research and discover land-use history brazil heather bain, college of the holy cross dr. george...
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Land Use Total Carbon Land-use Reconstruction In Action Hurtt et al N C P STRANSCRIPT
Research and Research and DiscoverDiscover
Land-use HistoryBrazil
Heather Bain, College of the Holy CrossDr. George Hurtt, UNH
Motivation
Ecosystem Modeling
Current state of ecosystem
•Direct Measurement
•Land-use history
•Carbon projections
•Future dynamics
1700
1850
1920
1990
Land Use Total Carbon
Land-use Reconstruction In Action
Hurtt et al. 2002
N C P S
The Math of a Land-use History Reconstruction
C
P
N
S
C
P
N
S
a11 a12 a13 a14
a21 a22 a23 a24
a31 a32 a33 a34
a41 a42 a43 a44
l(x,y,t+1) = A(x,y,t) l(x,y,t)
t+1 t
This makes for 462x300x12 = 1,663,200 unknown parameters!!!longitud
e
latit
ude
time
Assumptions & Constraints Conjecture with reason!
Minimum flows assumption Release of cropland
Be consistent with as many sources of data as possible
Constraints1. Land cover vegetation from NOAA-AVHRR (1992)2. County land-use totals from census data from
IBGE (1992)3. National land-use totals from census data from
FAO (1961-1992)4. Population estimates from IBGE (1700-1961)5. *Deforestation rates from INPE (1985-1992)6. *Spatial deforestation analysis from Skole et al.
(1986, 1992)7. **Secondary estimates
Goal: create a spatial map of land use
Tools: AVHRR vegetation
classification IBGE census data
(county level) Method: develop a
mathematical translation, following Hurtt et al. 2001
1.&2. Land Use Mapping Project
Math of LUMPl(x,y) = B r(x,y)
17x1
C
P
N
W1x4
b11 b12 b13 …
b21 b22 b23 …
b31 b32 b33 …
b41 b42 b43 …4x17
r1
r2
r3
*
*
*
r17
fractional information for cell = transition matrix * vegetation matrix
3.&4. FAO and IBGE population Regional information on land use
through time Census data on land use from FAO
(1961-1992) Population estimates from IBGE
(1700-1961)
Land-Use History in Brazil
0
1000000
2000000
3000000
4000000
5000000
6000000
7000000
8000000
9000000
1700 1750 1800 1850 1900 1950 2000time (in yrs)
area
(in
kmkm
)
pasture
totalnatural
crop
Fao-lump
IBGE
A land-use movie
5.&.6. INPE and Skole
Verify annual gross deforestation flows (1986-1992) Regional totals Spatial pattern
Regional Deforestation Comparison
1986 1987 1988 1989 1990 19910
5000
10000
15000
20000
25000
area (km 2̂)
time (years)
INPEgross flows
Amazonia forest cover
Distribution of forest cover fraction values Map based on 0.5o grid-interpolated forest
cover data from Skole et al. (1993)
1992
1986
Forest Cover Difference
Skole et al. (1993)
Distribution of the difference of forest cover b between 1992 and 1986
Spatial Distribution of Deforestation
Reasonable preliminary results!
Symmetric distribution
Slight bias-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
-100 -50 0 50 100
% Difference
Freq
uenc
y
Summary It is possible to produce a land-use
history reconstruction consistent with many sources of data
These reconstructions can include estimates of all underlying land-use transition rates
Preliminary version is promising
Future Refine land-use history reconstruction
with additional sources of data Combine with an ecosystem model to
produce estimates of past and current states of ecosystems and associated carbon fluxes
Assess the sensitivity of the ecosystem to alternative reconstructions
Produce future projections of ecosystems and carbon fluxes
Acknowledgements NASA-UNH Research and Discover
program and initiators. Dr. George Hurtt for his patience and
dedication to his work and the interns. Manoel Cardoso for his various
contributions. Staff at EOS department, UNH. Dr. Edward Soares for his constant support
and encouragement.