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Magnitude and Spatial Distribution of Uncertainty in Ecosystem Production and Biomass of Amazonia
Caused by Vegetation Characteristics
Christopher Potter and Sassan SaatchiNASA Ames Research Center, Moffett Field, California, USA
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109
Steven Klooster and Vanessa GenoveseCalifornia State University Monterey Bay
LBA-ECO Science ThemeLC - Carbon Dynamics
Existing Vegetation Maps for Model InputExisting Vegetation Maps for Model Input
1.1. JPL Amazon Basin Map Based on SPOT VGT 98-01, JERS-1 95-JPL Amazon Basin Map Based on SPOT VGT 98-01, JERS-1 95-96, (Saatchi, et al., 2003)96, (Saatchi, et al., 2003)
2.2. UMD global classification Based on AVHRR 92-93 data, (Hansen et UMD global classification Based on AVHRR 92-93 data, (Hansen et al., 2000)al., 2000)
3.3. TREES Vegetation Map of South America Based on SPOT VGT, TREES Vegetation Map of South America Based on SPOT VGT, JERS-1, ATSR-1, AVHRR, GTOPO30 (Eva et al., 2002)JERS-1, ATSR-1, AVHRR, GTOPO30 (Eva et al., 2002)
4.4. USGS Global Vegetation Map Based on AVHRR 92-93 (Loveland USGS Global Vegetation Map Based on AVHRR 92-93 (Loveland et al., 2000)et al., 2000)
5. Woods Hole Research Center Vegetation Map of South America 5. Woods Hole Research Center Vegetation Map of South America Based on AVHRR 88-91 LAC, GVI (Stone et al., 1994)Based on AVHRR 88-91 LAC, GVI (Stone et al., 1994)
Evergreen Forest
Deciduous Forest
Woody Savanna
Savanna
Flooded Forest
Flooded Nonforest
Secondary Forest
Pasture/Crops
Vegetation Map of Amazon Basin Data Fusion (Saatchi et al., 2003)
Vegetation Map of Amazon Basin Data Fusion SPOT VGT, JERS-1(Saatchi et al., 2003)
Deforestation Pattern in Rondonia, Brazil
Santarem
Deforestation along Transamazonian Highway BR230
Deforestation Pattern in Rondonia, Brazil
Santarem
Deforestation along Transamazonian Highway BR230
UMD Global Vegetation MapDecision Rule, AVHRR 92-93Hansen et al., 2000
Santarem
Deforestation Pattern in Rondonia, Brazil
Deforestation along Transamazonian Highway BR230
TREES Vegetation Map of South AmericaMulti-Resolution, SPOT VGT, JERS-1,ATSR-1, AVHRR, GTOPO30 Eva et al., 2002
Santarem
Deforestation Pattern in Rondonia, Brazil
Deforestation along Transamazonian Highway BR230
USGS Global Vegetation MapStandard Supervised, AVHRR 92-93 Loveland et al., 2000
Santarem
Deforestation Pattern in Rondonia, Brazil
Deforestation along Transamazonian Highway BR230
Woods Hole Research Lab.Vegetation Map of South AmericaClustering Approach AVHRR 88-91, LAC, GVI Stone et al., 1994
Santarem
Percent Cover of Land Cover Types in the Amazon Basin Percent Cover of Land Cover Types in the Amazon Basin
Class Type JPL % cover UMD% cover TREES %cover
USGS % cover WHRC % cover
Evergreen Forest 69.16 79.12 80.53 79.78 77.72Deciduous Forest 1.74 1.81 -- --- 1.56Woodland Savanna 5.67 5.32 4.86 4.61 7.76Savanna 4.55 11.24 3.27 7.03 3.49Flooded Forest 7.65 -- 2.73 -- 1.39Flooded Nonforest 2.43 -- 0.61 0.62 0.23Secondary Forest 1.88 -- 2.12 -- 0.28Pasture/Crops 4.99 0.60 4.59 6.26 4.23Water 1.57 1.79 1.27 -- 0.73
Percent Pixel-to-Pixel Agreement Between Land Cover Types
Maps JPL UMD TREES USGS WHRCJPL 100
UMD 60.6 100
TREES 63.5 76.0 100
USGS 68.7 77.2 76.2 100
WHRC 78.7 74.2 74.7 75.2 100
Maps JPL UMD TREES USGS WHRCJPL 100
UMD 84.3 100
TREES 91.6 96.3 100
USGS 88.9 95.2 96.3 100
WHRC 91.0 93.5 94.7 55.2 100
Percent Pixel-to-Pixel Agreement of Forest Type Between Maps
Maps JPL UMD TREES USGS WHRCJPL 100
UMD 32.2 100
TREES 41.2 38.8 100
USGS 37.1 53.6 44.7 100
WHRC 43.2 40.9 36.2 41.4 100
Percent Pixel-to-Pixel Agreement of Nonforest Type Between Maps
Results From Map ComparisonResults From Map Comparison
1.1. Agreement between maps range from 60-75% averaged over Agreement between maps range from 60-75% averaged over all class typesall class types
2.2. Approximately 80% of the basin is covered by forest and Approximately 80% of the basin is covered by forest and the agreements among maps for forest class are above 90%the agreements among maps for forest class are above 90%
3.3. Major disagreement between maps are in nonforested areas.Major disagreement between maps are in nonforested areas.On the average the maps are only 30-50% in agreement. On the average the maps are only 30-50% in agreement.
4. Differences are due to the prediction of deforested and regrowth 4. Differences are due to the prediction of deforested and regrowth areas in 1-km resolution maps. Savanna pixels with differentareas in 1-km resolution maps. Savanna pixels with differentdegrees of woody vegetation are misclassified as forest ordegrees of woody vegetation are misclassified as forest ornonforest in different maps.nonforest in different maps.
5.5. Deforested areas covered with pasture and crops are betterDeforested areas covered with pasture and crops are better estimated by JPL and TREES maps because of the use ofestimated by JPL and TREES maps because of the use of
high resolution imagery.high resolution imagery.
NASA-CASA ModelNASA-CASA Model
f(TEMP)f(WFPS) f(Lit q)
(a) Soil Moisture Balance and Plant Functional Types
(b) Ecosystem Production Nutrient Mineralization
(c) Biogenic Trace Gas Flux
Leaf Litter
Root Litter
Microbes
Soil OrganicMatter
CO2
Mineral Nf(Lit q)
SoilProfile Layers
Heat &WaterFlux
PPT
N2O NO
f(WFPS)
CH4
Grass/Crop Shrub Tree
PET
FPAR
NPP
M 0
M 1
M 2
M 3
M 0
M 1
M 2
M 3
M 0
M 1
M 2
M 3
Soil Surface
Biomass
CO2NEP
Rh
f(TEMP)f(WFPS) f(SOLAR)
NASA-CASA Model SimulationsOver Legal Amazon
1. Five land cover types are used as input layers in the model and allother variables are considered constant for each run
2. Land cover maps are resampled to 8 km x 8 km grid cells using a majority filter. Cover types are combined to four general
classes of evergreen forests, wooded grassland and savanna,pasture and cultivated land, and other classes. Wetland classes are integrated into forest and savanna types.
3. Annual Net Ecosystem Production (NEP) are simulated for twoextreme years: 1983 (dry condition) and 1990 (wet condition).
4. Total above ground wood biomass carbon is simulated for 1990.
NEP Simulations Over Legal AmazonBased on JPL Map (g C m-2 yr-1)
19831990
-500 -250 0 250 500 g C m-1 yr-1
Changes in NEP Simulations1983
JPL-UMD JPL-TREES
JPL-USGS JPL-WHRC
No Change
> 0
< 0
Changes in NEP Simulations1990
JPL-UMD JPL-TREES
JPL-USGS JPL-WHRC
No Change
> 0
< 0
NEP Profile Across Basin, 1983
NEP Profile Across Basin, 1990
NEP83 JPL UMD TREES USGS WHRCJPL 100
UMD 82.0 100
TREES 82.3 83.5 100
USGS 81.7 80.3 81.2 100
WHRC 81.9 82.4 84.6 80.3 100
Percent Pixel-to-Pixel Agreement of Between NEP-83 Simulations
-3.54
-3.53
-3.52
-3.51
-3.5
-3.49
-3.48
-3.47
-3.46
0.08 0.1 0.12 0.14 0.16 0.18
Total NEP (pg C yr
-1)
Ratio of Area Non Forest/ Forest
JPL
UMD
WHRC
TREES
USGSFloodplain Areas are Excluded
NEP90 JPL UMD TREES USGS WHRCJPL 100
UMD 82.2 100
TREES 82.6 83.6 100
USGS 81.9 80.5 81.5 100
WHRC 82.2 82.6 84.5 80.7 100
Percent Pixel-to-Pixel Agreement of Between NEP-90 Simulations
3.21
3.22
3.23
3.24
3.25
3.26
3.27
3.28
0.08 0.1 0.12 0.14 0.16 0.18
Total NEP (pg C yr
-1)
Ratio of Area Non Forest/ Forest
JPL
UMDWHRC
TREES
USGS
Floodplain Areas are Excluded
Summary
1. Differences in land cover maps cause 0.1-0.4 pg C yr-1 uncertainty in total Net Ecosystem Production over the Legal Amazon
2. The impact of land cover uncertainties are higher during wet year (carbon sink flux) over the region.
3. Ratio of nonforest area over forest area explains the changes of total annual NEP. Relationship is significant in wet years and insignificant during the dry years (regional source flux).
4. The impacts of uncertainty in land cover types (e.g. deforested, pasture, crops) are the same magnitude of the NEP interannual variability.
5. During dry years other variables such as fire rainfall distribution anomalies dominate the impact of land cover differences
Above Ground Woody Biomass CarbonDerived from NASA_CASA Model
Early 1990s
0 5,000 10,000 18,000 g C m-2
Changes in Biomass Carbon1990
JPL-UMD JPL-TREES
JPL-USGS JPL-WHRC
No Change
> 0
< 0
BIOMASS90 JPL UMD TREES USGS WHRCJPL 100
UMD 96.1 100
TREES 96.2 96.5 100
USGS 96.0 95.7 96.0 100
WHRC 96.2 96.2 96.6 96.1 100
-2
-1
0
1
2
3
0 5 10 15 20
Wood Biomass Difference (pg C)
Normalized Ratio of Nonforest
JPL-UMD
JPL-USGSJPL-TREES
JPL-WHRC
54
55
56
57
58
59
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08
Total Wood Biomass (pg C)
Ratio Nonforest/Forest
UMD
JPL
WHRC
TREES USGS
Percent Pixel-to-Pixel Agreement of Between Biomass Simulations
Summary1. NASA-CASA model predicts 54-58 pg C of above ground woody
biomass across legal Amazon for the early 1990s
2. The impact of land cover differences are on the order of 1-3 pg Cthat are primarily due to misclassification of areas of nonforest types in land cover maps.
3. Total forest cover defines the above ground woody biomass
carbon. All five maps show above 95% agreement on forest cover. Differences in normalized ratio of nonforest/forest explain changes of above ground woody biomass across the region.
4. Coarse resolution maps do not allow accurate classification of areas of disturbance on annual basis.