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.