Study of N2O Flux overCentral Amazon

Monica Tais Siqueira D'Amelio (IPEN/LQA) (monicatais@yahoo.com)

Luciana Vanni Gatti (IPEN/LQA)John Bharat Miller (NOAA/ESRL)

Filipe Vaz (IPEN/LQA)Andrew Crottwell (NOAA/ESRL)

Pieter Tans (NOAA/ESRL)

N2O Sources and Sinks N2O is the 3rd most important

anthropogenic greenhouse gas. Life time: 120 years

Main sources: Nitrification and denitrification in soils: 9-31

TgN2Oyr-1

Ocean: 9-19 TgN2Oyr-1 Agricultural soil: 19.5 TgN2Oyr-1 (77% of

anthropogenic contribution) Main sinks

Decomposition in stratosphere by photodissociation (90%)

Reactions with excited oxygen (10%).

Measurement SitesCuieiras Biological Reserve – Manaus - AM

Tapajós National Forest – Santarém - PA

Flux CalculationBarbados

(RPB)

Ascension(ASC)

SANMAN FLOW

time

)O][N-O]([NF

4km

0zbg2site2

ON2

dz

Miller et al., 2007 method

Trajectories Study (Hysplit model)

“A Very Large Flux Chamber”

Back trajectories Used to calculate time air has been over land at 8 altitudes. Typically quite similar as a function of altitude.

Calculating the background

‘No’ Emissions

2x105

Step 1. Chose SF6 like a tracer transport

Calculating the background

Step 2. Calculate NHand SH contribution

ASC

RPB SF6 Time Series

4.44.64.85.05.25.45.65.86.06.26.46.6

9/11/2000 5/9/2001 1/4/2002 9/1/2002 4/29/2003 12/25/2003 8/21/2004 4/18/2005 12/14/2005 8/11/2006 4/8/2007

Con

cent

raçã

o (p

pt)

ASC RPB Flona Tapajós Cuieiras

(a)

Normalizing Profiles

0

500

1000

1500

2000

2500

3000

3500

4000

4500

314.0 316.0 318.0 320.0 322.0 324.0 326.0

N2O Minxing ratio (ppb)

Alti

tude

(m)

dry 20002001200220032004200520062007

0

500

1000

1500

2000

2500

3000

3500

4000

4500

314.0 316.0 318.0 320.0 322.0 324.0 326.0

N2O mixing ratio (ppb)

Alti

tude

(m)

wet

0

500

1000

1500

2000

2500

3000

3500

4000

4500

-4.0 -2.0 0.0 2.0 4.0

N2O Minxing ratio (ppb)

Alti

tude

(m)

dry 20002001200220032004200520062007

4

0

500

1000

1500

2000

2500

3000

3500

4000

4500

-4.0 -2.0 0.0 2.0 4.0

N2O mixing ratio (ppb)

Alti

tude

(m)

wet

Profiles Normalized

Integration of profiles

z

bgisiteibgisitei

timezONONONON 2/)}][]([)][]{([

F 221212ON2

04/24/2007

0

500

1000

1500

2000

2500

3000

3500

4000

4500

320.5 321 321.5 322 322.5 323 323.5 324

N2O mixing ratio (ppb)

Alti

tude

(m)

background 04/24/2007

0

500

1000

1500

2000

2500

3000

3500

4000

4500

0 0.5 1 1.5 2 2.5 3

N2O mixing ratio (ppb)

Alti

tude

(m)

Normalized

From Coast to Flona Tapajós

-4.0

-2.0

0.0

2.0

4.0

6.0

0 1 2 3 4 5 6 7 8 9 10 11 12

months

Flux

(mg/

m2 /d

ay)

2000 2001 2002 2003 2004 2005 2006

“Santarém” Fluxes

WET DRY

2005 Wet season enhancement – probably related to agriculture

From Coast to Cuieiras

-4.0

-2.0

0.0

2.0

4.0

6.0

0 1 2 3 4 5 6 7 8 9 10 11 12

months

Flux

(mg/

m2 /d

ay)

2004 2005 2006

“Manaus” Fluxes

WET DRY

Summary and Comparison with other estimates

Years/Site SAN   MAN  

  Wet Dry Wet Dry

2001-2003 0.0 ± 1.2 -1.65 ± 2.2  

2004-2006 2.1 ± 1.6 0.8 ± 0.6 1.9 ± 0.8 1.1 ± 0.7

•Comparison (mg N2O/m-2yr-1)1.9 – Primary Forest,

Rondônia, Brazil (Garcia-Montiel, et al., 2004)0.38 – Primary Forest, Manaus, Brazil (Coolman, 1994)0.44 – Young Pasture, Manaus, Brazil (Coolman, 1994)

Conclusions The normalized profiles show a clear

enhancement during wet season. SAN fluxes were enhanced until 2005.

In 2006 political programs decreased the N-fertilizer used in Para.

MAN fluxes are lower in 2006 for the same reason.

Fluxes calculated are similar other studies over near regions.

Question: What is the Forest Contribution?

Barbados(RPB)

Ascension(ASC)

SANMAN FLOW

Two Methods:1. Subtracting fluxes

sancoastmancoast FF forestF

2. Use SAN as the background for MAN3. Both methods: choose trajectories where air comes from SAN to MAN.

Preliminary Results Profiles considering: same trajectory,

close date

1. Subtracting2. SAN = BGD04/24/07 2.826 04/27/07 2.629 -0.197 0.38506/23/07 3.078 06/25/07 2.744 -0.335 0.44007/27/07 1.242 07/28/07 2.119 0.878 4.69908/03/07 1.096 08/06/07 1.035 -0.061 -3.108

Preliminaries Fluxes(mg/m2/day)

SAN MAN(mg/m2/day)

Uncertainty is large, but little evidence for large emissions in forest between SAN and MAN.

Conclusions The normalized profiles show a clear

enhancement during wet season. SAN fluxes were enhanced until 2005. In

2006 political programs decreased the N-fertilizer used in Para.

MAN fluxes are lower in 2006 for the same reason.

Coast to SAN present higher fluxes than coast to MAN.

Fluxes calculated are similar other studies over near regions.