Development of sea ice climate data records W. Meier WOAP Workshop, Frascati, Italy, 18 April 2011
Passive microwave sea ice data 32+ year record able to track long-term trends Near-complete, daily fields (all-sky conditions) Consistent data source, algorithm, and processing methods high confidence in comparing sea ice conditions through the years But issues remain: Several algorithm products Limited quality/error information Little or no metadata September Monthly Mean Sea Ice Concentration 1979 2010
Timeline of passive microwave sensors for sea ice 1970 1980 1990 2000 2010 2020 ESMR Nimbus-5 (single channel) SMMR Nimbus-7 F8 DMSP F11 F13 * F17 SSM/I SSMIS F18 F19, F20 JPSS MIS? NASA EOS Aqua AMSR-E JAXA GCOM-W AMSR2 AMSR3,4 *May 2009 Intercalibration of F13 and F17 sea ice products: first time done for near-real-time sea ice data
How much sea ice is there? (Arctic) ArcticROOS NSIDC U. Bremen JAXA DMI U. Illinois
Satellite-derived Sea Ice Products Community Workshop 15-16 March 2011 NASA Goddard Workshop inspired and supported by WCRP CliC Hosted by the NASA Goddard Cryosphere Branch 26 total attendees Algorithm developers Product distributors Operational community Users (models, remote sensing) Attendees from U.S., Canada, UK, Norway, Denmark, Germany, Turkey, Japan Input solicited from invitees who could not attend Focused mostly on discussion of major issues Uncertainties Documentation Conventions and methods (e.g., concentration threshold, landmasks Data formats Future plans for collaboration Continued communication CliC Meeting Report/White Paper Journal articles (Eos article on meeting issues, review article on product intercomparisons) Cooperation on input to future assessments and reports (e.g., SEARCH Sea Ice Outlook, IPCC) Possible ensemble sea ice extent estimates? Updated land and region masks to be shared among community
OSI SAF Operational (DMI+met.no) Title/Product Name Algorithm(s) Sensor(s) Channels (Freq./Pol.) Concentration cutoff/weather filters/qc Grid/projection Format Temporal frequency OSI SAF Global Operational Sea Ice Concentration (OSI 401) Bootstrap (frequency mode) + Bristol SSM/I. Soon to include SSMIS. 19v, 37v, and 37h Cutoff at 0% and 100%. No weather filter (but atm. correction via an RTM). Monthly tie points (diff for NH and SH). Climatology mask. Polar stereographic (both NH and SH). 10 km. GRIB, HD5, and NetCDF (CF 1.4) Daily (average centered on 12 UTC) Time period NRT (archived since 2005) Distribution/access Metadata Website FTP, EUMETCast, EDC, THREDDS/OpenDAP, browse imagery Product level, full file level (netcdf CF), cell level (confidence from 1 to 5) http://osisaf.met.no (docs, quicklooks, data)
OSI SAF Re-processing (DMI+met.no) Title/Product Name Algorithm(s) Sensor(s) Channels (Freq./Pol.) Concentration cutoff/weather filters/qc Grid/projection and Resolution Format Temporal frequency OSI SAF Global Sea Ice Concentration Reprocessing (OSI 409) Bootstrap FM + Bristol SMMR, SSM/I 19v, 37v, and 37h Cutoff at 0% and 100%. No weather filter (but atm. corr via an RTM). Dynamic tie points. Climatology mask. T2m check. Polar stereographic 10km (NH+SH), Polare EASE 12.5km and 25km. NetCDF (CF 1.4) Daily and Monthly Time period 1978 2007 (soon to 2009) Distribution/access Metadata Website FTP, browse imagery Product level, full file level (netcdf CF), cell level (uncertainties as error bars) http://osisaf.met.no (docs, quicklooks, data)
ASI / University of Bremen Title/Product Name ASI Sea ice concentration Algorithm(s) Sensor(s) Channels (Freq./Pol.) Concentration cutoff/weather filters/qc Grid/projection (or swath) and Resolution Format ARTIST Sea Ice (ASI) AMSR E 89V, 89H Cutoff: 15% 3 Weather filters: IC = 0 if GR(37,19) >= 0.05 or GR(24.19) >= 0.04 or IC(Bootstrap)= 0. Polar stereographic, 6.25 km (hemispherical products) and 3.125 km (regional products). Resolution 4x6 km (AMSR E 89GHz).png,.hdf,.ps,.tif
ASI / University of Bremen (cont'd) Title/Product Name ASI Sea ice concentration Temporal frequency Time period Since Oct 2002 Distribution/access NRT daily: 0300 UTC (day before) 1800 (current ) Free for occasional and scientific users of standard products. Online archive. Metadata G. Spreen, L. Kaleschke and G. Heygster 2008: Sea ice remote sensing using AMSR-E 89 GHz channels. J. Geophys. Res 113, C02S03, doi:10.1029/2005jc003384. Website http://www.iup.uni-bremen.de/seaice/amsr/
NASA GSFC Sea Ice Concentrations (NT) Title/Product Name Algorithm(s) NASA Team Nimbus-7 SMMR and DMSP SSM/I-SSMIS Daily Polar Gridded Sea Ice Concentrations NASA Team Sensor(s) SMMR, SSM/I (F8, F11, F13), SSMIS (F17) Channels (Freq./Pol.) 19V, 19H, 22V, 37V, Concentration cutoff/weather filters/qc Grid/projection (or swath) and Resolution Format Temporal frequency Time period Distribution/access Metadata Website Cutoff: 15%; Wx: GR3719, GR2219; land-spillover correction; ocean SST climatology mask Polar stereographic, 25 km Flat binary with 300-byte header Daily and monthly Nov 1978 Dec 2008 (NRT product through present, updated daily) NSIDC FTP for sea ice concentrations; NSIDC and GSFC websites for sea ice extents and areas time series Journal reference, guide doc., file-level basic header NSIDC Data: http://nsidc.org/data/nsidc-0051.html GSFC Data: http://neptune.gsfc.nasa.gov/csb/index.php?section=59
NASA GSFC Sea Ice Concentrations (NT2) Title/Product Name Algorithm(s) Sensor(s) Channels (Freq./Pol.) Concentration cutoff/weather filters/qc Grid/projection (or swath) and Resolution Format Temporal frequency Time period Distribution/access Metadata Website NASA Team 2 DMSP SSM/I-SSMIS and AMSR-E Daily Polar Gridded Sea Ice Concentrations NASA Team 2 (NT2) SSM/I (F8, F11, F13), SSMIS (F17), AMSR-E 19V, 19H, 22V, 37V, 89V, 89H Cutoff: 15%; Wx: GR3719, GR2219; land-spillover correction; ocean SST climatology mask Polar stereographic, 25 km Flat binary Daily SSMI (1992-2008); AMSR-E (2002-present) NSIDC website for AMSR-E sea ice concentrations; GSFC website for SSMI sea ice concentrations SSMI and AMSR-E: Level 3 gridded satellite-derived; partially validated NSIDC Data: http://nsidc.org/data/ae_si12.html (AMSR-E) GSFC Data: http://neptune.gsfc.nasa.gov/csb/index.php?section=55
NASA GSFC Bootstrap Title/Product Name Algorithm(s) Sensor(s) Channels (Freq./Pol.) Concentration cutoff/weather filters/qc Grid/projection (or swath) and Resolution Format Temporal frequency Time period Distribution/access Metadata Website BASIC/SMMR, SSM/I, and AMSR E Polar Gridded Sea Ice Concentrations, Ice Extent and Ice Area Bootstrap Algorithm SMMR, SSM/I (F8, F11, F13), SSMIS (F17), AMSR E 19H, 37V, 37H Cutoff: 8%; Ocean Mask: 19V, 22V, 37V, surface temperature climatology; land spillover correction Polar stereographic, 25 km for SMMR, SSM/I and AMSR E, 12.5 for AMSR E Flat binary with 300 byte header Daily and monthly 1978 present for SMMR and SSM/I, 2002 present for AMSR E FTP from NSIDC Dataset level journal ref. and guide doc., no file level Data: http://nsidc.org/data/nsidc 0079.html Imagery: http://nsidc.org/data/nsidc 0079.html
NSIDC Sea Ice Concentration CDR Title/Product Name NOAA/NSIDC Sea Ice Concentration Climate Data Record Algorithm(s) Sensor(s) Channels (Freq./Pol.) Concentration cutoff/weather filters/qc Grid/projection and Resolution Format Temporal frequency Bootstrap + NASA Team SMMR, SSM/I, SSMIS intercalibrated at product level 19v, 19h, 22v, 37v, and 37h Cutoff at 15% and 100%. Weather filter, climatology mask. Near coast/melt flags, concentration st. dev. Polar stereographic, 25 km NetCDF4_CF (climate and forecasting attributes) Daily and Monthly Time period 1978 present: planned release end summer 2011 Distribution/access Metadata Website FTP from NSIDC and NOAA CDR program Product level (ISO 19115), full file level (NetCDF_CF and ISO 19115), grid cell level (data quality flags, st. dev.), DOI http://www.ncdc.noaa.gov/cdr/
NOAA/NSIDC Sea Ice Concentration CDR Maturity Matrix Current NSIDC sea ice concentration products are level ~3-4 CDR product will be level 5-6 Will meet GCOS requirements Source code and processing methods will be provided Version control on code Metadata, including dataset DOI
Current NSIDC Sea Ice Concentration Products NASA Team (NT) 1 byte integer array Flat binary format Concentration scaled 0 250 (quarter %) Land, coast, pole, missing flag values 300 byte header w/ limited metadata No quality/error information NT Antarctic landmask Bootstrap (BT) 2 byte integer array Flat binary format Concentration scaled 0 1000 (tenth %) Land, pole/missing flag values No header, no file level metadata No quality/error information BT Antarctic landmask Future Sea Ice Concentration CDR Sea Ice Concentration CDR Suite of 1 byte integer array for NT, BT and a combined field NetCDF4_CF format Concentration 0 100% Land, coast, pole, missing, lake flag values Full ISO 19115 standard metadata Extent and data quality fields Consistent landmask in Antarctic Funded by NOAA Climate Data Record Program
Combined sea ice field 1. BT ice edge Coarse spatial resolution leads to ambiguous ice edge 37 GHz channel has smaller footprint and more sensitive to thin ice o BT edge uses only 37 GHz o NT uses 19 and 37 GHz 2. Max(BT NT) for each grid cell PM concentration generally biased low o NT for thin ice and melt o BT for interior cold temps.
% Concentration 100 0 Combined NT & BT Conc. Sea Ice Extent Concentration CDR Product Suite BT Only NT Only NT > BT BT > NT BT = NT Original NASA Team (NT) and Bootstrap (BT) products also included in same format and scaling +100 Conc. Diff. Quality Field 15 July 2007 % BT NT Conc. Diff. 100 NT & BT 3x3 St. Dev. 0 % 50 no melt melt
% Concentration 100 0 Combined NT & BT Concentration Sea Ice Extent Concentration CDR Product Suite BT Only NT Only NT > BT BT > NT BT = NT Original NASA Team (NT) and Bootstrap (BT) products also included in same format and scaling +100 Concentration Diff. Quality Field 15 Sep 2007 % BT NT Conc. Diff. 100 NT & BT 3x3 St. Dev. 0 % 50
2007 Sea Ice Extent Arctic Antarctic
September Trends (NOTE: SCALE VARIES) Bootstrap NASA Team BT - NT
Operational sea ice analyses Operational ice analysis groups, e.g.: U.S. National Ice Center Canadian Ice Service Danish Meteorological Institute Daily or weekly ice charts High resolution information Human analysis Focused on near-ice-edge regions Accurate, but not consistent over time Useful for intercomparison/validation with satellite products
Multi-sensor Analyzed Sea Ice Extent (MASIE) Collaboration between NSIDC and NIC Based on NOAA IMS product Vis/IR/SAR/PM inputs + human analysis 4 km resolution Daily extent/edge Several formats http://nsidc.org/data/masie/
Other satellite-derived sea ice products Melt onset, duration Motion Age, multiyear fraction Also VIS/IR sea ice products
Sea ice age Proxy for ice thickness Other things being equal: Older ice = Thicker ice Developed by J. Maslanik and C. Fowler, U. Colorado Lagrangian tracking of ice parcels (input motion data) Passive microwave data, visible imagery, buoys 1979-present Similar approach used with buoys (I. Rigor, U. Wash.) Part of NOAA project (J. Key, PI) to transition to CDR-level product over next two years
Ice is getting younger and thinner Much of older, thicker ice north of Alaska melting away during sum Mar 1985 Mar 1986 Mar 2010 Mar 2011 Based on satellite observations; from J. Maslanik, C. Fowler, Univ. Colorado
Multiyear ice from scatterometer data From NASA QuikScat scatterometer data From Kwok et al., 2009
ICESat sea ice thickness and volume From Kwok et al., 2009
Submarine and ICESat ice thickness From Kwok and Rothrock, 2009
Sea Ice Thickness Continuing data: Cryosat-2, IceBridge, ICESat-2 Unified Sea Ice Thickness CDR Gridded product R. Lindsay, Univ. Washington Submarine and in situ http://psc.apl.washington.edu/sea_ice_cdr/
Thanks!