Artikkelit jotka sisältää sanan 'climate'
Häädetkeitaan ja Kauhanevan allikkorakenteen muutokset vuosina 1947–2017 kaukokartoituksen perusteella.
English title: Changes in the open water hollows in Häädetkeidas and Kauhaneva mires during 1947–2017 based on remote sensing.
Original keywords:
ilmastonmuutos;
geomorfologia;
ilmakuvat;
kaukokartoitus;
keidassuot;
maximum likelihood;
ohjattu luokittelu;
PlanetScope
English keywords:
climate change;
Remote Sensing;
Aerial images;
Geomorphology;
Maximum likelihood;
PlanetScope;
Supervised classification
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Keidassuot ovat Etelä-Suomen yleisin suoyhdistymätyyppi. Ne saavat vetensä ja ravinteensa sateen mukana. Keidassoiden pintaa luonnehtivat kuivat harjanteet, kermit, ja märät painanteet, kuljut. Ilmaston lämpeneminen vähentää talven lumisuutta ja lisää haihduntaa, minkä on arvioitu laskevan keidassoiden vedenpintaa. Tämä voi aiheuttaa muutoksia keidassoiden ekosysteemissä ja kiihdyttää ilmaston lämpenemistä paikallisesti. Keidassoilla tapahtuvia pitkäaikaismuutoksia on tutkittu kuitenkin verraten vähän.
Tässä työssä tarkastellaan vesipintaisten kuljujen eli allikoiden määrässä 70 vuoden aikana tapahtuneita muutoksia ilma- ja satelliittikuvien avulla. Tutkimuskohteina ovat kaksi Länsi-Suomessa sijaitsevaa keidassuota: Häädetkeidas ja Kauhaneva. Pitkän ajan muutosta seurataan ilmakuvien objektiperusteisen segmentoinnin ja ohjatun suurimman todennäköisyyden luokittelun avulla. Yksittäisen kasvukauden aikaista muutosta tarkastellaan satelliittikuvien ja ohjatun suurimman todennäköisyyden luokittelun avulla. Tuloksia verrataan tarkasteluajanjaksolta kerättyihin säätietoihin.
Tulosten perusteella allikoiden lukumäärä ja pinta-ala ovat vaihdelleen tarkastelujakson aikana. 1940-luvulta 1970-luvulle asti pinta-aloissa ja lukumäärissä on ollut kasvua, minkä jälkeen ne ovat vähentyneet. 1940-luvun tilanteeseen nähden allikoiden lukumäärä on Häädetkeitaalla vähentynyt 13,8 % ja pinta-ala on vähentynyt 14,8 %. Kauhanevalla lukumäärä on vähentynyt 5,3 % ja pinta-ala on vähentynyt 6,3 %. Alueen keskilämpötila on samaan aikaan noussut yli 1 °C. Satelliittikuva-analyysin perusteella vaihtelu voi yksittäisen kasvukauden aikana olla kuitenkin voimakasta, mikä aiheuttaa epävarmuutta pitkän ajan muutoksen tulkintaan.
Tulokset osoittavat, että keidassoilla tapahtuu kaukokartoitusmenetelmin havaittavia pintarakenteen muutoksia, joilla on todennäköisesti kytkös ilmasto-olosuhteiden muutokseen.
Luonnontilaisten soiden pitkänajan- ja nykykertymät boreaalisella ja subarktisella kasvillisuusvyöhykkeellä: katsaus.
English title: Past and present carbon accumulation in undisturbed boreal and subarctic mires: a review.
Avainsanat:
fens;
climate change;
carbon accumululation;
bogs;
boreal region;
subarctic region;
Holocene
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This review integrates the results from several recent studies on carbon (C) accumulation in undisturbed boreal and subarctic mire ecosystems in Finland, Sweden, Russia, Canada, and USA. Generally, a large variation in the average long-term apparent rate of carbon accumulation (LORCA) has been found among mires based on the mire type, age and geographical location. The differences in LORCA between the raised bog region and the aapa mire regions were found to be significant. The updated LORCA for undrained boreal and subarctic mire regions has been estimated at 13–20 g C m–2 a–1 throughout the Holocene, which is clearly lower than previous estimates for these northern mire regions. The age of the peat column is an important predictor of C accumulation and has to be taken into account when comparing results. The results indicate a rapid mire expansion in southern Finland from ca. 10 500 to 8500 cal. year BP, from 5000 to 3000 cal. year BP and around 2000 cal. year BP. In northern Finland the extensive mire expansion occurred from ca. 10500 to 8000 cal. year BP. The recent apparent rate of C accumulation (RERCA) in boreal and subarctic mire regions over the past 100 to 200 years ranges from 30 to 120 g C m-2 a-1. The future C balance scheme of mires is also briefly discussed. Key words: carbon accumulation, bogs, fens, boreal region, subarctic region, Holocene, climate change
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Turunen,
Geological Survey of Finland, Kuopio Unit, P.O. Box 1237, 70211 Kuopio, Finland
Sähköposti:
ei.tietoa@nn.oo
Turpeen kokonaistyppipitoisuuden ja lannoituksen vaikutus männyn neulasten typpipitoisuuteen kolmessa eri lämpösummavyöhykkeessä.
English title: The effect of peat nitrogen concentration and fertilization on the foliar nitrogen concentration of Scots pine (Pinus sylvestris L.) in three temperature sum regions.
Avainsanat:
fertilization;
nitrogen;
foliar analysis;
climate;
peat nitrogen;
Deficiency;
temperature sum
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Wood production capacity on drained peatlands depends on the site type and temperature
sum. Site type is closely related to the peat total nitrogen concentration. This study
aims at clarifying the effect of peat nitrogen, fertilization and refertilization on the
foliar nitrogen concentration of Scots pine in different temperature sum conditions
(850, 950 and 1080 d.d.) on peatland sites with a wide peat nitrogen gradient (0.79-
2.80% in the 0-10 cm layer). In the coldest region, regardless of the peat total nitrogen
concentrations in the 0-10 cm surface peat layer and PK- fertilization or PK-refertilization
(37 and 26 years earlier respectively), the needle nitrogen concentrations
were mostly below the severe deficiency limit (N = 1.2%) and also the arginine concentrations
revealed a nitrogen shortage (<0.5 mg g-1). In the middle region the mean
nitrogen concentrations in the needles were clearly higher and in the PK- fertilization
and PK-refertilizations (32 and 22 years earlier respectively) surpassed the slight nitrogen
deficiency limit (N = 1.3%). Also the arginine concentrations surpassed the deficiency
limit (0.5 mg g-1 ) in both fertilization treatments although the mean arginine
concentrations were near or under the deficiency limit. In the warmest region 25-26
years after the spot fertilization the mean nitrogen concentration was 1.84% and the
arginine concentration was 3.04 mg g-1 revealing a surplus of nitrogen caused by phosphorus
and potassium deficiencies. The PK-fertilization given 10 years later decreased
the nitrogen concentration to 1.56% and the arginine concentration to 0.58 mg g-1. In
the more favourable conditions the nitrogen and arginine in the needles increased when
the nitrogen in the peat increased. In conclusion, tree growth in the middle and the
warmest temperature sum region would respond to PK-refertilisation above a certain
total peat nitrogen level but in the coldest temperature sum region tree growth would
not respond to PK-refertilization in any of the studied peat total nitrogen conditions
because of nitrogen deficiency.
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Pietiläinen,
The Finnish Forest Research Institute, Muhos Research Station, Kirkkosaarentie 7, FIN-91500 Muhos, Finland
Sähköposti:
ei.tietoa@nn.oo
- Kaunisto, Sähköposti: ei.tietoa@nn.oo
Typpioksiduulivirrat suunnitellun Vuotoksen tekojärven alueen soilta.
English title: Fluxes of nitrous oxide on natural peatlands in Vuotos, an area projected for a hydroelectric reservoir in northern Finland.
Avainsanat:
global change;
Northern boreal peatlands;
climate warming;
flooding;
greenhouse gas emission;
hydro dam
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Nitrous oxide (N2O) fluxes were measured on ten natural minerotrophic peatlands in an area planned for a hydroelectric reservoir (Vuotos) in northern Finland. The mean N2O fluxes from the sites with mean water tables from –25 to 3.4 cm (negative below the peat surface) ranged from –30 to 230 µg m–2 d–1 during summer 1994. At the driest site, the herb-grass spruce mire with the mean water table at –38 cm, the mean summertime N2O emission was 940 µg m-2 d-1 in 1994, attributable to the increased N2O release at low peat temperatures in autumn. A similar increase in the N2O emissions was not found in 1995, as the measurements were finished before the peat started to freeze. The mean N2O fluxes at the sites correlated negatively with the mean water table levels. The peatlands in the northern boreal zone are unlikely important sources of atmospheric N2O in their natural state. The planned reservoir would barely have large long-term N2O emissions from the pelagic zone, but the importance of temporally flooded areas in the postflood N2O release is uncertain similar to the short-term emissions following the flooding.
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Huttunen,
Research and Development Unit of Environmental Health, Department of Environmental Sciences, Bioteknia 2, University of Kuopio, PO Box 1627, FIN-70211 Kuopio, Finland
Sähköposti:
ei.tietoa@nn.oo
- Nykänen, Sähköposti: ei.tietoa@nn.oo
- Turunen, Sähköposti: ei.tietoa@nn.oo
- Nenonen, Sähköposti: ei.tietoa@nn.oo
- Martikainen, Sähköposti: ei.tietoa@nn.oo
A model of organic matter accumulation in a developing fen/raised bog complex.
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A mechanistic simulation model of organic matter accumulation for a developing fen/ raised bog complex in Ireland is presented.Parameter/variable values have been prima rily drawn from the published literature.The development of the theoretical considera tions of fen peat as a substratum to a raised bog is evaluated using the model.Terrestri alization is the pathway of hydroseral succession.The conceptual model treats peat growth as the accumulation of a series of parcels comprising both a labile and a non- labile component.The fen phase of the model uses a discrete description of organic matter accumulation while the raised bog phase uses a continuous description.Both phases use a constant decay rate.The model integrates changes in net primary produc tivity and aerobic decay to simulate four climatic periods.The model generates outputs for peat depth and mass with time and profiles of bulk density with depth.Results over a simulated period of 10 000 years demonstrate how changes in surface net primary productivity and aerobic decay can change the rate of peat accumulation in the develop ing fen/raised bog complex.Sensitivity analysis showed that the most important pa rameters influencing simulated depth and mass were the labile fraction in organic mat ter (raised bog)followed by net primary productivity (raised bog).The potential sig nificance of underlying fen peat as a proportion of the total depth and mass of a devel oping fen/raised bog complex was evaluated and shown to be substantially diminished after 5 000 years.It was established that the model predictions corresponded well with data for Irish Midland bogs and given suitable adjustment of values, could potentially simulate Fennoscandian conditions as well.
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Gilmer,
Department of Agricultural & Food Engineering (Peat Technology Centre), University College Dublin, Earlsfort Terrace, Dublin 2, Ireland
Sähköposti:
ei.tietoa@nn.oo
- Holden, Sähköposti: ei.tietoa@nn.oo
- Ward, Sähköposti: ei.tietoa@nn.oo
- Brereton, Sähköposti: ei.tietoa@nn.oo
- Farrell, Sähköposti: ei.tietoa@nn.oo
Karttoja suo-ojitusten vaikutuksesta Suomen ilmastoon.
English title: Charts of the climatic impact of the drainage of mires in Finland.
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Widespread drainage measures, which were carried out mainly in the period 1950-
1990 on Finnish mires, have had significant climatic consequences, part of them being
temporary, part permanent. The aim of this study was to prepare charts of these climatic
effects by combining three sources of knowledge: (I) the climatic effect of drainage (e, °C),
as given by (Solantie 1994, 1998) for a 100% mire area in the climatically most affecting
stage, (2) fresh grid-square statistics of the proportion of drained mires compared
with the total area, and (3) annual statistics of the proportion of drained mires in various
stages having characteristic climatic effects, compiled by the Finnish Forest Research
Institute. Three charts show the maximum cooling effect of peatland drainage in Finland
during the first 15 years after the drainage in the period 1973-1982, as drained
mires in such a stage of drainage were then most common. Two charts show the warming
effect after successful afforestation and canopy closure; the canopy acts as a radiation
shelter and a mixing generator for the air beneath. In the middle boreal natural
zone, that most heavily drained, the mean monthly minimum temperatures in the period
1973-1982 were reduced by 1.5°C and the yearly frost-free period was shortened by 17
days. As a result of successful afforestation, the annual minimum temperature in the
middle boreal zone will be raised by 2°C to 3°C by the year 2005.
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Solantie,
The Finnish Meteorological Institute, P.O. Box 503, FIN-00101 Helsinki, Finland
Sähköposti:
ei.tietoa@nn.oo
Turvestratigrafisen tutkimuksen historiasta ja kvartaaritieteellisestä merkityksestä Pohjoismaissa.
English title: On the history and Quaternary scientific significance of peat stratigraphical research in the Nordic countries.
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The early development of peat stratigraphical research was concentrated in the Nordic countries. Although this field of science originated in Denmark at the beginning of the 19th century, the most important pioneer of palaeoecological peatland research was the Norwegian, Axel Blytt. His model, as modified by the Swedish scientist Rutger Sernander, spread throughout Europe and from there to other continents and has had a major impact on peat stratigraphy and Quaternary science. However, our present knowledge of the regional differences in postglacial vegetation and climate history speaks against the use of the Blytt-Sernander scheme outside southern Scandinavia. Especially, the compulsive application of the Blytt-Sernander scheme in the zoning of pollen diagrams has lead to distortions and erroneous interpretations.
Keywords: Nordic countries, peat stratigraphy, postglacial climate history, pollen analysis
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Seppä,
Department of Geography, Laboratory of Physical Geography, P.O. Box 9, FIN-00014 University of Helsinki, Finland
Sähköposti:
ei.tietoa@nn.oo
Differences in response of two Sphagnum species to elevated CO2 and nitrogen input.
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Cushions of Sphagnum fuscum and S. angustifolium were grown in the laboratory in four different C02 concentrations (350, 700, 1 000, and 2 000 ppm) and N deposition levels (0, 10, 30, and 100 kg ha-1 a-1). The same N deposition levels were also applied in the field. C02 concentration increased both the shoot density and dry mass of S. fuscum but decreased the length increment. There was no net effect on production. For S. angustifolium, shoot density did not alter with elevated C02 con-centration but the C02 induced increment in dry mass and length caused increased production. S. angustifolium suffered from nutrient deficiency on the 0 kg N ha-1a-1 treatment and S. fuscum had difficulties to survive at the heaviest N load. No clear trends in length increment or cover was noticed in the field study during the first year.
Keywords: Bryophyte ecology, climate change, peatlands, production
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Jauhiainen,
University of Joensuu, Department of Biology, P.O. Box 111, FIN-80I0I Joensuu, Finland
Sähköposti:
ei.tietoa@nn.oo
- Vasander, Sähköposti: ei.tietoa@nn.oo
- Silvola, Sähköposti: ei.tietoa@nn.oo
Methane flux from boreal peat-lands.
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The peatlands found in the boreal zone (roughly 45°-60°N) store a significant reservoir of carbon, much of which is potentially available for exchange with the atmosphere. The anaerobic conditions that cause these soils to accumulate carbon also makes wet, boreal peatlands significant sources of methane (CH4) to the global troposphere. We estimate that boreal wetlands contribute approximately 19.5 Tg CH4 yr-1. The data available on the magnitude of boreal CH4 emissions have rapidly accumulated in the past twenty years. This paper offers a short review of the flux measurements (which range from roughly I to 2 000 mg CH4 m-2 d-1'), considers environmental controls of the flux and briefly discusses how climate change might affect future fluxes.
Keywords: Carbon, climate change, global change
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Crill,
Complex Systems Research Center, Institute for the Study of Earth, Oceans and Space, University of New Hampshire, Durham, New Hampshire, U.S.A. 03824
Sähköposti:
ei.tietoa@nn.oo
- Bartlett, Sähköposti: ei.tietoa@nn.oo
- Roulet, Sähköposti: ei.tietoa@nn.oo
Viimeisten vuosisatojen lämpimien ja kylmien ilmastovaiheiden vaikutus ikiroutasoiden hiilidynamiikkaan ja hydrologisiin muutoksiin.
English title: Response of permafrost peatland hydrology and carbon dynamics to warm and cold climate phases during the last centuries.
Original keywords:
hiilen kertyminen;
ilmastonmuutos;
hydrologiset muutokset;
ikiroutasuot;
kasvimakrofossiilit;
kuoriamebat
English keywords:
climate change;
Carbon accumulation;
hydrological changes;
permafrost peatlands;
plant macrofossils;
testate amoeba
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