http://www.cnr.it/ontology/cnr/individuo/prodotto/ID172351

Carbon and energy fluxes over Mediterranean maquis (Abstract/Poster in atti di convegno)

Type

Prodotto della ricerca (Classe)
Abstract/Poster in atti di convegno (Classe)

Label

Carbon and energy fluxes over Mediterranean maquis (Abstract/Poster in atti di convegno) (literal)

Anno

2008-01-01T00:00:00+01:00 (literal)

Alternative label

DUCE P., SPANO D., SIRCA C., MARRAS S., ZARA P., ARCA A., VENTURA A., SNYDER R. L. (2008)
Carbon and energy fluxes over Mediterranean maquis
in 28th Conference on Agricultural and Forest Meteorology, Orlando, Florida, USA, 28 April - 2 May 2008
(literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori

DUCE P., SPANO D., SIRCA C., MARRAS S., ZARA P., ARCA A., VENTURA A., SNYDER R. L. (literal)

Pagina inizio

139132 (literal)

Pagina fine

139132 (literal)

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https://ams.confex.com/ams/28Hurricanes/webprogram/Paper139132.html (literal)

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Proceedings of the 28th Conference on Agricultural and Forest Meteorology (literal)

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1 (literal)

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Objectives of the research were to describe diurnal and seasonal variation in energy and mass fluxes over a Mediterranean maquis ecosystem for 4-years period and to investigate the relationships between ecosystem productivity and environmental variables. On the seasonal basis, the ecosystem was a source of carbon in fall while the C uptake mainly occurred in spring and winter. However, NEE can be also negative in summer in dependence on weather variability. The annual totals showed that the ecosystem was a small C sink during the experimental period. The differences between years can be attributed to the increase in respiration rates determined by changes in rainfall distribution. Results obtained during the experimentation showed that H was the dominant component in the energy budget, G ~ zero and LE a small part of the available energy during the summer drought. The mean net ecosystem production was about 1.5 Mg C/ha/yr (max 2.3 min 0.9). The variability of GPP was strictly related to water availability for most of the year. Ecosystem respiration was affected by the water availability in spring and summer. NEE was largely negative in spring and largely positive in fall. In summer, the sign of NEE depended on water availability. (literal)

Note

Abstract (literal)

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Spano D, Sirca C, Marras S: Dipartimento di Economia e Sistemi Arborei, Unicersità di Sassari Snyder RL: Department of Land, Air and Water Resources, University of California, Davis (literal)

Titolo

Carbon and energy fluxes over Mediterranean maquis (literal)

Abstract

Mediterranean maquis is a shrubland ecosystem that is widely spread throughout the Mediterranean Basin, and comparable vegetation is found in similar climates worldwide. Little is known about the energy and carbon exchange over maquis, and learning more about CO2 fluxes and the relationship between NEP and environmental variables is important to understand the interaction between this ecosystem and climate. Micrometeorological data were collected near the northwest coast of Sardinia, Italy, over maquis for several periods during 1997-2007. The climate has cool, wet winters and hot, humid summers. There is a significant water deficit from May through September each year. An eddy covariance system (using a 3-D sonic and an open-path IRGA) were used to measure fluxes of momentum, sensible heat, latent heat, and CO2. All flux and meteorological data were quality-controlled. Gaps in the data were filled following the procedures reported by Reichstein et al. (2005). The vegetation is mainly sclerophyll species with some shrubs reaching a maximum height of 2.0 m. An LI-2000 leaf area instrument was used to estimate the LAI. Soil chambers in an open-system configuration were used to measure soil CO2 exchange approximately every four hours. The decoupling coefficient (?) was calculated according to Jarvis and McNaughton (1986) and the ecosystem surface conductance was estimated using the Penman-Monteith equation (Monteith, 1965). The ratio (H+LE)/(Rn-G) was approximately equal to 0.92; indicating good energy balance closure. The Bowen ratio values were high in the winter and clearly decreased during the summer drought season. CO2 uptake was highest in the spring and fall and lowest during the summer drought period. The NEP varied from year-to-year depending on drought and temperature conditions. In general, NEP was relatively low compared to other forest ecosystems. Surface conductance was clearly depressed during the summer drought period. A good relationship was found between GPP and LE. (literal)

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