
Currently the following characteristics have been identified for images in the Global Map data set:
Allocation of science data:
- One-time coverage,
- High sun angle,
- Optimum gain for the local land surface,
- Minimum snow and ice cover,
- Minimum vegetation cover, and
- No more than 20% cloud cover (perhaps more for special sub-regions).
At the present time, it is expected that approximately 25% of ASTER resources will be allocated to Local Observations, 50% to Regional Monitoring, and 25% to the Global Map.
Global Map data has been further sub-divided among high priority areas which are currently allocated 25%, medium priority areas which are currently allocated 50%, and low priority areas which are currently allocated 25%.
DARs and STARs:
Individual ASTER users can request that the instrument acquire certain data by submitting Data Acquisition Requests (DARs). A DAR Tool will be provided by the ESDIS Project to enable users to do so. Note that only authorized ASTER Users can use this tool. ASTER Team Members and EOS Principal Investigators are already authorized users. Other investigators interested in becoming authorized ASTER Users may submit User Authorization Proposals from this website.
Regional Monitoring data sets and the Global Map will be acquired by ASTER, in response to acquisition requests submitted by the ASTER Science Team acting on behalf of the science community. These Science Team Acquisition Requests (STARs) are submitted directly to the ASTER Ground Data System in Japan. Under limited circumstances, STARs for Local Observations may also be submitted by the Science Team.
STARs for Regional Monitoring data are submitted by the ASTER Science Team only after a proposal for the Regional Monitoring task has been submitted and accepted. These "STAR Proposals" will be evaluated by ASTER's science working groups before being formally submitted to the Science Team.
An already-authorized ASTER User, who wants ASTER to acquire far more data than he or she is allocated, may submit a STAR Proposal to the Science Team. Please note that the process for evaluating STAR proposals is cumbersome and time-consuming. Far fewer STAR Proposals will be approved than ASTER User Authorization Proposals.