Polar Space Task Group 2017 Meeting CNES contribution to polar activities. Anne Lifermann CNES/DIA/TEC

Transcription

1 Polar Space Task Group 2017 Meeting CNES contribution to polar activities Anne Lifermann CNES/DIA/TEC

2 CNES Contribution to polar activities Outline On behaf of CNES and scientific teams YOPP, MOSAIC PSTG glaciers Pleiades Glacier Observatory CNES Contributions to polar science studies - LEGOS : sea ice, Antarctica - LOPS : Altiberg, SARice - LOCEAN : IAOOS, Seals - TAKUVIK, LOV : Greenedge - CESBIO, CNRM, IGE : snow In-situ observations Technology advancement Alti-Cryo phase 0 study Future missions CFOSAT, SKIM Algorithm development Contribution to Radar/Altimetry missions Arctic sea ice thickness and snow retrieval Snow 2

3 Pléiades Glacier Observatory PGO Berthier E., Fontannaz D., Hosford S., Lifermann A., Zemp M. PGO In a few words: Facilitate access to Pléiadessatellite stereo-imagery and DEMs for glaciologists Acquire imagery at the right time of the year (i.e., generally, end of the melt season) PGO stereo images are freely available to all science users, on the condition that they sign an agreement with CNES. Raw stereo-data are provided. Possibility to get a DEM + ortho-image using Ames Stereo Pipeline) Three acquisition campaigns nearly completed: Aug-Oct 2016 & 2017 (NH) and Feb-April 2017 (SH). Highly successful etienne.berthier@legos.obs-mip.fr Sites selected in coordination with WGMS: initial goals are to use these data to (i) provide a DEM/image of benchmark glaciers and (ii) help to assess the regional representativeness of the glaciers monitored in the field. 20sites/year, > 80 sites, 5 yrsrepeat One contact scientist for each site to define the acquisition parameters and validate the images when acquired.

4 North America PGO Summer2016 northern Hemisphere Europe Central Asia

5 New Zealand Andes and Antarctic Peninsula PGO Summer2017 Southern Hemisphere Central Asia

6 Arctic PGO Summer2017 northern Hemisphere ALPS CAUCASUS & High Mountain Asia

7 DEM of Elbrus, september 2017

8 Example of first results: D. Burgess Natural Resources Canada

9 Technology advancement PSTG 2017 AltiCryo : a CNES altimetry concept dedicated to cryosphere Phase 0 study > to propose an altimetry concept optimized for cryosphere (sea ice and ice sheets) and based on the SARAL/AltiKa heritage (Ka-band, 1 antenna). Users needs ( and the whole European community) collected with Instrument design performed by TAS-F Ka/Ku altimeter in SAR mode K/Ka radiometer PF ~ Proteus SAR/SARin configuration compared for range estimation over ice performance by CLS On-going (will end this December) 9

10 Technology advancement PSTG 2017 Analysis of Ku / Ka information content Comparison between Ku and Ka band over the Antarctica ice sheet Ku SAR for Ka/ LRM for Ku In SAR mode, volume appears,mostly inthe trailing edge part Ka > different information > possibility to invert volume parameters > extend previous Ku series Ku (Envisat) Penetration depth 4-5 m Temporal variab explained by surface Ka Band (AltiKa) Penetration depth 0.5 to 1 m Temporal variab explained by both surface and volume > modelise the volume echo to correct for Rémy et al, CNES/ESA User workhop, Paris 02/2017 Rémy et al, 2015, Verron et al, 2015,

11 CNES support to science studies 11

12 CNES support to insitu measurements by LOPS 12

13 Future missions PSTG 2017 China France Oceanography SATellite A new satellite for the observation of wind and waves Launch October 2018 CNES/Emmanuel GRIMAULT, 2017

14 Two Ku radar payloads on CFOSAT SWIM: the first spaceborne wave scatterometer 6 incidence angles: 0, 2, 4, 6, 8, 10 SWIM Rotating antenna: 5,6 rpm Ku band Minimum detectable wavelength of about 70 m, maximum detectable wavelength about 500 m. Accuracy in wave propagation direction of about 15 Accuracy in wavelength of 10% to 20%. Accuracy on wind speed estimates of ±2 m/s or 10% SCAT: a wind scatterometer Fan beam concept Large swath SCAT Rotating antenna: 3 rpm Incidences between 26 and ~50 Ku band

15 Future mission PSTG 2017 CFOSAT assets for ice studies Polar orbit Daily revisit of polar areas 97,5 inclination/83 obs 1 day of CFOSAT orbits over Antarctica 3 days global coverage Available data: Large range of incidence angles (0 to 50 with small gaps) Full azimuth scanning Calibrated radar waveforms Applications Improvement of σ 0 models and physics understanding Better characterization of ice/snow properties Synergy with altimeters (Sentinel-3, Cryosat-2 and AltiKa) Impact of waves on the ice sheet

16 Future missions PSTG 2017 SKIM SKIM combines - A nadir looking altimeter (Ka-band, 32 Khz PRF, 200 MHz bandwidth, SAR LRM) very low noise for sea level, wave height, ice freeboard - A novel wave + current spectrometer: 5 to 7 rotating 6 and 12 incidence measurement of full wave spectrum L > 20 m, 5 resn + Stokes drift, current & wind vectors heritage of SWIM on CFOSAT, translated to Ka (HPA from SWOT) + Doppler Instrument : < 130 kg, 414 W Data rate: 15 Mbits/s 5 to 7 year lifetime duration F. Ardhuin, et al., 2017 doi : /os / 16

17 Future missions PSTG 2017 SKIM 17

18 Algorithm LOPS PSTG

19 Algorithm CNES PSTG 2017 CNES studies focused on cryosphere Sea ice AltiKa and Sentinel3 freeboard (data to be released in 2018) SAR imagery/altimetry comparison for lead detection (ESTEC contract) Land ice SAR mode altimeter performances over ice sheet New method for DEM estimation over Antarctica 19

20 Algorithm LEGOS PSTG 2017 First continuous Arctic Sea Ice Thickness (SIT) from space record for A first continuous record of the Arctic SIT up to 81.5 N for has been published this year Extensions to the past (from 1995 using ERS2) and to the future (S3A, S3B, ) are expected soon ranges FB Sea- Ice Water (lead, polynya) SIT Such product can strongly improve: sea ice model (such as PIOMAS above) cold oceans circulation models, global climatic models, water mass for sea level studies, > urgent need for topographic data continuity over the poles Envisat SIT 03/2011 CryoSat SIT 03/2011 References: [Kwok-2009, Laxon-2013, Ricker-2014, Tilling-2015, Guerreiro-2017] Projects: SI-CCI, ESA CryoSeaNice, ESA Arctic+, CNES SICKAyS/Sea Change, OIB, CryoVex

21 Algorithm LEGOS PSTG 2017 First Arctic Snow Depth (SD) from space over sea ice Cryosat-2 Range Ku Snow Sea Ice Water Saral/AltiKa Range Ka ΔRanges SD Alti Snow Depth April 2014 Alti Snow Depth OIB airborne snow radar SD Corrected Warren99 climatology Snow Depth CMIP5 CNRM dynamic model OIB airborne snow radar SD Snow depth is a critical parameter for the sea ice community: Snow depth uncertainties can induce 100% error on SIT retrieval Because of its insulation properties snow depth is a key parameter for ice growth in sea ice models. Snow absorbs the solar radiation and limits the photosynthesis below the ice. OIB airborne snow radar SD References: [Guerreiro-2016, Armitage-2016] Projects: airborne Ka/Ku within CryoVex/Karen2017 campaign, SI-CCI, Clic, ESA CryoSeaNice, ESA Arctic+, CNES SICKAyS, OIB, > urgent need for dual-frequency polar topographic satellite mission

22 Algorithm LOPS PSTG 2017 ALTIBERG Project Detection and analysis of icebergs (0.01 to 9 km²) using altimeter waveforms data in the Southern Ocean. 9 Altimeters processed from 1992 to 2017 Level1 product Individual icebergs location time and area Level2 Monthly gridded fields on regular polar or lat/lon grid Probability of presence of icebergs Meanarea of icebergs Volume of ice Product by satellite and merged Distributed by CERSAT (ALTIBERG) Ref J.Tournadre et al

23 Algorithm development for SNOW PSTG 2017 SNOW Snow products from thematic center > Kalideos Alps F. Karbou & M. Dumont (CNRM/CEN); C. Proy & A. Sellé (CNES) Data base over the French Alps : PLEIADES (50cm), SPOT-6 (1.5m), SPOT-7 (1.5m), SENTINEL-2 (10m, 20m, 60m) SAR SENTINEL-1 (20m), ALOS-2 (3m, 6m, 10m), TERRASAR-X (25cm, 3m, 19m) Grenoble snow community Ghislain Picard (IGE), Vincent Vionnet (CEN), Florence Naaim (IRSTEA) Pyrenees Climate Change Observatory CLIM'PY Pléiades CESBIO contributes to the Pyrenees Climate Change Observatory through the analysis of the snow cover evolution using satellite imagery Daily cloud-free maps of the snow cover area in the Pyrenees at 500 m resolution since 2000 from; MODIS Maps of the snow cover area in the Pyrenees at 20 m and 30 m resolution since 2013 from Sentinel-2 and Landsat-8 Maps of the annual peak snow depth in the Bassiès-Vicdessos region at 4 m resolution since 2015 (one map per year) from Pléiades stereo imagery TANDEM X MNT 23

24 Thank you for your attention! Greenland, Olsen Ice Cap Pléiades stereo acquisition 22 July