1. Advanced Spaceborne Thermal Emission and Reflection Radiometer
ASTER
Advanced Spaceborne Thermal Emission and Reflection Radiometer

2. Terra Launch from VAFB

4. Terra Orbit Parameters
Orbit Sun Synchronous
Descending Node
Time of Day 10:30 am
Altitude 705 km
Inclination 98.2o
Repeat Cycle 16 days

5. 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 NASA’s Terra platform
Science team consists of Japanese, American and Australian scientists

6. ASTER Characteristics
Wide Spectral Coverage
3 bands in VNIR (0.52 – 0.86 μm)
6 bands in SWIR (1.6 – 2.43 μm)
5 bands in TIR (8.125 – μm)
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 (3σ)
DEM Geolocation accuracy: 50m (3σ)
Terra
ASTER

7. ASTER Bands

8. ASTER Spectral Bandpass

9. Baseline Performance Requirements

10. 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

11. 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

12. 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)

13. 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

14. 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/µm)
A: linear coefficient
C: nonlinear coefficient
D: offset
V: DN value
G: gain
For TIR, radiance can be converted into brightness temperature using Plank’s Law as shown below.
i : the wavelength
TBB : the brightness temperature
C1 = x (W cm-2 µm4)
C2 = x (µm K)
(Fujisada, 2001）

15. Level-1B Data Product
• The Level-1B data product can be generated by applying the Level1A coefficients for 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）

16. 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 kept in the same values throughout mission life.
(Fujisada, 2001）

17. 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

18. 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

19. 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)

20. 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

21. 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.

22. VNIR In-flight Calibration Trend

23. SWIR In-flight Calibration Trend

24. 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

25. 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

26. 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)

27. 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

28. 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

29. ASTER Operation Complexity
Data Acquisition Based Upon User’s 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

30. ASTER US-JAPAN Relation
Terra
ASTER Sensor
TDRS
Downlink
ATLASⅡ
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 0→Level 1)
(High Level Product)
・Mission Operation
　(Observation Scheduling)
・Data Archive/Delivery
User
User
Pacific Link

31. ASTER Standard Data Products

32. ASTER Primary Objectives
To improve understanding of the local- and regional-scale processes occurring on or near the earth’s surface.
Obtain high spatial resolution image data in the visible through the thermal infrared regions.
Why?
Actually, ASTER-that I’m 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 said to 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 Earth’s 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 Earth’s 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!

33. ASTER Web Site:

34. APPLICATIONS Surface Energy Balance Geology Wild Fires
Urban Monitoring
Glacial Monitoring
Volcano Monitoring
Wetland Studies
Land Use

35. Surface Energy Balance

36. Surface Energy Balance from ASTER data
El Reno OK, 4-Sep-2000, Kustas & Norman 2-source model

37. ASTER data of El Reno OK, 4-Sep-2000: NDVI & Surface Temperature

38. Geology

39. 3 2 1
3 2 1 DST
4 6 8 DST
DST

40. Wild Fires

41. Hayman Fire, Colorado
June 16, 2002
ASTER bands as RGB

42. Urban Monitoring

43. Eiffel Tower Arc de Triomphe Louvre La Defense
Major cultural landmarks easy to see
La Defense

44. Glacial Monitoring

45. Global Land Ice Measurements from Space
View from top of Llewellyn Glacier, British Columbia
Goal is to determine the extent of world’s 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

46. Volcano Monitoring

47. 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.

48. Wetland Studies

49. Sediment Image Temperature Image
Sediment image is B1 color coded, T image is b12 color-coded. Land is masked out in both

50. Land Use

51. US-Mexico border at Mexicali
Note major irrigatin differences across border, field sizes, shapes, etc

52. 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