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Mark R. Drinkwater European Space Agency ESA-ESTEC Noordwijk, NL
“Progress and New Frontiers in Ice Sheet Remote Sensing”
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 2
Contents
Introduction
Recent Progress
New Frontiers
Summary
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 3
IPY 2007-2008: Satellite Remote Sensing
2000 Modified Antarctic Mapping Mission ice velocity model.
– The International Polar Year (IPY) provided an international framework for understanding polar processes and high-latitude climate
– IPY era spaceborne instrumentation represented a technological leap beyond the capabilities of the IGY
– Spaceborne technology offered unique capabilities for obtaining essential data for predictive models
– Unique opportunity to assess current state of art in remote sensing of polar regions.
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 4
Aircraft and in-situ Sounders and GPR Systems
DMSP
IceSat
Collecting satellite polar snapshots
MetOp
GOCE
GRACE SPOT-4
HRVIR / VGT
SMOS
Aqua & Terra
ALOS
RADARSAT
Envisat
ASAR MERIS / A-ATSR
MODIS / ASTER AMSR-E ASCAT
AVHRR SSMI
PALSAR PRISM / AVNIR-2
wavelength (m)
Frequency (Hz)
ERS-2
M. Drinkwater (ESA)
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 5
03
02
04
06
08
10
11
12
13
15
16
07
09
05
14
RCM
SAR/COSMO-SKYMED X-band TerraSAR/Tandem-X X-band
ICESAT GMES S-3A, B
RADARSAT-2 C-band RADARSAT-1 C-band
ICESAT-2 CryoSat-2
SAR/RISAT C-band IPY
Ku-Scat & MSMR/OCEANSAT-2
HY-3 WSAR
Seawinds/QuikSCAT Ku-band
GMES S-1A, B
GRACE
SMOS WindSat
AMSR-2/GCOM-W1 OLS & SSMI/DMSP— AVHRR & AMSU/NOAA
GOCE
HY-1B COCTS/HY-1A JPSS 1 VIIRS/NPP
Courtesy: M. Drinkwater Arctica-M 1 & 2
HEO missions PCW 1 & 2
MetOp -2, -3
GRACE-C
LEO missions
PALSAR/ALOS L-band
ASCAT & AVHRR/MetOp -1
ALOS-2
Landsat DCM Landsat-5, -7
Aster/MODIS/EOS-Terra
RA2 & ASAR/Envisat C-band RA, SAR & Wind Scat/ERS-2
HY-2B HY-2B HY-2A
MODIS & AMSR-E/EOS-Aqua
Cryosphere Satellite Missions
Planned/Pending approval In Orbit Approved Solid = R & D; Hatched = operational mission
SPOT-4/5
FY-3C FY-3B MODI & MERSI/FY-3A VIRR/FY-1D
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 6
Ice Sheet Mass Balance
gma MMMδaδM −−≅/
Ma
Mm Mc
Mb
Mass change per year AccumulationRate
Surface Melt flux
Flux across grounding
line
Mg
cMCalving Flux
Where
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 7
Recent Progress:
Quantifying components of the Mass budget
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 8
Assessing Continental Scale Volume/Mass Changes:
gma MMMδaδM −−≅/
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 9
Envisat IceSat GRACE
m/yr m/yr mm/yr water eq.
Greenland: Elevation (Volume)/ Mass Change
Courtesy R. Forsberg et al. (ESA, CCI Project)
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 10
Antarctica: Elevation(Volume)/Mass Change
Courtesy T. Flament, LEGOS(2013)
m/y
r
Envisat (2003-2012) IceSAT (2003-08)
Pritchard et al. (2009)
GRACE (2003-06)
Velicogna (2009)
• Envisat RA2 limited latitude (<82o) but all-weather; firn densification and isostatic adjustment models needed to convert from elevation change (volume) to mass change
• IceSAT limited by cloud and discontinuous temporal sampling, and density of cross-overs; firn densification model needed to convert to mass
• GRACE – low res.; of limited use in Ant. Peninsula; Considerable residual uncertainty due to Glacial Isostatic Adjustment (GIA)
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 11
ESA’s CryoSat Ice Mission: Basic Facts
– Instruments:
SIRAL (SAR/Interferometric Radar Altimeter)
Star trackers DORIS (Doppler Orbit and Radio
Positioning Integration by Satellite) receiver
Laser retro-reflector
– High inclination orbit - 88°latitude
– Non sun-synchronous orbit
– SARIn mode improves across track resolution designed for rugged ice-sheet terrain
– 369 day repeat (30 day sub cycle) gives dense across track sampling and captures temporal changes
http://earth.esa.int/cryosat
Launched: April 8th 2010
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 12 © CPOM/UCL/ESA/Planetaryvisions
Antarctica: CryoSat ice sheet topography
CryoSAT ice-sheet elevation models
• 1 km grid spacing
• LRM & SARIn
• Greenland & Antarctica
• Validation in progress
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 13
CryoSat ice sheet topography & BEDMAP-2
© CPOM/UCL/ESA/Planetaryvisions
Former limit of altimetry coverage (ERS/Envisat)
CryoSat coverage to 2 deg. off pole
CryoSat Topography & BEDMAP basal boundary conditions – key properties governing ice flow
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 14
Continental Scale Melt Flux:
& Key Surface Radiative Quantities
gma MMMδaδM −−≅/
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 15
– Extreme July 2012 melt, and extensive melting in 2013
– Strong southeasterly winds across the western coast
– Record warmest temperature of 25.9 degrees Celsius in Maniitsoq
Passive Microwave: daily melt products
Weather map courtesy - DMI.
July 30, 2013
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 16
Ice Sheet Reflectivity (Albedo) & Melting
Before melt After melt
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 17
gma MMMδaδM −−≅/Mass Flux across Grounding Line: & Ice shelf Calving Flux
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 18
SAR: IPY Pole-to-Coast Ice Velocity Mapping
Adapted from Rignot et al, Science Courtesy: Schuechl, UCI
Satellite InSAR data
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 19
ERS-2: Kangerdlussuaq Tidewater Glacier Calving and Retreat
• ERS-2 placed in 3d repeat orbit before deorbiting.
• Images focus on Greenland outlet glaciers (March-May 2011)
• Comparison of ERS-1, ERS-2, T-SAR-X indicate 20 year changes
Bevan et al. (2013)
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 20
The Grounding Line is the boundary between the grounded ice and the floating ice
Ice Sheet/Shelf Grounding Line
It is important for:
a) the ice sheet and the ice shelves mass budget calculation
b)numerical modelling of ice sheet dynamics
c) Ice-ocean interactions
d)oceanic tides
e)Sub-glacial environments
Grounding zone
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 21
CryoSat: Ice shelf Grounding Line (GL) Location & GL Ice Thickness
University of Leeds (UK), of CryoSat+ GLITter consortium 27 metres ice shelf freeboard translates to ~220 m ice thickness.
Courtesy, ENVEO
metres
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 22
Petermann Glacier: 1992 – 2011 Grounding Line Retreat & Thinning
2911
2011
Courtesy N. Gourmelen (Univ. Edinburgh)
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 23
Recent Progress:
Gravimetry – **Covered by P. Ditmar
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 24
New Frontier:
Better resolution of time-space variability, and process understanding
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 25
CryoSat: Basin-resolved rates of Ice Sheet Elevation/Volume Change
m/
yr
5½ years of ICESat data 2 years of CryoSat-2 data
ESA/University of Leeds
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 26
– CryoSat features a unique capability to map changes in Antarctica’s sub-glacial lakes in 3D.
– Sub-glacial lakes interesting in terms of water transport and ice dynamics beneath the surface.
– The crater shown was formed when 6 km3 of lake water drained
Malcolm McMillan et al – GRL (2013)
CryoSat: Sub-glacial Lakes & Basal Hydrologic conditions
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 27
• Standard CryoSat level 2 SARIn height product is from point of closest approach (POCA)
• Over sloping terrain, SARIn echo maps a wide swath across the ground track, beyond the POCA
• Swath SARIn mode returns valid in range 0.5 to 2.0 degrees
• Elevations retrieved where good coherence
CryoSat: across-track swath elevations
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 28
Swath topographic mapping with CryoSat
Source: Noel Gourmelen and CryoSat+ CryoTop team (ESA STSE Study)
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 29
New Frontier:
Seeing beneath the surface
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 30
AMSR-E C-band v-pol
SMOS L-band v-pol
SMOS: Polar Ice Sheet Data
– Ice sheets used as natural, uniform stable calibration reference site (Dome C)
– But subtle variability observed in signatures
– Absorption in ice is very low at L-band
– Thermal microwave emission could originate from up to kilometres depth.
– Potential for microwave thermometry? (i.e. in-ice temperature sounding)
– Lowest temperatures correspond with subglacial lake basins
Courtesy L. Kaleschke U. Hamburg
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 31
DomeCAir: L-band airborne Campaign Results
Tb Cold = Deep basins (counterintuitive)
Why? Normally warmer at depth
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 32
New Frontier:
Remaining Challenges
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 33
– Measure continental snow accumulation directly by remote sensing
– Unify models for converting volume to mass (firn compaction) in context of Surface Mass Balance efforts
– Direct, routine measurement of ice thickness at grounding lines (P-band?)
– Tomography of in-ice layering properties using P-band (ESA Biomass)
– Sub-surface sounding of ice profile properties (L-band and UHF frequency range)
– Push temporal resolution of observations to sub-daily (i.e. diurnal/tidally forced processes) at suitable spatial scales.
Remaining Challenges
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 35
POLARIS: P-band coherent radar sounding in Greenland
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 36
Summary
– IPY allow documenting state-of-art in satellite remote sensing of high latitude regions and the cryosphere
– Satellites provide global perspective on the ice sheet processes on a range of space and time scales (daily – decadal)
– Huge progress made in study of the mass balance (since early 1990s)
– Space observing system capabilities never better for investigating cryosphere in a changing climate
– Legacy satellite datasets (ERS, Envisat) and the sustained met satellite measurements support ice sheet climate research
– ESA’s new satellite missions (CryoSat, GOCE and SMOS) deliver new data products with exciting potential
– Benefits of long satellite data time series self evident:
– ESA’s Climate Change Initiative helping to construct fundamental climate data records and Ice Sheet Essential Climate Variables
– ESA/EC Copernicus Sentinels coming in 2014 to sustain some capabilities
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 38
Additional Spare Slides
Progress and Frontiers in Ice Sheet Remote Sensing | M. Drinkwater | TU Delft Climate Inst., 17 Oct 2013 | Pag. 39
Accessing ESA Data Products
http://earth.esa.int