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