The Snow Product Intercomparison Experiment Snow PEx Chris

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The Snow Product Intercomparison Experiment (Snow. PEx) Chris Derksen Climate Research Division Environment Canada

The Snow Product Intercomparison Experiment (Snow. PEx) Chris Derksen Climate Research Division Environment Canada

Simulated vs. Observed Arctic SCE 1. NOAA CDR NA EUR Historical + projected (16

Simulated vs. Observed Arctic SCE 1. NOAA CDR NA EUR Historical + projected (16 CMIP 5 models; rcp 85 scenario) and observed (NOAA snow chart CDR) snow cover extent for April, May and June. SCE normalized by the maximum area simulated by each model. Updated from Derksen, C Brown, R (2012) Geophys. Res. Letters

Simulated vs. Observed Arctic SCE NA 1. NOAA CDR 2. Liston & Hiemstra 3.

Simulated vs. Observed Arctic SCE NA 1. NOAA CDR 2. Liston & Hiemstra 3. MERRA 4. GLDAS-Noah 5. ERA-int Recon. EUR Historical + projected (16 CMIP 5 models; rcp 85 scenario) and multi-observational snow cover extent for April, May and June. SCE normalized by the maximum area simulated by each model.

Arctic SCE and Surface Temperature Trends: 1980 -2009 SCE Tsurf NA • Simulations slightly

Arctic SCE and Surface Temperature Trends: 1980 -2009 SCE Tsurf NA • Simulations slightly underestimate observed spring SCA reductions • Similar range in observed versus simulated SCA trends • Observed Arctic temperature trends are captured by the CMIP 5 ensemble range EUR 1. CRU 2. GISS 3. MERRA 4. ERA-int

Why do CMIP 5 models underestimate observed spring SCE reductions? North America Eurasia Model

Why do CMIP 5 models underestimate observed spring SCE reductions? North America Eurasia Model vs observed temperature sensitivity (d. SCE/d. Ts), 1981 -2010 • Models exhibit lower temperature sensitivity (change in SCE per deg C warming) than observations • Magnitude of observational d. SCE/d. Ts depends on choice of observations (both snow and temperature)

Background WMO Global Cryosphere Watch snow workshop held at Environment Canada in January 2013.

Background WMO Global Cryosphere Watch snow workshop held at Environment Canada in January 2013. One of the actions was to: “Initiate a satellite snow products evaluation/intercomparison activity” Support for European participation provided by the European Space Agency; Canadian and American participation is in-kind. Proposal submitted to ESA in December 2013; initial scoping meeting held at ESRIN in January 2014. Initial scope will be hemispheric snow extent (1 km) and snow water equivalent (25 km) products, derived primarily from earth observation. Reanalysis/model approaches will be included for SWE.

Objectives • Utilize ground reference measurements to perform a standardized assessment of all datasets.

Objectives • Utilize ground reference measurements to perform a standardized assessment of all datasets. • Inter-compare time series to determine agreement relative to multi-dataset statistics. • Derive trends with uncertainty estimates.

First Workshop 19 -21 July 2014 – Washington DC • Finalize participating datasets •

First Workshop 19 -21 July 2014 – Washington DC • Finalize participating datasets • Standardize intercomparison protocol

Relevance to Can. SISE • Area A: Can. SIPS initialization • Area B: Detection

Relevance to Can. SISE • Area A: Can. SIPS initialization • Area B: Detection and attribution study