Search

The processes responsible for methane (CH4) emissions from boreal wetlands are complex, and hence their model representation is complicated by a large number of parameters and parameter uncertainties. The arctic-enabled dynamic global vegetation model LPJ-GUESS is one such model that allows quantification and understanding of the natural wetland CH4 fluxes at various scales ranging from local to regional and global, but with several uncertainties. The model contains detailed descriptions of CH4 production, oxidation, and transport controlled by several process parameters. Complexities in the underlying environmental processes, warming-driven alternative paths of meteorological phenomena, and changes in hydrological and vegetation conditions are highlight the need for a calibrated and optimised version of LPJGUESS. In this study we formulated the parameter calibration as a Bayesian problem, using knowledge of reasonable parameters values as priors. We then used an adaptive Metropolis Hastings (MH) based Markov Chain Monte Carlo (MCMC) algorithm to improve predictions of CH4 emission by LPJ-GUESS and to quantify uncertainties. Application of this method on uncertain parameters allows greater search of their posterior distribution, leading to a more complete characterisation of the posterior distribution with reduced risk of sample impoverishment that can occur when using other optimisation methods. For assimilation, the analysis used flux measurement data gathered during the period 2005 to 2014 from the Siikaneva wetlands in southern Finland with an estimation of measurement uncertainties. The data are used to constrain the processes behind the CH4 dynamics, and the posterior covariance structures are used to explain how the parameters and the processes are related. To further support the conclusions, the CH4 flux and the other component fluxes associated with the flux are examined. The results demonstrate the robustness of MCMC methods to quantitatively assess the interrelationship between objective function choices, parameter identifiability, and data support. As a part of this work, knowledge about how the CH4 data can constrain the parameters and processes is derived. Though the optimisation is performed based on a single site's flux data from Siikaneva, the algorithm is useful for larger-scale multi-site studies for more robust calibration of LPJ-GUESS and similar models, and the results can highlight where model improvements are needed. [ABSTRACT FROM AUTHOR]

In Finland, there are almost 500,000 second homes and in some areas the number of second home owners exceeds that of permanent residents. Currently, second home owners are also spending more time in their second homes. If second home owners are not permanent residents, administration may exclude them from local institutions, and treat second home owners as only partial members of the community. It has been stated that municipal decision making and the role of the municipality as an actor in the local community should be broadened in order to strengthen democracy and the participation of its residents as a core of municipal self-administration. Hence, participating in communal decision making is mainly possible only for permanent residents. The issue is whether it is possible to change this situation via the municipalities' own reforms and state regulations. New municipal administration experiments have recently emerged in Finland. Here we study how the new local administrative model, the Communal District Committee, has affected local participation and local governance in a rural areas by exploring second home owners' opportunities to participate in local decision making and development processes. The data consists of documents, focus group discussions and a questionnaire. We used qualitative and quantitative methods in the data analysis. We found, on one hand, that permanent residents of villages recognise second home owners' hesitation to participate in local issues requiring planning and decision making. On the other hand, local-level communal decision making does not promote the participation of second home residents. On the basis of the findings of the study, we suggest that the municipal authorities should recognise the existence and importance of second home owners in the area, acknowledge them better in municipal plans and strategies, and offer them more resources and means to participate. [ABSTRACT FROM AUTHOR]

The concept of ecosystem services is entering the agenda of land-use planning and scientists optimistically expect it to inform planners and decision-makers about the benefits that ecosystems provide. While tools and methods have been developed for mapping and valuing ecosystem services, only little attention has been paid to the practical application of the approach or its institutional preconditions and implications. We empirically analysed two urban planning processes for building residential areas in the outskirts of growing population centres in Finland. Our analysis of documents and interviews with planners focused on the benefits provided by ecosystems as well as the associated rights and responsibilities. We found that the concept ‘ecosystem service’ was not used, yet various benefits were identified. The rights of different stakeholders to ecosystem services were not explicitly identified, but many ecosystem services were perceived as public goods and particularly access to recreation was highlighted as an important justification for green areas. The results show that while the ecosystem services approach introduces new insights to land-use planning, it is still not embedded in the current practices or institutions. Operationalizing ecosystem services requires institutional adaptation, case-specific tailoring of methods, and deliberation among practitioners and stakeholders. [ABSTRACT FROM PUBLISHER]

Governing urban green infrastructure is challenging due to the various institutions, interests and values involved in municipal planning, decision-making and management processes. Indicators of urban ecosystem services and green infrastructure may support the development of mutual understanding among municipal authorities and the creation of usable information. In this study, the application of ecosystem services (ES) indicators is approached through knowledge-brokering and boundary work theories. We apply a set of GIS-based ES indicators in a medium-sized Finnish city in a collaborative process with local civil servants in order to provide overarching information on the green infrastructure and to enhance dialogue among civil servants. We present the three phases of the indicator application process (conceptual, instrumental and reflection phases) describe the indicator-based boundary work, and identify factors affecting the process. The results highlight the importance of collaboration and active knowledge brokering in indicator applications, involving a combination of conceptual and methodological expertise on the ES approach with knowledge on local environment and relevant policy and planning issues, as well as iterative reflection throughout the indicator application process. Finally, some critical characteristics of boundary work in applying the ES indicators are proposed. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Policy Research in Tourism, Leisure & Events is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Peoples' housing practices are changing and their mobility is increasing in contemporary society. An increasing and more diverse use of second homes raises new governance challenges. We apply the concepts of policy integration and policy coherence to analyze the governance of second homes in Finland. We explore two case study areas rich with second homes by analyzing policy and planning documents and conducting interviews in four policy areas: (i) land use planning policy, (ii) regional and municipal development policies, (iii) tourism policy, and (iv) rural and island policies. The results show that second homes are often addressed only implicitly or indirectly. Contradicting policy goals between land use planning policy and rural policy are identified at the national level, as well as numerous conflicts at the local level. Interviews reveal that second homes are considered as a major societal phenomenon that should be addressed more in policy and planning instruments. [ABSTRACT FROM AUTHOR]

Long-term measurements of fluxes of sensible heat ( H), latent heat ( LE) and carbon dioxide ( Fc) were made from December 2005 to August 2006 over an urban landscape in Helsinki, Finland using the direct micrometeorological eddy covariance technique. Three distinguished sectors of land-use cover (vegetation, roads and buildings) allowed comparisons of fluxes over different urban surfaces. The normalized standard deviation of wind and scalars as a function of atmospheric stability were typical for rough surfaces, as were turbulence spectra and cospectra. Footprint analysis was performed by a boundary-layer one and half-order closure model allowing for discrimination of surface and canopy sinks/sources and complex topography. Fluxes were analysed as average diurnal courses over winter, spring and summer periods. H exceeded LE reaching 300 W m–2 over urban and road surfaces in the summer and it was close to 100 W m–2 in the winter. LE was highest in the summer over vegetation cover attaining 150 W m–2. The emission rate of CO2 was high over road sector [20 μmol (m2s)–1][Correction added after online publication 16 Oct 2007: 30 μmol changed to 20 μmol] while in the vegetation sector it remained below 5 μmol (m2s)–1 and at summertime reached even −10 μmol(m2 s)−1[Correction added after online publication 16 Oct 2007: wording of sentence altered]. Effluxes from soil measured by chambers were 1–3 μmol (m2s)−1. Fc correlated with traffic density and a background non-vehicle flux was 1 μmol (m2s)−1[Correction added after online publication 16 Oct 2007: 2 μmol changed to 1 μmol]. [ABSTRACT FROM AUTHOR]

Eddy covariance (EC) measurements of net ecosystem CO2 exchange (NEE) were conducted on a boreal sedge fen in southern Finland (61°50′N, 24°12′E) during a 1.5-yr period covering two summers in 2004–2005. The EC data were complemented by chamber measurements, which enabled the partition of the daytime NEE into respiration and photosynthesis. A special emphasis was put on the hydrometeorological responses of CO2 exchange during a drought period in July 2005. A mean CO2 efflux of 0.009 mgCO2 m−2 s−1 was observed during mid-winter (January–February), while the night-time respiration during the two Julys averaged 0.09 mgCO2 m−2 s−1. During both years the mean mid-day uptake in late July was about −0.16 mgCO2 m−2 s−1. An annual CO2 balance of −188 gCO2 m−2 was observed in 2005. A slightly higher net sink of −219 gCO2 m−2 was estimated for 2004. The drought period experienced in July 2005 caused a clear depression in the daily NEE values. From the combined analysis of EC and chamber measurements it was concluded that this was mainly due to increased respiration, but evidence was also found of suppressed photosynthesis due to a high VPD. [ABSTRACT FROM AUTHOR]

Peatlands play an important role in the global carbon cycle as they contain a large soil carbon stock. However, current climate change could potentially shift peatlands from being carbon sinks to carbon sources. Remote sensing methods provide an opportunity to monitor carbon dioxide (CO2) exchange in peatland ecosystems at large scales under these changing conditions. In this study, we developed empirical models of the CO2 balance (net ecosystem exchange, NEE), gross primary production (GPP), and ecosystem respiration (ER) that could be used for upscaling CO2 fluxes with remotely sensed data. Two to three years of eddy covariance (EC) data from five peatlands in Sweden and Finland were compared to modelled NEE, GPP and ER based on vegetation indices from 10 m resolution Sentinel-2 MSI and land surface temperature from 1 km resolution MODIS data. To ensure a precise match between the EC data and the Sentinel-2 observations, a footprint model was applied to derive footprint-weighted daily means of the vegetation indices. Average model parameters for all sites were acquired with a leave-one-out-cross-validation procedure. Both the GPP and the ER models gave high agreement with the EC-derived fluxes (R2 = 0.70 and 0.56, NRMSE = 14% and 15%, respectively). The performance of the NEE model was weaker (average R2 = 0.36 and NRMSE = 13%). Our findings demonstrate that using optical and thermal satellite sensor data is a feasible method for upscaling the GPP and ER of northern boreal peatlands, although further studies are needed to investigate the sources of the unexplained spatial and temporal variation of the CO2 fluxes. [ABSTRACT FROM AUTHOR]

Boreal/arctic wetlands are dominated by diverse plant species, which vary in their contribution to CH 4 production, oxidation and transport processes. Earlier studies have often lumped the processes all together, which may induce large uncertainties into the results. We present a novel model, which includes three vegetation classes and can be used to simulate CH 4 emissions from boreal and arctic treeless wetlands. The model is based on an earlier biogeophysical model, CH4MOD wetland . We grouped the vegetation as graminoids, shrubs and Sphagnum and recalibrated the vegetation parameters according to their different CH 4 production, oxidation and transport capacities. Then, we used eddy-covariance-based CH 4 flux observations from a boreal (Siikaneva) and a subarctic fen (Lompolojänkkä) in Finland to validate the model. The results showed that the recalibrated model could generally simulate the seasonal patterns of the Finnish wetlands with different plant communities. The comparison between the simulated and measured daily CH 4 fluxes resulted in a correlation coefficient ( R 2 ) of 0.82 with a slope of 1.0 and an intercept of − 0.1 mg m − 2 h − 1 for the Siikaneva site (n = 2249, p < 0.001) and an R 2 of 0.82 with a slope of 1.0 and an intercept of 0.0 mg m − 2 h − 1 for the Lompolojänkkä site (n = 1826, p < 0.001). Compared with the original model, the recalibrated model in this study significantly improved the model efficiency (EF), from − 5.5 to 0.8 at the Siikaneva site and from − 0.4 to 0.8 at the Lompolojänkkä site. The simulated annual CH 4 emissions ranged from 7 to 24 g m − 2 yr − 1 , which was consistent with the observations (7–22 g m − 2 yr − 1 ). However, there are some discrepancies between the simulated and observed daily CH 4 fluxes for the Siikaneva site ( RMSE = 50.0%) and the Lompolojänkkä site ( RMSE = 47.9%). Model sensitivity analysis showed that increasing the proportion of the graminoids would significantly increase the CH 4 emission levels. Our study demonstrated that the parameterization of the different vegetation processes was important in estimating long-term wetland CH 4 emissions. [ABSTRACT FROM AUTHOR]

Holocene peatland development and associated carbon (C) dynamics were reconstructed for a southern boreal Finnish peatland complex with fen and bog areas. In order to assess the role of local factors and long-term allogenic climate forcing in peatland development patterns, we studied a total of 18 peat cores and reconstructed vertical peat growth and lateral peat area expansion rates, the C accumulation rate (CAR), past vegetation composition and past methane (CH 4 ) fluxes. We combined fossil plant data with measured contemporary CH 4 flux – vegetation relationship data to reconstruct CH 4 fluxes over time. When these reconstructions were added to the CAR estimations, a more complete picture of Holocene-scale C dynamics was achieved. Basal peat ages showed that expansion of the peat area was rapid between 11,000 and 8000 cal. BP, but decreased during the dry mid-Holocene and is probably currently limited by basal topography. A similar pattern was observed for peat growth and CAR in the fen core, whereas in the bog core CAR increased after ombrotrophication, i.e. after 4400 cal. BP. The effect of fire on vegetation and CAR was more conspicuous at the bog site than at the fen site. The CH 4 flux reconstructions showed that during the Holocene CH 4 emissions at the fen site decreased from 19 ± 15 to 16 ± 8 g CH 4 m −2 yr −1 and at the bog site from 20 ± 15 to 14 ± 8 g CH 4 m −2 yr −1 . Our results suggest that a combination of changing climate, fire events and local conditions have modified the autogenic peatland development and C dynamics. [ABSTRACT FROM AUTHOR]

Abstract: We determined the accuracy of the dynamic chamber system for measuring VOC emissions of trees and soil in the field at SMEAR II station, Hyytiälä, Southern Finland. The study was based on creating a known source of different VOCs inside the chamber and measuring the concentration dynamics in the chamber by a proton transfer reaction mass spectrometer (PTR-MS) connected to the chamber. The chamber system underestimated the artificially generated VOC emission rates at varying degree. In isoprene, monoterpene and many oxygenated VOCs the underestimation was 5–30% but in some compounds with protonated mass >100 amu the signal was almost completely lost. The underestimation mainly originated in the chamber but the length of the sample tubing also affected the observed magnitude of the standard gas emission. The systematic error was higher at high relative humidity than in drier conditions, which suggests that the thickness of the water film adsorbed on the chamber inner surfaces contributes to the VOC loss rate in the chamber. Increasing the length of the chamber closure time slightly reduced the systematic underestimation of emission in most of the studied compounds although the underestimation persisted for at least 10 min. A dynamic chamber setup enables measurement of VOC emissions with good accuracy and precision while minimising the disturbance of the chamber to the object being measured. [Copyright &y& Elsevier]

Continuous and area-integrating monitoring of methane (CH4) and carbon dioxide (CO2) emissions was performed for 6 and 9 months, respectively, at a municipal landfill in Finland with the micrometeorological eddy covariance (EC) method. The mean CH, emission from June to December was 0.53 mg m-2 s-1, while the CO2 emission between February and December averaged 1.78 mg m-2 s-1. The CH4 emissions from the summit area of the landfill, where active waste deposition was going on, were 1.7 times as high as from the slope area with a better surface cover. The variation in emissions over the source area of the measurement was high. Significant seasonal variation, linked to air and soil temperature, was only seen in the CO2 release rates. Results obtained with the EC method were comparable to those measured with closed static chambers. According to the EC measurements, the gas recovery system decreased CH4 fluxes by 69–79%. The ratio of the measured CH4 and CO2 emissions roughly indicated the route of the landfill gas emission, resembling the ratio of the gases measured in the gas wells (1.24) when the emission originated from the area with no oxidizing cover layer and being smaller when CH4 oxidation had taken place. [ABSTRACT FROM AUTHOR]

The first measurements of nitrous oxide (N20) emissions from a landfill by the eddy covariance method are reported. These measurements were compared to enclosure emission measurements conducted at the same site. The average emissions from the municipal landfill of the Helsinki Metropolitan Area were 2.7 mg N m(-2) h(-1) and 6.0 mg N m(-2) h(-1) measured bythe eddy covariance and the enclosure methods, respectively. The N20 emissions from the landfill are about 1 order of magnitude higher than the highest emissions reported from Northern European agricultural soils, and 2 orders of magnitude higher than the highest emissions reported from boreal forest soils. Due to the small area of landfills as compared to other land-use classes, the total N20 emissions from landfills are estimated to be of minor importance for the total emissions from Finland. Expressed as a greenhouse warming potential (GWP100), the N2O emissions make up about 3% of the total GWP100 emission of the landfill. The emissions measured by the two systems were generally of similar magnitude, with enclosure measurements showing a high small-scale spatial variation.