SMEAR Estonia: Perspectives of a large-scale forest ecosystem – atmosphere research infrastructure

Noe, Steffen M.; Niinemets, Ülo; Krasnova, Alisa; Krasnov, Dmitrii; Motallebi, Azimeh; Kängsepp, Vivika; Jõgiste, Kalev; Hõrrak, Urmas; Komsaare, Kaupo; Mirme, Sander; Vana, Marko; Tammet, Hannes; Bäck, Jaana; Vesala, Timo; Kulmala, Markku; Petäj̈ä, Tuukka; Kangur, Ahto

doi:10.1515/fsmu-2015-0009

Cited by 26 publications

(15 citation statements)

References 69 publications

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“…; Noe et al, 2015;Vana et al, 2016). The site, located in the vicinity of Lake Peipus, is surrounded by mixed forest in the hemi-boreal forest zone.…”

Section: Rural Sitesmentioning

confidence: 99%

Global analysis of continental boundary layer new particle formation based on long-term measurements

Nieminen¹,

Kerminen²,

Petäj̈ä³

et al. 2018

Preprint

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Atmospheric new particle formation (NPF) is an important phenomenon in terms of the global particle number concentrations. Here we investigated the frequency of NPF, formation rates of 10 nm particles and growth rates in the size range of 10-25 nm using at least one year of aerosol number size-distribution observations at 36 different locations around the world. The majority of these measurement sites are in the Northern Hemisphere. We found that the NPF frequency has a strong seasonal variability, taking place on about 30% of the days in March-May and on about 10% of the days in December-February. The median formation rate of 10 nm particles varies by about three orders of magnitude (0.01-10 cm −3 s −1 ) and the growth rate by about an order of magnitude (1-10 nm h −1 ). The smallest values of both formation and growth rates were observed at polar sites and the largest ones in urban environments or anthropogenically influenced rural sites. The correlation between the NPF event frequency and the particle formation and growth rate was at best moderate between the different measurement sites, as well as between the sites belonging to a certain environmental regime. For a better understanding of atmospheric NPF and its regional importance, we would need more observational data from different urban areas in practically all parts of the world, from additional remote and rural locations in Northern America, Asia and most of the Southern Hemisphere (especially Australia), from polar areas, and from at least a few locations over the oceans.

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“…; Noe et al, 2015;Vana et al, 2016). The site, located in the vicinity of Lake Peipus, is surrounded by mixed forest in the hemi-boreal forest zone.…”

Section: Rural Sitesmentioning

confidence: 99%

Global analysis of continental boundary layer new particle formation based on long-term measurements

Nieminen¹,

Kerminen²,

Petäj̈ä³

et al. 2018

Preprint

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“…At the SMEAR II station, soil temperature was monitored using thermistors (Philips KTY81-110, Philips Semiconductors, Eindhoven, The Netherlands) and soil water content using the TDR method (TDR 100, Campbell Scientific, Inc., Logan, USA) from the O-, A-, B-and C-horizon (n = 5) in 2017-2018 (supporting data from the SMEAR II station is available from https://avaa.tdata.fi/web/smart). At the SMEAR Estonia station, soil water content and temperature were measured next to each soil collar using the Soil Moisture Probe with ThetaProbe moisture sensor (ML3-PR2, Delta-T, UK) and temperature sensors (KM330, Comark Instuments, UK) (Noe et al 2015) from the Norway spruce and mixed stands (n = 2-4) in 2017-2018. We measured monthly litterfall using litter collectors from both forest stands at the SMEAR Estonia station, and from the Scots pine stand at the SMEAR II station.…”

Section: Voc Flux Measurements From the Forest Floor And Supporting Datamentioning

confidence: 99%

Stand type affects fluxes of volatile organic compounds from the forest floor in hemiboreal and boreal climates

et al. 2019

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Aims The forest floor is a significant contributor to the stand-scale fluxes of biogenic volatile organic compounds. In this study, the effect of tree species (Scots pine vs. Norway spruce) on forest floor fluxes of volatile organic compounds (VOC) was compared in boreal and hemiboreal climates. Methods Monoterpenoid and sesquiterpene flux rates were determined during 2017-2018 using dynamic (steady-state flow-through) chambers placed on permanent soil collars on boreal and hemiboreal forest floors, where the canopy was formed by Scots pine (Pinus sylvestris), Norway spruce (Picea abies) or dominated by Scots pine with small coverage of Norway spruce and birches (Betula pendula and Betula pubescens). Results The total monoterpenoid fluxes were higher from the Scots pine forest floor (boreal 23 μg m −2 h −1 ) and from the mixed forest floor (hemiboreal 32 μg m −2 h −1 ) compared to the Norway spruce forest floor in both boreal (12 μg m −2 h −1 ) and hemiboreal (9 μg m −2 h −1 ) climates. Due to higher litterfall production, the forest floor seems to be a greater source of monoterpenoids and sesquiterpenes in the hemiboreal mixed stand dominated by Scots pine compared to the boreal Scots pine stand, although the difference was not statistically significant. Forest floor VOC fluxes followed a similar seasonal dynamic in different forest stands, with the highest flux rates in spring and summer. Significant VOC sources in the boreal forest floor were synthesis and release from vegetation and living roots together with litter decomposition of fungi and other microbes, where VOCs are released from needle storage pools. Ground vegetation in the hemiboreal forest is scanty under the dense tree canopy, meaning soil processes, such as litter decomposition, microbial metabolism and root release, were likely the dominating VOC sources. VOC fluxes from the hemiboreal forest floor were reduced by increases in soil moisture.Conclusions This study indicates that if the warming climate changes tree species' abundance and stand biomass, by increasing tree growth and coverage of broadleaf species, it may affect VOC fluxes from the forest floor and impact the total VOC emissions from northern soils.

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“…The site is a managed, 55-year old Scots pine (Pinus sylvestris L.) forest stand with closed canopy and average tree height ca 18 m. SMEAR I (Hari et al, 1994) is the site characterized by the highest latitude, it is located in Finnish Lapland. The site has ca 60-year old Scots pines with a rather open canopy, average tree height is ca 10 m. SMEAR Estonia (Noe et al, 2015) is located in a hemiboreal forest zone and the stands in the tower footprint consist of 30 a mixture of coniferous (Scots pine and Norway spruce (Picea abies L. Karst)) and deciduous (silver birch (Betula pendula Roth.) and downy birch (Betula pubescens Ehrh.))…”

Section: Sites and Data Setsmentioning

confidence: 99%

Direct effect of aerosols on solar radiation and gross primary production in boreal and hemiboreal forests

Ezhova¹,

Ylivinkka²,

Kuusk³

et al. 2018

Preprint

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Abstract. The effect of an aerosol loading on solar radiation and further on photosynthesis is a relevant question for estimating climate feedback mechanisms. This effect is quantiﬁed in the present study using ground-based measurements from ﬁve remote sites in boreal and hemiboreal (coniferous and mixed) forests of Eurasia. The diffuse fraction of global radiation associated with the direct effect of aerosols, that is excluding the effect of clouds, increases with an increasing aerosol loading. The increase in the diffuse fraction of global radiation from approximately 0.11 on the days characterized by low aerosol loading up to 0.2–0.27 pertaining to relatively high aerosol loading leads to the increase in gross primary production (GPP) at all sites by 6–14 %. The largest increase in GPP (relative to the days with low aerosol loading) is observed for two types of ecosystems: a coniferous forest at the high latitudes and a mixed forest at the middle latitudes. For the former ecosystem the change in GPP due to relatively large increase in the diffuse radiation is compensated by the moderate increase in the light use efﬁciency. For 10 the latter ecosystem, the increase in diffuse radiation is smaller for the same aerosol loading, but the smaller change in GPP due to this relationship between radiation and aerosol loading is compensated by the higher increase in the light use efﬁciency. The dependency of GPP on the diffuse fraction of solar radiation has a weakly pronounced maximum related to clouds.

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SMEAR Estonia: Perspectives of a large-scale forest ecosystem – atmosphere research infrastructure

Cited by 26 publications

References 69 publications

Global analysis of continental boundary layer new particle formation based on long-term measurements

Global analysis of continental boundary layer new particle formation based on long-term measurements

Stand type affects fluxes of volatile organic compounds from the forest floor in hemiboreal and boreal climates

Direct effect of aerosols on solar radiation and gross primary production in boreal and hemiboreal forests

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