ESA GlobSnow - project overview

Transcription

1 ESA GlobSnow - project overview GCW 1 st Implementation meeting Geneve, 23 Nov K. Luojus & J. Pulliainen (FMI) + R. Solberg (NR) Finnish Meteorological Institute

2 ESA GlobSnow ESA-GlobSnow project: Production of novel hemispherical snow extent (SE) and snow water equivalent (SWE) climate data records. Generation of long time-series employing FMI supercomputing facilities at Helsinki (daily, weekly and monthly maps of SE and SWE for northern hemisphere) Near-real-time GlobSnow processing system and data archives located in Sodankylä. Consortium members: Finnish Meteorological Institute (FMI) with ENVEO IT GmbH (Austria), GAMMA Remote Sensing (Switzerland), Norwegian Computing Center, Finnish Environment Institute (SYKE), and Environment Canada (EC). Details and products available at Finnish Meteorological Institute

3 30 year-long CDR time-series on snow conditions of Northern Hemisphere (ESA-GlobSnow SWE) First time reliable daily spatial information on SWE (snow cover): - Snow Water Equivalent (SWE) - Snow Extent and melt (+grain size) - 25 km resolution (EASE-grid) - Time-series for Passive microwave radiometer data combined with ground-based synoptic snow observations - Variational data-assimilation Available at open data archive ( Demonstration of NRT processing started on October 2010 Greenland, glaciers & mountains masked out

4 SWE algorithm selection & validation SWE estimates from 5 algorithms evaluated for Eurasia ( ) FMI Assimilation algorithm (Pulliainen 2006) EC SWE suite (Goodison, Walker, Goita, Derksen et al ) Chang et al (original channel difference algorithm) SPD-algorithm (Asbacher 1989) Armstrong and Brodzik 2001-algorithm (Improved channel difference) SWE algorithm evaluation for 09/1994 and 12/1997 (SSM/I data) Evaluations for North America and Finland were carried out in addition to the analyses for Eurasia Finnish Meteorological Institute

5 Validation data INTAS SSCONE data INTAS SSCONE data (from the former USSR and Russia) There are 1294 snow path stations with data from the USSR Manual (0.5 2km) transects measuring snow depth There were 450 path stations with data for Finnish Meteorological Institute

6 Overall performance for SWE algorithms Eurasia 09/ /1997 Reference data: independent snow transects Name RMSE bias Corr.coeff Unbiased RMSE Samples FMI algorithm used for GlobSnow) 43.2 mm -3.1 mm mm EC algorithm 67.6 mm mm mm Chang et al (asc node) Chang et al (desc node) 71.6 mm 70.7 mm -8.4 mm 1.6 mm mm 70.8 mm SPD algorithm (asc node) SPD algorithm (desc node) 67.1 mm 63.9 mm mm -3.1 mm mm 63.9 mm Armstrong et al (asc node) Armstrong et al (desc node) 72.3 mm 73.7 mm mm mm mm 59.9 mm Finnish Meteorological Institute

7 SWE retrieval (data assimilation vs. channel diff.) Density scatterplot (assimilated vs. satellite only SWE) Ground truth data is INTAS SCCONE SWE transect data

8 Consistency of SWE retrieval RMS error and retrieval bias calculated independently for each year Reference data: snow transects from Russia (INTAS-SCCONE) SMMR F 8 SSM/I F 11 SSM/I F 13 SSM/I F 17 SSM/I SMMR F 8 SSM/I F 11 SSM/I F 13 SSM/I F 17 SSM/I SWE<150 mm

9 GlobSnow SE Dataset SE retrieval using ERS-2 ATSR-2 and Envisat AATSR data - Finnish Environment Institute s SCAmod algorithm. - Norwegian Linear Reflectance (NLR) fractional snow cover (FSC) algorithm; - 15 years SE data record has been produced using optical imagery from ATSR-2 (1995-) and AATSR (2002-) on a hemispherical scale. yellow clouds green bare ground white snow cover Finnish Meteorological Institute

10 Daily, weekly and monthly products Optical data ~ 1km spatial resolution 310 March April March April March April Finnish Meteorological Institute

11 Examples of monthly products, 2010

12 Examples of monthly products, 2010 April 2003 May 2003 June 2003

13 Example: Trend analysis using SWE product Apr

14 Snow clearance date Example for year 2008 Time series of 30 years processed and distributed along the SWE product Apr

15

16 Frost tube measurements in Finland Operated by Finnish environmental institute Default configuration: Three frost tubes in three different locations: Open area, Forest and Bog site. Manually recorder three times per month (usually 6 th, 16 th and 26 th ). During freezing and thawing 5 times. Almost 40 manually recorded frost tube stations. In Sodankylä, automatic temperature profile measurements installed next to frost tubes for comparison.

17 Frost tube locations Typically three tubes in three main land classes: forest, bog, open Forest Bog Open

18 Two winter time-series: ELBARA-II and frost/snow Inc. angle: 50 Snow Snow Frost Frost

19 Hemispherical trend of snow extent (PMW ~25km) Finnish Meteorological Institute

20 Hemispherical trend of snow mass Finnish Meteorological Institute

21 GlobSnow - Summary Production of novel global snow extent (SE) and snow water equivalent (SWE) climate data records (15 and 30 years of snow cover information) - coarse resolution (25km) SWE and SE for medium resolution (1km) SE for Additionally, near-real-time GlobSnow processing demonstration is ongoing with open data access (started on October 2010) Additional information and all GlobSnow products available at Finnish Meteorological Institute

22 Any Questions? (GlobSnow-handouts available ) Finnish Meteorological Institute