nara luísa reis de andrade, luciana sanches, peter zeilhofer, segundo durval rezende pereira, josé...
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Nara Luísa Reis de Andrade, Luciana Sanches, Peter Zeilhofer, Segundo Durval Rezende Pereira, José de Souza Nogueira
Environmental Physics Research GroupFederal University of Mato Grosso
Manaus, November 2008.
Research conducted at:
Relationship between litterfall and Modis vegetative index in a transitional forest of Mato Grosso (Sinop LBA test)
1. Introduction
• Litterfall is an important component of the CO2 cycle in seasonal tropical forests, guaranteeing nutrients and energy fluxes to the soil.
• Remotely sensed Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) were already shown to be a good measure of ground-based measurements of forest tree productivity in temperate and tropical moist evergreen forests.
• The knowledge on these relationships in the transitional semi-deciduous forests of the southern Amazon is little.
In this paper we compare seasonal variations of litterfall measured at ground at the LBA Sinop test site with NDVI and EVI composites for five-year experiment.
Cover vegetation and biomass of Legal Amazon 2001Source: INPE, 2003; WWF, 2000; IBGE, 1997; WHRC, 1992.
2. Site description
Location of tower and arc of deforestion.
Tower
Location of Transitional forest Amazônian Cerrado.
2. Site description
Source: Voulitis et al. (2008); Priante-Filho (2004); Sanches et al. (2005); Vilani et al. (2006).
• Location: North of Mato Grosso• Annual precipitation = 2.0 m• Defined Season• Duration of dry season = 3-5 months• Average canopy = 25-30 m tall• Leaf Area Index (LAI) = 2.5 - 6 m2 m-2
Tower
View over the canopy
3. Material and Methods
(a) Field Measurements: Rainfall and temperature(b) Litterfall collected(c) NDVI and EVI by MODIS products (d) Data analysis and derived quantities
d.1 Monthly average of litterfall productiond.2 Gap filling of litterfall production by linear regression to coincide with data of
NDVI by MODIS productd.3 Moving average of litterfall productiond.4 Singular Spectrum Analysis by software CatMV (Gistat)d.5 Relationship between :
Original NDVI vs Moving total litterReconstructed NDVI vs Moving total litterOriginal EVI vs Moving total litterReconstructed NDVI vs Moving total litter
• Tower: 41 m • Measurements of rainfall and Temperature• Measurements from 1999 – Until last Thursday
(The tower has fallen due to strong winds)
Rainfall and temperature measurements3. Material and Methods
Tower Pluviometer
Source: Pinto-Júnior et al. (submitted)
• Box of 1 m2
• Collect: Monthly (n = 20 points)• From 2001 to 2006
Litterfall Collect3. Material and Methods
Tower
Collect points
Location of boxes
NDVI and EVI MODIS Products
• 250 m resolution 16-day MODIS NDVI composites (Land Products, Collection 5, C5_MOD13Q1), • obtained from the Oak Ridge National Laboratory (ORNL DAAC).
3. Material and Methods
Singular Spectrum Analysis by software CatMV (Gistat)
Original serie
Reconstructed series (main ciclic component)
3. Material and Methods
• The CatMV for analysis of time series, which may contain missing values.
• The implemented algorithms result in extraction of additive components of time series such as trends and periodic components, with simultaneous filling in the missing data (if any).
Seasonality of Rainfall and Temperature
Source: Sanches et al. (2008)
4. Results and discussion
(a) Total monthly rainfall and (b) average monthly temperature for January 2001-07. For total monthly rainfall, annual totals (mm) are displayed for each year, while for average annual temperature, annual average temperature (oC) is displayed for each year. Intervals between vertical dash lines represented a year.
(a)
(b)
Seasonality of Rainfall and Temperature
Source: Sanches et al. (2008)
4. Results and discussion
(a) Total monthly rainfall and (b) average monthly temperature for January 2001-07. For total monthly rainfall, annual totals (mm) are displayed for each year, while for average annual temperature, annual average temperature (oC) is displayed for each year. Intervals between vertical dash lines represented a year.
(a)
(b)
El Niño event of 2002 (Tolan, 2007)
La Niña event
Seasonality of Rainfall and Temperature
Source: Sanches et al. (2008)
4. Results and discussion
(a) Total monthly rainfall and (b) average monthly temperature for January 2001-07. For total monthly rainfall, annual totals (mm) are displayed for each year, while for average annual temperature, annual average temperature (oC) is displayed for each year. Intervals between vertical dash lines represented a year.
(a)
(b)
Seasonality of Rainfall and Temperature
Source: Sanches et al. (2008)
4. Results and discussion
(a) Total monthly rainfall and (b) average monthly temperature for January 2001-07. For total monthly rainfall, annual totals (mm) are displayed for each year, while for average annual temperature, annual average temperature (oC) is displayed for each year. Intervals between vertical dash lines represented a year.
(a)
(b)
Leaf
020406080
100120140
Stem
0
10
20
30
40
50
60
Reproduction
Litte
r p
rod
uctio
n (
g m
-2 m
on-1
)
0
10
20
30
40
50
Total
0
30
60
90
120
150
180
Jan-01 Jul-01 Jan-02 Jul-02 Jan-03 Jul-03 Jan-04 Jul-04 Jan-05 Jul-05 Jan-06 Jul-06 Jan-07
Source: Sanches et al. (2008)
Inter-annual litter production4. Results and discussion
Average (+se; n = 20) leaf, stem, reproductive (flower + fruit) and total litter production for January 2001-07. Solid symbols are measured values and open symbols are interpolated or forecast values calculated using auto-regressive, integrated moving average (ARIMA) models.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Litt
erf
all
Le
af(g
m-2
mo
nth-1
)
0
20
40
60
80
100
120
140
Leaf
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Litt
erf
all
(gm
-2m
on
th-1
)
0
20
40
60
80
100
120
140
160
Total
Annual average litter production (2001-2006)
4. Results and discussion
Month
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
EV
I
4000
4500
5000
5500
6000
6500
7000
EVI
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
ND
VI
8400
8600
8800
9000
9200
9400
NDVI
4. Results and discussion
Annual average NDVI and EVI (2001-2006)
Litterfall, NDVI and EVI
0 365 730 1095 1460 1825 2190
Litt
erfa
ll (g
m-²
)
0
20
40
60
80
100
120
140
0 365 730 1095 1460 1825 2190
Orig
inal
ND
VI
8400
8600
8800
9000
9200
Rec
onst
ruct
ed N
DV
I
-9000
-6000
-3000
0
3000
6000
9000
Time (days/years)
0 365 730 1095 1460 1825 2190
Orig
nal E
VI
4000
4500
5000
5500
6000
6500
7000
Rec
onst
ruct
ed E
VI
-10000
-5000
0
5000
10000
Original NDVI Rec_NDVI
Original EVI Rec_EVI
Litter total movel Litter leaf movel
4. Results and discussion
Original Total Litter (g m-²)
20 40 60 80 100 120 140
Ori
gin
al N
DV
I
8400
8500
8600
8700
8800
8900
9000
9100
9200
Moving AverageLitter(g m-²)
20 40 60 80 100 120
Re
con
stru
cte
d N
DV
I
-10000
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
10000
Oring Total Litter (g m-²)
20 40 60 80 100 120 140
Ori
gin
al E
VI
4000
4500
5000
5500
6000
6500
Moving Average Litter (g m-²)
20 40 60 80 100 120
Re
con
stru
cte
d E
VI
-8000
-6000
-4000
-2000
0
2000
4000
6000
Correlations R α
(a) Original NDVI vs Moving total litter 0.3100 -0.0606(b) Reconstructed NDVI vs Moving total litter 0.6450 -0.150(c) Original EVI vs Moving total litter 0.2302 -0.0131(d) Reconstructed NDVI vs Moving total litter 0.5830 -81.662
NDVI vs Litterfall, EVI vs Litterfall4. Results and discussion
Considerations
•Seasonal and annual variations in litterfall dynamics were coincident with associated variations in NDVI and EVI by MODIS products after Singular Spectrum Analysis .
•Future work will include correlation studies between further ground measures (efflux, leaf area index) and additional MODIS products (original bands, EVI, fPar, LAI, NPP, GPP).
•Thus, future changes in seasonal and/or interannual rainfall patterns, whether in response to El Niño (Poveda et al., 2001) or to anthropogenic climate change (Giorgi et al., 2001), will likely have important direct and indirect consequences for the litter dynamics of Amazonian semi-deciduous forest.