ESA snow monitoring initiatives

Transcription

1 ESA snow monitoring initiatives Bojan R. Bojkov Head, Sensor Performance, Products and Algorithms (SPPA) Directorate of Earth Observation Programmes ESA/ESRIN

2 Why snow at ESA? Downstream services ESA instrument snow time-series Future/candidate missions

3 Downstream Services Downstream services are activities that use EO data as input to generate higher level products and services such as for example the provision of daily pan-european fractional snow and melting snow maps derived from SAR measurements in CryoLand These downstream services form the baseline for the European Commission s Copernicus programme (formerly the Global Monitoring of the Environment and Security programme GMES) consisting of a series of 10 new satellites (Sentinels) and core services for atmosphere (MACC), ocean (myocean) and land (GeoLand) The objective of the downstream services is to address the needs of the global citizen through clear requirements from user communities (in a long-term sustainable manner)

4 Polar View snow services Part of the ESA GMES Service Element (GSE) since 2005 Regional Products with user defined specifications Scandinavia (FSC) Baltic Area (FSC) Central Europe and Alps (SCA & SWE) VISTA - KSAT - SYKE daily SCA & FCA products resolution sampling 10 day aggregation Since 2010 Combined Product Pan-European snow map Online Portal:

5 Polar View snow service facts Service Experience During the last 7 years of service an annual number of about 1200 snow maps for the different areas and users could be achieved The Polar View Snow Service Portal provides easy access to the public on services and achievements of the GMES initiative Polar View User Integration Polar View snow services serve a important source for the decisions of large group of users (flood forecast, hydrology, hydropower, Northern residents..) Snow products had been developed in close cooperation with the individual users to meet their requirements and operational needs and built up confidence during service operation Perspectives Polar View was formally incorporated under the name Polar View Earth Observation Ltd. in the UK in 2011, to carry on coordination, communication and promotion in the domain of polar research and service provision Contact: Florian Appel (appel@vista-geo.de)

6 Snow time-series Goal of ESA is to support the development European expertise in (snow) remote sensing and to maximise the use of European sensors Target efforts, through dedicated ESA programmes: DUE, STSE, SEOM, to meet the needs of specific snow user communities such as NWP, climate researchers, etc. Snow is also an interference to many other retrievals for example snow extent for atmospheric retrievals, snow/cloud mix for land or atmosphere, mixed optical scenes, etc.

7 Globsnow NH SE maps ( ) March April May 2003 Fractional snow: Daily & Monthly composites NH coverage: N Satellite & Sensors ERS-2 ATSR-2 Grid: Data access: Envisat AATSR

8 DUE GlobSnow-2 Budget: 750 k (STRIN) Duration: 24 months ( ) Objectives: Provide global long term records of fully characterised satelliteretrieved snow information for climate research (SWE & SE). Fully qualify the near-real time component for operational conditions in cooperation with EUMETSAT Hydrology-SAF Upgrade the GlobSnow system to be ready for operational exploitation of Sentinel-3 data in Project Consortium: FMI (FI), ENVEO (A), ZAMG (A), NR (N), GAMMA (CH), SYKE (FI), MeteoSwiss (CH), U. Bern (CH) [+ GISAT (CZ)] Project manager: Kari Luojus (FMI)

9 Study Overview SnowRadiance Study objectives: Investigate the potential for snow parameter retrievals from current and future ESA passive imaging instruments operating in the UV to TIR spectral range, namely Envisat, Sentinel-2 and Sentinel-3 Develop the algorithm theoretical basis for retrievals Undertake validation campaign(s) Provide a toolbox for the scientific user community (BEAM) The ESA Support To Science Element (STSE) aims at providing scientific support for both future and on-going missions, by taking a proactive role in the formulation of new mission concepts and of the related scientific agenda, by offering a multi-mission support to the scientific use of ESA Earth Observation missions data and to the promotion of the achieved results.

10 Grain Size Sensitivity 865 nm 1020, 1610, 2200 size A. Kokhanowski, IUP Bremen

11 Project Conclusions The most sensitive channels for the soot retrieval: nm of Envisat/MERIS The most sensitive channels for the grain size retrieval nm, depending on the grain size The soot concentration can be retrieved from space only for rather high levels of pollution (above 300ng/g or so) and also only for a clear atmosphere case (from the measurements in the blue spectral region, where soot leads to the considerable snow darkening)

12 The Sentinel-3 Mission Joint mission between Eumetsat (ocean) and ESA (terrestrial)

13 Operational mission in high-inclination, low earth orbit designed for GMES Full performance achieved with 2 satellites in orbit Ocean and Land Colour Instrument (OLCI): 5 cameras, spectral range from 400 to 1020 nm 15 (MERIS) & 6 additional bands; Swath: 1270 km Camera tilt in west direction (12.20 ) On-board diffuser based radiometric calibration Full res. 300m acquired systematically (land/ocean) Reduced res. 1200m binned on ground (L1b) Ocean coverage < 4 days, (< 2 days with 2 satellites), land coverage <2 days (<1 day with 2 satellites) 100% overlap with SLSTR Sea and Land Surface Temperature Radiometer Microwave Radiometer Ocean and Land Colour Instrument Sea & Land Surface Temperature Radiometer (SLSTR): 7 AATSR & 2 additional bands, plus 2 additional Fire channels, with 500 m (solar) and 1 km (TIR) ground res. Swath: 1400 km/740 km (single or dual view) Topography package: SRAL Ku-C altimeter (LRM & SAR measurement modes), MWR, POD (with Laser Retro Reflector, GPS and DORIS) GPS Laser retroreflector S-band Antenna SAR Radar Altimeter X-band Antenna DORIS Antenna 7.5 years lifetime (fuel for 5 add. years) Launch S3A April 2014 Launch S3B Mid 2015 or later

14 Sentinel-3 and snow Sentinel-3, the GMES operational continuation of the optical sensors of Envisat, have a very strong potential for snow retrievals Strong recommendation for snow products from the Sentinel for Science review ( but currently there is no plan for such a service by ESA or in Copernicus (GMES) Note, proposed GMES collaborative ground segments have been proposed by numerous countries, but formalities of this GMES mechanism (data access/distribution) still need to be formally addressed by the European Commission

15 FSC Map 10 April 2011 AATSR Meris / AATSR 1km 300 m Lake Constance snowfree ->35% ->60% ->85% ->100% Lake Como Lake Garda Bojkov: ESA Thomas snow monitoring Nagler initiatives

16 AATSR Meris / AATSR 1km 300 m snowfree ->35% ->60% ->85% ->100%

17 CoReH2O scientific questions (Earth Explorer 7 candidate mission) Quantify the amount and variability of fresh water stored in terrestrial snow packs and of accumulation on glaciers Improve hydrological modelling and forecasting for cold regions Improve the representation of snow and ice processes in regional and global climate models, including model validation and downscaling Observe the distribution of snow properties in high-latitudes to support process studies for terrestrial carbon cycling, tracegas exchange and permafrost Support the accounting of glacier mass balance worldwide to improve understanding and modelling of glacier/climate interactions and atmospheric forcing

18 CoReH 2 O SAR Sensor Requirements Parameter Ku-band SAR X-band SAR Frequency 17.2 GHz 9.6 GHz Polarization Swath width, Inc angle Spatial resolution VV, VH 100 km; 30 to 45 range 50 m x 50 m ( 4 ENL) NESZ -25dB VH -27dB VH Radiom. Stability / Bias 0.5 db / 1.0 db ScanSAR 2 concepts proposed Mission Selection Report. ESA, 2012.

19 SWE Map from Airborne Backscatter SWE SWE SWE map, derived from SnowSAR data, Sodankylä, 15/03/2011 (Enveo) SWE retrieved from SnowSAR data vs. in situ point measurements SWE obs SWE ret = -5 mm Stand. error : 12.7 mm

20 Earth Explorer 7 Mission Selection Earth Explorer User Consultation Meeting: 5 6 March 2013 Graz, Austria ESA consults the Science Community on selection of one EE-7 satellite mission for implementation. You are welcome to participate in the meeting and support CoReH 2 O!

21 ESA s interest in GCW ESA welcomes the WMO GCW (and its initiatives) and is keen to collaborate in areas of mutual interests The WMO GAW activities (as a model) have been extremely useful for satellite atmospheric validation (especially ozone) in large part because of the controlled and well defined measurement protocols, as well the easily accessible data through the GAW WDCs In the frame of GCW snow-watch, ESA would really like to see comprehensive measurements systems (incl. auxiliary data) that follow clear measurement and reporting protocols, as well as provide uncertainty estimates

22 ESA s interest in GCW (ii) Ideally, ESA would like to see GCW sites similarly equipped like FMI-ARC at Sodankylä or special infrastructure such as in the Svalbard Integrated Earth Observing System (SIOS) initiative i.e. the satellite community need of well characterised datasets, with co-located supporting data ESA is particularly interested in high latitude measurements for the Sentinels (and CoReH2O) era and is willing to help define and formulate satellite requirements (ie User Requirements Documents), starting specifically for the NH higher latitudes and the Arctic Close cooperation between GCW and space agencies could be through the Cal/Val Infrastructure WG (which incudes most European space agencies and Canada)

23 Thank you! Acknowledgements: F. Appel (Vista), C. Brockmann (BC), M. Drinkwater, D. Fernandez-Prieto, P. Goryl, M. Kern, A. Kokhanowski (IUP Bremen), T. Nagler (Enveo), S. Pinnock, P. Regner, H. Rott (U. Innsbruck/Enveo)