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Polar Space
Task Group
Polar Space Task GroupSAR Coordination Working Group Meeting 5
Ice SheetsBernd Scheuchl (UCI) & Thomas Nagler (ENVEO)
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
Relevant News ‐ SAR
This is a great time to work in polar remote sensing.• SAR data continuity seems almost guaranteed with new satellites launched and significant commitment of space agencies in support of Polar Science (largely through this forum)
• The scientific community showing capability and to process the data and interest in the information generated.
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
Other Relevant News ‐ Landsat
A significant commitment of USGS for Landsat‐8 acquisitions in Antarctica and Greenland.‐ High latitude
acquisitions (off nadir)
‐ Ascending node (night time) coverageof selected HMA regions
Sentinel‐2 is equally suited Fahnestock, M., Scambos, T., Moon, T., Gardner, A., Haran, T. and Klinger, M., 2015. Rapid large-area
mapping of ice flow using Landsat 8. Remote Sensing of Environment, doi: 10.1016/j.rse.2015.11.023.
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
Other Relevant News ‐WorldView
Large scale WorldView stereo data collection in Polar regions. DEM production is underway.
Material courtesy of Ian Howat (Bird Polar Research Center, OSU) and Paul Morin (Polar Geospatial Center UMN).
Antarctic OIB 2015-16 Stereo CollectionsArctic OIB 2016 Stereo Collections
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
Ice Sheet Science Issues
Key ice sheet science issues include:• Surface elevation change• Ice velocity• Grounding line location• Calving front location
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
Ice Sheet Requirements
A general set of recommendations for SAR include the following:• Polarization: HH preferred• Acquisition mode: Stripmap preferred,
Notable exception is Sentinel‐1 IWS, a TOPS mode.• Incidence angle range: Based on experience, 23 to 45 degrees
worked fine (even 57 deg. to cover South Pole). Where possible, the same range of incidence angles should be used over individual glaciers and super sites to simplify result comparisons.
• Acquisition strategy: Acquire at least some long tracks (i.e. coast to coast, rock to rock) to aid processing and calibration
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
Ice Sheet Requirements ‐ Antarctica
General• Annual coverage of all of Antarctica with at least 3 consecutive cycles – winter observations.
More cycles are considered an asset. • More frequent (monthly) observations of critical areas with every possible acquisition of
selected tracks
Reduced• Plan for a full Antarctic coverage at least every 3 years.• Provide annual coverage of coastal regions (right looking: all coastal areas; left looking: TAM
+ Ross and Ronne with their tributaries).• More frequent (monthly) observations of critical areas with every possible acquisition of
selected tracks
Science• Ongoing coverage of the visible area with coast‐to‐coast tracks (right looking: coastal areas;
left looking: Central Antarctica). • Acquisition of additional tracks covering large outlet glaciers with higher resolution modes • Capture seasonal changes over major ice streams
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
Ice Sheet Requirements ‐ Greenland
General• Annual coverage of all of Greenland with at least 3 consecutive cycles – Arctic winter
observations. More cycles are considered an asset. Time of Year: December to March. • A secondary full coverage each year would be an asset (3 cycles). Suggested timing for such a
secondary campaign would be July‐September.• More frequent observations of critical areas with every possible acquisition of selected
tracks (see section 5.5). • Acquire ascending and descending coverages. This aspect would allow the use of the
interferometric phase for improved accuracy.
Reduced• Annual coverage of all of coastal Greenland with at least 3 consecutive cycles (Arctic winter
acquisitions preferable). • Full coverage every second year.• Provide additional coverages of coastal regions.
Science• Ongoing coverage of the entire area (ascending and descending).• Acquisition of additional tracks covering large outlet glaciers with higher resolution modes.
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
Ice Sheet Requirements ‐ Greenland
General• Annual coverage of all of Greenland with at least 3 consecutive cycles – Arctic winter
observations. More cycles are considered an asset. Time of Year: December to March. • A secondary full coverage each year would be an asset (3 cycles). Suggested timing for such a
secondary campaign would be July‐September.• More frequent observations of critical areas with every possible acquisition of selected
tracks (see section 5.5). • Acquire ascending and descending coverages. This aspect would allow the use of the
interferometric phase for improved accuracy.
Reduced• Annual coverage of all of coastal Greenland with at least 3 consecutive cycles (Arctic winter
acquisitions preferable). • Full coverage every second year.• Provide additional coverages of coastal regions.
Science• Ongoing coverage of the entire area (ascending and descending).• Acquisition of additional tracks covering large outlet glaciers with higher resolution modes.
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
Ice Sheet RequirementsRevisited
Simplified, but ambitious formulation for Antarctica and Greenland:
• continuous monitoring of margins, • annual ice sheet wide ice velocity map
(with polar gap for Antarctica), and
• 5 (better 3) years complete ice sheet wide velocity map (Antarctica – pole hole filled).
3-5 year
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
Required Data from SAR Missions
• Remind the group of the required data from SAR missions, with special mention of any changes since the last meeting
• Please provide clarification on data policy and access to data for upcoming missions (SAOCOM, RCM)
Polar Space
Task Group
Sentinel‐1 Acquisition Strategy ‐Greenland Revised
‐ Continous monitoring of Greenland margins (every cycle). Enables continuous short term variations of ice dynamics of ice drainage(mass flux) of outlet glaciers and estimation, and calving front variations‐ Current STATUS: Sentinel‐1 A using 6 tracks (implemented by ESA in
June 2015)‐ Proposed Extension: Apply S1A acquisition plan also to Sentinel‐1B,
will result in 6 days repeat observation using both satellites
‐ Greenland Icesheet wide Ice velocity Product ‐ Annual:‐ STATUS: One Sentinel‐A acquisition campaign with 4 (to 6)
continuous repeat observations per track; (recent campaign Dec2015 to March 2016)
‐ Proposed: Extend current S1A campaign with S1B , this provides 8 to12 repeat observations with 6 days interval using both satellites.
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
Polar Space
Task Group
Sentinel‐1 Acquisition Strategy ‐Antarctica Revised
Annual coverage of visible area.Status:Sentinel‐1A annual ice sheet wide coverage (with polar gap) with ca 4 continuous repeat acquisitions (12 days repeat). Campaign is split into 2 parts.Proposed:Extend S1A acquisition campaign with S1B providing 8 continuous repeat acquisitions with 6 days (this reduces decorrelation and enables the formation of many 6 & 12 & 18 & 24 days interval pairs). Note: Filcher and Ross ice shelf to be covered with RADARSAT‐2
R‐2
S1A,B (Lower Priority)
S1A,B
Margins – Proposed:.continuous acquisition of data over the margins with 6 / 12 days repeat. Selection of tracks for covering the margins need to be optimized.
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
RADARSAT‐2 Acquisition Strategy
Greenland – no current acquisitions. Many conflicts in previous background missions.Antarctica – A 3 year plan to cover the Pole Hole is underway.Proposed: ‐ Increase repeats from 3 to 5 for better chanceof successful acquisitions.‐ Intensify margin monitoring.
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
X‐band SAR Missions
TerraSAR‐X / TanDEM‐X• Continuation of supersite data collection.• TanDEM DEM – when will the data be available?
Cosmo SkyMed• Strive to collect 1‐, 3‐, or 4‐day InSAR pairs for improved grounding line detection. A minimum of 2 pairs is needed per track.
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
L‐band SAR Missions
ALOS‐2 PALSAR‐2 (in orbit), and SAOCOM (to be launched), are providing limited data for scientific use.• Focus on margins and key areas as identified in the ice sheet requirements document.
• Most impact (better correlation): – Southern Greenland– WAIS
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
SAR Data Used ‐ Greenland
Ice Sheet CCI(Sentinel-1)
MEaSUREs(multiple sensors)(combine speckle tracking, asc/dscphase, & Landsat-8)Joughin et al.
NASA Cryo Program (multiple sensors)(annual map with all available data) Rignot, Mouginot, Scheuchl.
Several more groups presented Sentinel-1 based results at the ESA Living Planet Symposium 2016 in Prague!
Polar Space
Task Group
Greenland Ice velocity Maps from RSAT‐2
RADARSAT‐214 Dec 2014‐24 Feb 2015
RADARSAT‐221 Jan – 4 Apr
2014
Radarsat Data provided by CCRS / MDA through MURF initiated by PSTG / SCWG (signed in May 2015)
European MURF:• ENVEO / AT• DLR / GER• DTU / DAN• GEUS / DAN• S&T /NOR• Univ Leeds / UK
Polar Space
Task Group
IV: Monitoring Ice Sheet Margins
~50 Individual Glaciers
Velo
city
(m/d
)
Distance (km) Date
Data available within a few days
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
SAR Data Used ‐ Antarctica
S1 A Ice Velocity Map200 m gridAntarctic Campaign 2015/16Data Base: S1 IWS >3800 Scenes>71800 burst pairs
Ice Sheet CCI(Sentinel-1)
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
SAR Data Used ‐ Antarctica
MEaSUREs
Courtesy of J. Mouginot, E. Rignot, and B. Scheuchl
Sensor integration and update of the continent-wide ice velocity map
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
SAR Data Used ‐ Antarctica
MEaSUREs
Scheuchl, B., Mouginot, J., Rignot, E., Morlighem, M., & Khazendar, A. (2016). Grounding line retreat of Pope, Smith, and Kohler Glaciers, West Antarctica, measured with Sentinel‐1a radar interferometry data. Geophysical Research Letters.
Sentinel-1A based grounding line
Velocity and ice flux time series for Pope, Smith, and Kohler Glaciers
Pope, Smith, and
Kohler Glaciers
Polar Space
Task Group
PSTG SAR CWG‐5 Meeting, ESA ESTEC, 12 – 13 Sept. 2016
Progress since Last Meeting
Significant progress has been made since the last meeting:• Expansion of available science products• More groups are actively using the SAR data collected – the open data policy helps!
• Several recommendations made here have already been implemented or are being evaluated.