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Terra Launch from VAFB
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Advanced Spaceborne Thermal Emission and Reflection
Radiometer
ASTER Advanced Spaceborne Thermal Emission and Reflection
Radiometer Terra Launch from VAFB Terra Orbit Parameters
OrbitSun Synchronous Descending Node Time of Day10:30 am
Altitude705 km Inclination98.2o Repeat Cycle16 days ASTER
Instrument Overview
ASTER is an international effort: Japanese government is providing
the instrument under METI (Ministry of Economy, Trade and Industry)
and is responsible for Level 1 data processing Flies on NASAs Terra
platform Science team consists of Japanese, American and Australian
scientists ASTER Characteristics
Wide Spectral Coverage 3 bands in VNIR(0.52 0.86 m) 6 bands in SWIR
(1.6 2.43 m) 5 bands in TIR(8.125 m) High Spatial Resolution 15m
for VNIR bands 30m for SWIR bands 90m for TIR bands Along-Track
Stereo Capability B/H 0.6 DEM Elevation accuracy: m (3) DEM
Geolocation accuracy: 50m (3) Terra ASTER ASTER Bands ASTER
Spectral Bandpass Baseline Performance Requirements ASTER
Characteristic Functions
Item VNIR SWIR TIR Scan Pushbroom Whiskbroom Reflective (Schmidt)
Refractive Reflective (Newtonian) D=82.25 mm (Nadir) D=190 mm D=240
mm D=94.28 mm (Backward) Dichroic and band pass filter Si-CCD
PtSi-CCD HgCdTe (PC) 5000 x 4 2048 x 6 10 x 5 Cryocooler
(Temperature) not cooled Stirling cycle, 77 K Stirling cycle, 80 K
Telescope rotation Pointing mirror rotation Scan mirror rotation +
24 deg. deg. Cold plate and Radiator 2 sets of Halogen lamps
Blackbody and monitor diodes K Thermal control Calibration method
Telescope optics Spectrum separation Band pass filter Focal plane
(Detector) Cross-track pointing ASTER Observation Modes
Subsystem Data Rate (Mbps) VNIR SWIR TIR Daytime Full Mode 89.2
VNIR Mode -- 62.0 Stereo Mode 31.0 TIR Mode 4.1 Nighttime S+T Mode
27.2 ASTER Cross-Track Pointing
EOS AM-1 Orbit Interval:172 km on the equator ASTER Imaging Swath:
km Fixed 7 Pointing Positions + Arbitrary Pointing (rare cases)
Total Coverage in Cross-Track Direction by Pointing Full Mode:232
km(+116 km / degrees) Recurrent Period:16 days (48 days for
average) VNIR :636 km(+ 318 km / +24 degrees) Recurrent Pattern:
days(4 days average) Comparison between ASTER Recurrent Period
(day)
and the other imagers Terra ASTER JERS-1 OPS Landsat ETM SPOT HRV
Spectral Bands VNIR: 3 3 4 SWIR: 6 2 TIR: 5 1 Stereo Capability
Along-track B/H = 0.6 B/H = 0.3 Multi-orbit B/H: up to 1.0 Spatial
Resolution (m) VNIR: 15 18 x 24 30 (15) 20 (10) SWIR: 30 30 TIR: 90
60 Pointing Angle VNIR: +24 +27 SWIR: +8.55 TIR: +8.55 Swath (km)
75 185 Recurrent Period (day) 16 44 26 Conversion of DN to
Radiance
(Level-1A) DN values can be converted to radiance as follows. L = A
V /G + D (VNIR and SWIR bands) L = AV + CV2 + D (TIR bands) Where
L: radiance (W/m2/sr/m) A: linear coefficient C: nonlinear
coefficient D: offset V: DN value G: gain For TIR, radiance can be
converted into brightness temperature using Planks Law as shown
below. i : the wavelength TBB : the brightness temperature C1 = x
(W cm-2 m4) C2 = x (m K) (Fujisada, 2001 Level-1B Data Product The
Level-1B data product can be generated by applying the Level1A
coefficientsfor radiometric calibration and geometric resampling.
Map projection : UTM, LCC, SOM, PS, Lat/Long Resampling : NN, BL,
CC The geolocation field data are included in the Level-1B data to
know the pixel position (latitude/longitude) on the ground.
(Fujisada, 2001 Conversion of DN to Radiance (Level-1B)
Radiance value can be obtained from DN values as follows; Radiance
= (DN value -1) x Unit conversion coefficient Unit conversion
coefficients, which is defined as radiance per 1DN, are used to
convert from DN to radiance. The unit conversion coefficient will
be keptin the same values throughout mission life. (Fujisada, 2001
Band-to-band Registration Accuracy for Level-1B Data
Band-to-band Registration Accuracy for Level-1B Data Band-to-band
Registration Errors Pixel Geolocation Knowledge Within Each
Telescope Among Telescopes Relative Absolute SWIR/VNIR TIR/VNIR
ver. 1.02 < 0.2 pixels < 0.5 pixels < 15 m < 50 m ver.
2.0 < 0.1 pixels SNRs Measured in Actual Data
212 > 54 9 213 > 70 8 177 7 181 6 5 Onboard lamp data (the
minimum values for Lamp-A, higher than the specified input
radiance) 218 > 140 4 SWIR 136 3N 200 2 (slightly lower than the
specified input radiance) 224 1 VNIR Remarks Measured Value
Specified Band # Subsystem ASTER Gain Settings Gain Normal High
Low-1 Low-2 VNIR 1.0 2.5 or 2.0
0.75 N/A SWIR 2.0 0.12 0.18 Detection of High Temperature Targets
SWIR Band # 4 5 6 7 8 9 Saturation Radiance (W/m2/sr/um) 73.3 103.5
98.7 83.8 62.0 67.0 Highest Temperature (deg. C.) 466 (739K) 385
(658K) 376 (649K) 358 (631K) 330 (603K) 326 (599K) ASTER Science
Team Selects algorithms for higher level standard products Produces
software for standard products Conducts joint calibration and
validation exercises Conducts mission operations, scheduling, and
mission analysis ASTER Calibration Activities
1. Onboard Calibration Devices VNIR: Halogen lamp + photodiode
monitor (dual units) SWIR: Halogen lamp + photodiode monitor (dual
units) TIR : Variable temperature blackbody (BB) 2. Onboard
Calibration (OBC) (1) Long-term calibration: Every 17 days ( Every
33 days) VNIR, SWIR: Halogen lamp + earth night side observation
TIR: BB temperature changed from 270 K to 340 K (2) Short-term
calibration: Before each TIR observation TIR: BB temperature fixed
at 270 K 3. Vicarious Calibration (VC) VNIR, SWIR: Ivanpah Playa,
Railroad Valley Playa, Tsukuba, etc. TIR: Lake Tahoe, Salton Sea,
Lake Kasumigaura, etc. VNIR In-flight Calibration Trend SWIR
In-flight Calibration Trend ASTER Instrument Operations
ASTER has a limited duty cycle which implies decisions regarding
usage must be made Observation choices include targets, telescopes,
pointing angles, gains, day or night observations Telescopes
capable of independent observations and maximum observation time in
any given orbit is 16 minutes Maximum acquisitions per day
Acquired~750 Processed~330 Science Prioritization of ASTER data
acquisition
NASA HQ, GSFC, and METI have charged the Science Team with
developing the strategy for prioritization of ASTER data
acquisition Must be consistent with EOS goals, the Long Term
Science Plan, and the NASA-METI MOU Must be approved by EOS Project
Scientist Global Data Set A one-time acquisition
All land surfaces, including stereo Maximize high sun Optimal gain
Consists of pointers to processed and archived granules which: Meet
the minimum requirements for data quality Are the best acquired
satisfying global data set criteria Science Team has prioritized
areas for acquisition (high, medium and low) Regional Data Sets
Focus on specific physiographic regions of Earth, usually requiring
multi-temporal coverage Acquisitions are intended to satisfy
multiple users, as opposed to specific requirements of individual
investigator or small team Defined by the ASTER Science Team in
consultation with other users (e.g., EOS interdisciplinary
scientists) Science team provides prioritization (relative to other
regional data sets) on a case-by-case basis Targeted
Observations
Targeted observations are made in response to Data Acquisition
Requests (DARs) from individual investigators or small groups for
specific research purposes Japanese Instrument Control Center (ICC)
does prioritization of DAR based on guidelines provided by Science
Team Targeted observation may also be used to satisfy the global
data set or regional data set acquisition goals, where appropriate
ASTER Operation Complexity
Data Acquisition Based Upon Users Requests Instrument Operation
Constraints (1) Data Rate Maximum average data rate:8.3 Mbps Peak
data rate: Mbps (2) Power Consumption (3) Pointing Change 3.
Selection of Operation Mode / Gain Settings 4. Utilization of Cloud
Prediction Data Duty Cycle : 8% Automatic Generation of Data
Acquisition Schedule ASTER US-JAPAN Relation
Terra ASTER Sensor TDRS Downlink ATLAS Science data Engineering
data Telemetry data Uplink Command Direct Downlink TDRSS Japan US
data Level-0 data DRS Expedited Data Set ASTER GDS Telemetry data
EOSDIS Activity Product Product DAR, DPR DAR, DPR Product Data
Processing/Analysis (Level 0Level 1) (High Level Product) Mission
Operation (Observation Scheduling) Data Archive/Delivery User User
Pacific Link ASTER Standard Data Products ASTER Primary
Objectives
To improve understanding of the local- and regional-scale processes
occurring on or near the earths surface. Obtain high spatial
resolution image data in the visible through the thermal
infraredregions. Why? Actually, ASTER-that Im gonna present here-is
the only high spatial resolution instrument on the TERRA platform.
The other sensors monitor the earth at moderate to coarse spatial
resolutions.For those, ASTER will serve as a 'zoom' lens.So ASTER
can be saidto be the core sensor of those five. (1) To promote
research into geological phenomena of tectonic surfaces and
geological history through detailed mapping of the Earths
topography and geological formations.(This goal includes
contributions to applied research in remote sensing.) (2) To
understand distribution and changes of vegetation. (3) To further
understand interactions between the Earths surface and atmosphere
by surface temperature mapping. (4) To evaluate impact of volcanic
gas emission to the atmosphere through monitoring of volcanic
activities. (5) To contribute to understanding of aerosol
characteristics in the atmosphere and of cloud classification. (6)
To contribute to understanding of the role coral reefs play in the
carbon cycle through coral classification and global distribution
mapping of corals. ASTER is the zoom lens of Terra! ASTER Web Site:
APPLICATIONS Surface Energy Balance Geology Wild Fires
Urban Monitoring Glacial Monitoring Volcano Monitoring Wetland
Studies Land Use Surface Energy Balance Surface Energy Balance from
ASTER data
El Reno OK, 4-Sep-2000, Kustas & Norman 2-source model ASTER
data of El Reno OK, 4-Sep-2000: NDVI & Surface Temperature
Geology 3 2 1 3 2 1 DST 4 6 8 DST DST Wild Fires Hayman Fire,
Colorado June 16, 2002 ASTER bands as RGB Urban Monitoring Eiffel
Tower Arc de Triomphe Louvre La Defense
Major cultural landmarks easy to see La Defense Glacial Monitoring
Global Land Ice Measurements from Space
View from top of Llewellyn Glacier, British Columbia Goal is to
determine the extent of worlds glaciers and the rate at which they
are changing. Acquire global set of ASTER images Map global extent
of land ice Analyze interannual changes in length, area, surface
flow fields Volcano Monitoring January 2002 Eruption of Nyiragongo
Volcano, Congo
Nyiragongo erupted January 17, 2002 sending streams of lave through
the town of Goma. More than 100 people were killed. This
perspective view combines ASTER thermal data (red) showing the
active lava flows and lava in the crater; Landsat Thematic Mapper
image, and Shuttle Radar Topography Mission digital elevation data.
Wetland Studies Sediment Image Temperature Image
Sediment image is B1 color coded, T image is b12 color-coded. Land
is masked out in both Land Use US-Mexico border at Mexicali
Note major irrigatin differences across border, field sizes,
shapes, etc How Do I Get ASTER Data? Browse the archive: use the
EOS Data Gateway (EDG) to find what data have already been
acquired. Order data products desired: Submit a Data Acquisition
Request: First become an authorized user; then request satellite
obtain your particular data