Satellite data products to support
climate modelling –Land Cover
Finnish Environment Institute
Pekka Härmä
Markus Törmä
Suvi Hatunen
Background
• In the standard versions of SNOWCARBO models Land cover is
descibed using Global Land Cover characteristics data base
(USGS)
• Old data set: Based on EO data received early 1990 !
• Global data set
• feasibility for regional modeling in nordic boreal conditions ?
• Up-to-date land cover data sets now available in different
resolutions (25m-300m)
• Enhanced land cover information for the modling
Content
1. Global Land Cover characteristics data base
2.
3.
Description of alternative data sources for land cover in northern
Europe
•
Corine Land Cover
•
GlobCover
•
Land cover based on MODIS products
Proposed land cover data for the modeling in SNOWCARBO
Global Land Cover characteristics data base
•
Produced by the U.S. Geological Survey
•
Based on time series of satellite data (NOAA
AVHRR) with 1 km spatial resolution
• received in 1992-1993
• Monthly NDVI maximum values
•
Unsupervised classification and data
integration with map data (DEM, ecoregions,
etc)
•
Nomeclature: 94 land cover categories
defined by Olson 1994 (Global ecosystems
framework)
•
Spatial distribution of land cover categories
for the modeling
Global Land Cover characteristics data base
Modified by Max Plank Institute
•
•
Allocation of land surface parameters for
each Olsson ecosystem type
•
Background surface albedo αs,
•
Surface roughness length due to vegetation z0,veg,
•
Fractional vegetation cover cv, L
•
Leaf area index LAI for the growing and dormancy
season,
•
Forest ratio or fraction cf,
•
Plant-available soil water holding capacity Wava,
•
Volumetric wilting point fpwp
Gives the characteristics of vegetation and
soils for the models
CORINE Land Cover
•
•
•
European Land Cover data
•
Funded by European Environmenrt Agency and MS
•
versions 1990, 2000, 2006
•
Changes 1990-2000; 2000-2006
•
44 land use and cover classes
•
vector data with MMU of 25 ha (100 m and 250 m raster)
•
Land cover changes mapped with MMU of 5 ha
Production method
•
Based on high resolution satellite data (20-30 meter resolution)
•
Produced by national teams
•
Coordinated, validated by EEA
•
Visual interpretation in most countries
•
Automated processing chains (Fin, Swe, No, …)
Continuous program
•
Future updates part of GMES land monitoring
•
Next update 2012
CORINE Land Cover in Finland
•
Standard version of Corine Land Cover does not meet
national data needs
•
SYKE has produced also a national version of CLC data
•
High spatial resolution (25*25 m raster)
• Land cover changes (mmu 0.5 – 1 ha)
•
•
More detailed nomenclature with national land cover
categories included
•
In Finland versions 2000 and 2006
•
Land cover changes 2000-2006
•
Next update 2012; changes 2006-2012
National cooperation
•
SYKE, Metla, GL
•
MML, VRK, Tike, Mavi
•
Utilization of existing data sources from different
organizations
An example
Corine Land Cover 2000
Corine Land Cover 2006
Corine Land Cover changes 2000-2006
Land Cover changes 2000-2006
Changed areas cover 4.2 % of the total area of Finland
•
•
•
•
Forest cuttings and regrowth about 90 %
build-up sprawl 2 %
Clearance for agriculture 5 %
Reforestation of agricultural areas 2 %
As a result
•
•
Area of build-up areas and agricultural areas increases
Area of forests decreases (regarded as source of co2)
2006
Rakennet Peltom Sulkeutun vähäpuusto kosteik
ut alueet aat
ut metsä inen metsä
ot
vedet
Rakennetut alueet
10,8
0,0
0,0
4,2
0,0
0,0
Peltomaat
61,9
0,0
0,0
256,3
1,0
0,0
Sulkeutunut
2000
metsä
164,9 276,7
0,0
6515,5
22,9
0,0
vähäpuustoinen
metsä
66,8 228,9
6229,9
0,1
18,5
0,0
kosteikot
2,2 219,8
0,0
0,0
76,8
0,0
vedet
1,5
0,0
0,0
0,0
0,0
0,0
New agricultural areas (blue)
and build-up areas (red)
GlobCover v2.2
Most recent global land cover data
•
Funded by ESA
•
Produced by Medias France, Brockmann
Consult, UCL, JRC, UCL, ….
•
Based on time series satellite data (ENVISAT
MERIS) with spatial resolution of 300 meters
• received 2004-2006
• Monthly mosaics of reflectance maps (15
bands)
•
Regional classification and class labeling with
existing land cover data
•
Global version with 22 land cover classes
•
Regional version with 51 classes
•
Nomenclature defined using UN land cover
classification system (LCCS)
New regional land cover data
Objective: Production of regional LC homogenous in terms of
surface parameters in nordic areas of Europe
Input Data
Time series of global MODIS-products in 1 km resolution
(produced by NASA) received 2007 and 2008
•
Vegetation Index (EVI)- (MOD13A3)
•
Leaf Area Index - (MOD15A2)
•
Albedo (MCD43B3)
Processing
•
Compute monthly (march-october) mean values (2007 & 2008)
•
Define minimum and maximum values
•
Unsuperviced classification
•
Class labeling using Finnish national Corine Land Cover 2000 and
GlobCover
Processing of revised land cover datasets for
the modeling
Processing steps
1. Recode into Olson land cover categories
Coparison of class descriptions in different data sets
•
Global Ecosystem Framework 1. Definitions (J.S.Olson)
•
GLOBCOVER – Products Description manual
•
CORINE nomenclature
Comparison of surface parameters of Olson classes with local data
covering Finland
•
Forest ratio – Crown coverage maps of Finland by Metla
•
LAI – LAI maps of Finland by J. Heiskanen (HY)
2. Filtering
3. Resample into 1 km resolution
4. Reproject into Olsson grid and projection
5. Merge new nordic data into global Olsson data set
Alternative set of land cover maps for the modeling
An example
a. Original Olson ecosystem classification
b. GlobCover recoded into Olson
c. Corine Land Cover recoded into Olson
Olson - GlobCover - Corine Land Cover
Comparison within Finnish territory
•
Areal distribution of land cover categories compared with
corresponding statistics
•
Classification accuracy (error matrix)
Remarks
• Proportion of forests overestimated (especially Olsson);
• Olson
• No open bogs, mires and marshes in Olson
• agricultural areas mostly interpreted as forest
•
GlobCover
• Proportion of agricultural areas underestimated – mixed
with sparsely vegetation areas
• GlobCover provides better distribution of land cover in
Finland than Olson data
Olson ecosystem classification
Corine Land Cover+GlobCover classification
GlobCover classification
Clustering analysis
Corine land Cover
National version of
Corine Land Cover
GlobCover
Thank you