S.3 El debate Impacto de la Inteligencia Artificial en la Sociedad Moderna
Monitoreo de flujos de vapor y carbono en agricultura
1. Flujos de Vapor y Carbono: Avances
en el monitoreo para la gestión de la
huella ecológica en Agricultura
Dr. Francisco J. Meza
Director Centro de Cambio Global UC
fmeza@uc.cl
Tercer Seminario Regional Agricultura y Cambio Climático
Septiembre , 2012
4. Paradigma de una Intensificación
Sostenible
while emissions from factors such as fertilizer production and
application have increased, the net effect of higher yields has avoided
emissions of up to 161 gigatons of carbon (GtC) (590 GtCO2e) since
1961
Burney J A et al. PNAS 2010;107:12052-12057
6. Net Ecosystem Exchange
NEP = Net ecosystem productivity= (-)NEE
Intercambio ( Flujo) de CO2
entre la atmósfera y el
ecosistema
7. Huella del agua de un producto
Huella Verde
► Volumen de agua de lluvia evaporado o incorporado en el
producto.
Huella Azul
► Volumen de agua superficial o subterránea evaporado,
incoporado en el producto o retornado en otra área o en el
mar.
Huella Gris
► Volumen de agua contaminado en el proceso de producción.
8. Donde:
H: Huella Hídrica (m3
/ha/Unidad de Producción)
ET: Evapotranspiración del cultivo (mm)
RHC: Requerimientos hídricos del cultivo (mm/ha)
PPef: Precipitación efectiva (mm)
Calculando entonces, la Huella Verde es:
9. Y la Huella azul…
Donde:
H: Uso de agua por el cultivo (m3
/ha/Unidad de producción)
RR: Riego (mm/ha)
RRef: Riego efectivo
10. – Método de Penmann-Monteith
– Modelos
– Otros
Requerimientos del Cultivo
11. Flujo de Vapor/Evapotranspiración
• Gran Problema es que en pocas circunstancias
se mide el flujo de vapor
• Ecuación de Penman Monteith es la más
completa desde el punto de vista teórico, pero
al momento de aplicarla la llevamos a su nivel
más simple ETo
• El uso de estaciones meteorológicas
automáticas permite el cálculo de ETo (pero
no la medición de la ET)
15. Metodología Eddy Covariance
• Ampliamente usada para medición de flujos
de gas y energía en la atmósfera. (Capa
Límite).
• Método de medición directo, no afecta el
medio de medición.
• Matemáticamente complejo y requiere de
instrumental sofisticado
16. Cierre Balance Energético
La formulación y justificación del EBC radica en la
primera ley de la termodinámica adaptada por los
micrometeorólogos y que estipula que la energía
incidente sobre un ecosistema debe ser transformada
y/o utilizada en distintos procesos que ocurren en el
ecosistema.
Rn
G
L
E
H
AsimilaciónCO2
Respiración
(Wilson et al., 2002)
18. Capa límite atmosférica
The lowest layer of the atmosphere that is in direct contact
with Earth’s surface. Conditions and processes within the
ABL will react to changes at the surface within a period of
less than an hour and within a distance of less than 100 km
4.5 ms-1
Capa de Mezcla zi = 1400 m
Eddy por
convección
térmica
Tarong, Queensland (AUS), stack height: 210 m, zi = 1400 m, w* = 2.5 ms-1
. Photo: Geoff Lane, CSIRO (AUS)
Troposfera libre
Atmospheric Boundary Layer (ABL)
Schmidt H. 2003. Micrometeorology, Biosphere-Atmosphere Exchange. Teachers Notes, Indiana University .
19. Flujo turbulento
Baldocchi, D. 2001. Wind and Turbulence, Surface Boundary Layer. Teachers Note. University of California, Berkele
20. a and Anderson, 2003. Introduction to the Eddy Covariance method, General Guidelines and Conventional Workflow. Li-Cor Bioscience
Burba and Anderson, 2003.
22. H+Le(Wm-2
)
-200
0
200
400
600
800
1000
y = 0.93x - 4.24
r
2
= 0.85
n = 4304
a)
Rnet - G (W m
-2
)
-200 0 200 400 600 800 1000
H+Le(Wm
-2
)
-200
0
200
400
600
800
1000
y = 0.94x - 7.09
r
2
= 0.86
n = 3310
b)
Cierre del Balance de Energía
23. Baldocchi, 2008
-182.9gC m-2
y-1
≈1.829tC ha-1
y-1
FN <0 representan una pérdida de CO2 de la atmósfera y
ganancia por la superficie en estudio (Hutley et al. 2005;
Baldocchi et al. 2001; Paw U et al. 2004; Sellers et al. 2010)
FN <0 representan una pérdida de CO2 de la atmósfera y
ganancia por la superficie en estudio (Hutley et al. 2005;
Baldocchi et al. 2001; Paw U et al. 2004; Sellers et al. 2010)
Flujos de CO2/Intercambio de Carbono
27. Comparison between estimated (LEe) and observed (LEo) latent heat flux over a drip-irrigated Merlot
vineyard. The solid line represents the 1:1 line.
S. Ortega-Farias , C. Poblete-Echeverr?a , N. Brisson
Parameterization of a two-layer model for estimating vineyard evapotranspiration using
meteorological measurements
Agricultural and Forest Meteorology Volume 150, Issue 2 2010 276 - 286
Otros Ejemplos
28. Desafíos
• Nuevas Hipótesis: Cómo las fluctuaciones
climáticas (Tº,pp, Rn) bajo ciertas condiciones
(sequías, heladas, eventos extremos), afectan el
flujo de CO2 y la fotosíntesis. (Baldocchi, 2008)
• Medición de otros gases traza en la atmósfera.
• Combinar métodos: LIDAR, mediciones aéreas.
• Expansión de redes de medición para mediciones
globales: distintos ambientes y países…
Notas del editor
Regional and global trends in population (Upper Left), crop production (Upper Right), crop area (Lower Left), and fertilizer use (Lower Right), 1961–2005.
The exchange of carbon between the atmosphere and the ecosystem is known as net ecosystem exchange (NEE) at any particular point in time (Moncrieff et al., 2000). NEP and NEE are widely used as indicators of the amount of carbon accumulated or lost (medium-term storage) by an ecosystem. However, not all these carbon remain
Green water footprint – Volume of rainwater consumed during the production process. This is particularly relevant for agricultural and forestry products (products based on crops or wood), where it refers to the total rainwater evapotranspiration (from fields and plantations) plus the water incorporated into the harvested crop or wood.
Blue water footprint – Volume of surface and groundwater consumed as a result of the production of a good or service. Consumption refers to the volume of freshwater used and then evaporated or incorporated into a product. It also includes water abstracted from surface or groundwater in a catchment and returned to another catchment or the sea. It is the amount of water abstracted from groundwater or surface water that does not return to the catchment from which it was withdrawn.
Grey water footprint – The grey water footprint of a product is an indicator of freshwater pollution that can be associated with the production of a product over its full supply chain. It is defined as the volume of freshwater that is required to assimilate the load of pollutants based on natural background concentrations and existing ambient water quality standards. It is calculated as the volume of water that is required to dilute pollutants to such an extent that the quality of the water remains above agreed water quality standards.
Source:
Hoekstra, A.Y., Chapagain, A.K., Aldaya, M.M. and Mekonnen, M.M. (2011) The water footprint assessment manual: Setting the global standard, Earthscan, London, UK.
See page 187, 189, 190.
Blue water use refers to the volume of irrigation water (withdrawn from surface or ground water) that evaporates from a crop field during the growing period. The distinction between green and blue water has been introduced by Malin Falkenmark, Swedish hydrologist.
EBC ha sido aceptado como uno de los más importantes para validar los datos de eddy covariance, por lo que su aplicación resulta formar un procedimiento estándar en la aplicación de esta metodología
S the rate of change of heat storage (air and biomass) between the soil surface and the level of the eddy covariance instrumentation, and Q the sum of all additional energy sources and sinks. (Wilson et al., 2002)
In temperate ecosystems, seasonal trend in CO2 exchange
(FN) follows the seasonal cycle of the sun, with qualifications.
In temperate coniferous forests, seasonal patterns of FA and FR
are in phase, causing FN to peak (most negative values, indicating
uptake) when FA and FR do. In cold regions, temperate conifer
forests lose carbon in the winter and gain it during the frostfree,
growing season. And in milder regions, such as the Pacific
North-west, south-western France and the south-eastern part of
the United States, temperate conifer forests can be net carbon
sinks year-round. In contrast, FR is delayed compared with FA
in temperate deciduous and boreal coniferous forests. This lag is
attributed to cold spring-time soils, which restrict FR and enable
FN to be most negative then. Arid and semi-arid systems, such
as Mediterranean and tropical savannas and annual grasslands,
are water-limited. Consequently, the most negative rates of net
carbon exchange occur during the wet winter and spring in
Mediterranean-type climates and during the summer wet period
for tropical savannas.
Perennial grasslands, growing in temperate
climates, experience summer rainfall, so their annual cycle of
carbon exchange is moderated by the freeze-free period of the
year, changes in leaf area index and vapour-pressure deficits. The
greatest rates of carbon uptake occur for C4, C3 and mixed C3–C4
grasslands during the summer growing season. Agricultural
crops achieve the highest short-termrates of carbon uptake. But,
ironically, their net annual uptake is not the greatest. Spring-sown
crops, such as soybeans and corn, experience a short season of
effective net carbon uptake because they must grow from seed
The ranking of FN, at annual time scales, is not explained
well by variations in climate variables, plant functional type or
photosynthetic potential (Law et al. 2002; Arain and Restrepo-
Coupe 2005; van Dijk et al. 2005; Reichstein et al. 2007b). A
step-wise, multiple regression analysis revealed that only 45% of
the variance in annual FN, for forests across central and northern
Europe, is explained by a combination of sunlight, leaf area index
and air temperature (van Dijk et al. 2005). More productive
ecosystems (those with greater values of FA), which occur under
wetter and warmer climates, do not necessarily produce large
values of FN because FR scales linearly with available light,
moisture and temperature (Arain and Restrepo-Coupe 2005; van
Dijk et al. 2005; Reichstein et al. 2007b). This point is illustrated
with data in Fig. 5,which shows that variations inFA explain only
42% of the variation in FN. Consequently, it is better to partition
FN into its components FA and FR, and relate the components to
abiotic and biotic drivers, as is shown below.
El sitio de estudio se encuentra en la Región Metropolitana de Chile, 33º02&apos;S 70º44&apos;O 660 m.s.n.m.