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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.
||Images of limited areas, as requested by
|Regional Monitoring data
||Multi-temporal images and/or images of large areas, in
support of EOS science objectives
||Images in all ASTER wavelengths (and stereo) of the
Earths entire land surface and a portion of the oceans, acquired once during the
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
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:
- The world's mountain glaciers,
- The world's active and dormant volcanoes, and
- The Long-Term Ecological Research (LTER) field sites.
As these and other tasks are defined further, more information will be provided
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
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:
- 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:
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
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.