globsnow: why?earth.esa.int/workshops/meris_aatsr2008/participants/479/pres_479_koetz.pdfsnow cover...
TRANSCRIPT
GlobSnow: WHY?
Motivation:Global areal extent of snow
recognized as Essential Climate Variable by GCOS
Snow plays a central role in hydrological cycle
Snow affects planetary albedo
Snow as indicator for climate change & variability
IPCC report, 2007
GlobSnow: WHY?Extents are derived from NOAA/NESDIS snow maps
Lemke et al. 2007, Observations: Changes in Snow, Ice and Frozen Ground. IPCC-WG1
GlobSnow: driven by GCOS
GCOS requirements for the Snow ECVProducts:
Snow areal extent (primary), snow water extent, snow depth
Target requirements: Accuracy: 5% omission/commission error
in snow area
Resolution: 1 km globally, 100 m in complex terrain
Fundamental Climate Data RecordMedium-resolution VIS/NIR/IR
Passive microwave imageryGCOS Implementation Plan(2004/06)
GlobSnow: What?
Project scope:3 years duration1 Mio. € budgetKick-Off: 1st of November 2008
Objectives:Specification of User RequirementsProduction of a relevant FCDRbased on EO dataDemonstration of a global snow monitoring serviceSupport of GCOS requirements Annual max. snow cover
extent in both hemispheres (Global Outlook for Ice & Snow, UNEP2007)
GlobSnow User consultation
30 participants from European & international entities University of Bern, Feb.
2008
GlobSnow: Who?GlobSnow user group:
WMO: WCRP, CliCNational Meteo-Offices: SwissMeteoECMWFEEA: climate change indicators11 user entities in total
Consolidation of User requirements
IGOS cryosphere report 2007
Resolution Measurement Range Measurement Accuracy Spatial Temporal Parameter
CT O L H U V U V U V U
Comment / Principal
Driver C 20 100 % 15-20 % 1 km day e.g. MODIS T 0 100 % 10 % 0.5 km 1 day Snow Cover O 0 100 % 5 % 0.1 km 12 hr Hydromet
C 0 0.2 m 2-10 cm 25 km 1 day e.g. AMSR-E T 0 0.3 m 3 cm 0.5 km 6 day
Snow Water Equivalent, satellite (Shallow) O 0 0.3 m 2 cm 0.1 km 12 hr Hydromet
C None --- --- --- --- --- --- --- --- Need HF SAR Snow Water Equivalent, satellite (Deep)
T 0.3 3 m 10 % 0.5 km 6 day Hydromet
Environment Canada
GlobSnow: How?Products:
Global areal snow extent (SE)FCDR and SE end-product spanning 15 yearsOperational near-real time productNorthern / Southern Hemisphere
Snow water equivalentFCDR and SWE-end product spanning 15 years Operational near-real time productNon-mountainous areas, Northern Hemisphere
Potential Sensors:Snow cover: Multi-sources EO data - Optical / IR & SAR
(e.g. MERIS, (A)ATSR, ASAR, MODIS, SPOT-Vegetation)Snow water content: Microwave radiometers (e.g. SSM/I,
AMSR-E)
GlobSnow: Snow Extent
SE products (FCDR & Oper. NRT product)Based on (to be selected in Phase I)
MERIS+AATSR+ASAR (2002-)MODIS+ASAR/ERS-2 (2001-)ATSR-2 + ERS-2 (1995-2004)AVHRR (depending on NOAA calibration initiative)
Potential algorithms:Best algorithms will be selected by benchmarkingSynergistic use of SWE & SE productFor mountains synergistic use of SAR & Optical data
Snow extent products
MODIS/MERIS: fractional snowcover (SCAmod)
MODIS snowcover
MODIS & ASAR: multi-sensorsnow cover
GlobSnow: SWE product
SWE products (FCDR & Oper. NRT product)Based on
AMSR-E data (2002 – present)SSM/I data (1987 – present)Global weather station data
Potential algorithms:Empirical formulae (probably not adequate)Analytical model-based assimilation with synoptic
snow depth dataSE mapping as by-product
Snow water equivalent product
8.3.2007
30.4.2007
Project Road Map
GlobSnow
Requirement engineering
Design engineering
Production & Validation
Service demonstration
User Consultation: GlobSnow workshop 14th Feb.Invitation To Tender (EMITS) – 3rd quarter 2008
Project Kick-Off – 1. November 2008Three years duration in three phases
Concluding RemarksGlobSnow: Demonstration of global snow
monitoring service for climate change
Added value: harmonized multi-sensor FCDR & snow products
Synergy with other ECV: Albedo, Soil moisture, LAI/FAPAR (phenology), Permafrost
Challenges: Consistency over sensors and landscapes,& Validation