OPERATING INSTITUTE: Consiglio Nazionale delle Ricerche (CNR).
MAIN PURPOSE: Ecosystem response, C and water biogeochemical cycles, ozone and aerosols, productivity.
ECOSYSTEM TYPE: Mediterranean ever-green forest.
EXPERIMENTAL TREATMENTS: Two stations with the same ecosystems under different water availability.
LOCALISATION: 42.5442098348755 11.890869140625
FACILITIES: The Estate of Castelporziano covers 6000ha close to Rome and has macchia and forest ecosystems (holm oak, mixed oaks, stone pine) distributed along the typical sea-inland belt with access to the ground water table.
Work at Castelporziano has focused on biodiversity and conservation as well as carbon, water and biogenic trace gas fluxes. Lecceto is a very typical holm oak coppice located in Tuscany with intense and prolonged droughts, where the impact of climate on ecosystem processes can be studied, with special emphasis on actual and potential carbon-sink capacity. Towers equipped for flux measurements are run all year round at both installations, with stations for meteorological and plant physiological parameters. Manipulation experiments are possible, particularly at Lecceto. Installations are closely connected with local research infrastructures with well equipped laboratories (mass spectrometry, chemistry, gas-exchange) and lodging possibilities close to- or on-site.
Since the beginning of ExpeER, the Castelporziano site of the Rome-Lecceto infrastructure has been improved with the installation of new equipment, in cooperation with Dr. Silvano Fares of the Research Centre for Soil-Plant System studies (RPS) of the Agricultural Research Council (CRA). In particular, the flux tower at the Quercus ilex dominated evergreen mixed forest has been impemented with continuous measure-ments of ozone concentration and fluxes, and below-canopy methane/CO2 fluxes. Additional meteorological sensors have been instal-led at the tower, complementing the two long-term meteorological stations installed at the Castelporziano estate.
● Fares, S., Matteucci, G., Scarascia Mugnozza, G., Morani, A., Calfapietra, C., Salvatori, E., Fusaro, L., Manes, F., Loreto, F. 2013. Testing of models of stomatal ozone fluxes with field measurements in a mixed Mediterranean forest. Atmospheric Environment, 67: 242–251.
● Fares, S., Vargas, R., Detto, M., Goldstein, A. H., Karlik, J., Paoletti, E., Vitale, M. 2013; Tropospheric ozone reduces carbon assimilation in trees: Estimates from analysis of continuous flux measurements. Global Change Biology, 19 (8): 2427–2443.
● P. C. Stoy, M. Mauder, T. Foken, (...) F. Vaccari, A. Varlagin. (2013) A data-driven analysis of energy balance closure across FLUXNET research sites: The role of landscape scale heterogeneity. Agricultural and Forest Meteorology 171–172, 137–152.
TA PROJECTS: Vertical profiles of foliage clumping in Mediterranean evergreen forest.
TA User (visit): Jan Pisek, Tartu Observatory, Toravere, Estonia (May/June, 2014 – 5 days).
Project Description: Clumping index (CI), quantifying the level of foliage grouping within distinct canopy structures relative to a random distribution, is a key structural parameter of plant canopies and is very useful in ecological and meteorological models. Recently, global foliar CI maps were developed using the multi-angle remote sensing data from Polarization and Directionality of Earth Reflectances (POLDER) instrument at 6 km resolution (Chen et al. 2005, Pisek et al. 2010), Moderate Resolution Imaging Spectroradiometer (MODIS) at 500 m resolution (He et al. 2012), and Multi-angle Imaging SpectroRadiometer (MISR) at 275 m resolution (Pisek et al. 2013). The vertical distribution of foliage and especially the effect of understory needs to be taken into account while validating foliage clumping products from remote sensing products with values measured in the field. Satellite measurements respond to the structural effects near the top of canopies, while ground measurements may be biased by the lower vegetation layers.
The objective of this project is to collect vertical profiles of foliage clumping for representative Mediterranean evergreen forest sites. No such vertical profiles are currently available for this ecosystem. The obtained profiles will be used for the validation and comparison of the existing foliage clumping products derived from remote sensing data. The results can be also used as an input for modeling local carbon and energy fluxes.
Partitioning of ozone deposition into stomatal and non-stomatal sinks.
TA User (visit): Jennifer Muller, University of Manchester, UK (May, 2013 – 30 days).
Project Description: The aim of this transnational access is to investigate the partitioning of ozone fluxes in a Mediterranean forest ecosystem. All measurements suggested for this TNA are complementary to the ongoing long-term measurements of above canopy fluxes of CO2, CH4, H2O and O3 which are conducted by CRA in collaboration with CNR, and link to activities within the EU Marie Curie project EXPLO3REVOC (Ecophysiological control by Mediterranean forest ecosystems on the exchange processes of ozone and reactive Volatile Organic Compounds with a polluted atmosphere) at the Castelporziano flux tower site coordinate by Dr Fares.
While the long-term measurements provide data on total ozone fluxes, the partitioning of these fluxes is uncertain, especially in the field site in Castelporziano, where evaporative component from soil is large during all year due to a superficial level of fresh water table, therefore the calculation stomatal conductance based on inversion of Monteith equation in a “big leaf” approach is not advisable. During this TNA, below canopy sinks including ozone deposition to soil and reaction with NOx emitted from soil will be investigated. Specifically for this experiment, a second flux measuring tower will be installed, with a fast response ozone sensor provided by University of Manchester, fast H2O instrument and sonic anemometer for eddy covariance flux measurements available at CRA, and analysis of the gradient in the NOx concentration.
Stomatal ozone uptake will be calculated based on leaf level stomatal conductance measurements using a portable IRGA (Infra-Red Gas Analyzer, mod. LICOR-6400).
In-canopy sinks will be investigated using a 4-point gradient, allowing sequential sampling of ozone and NOx concentrations at the soil level, below the canopy and at in-canopy and above-canopy levels, which will aid interpretation of above and below canopy eddy covariance deposition fluxes.
An intensive campaign to estimate reactive VOC emissions from leaves and the calculation of ozone removal by these molecules will be done using a modified cuvette from LICOR-6400 and adsorbent cartridges which will be successively analysed by GC-MS (at CRA laboratory, Rome).
The TNA is suggested to take place over a several month period, with one month active period in Rome, i.e. installation of equipment (1 week), intensive VOC sampling (1 week), data analysis and modelling (2 weeks), removal of instruments (2 days). The fast ozone sensor is to be left at the site from May to September, with the aim to capture seasonality in ozone deposition processes which partly depend on biophysical conditions, i.e. observe a range of conditions from mild & warm (May), to dry & hot (August).
TA User (visit): Daniel Hauser, University of Innsbruck, AUSTRIA (August, 2011).
Project Description: The modified PTR-MS developed at the University of Innsbruck (2010/11) provides ultra-fast response times, especially for sticky compounds i.e. like ammonia, due to high flow and high temperature. These new features, in contrast to the conventional PTR-Quad/TOF-MS techniques, in combination with switchable primary ions are decisive factors for online measurements at field sites.
For the CASTELPORZIANO field campaign 2011 we will use the O2+-Mode to ensure the maximal detection efficiency of Ethylene, Ammonia and Carbonyl sulfide (COS). Moreover, it might be possible to measure Ethylene, Ammonia and COS fluxes.
The three compounds mentioned above could be responsible for various interaction mechanisms between the atmosphere and biosphere. Therefore our modified PTR-MS allocates the required ultra-fast response times and ultra-high sensitivities to ensure precise concentration and flux measurements in the field for the first time.