Polar Space Task Group

PROGRESS IN ICESHEET MONITORING

Thomas Nagler, Markus Hetzenecker, Jan Wuite, Dana Floricioiu Anders Kusk, Bernd Scheuchl

Sentinel-1 Ice Velocity Southern Weddell Coast

Greenland Ice Sheets CCI Team: • IV: Ice velocity – costal regions + select areas (phase 1), all ice sheet (ph. 2) • SEC: Surface elevation changes, ERS/Envisat/CryoSat, 1991-present • GLL: Grounding lines from SAR, main northern floating glaciers 1991-present • CFL: Calving front locations - 20+ main outlet glaciers 1991-present • GMB: Gravimetric mass balance from GRACE (phase 2, starting 2015) ECV grid/line data

SEC

IV

GLL

CFL

GMB

- Horizontal resolution

5 km

500 m

200 m

200 m

50 km

- Temporal resolution

1 yr

1 yr (S1)

5 yr

1 yr

1 month

0.1 m/yr

20 m/yr

1 km

200 m

?

- Accuracy

Jakobshavn Glacier front

Nagler / ENVEO

Antarctic Ice Sheet CCI Team:

Products

Nagler / ENVEO

Sentinel-1 IV Map Greenland

2014/15 2016 Nagler et al., 2015 Product: 200 pixel spacing Method: Offset Tracking Period S1 Greenland Campaign 2015 & 2016 some scenes 2014

Nagler / ENVEO EGU General Assembly 2016 | Vienna | 17-22 April 2016

Jan Wuite

Data Source S1 IWS SLC HH >3100 Scenes >67 000 bursts ~330 pairs of tracks (12 d)

Greenland Ice velocity Maps from RSAT-2 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

RADARSAT-2 21 Jan – 4 Apr 2014 Nagler / ENVEO

RADARSAT-2 14 Dec 201424 Feb 2015

S1 – Acquisition Strategy for Margins

S1 Tracks for Greenland Margins, acquired every Cycle of 12 days (total year) in IW mode: Track 026 Track 074 Track 090 Track 112 Track 141 Track 170

Track 090

by T. Nagler / ENVEO, agreed by R. Forsberg / DTU, and B. Scheuchl / UCI

The same tracks should also be acquired during the campaigns with Full coverage of Greenland June 2015  Implemented by ESA Nagler / ENVEO

Thomas Nagler Icesheet6 16-17/1/2012

Greenland Outlet Glaciers - Calving Front Location

Nagler / ENVEO

Calving Fronts

Nagler / ENVEO

Velocity (m/d)

IV Timeseries: Monitoring Ice Sheet Margins

Distance (km)

Date

Data available within a few days

Nagler / ENVEO

~50 Individual Glaciers

Synergistic Use of S1 & S2 for mapping Ice velocities S1 S119-31.8 Average2015 IV Map 2015

S2 16.8-8.9.2015

S2 FT IV: 20150816 - 20150908 Profile 1

Profile 2 Summer period with strong surface melting Nagler / ENVEO

Ice Discharge Monitoring

Nagler / ENVEO

Thickness (m)

Velocity (m/d)

~315 Individual Glaciers

Distance (km)

Ice Thickness Morlighem et al. 2015. IceBridge BedMachine Greenland, V2

Ice Discharge Monitoring Basins: Flux gates based on IceBridge Flight Tracks

Velocity (m/d)

Thickness (m)

Distance (km) Contribution to ESA / NASA IMBIE 2016

Nagler / ENVEO

Ice Thickness Gogineni, Prasad. 2012. CReSIS Radar Depth Sounder Data

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: 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: - Current STATUS: One Sentinel-A acquisition campaign with 4 continuous repeat observations per track; (recent campaign Dec 2015 to March 2016) - Proposed: Extend current S1A campaign with S1B , this provides 4 to 6 repeat observations with 6 days interval using both satellites. Sentinel-2 Acquisition Strategy over Greenland needs discussed with ESA • During Summer: need for continous monitoring of margins for ice velocity in synergy with SAR and mapping ice / snow reology, support calving fronts Nagler / ENVEO

Sentinel-1: Enhanced Ice Velocity Products

S1 A Ice Velocity Map 200 m grid Antarctic Campaign 2015/16 Data Base: S1 IWS >3800 Scenes >71800 burst pairs Nagler / ENVEO

12 days Ice Velocity Time series Crane Glacier – Antarctic Pen-Insula

Velocity (m/d)

 1 Year of Ice velocity observed by Sentinel-1  Period: 2014.12.01-2016.03.01  Number of IV maps: 30 (12d)

Velocity (m/d)

Distance (km)

Date

Nagler / ENVEO EGU General Assembly 2016 | Vienna | 17-22 April 2016

Jan Wuite

15

Larsen C Ice Shelf – Rift Propagation and Acceleration

Velocity (m/d)

S1 Ice Velocity 2015

PALSAR 2010 Sentinel-1 2015

Distance (km)

Background: Sentinel-1 amplitude image Nagler / ENVEO

Grounding line Tanvir Chowdhury, Michael Baessler & Dana Floricioiu (DLR-IMF) ESA’s Climate Change Initiative http://cci.esa.int/ Aim: longterm and reliable production of a set of key parameters, e.g. • Grounding Line Location (GLL) over key areas in Antarctica http://www.esa-icesheets-antarctica-cci.org/ Method: DInSAR Data: ERS1/2 Tandem, TSX, Sentinel-1 1st operational AIS_cci products available at: http://cryoportal.enveo.at/data/ Grounding Line retreat: thinning of ice + ocean tide level (+ subglacial topography)

Sentinel-1 double difference interferogram and derived grounding line location

Lasarevisen Ice shelf

Grounded ice

Grounding zone

Ice shelf GL retreat Nagler / ENVEO

S-1A data from 2015/05/25, 2015/06/06 and 2015/06/18

Response after Larsen-A Collapse – Drygalski Glacier Drygalski Glacier

Central Flowline 2012

Sentinel-1 12/2014-04/2016

2013 2015 2007 Nov 1995

Sentinel-1 Velocity time series Nov 2014 to April 2016 along flowline 1993 Date

Flux Gt/yr

Bn Gt/yr

Pre-Collapse

1.42 (→ BA)

0 = Balance Flux

2008

3.40

-1.98

2013

3.80

-2.38

2015

3.00

-1.58

Nagler / ENVEO

Drygalski Glacier area (2012) 1008 km2 Retreat of grounded ice 1995-2012: 41 km2

A concept for monitoring Antarctica (i) continuous monitoring of margins / grounding zone (ii) annual ice sheet wide ice velocity map with polar gap (coverage given by S1) (iii) 3 (or 5) years complete ice sheet wide velocity map

Products: • • • • •

3(5) years

Nagler / ENVEO

Ice velocity Grounding line location Calving front Location Calving Events mass fluxes (requires auxiliary data sets)

Sub-Surface Glacier Information SAR Tomography ALPSTOMOSAR: Preparation for SAOCOM-CS

S. Tebaldini, T. Nagler, H. Rott, A. Heilig, IEEE TGARS,

Nagler / ENVEO

Elevation Change 2011- 2013 by TanDEM-X DEM Differencing TanDEM-X scenes

TanDEM-X DEM 9 June 2011 processed by DLR-IMF

S

Larsen-A

Total Change (Basin 1 to 8) ∆V = -4.54 ± 0.39 km3/yr ∆M = -4.21 ± 0.35 Gt/yr Nagler / ENVEO

Rott et al., GRL 2014

EE9 Ideas for New Sensors – Contributions by ENVEO

Mission Flash • SESAME is the key to a hidden treasure inherent to the Sentinel-1 mission: multi-static SAR observations • The space-segment of the SESAME mission consists of two identical passive SAR companions to Sentinel-1 C or D, flying in a reconfigurable close-formation, enabling single-pass cross-track SAR interferometry (SP-InSAR) and several other bistatic and multi-static acquisition geometries Proposal for an ESA Earth Explorer Mission Prepared by Francisco López-Dekker, Microwaves and Radar Institute, DLR Helmut Rott, ENVEO IT, Austria and the International Science Team

Nagler / ENVEO

Online by September 2016 Nagler / ENVEO