Inter-annual and seasonal variations of energy and water vapour fluxes
                        above a &lt;i&gt;Pinus sylvestris&lt;/i&gt; forest in the Siberian middle
                        taiga

Tchebakova, Nadezhda M.; Kolle, Olaf; Zolotoukhine, Daniil; Arneth, Almut; Styles, Julie M.; Vygodskaya, N. N.; Schluze, E.-Detlef; Shibistova, Olga; Lloyd, Jon

doi:10.3402/tellusb.v54i5.16686

Cited by 25 publications

(32 citation statements)

References 15 publications

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“…To calculate daily sums, gaps were filled using a respiration-temperature function for night-time values (see below) and a hyperbolical relationship with quantum flux density (Q) during daytime hours. The shape of the correction functions was plastic and parameter values varied throughout the year in response to seasonal changes observed in assimilation and respiration (Arneth et al, 2002a;Tchebakova et al, 2002;Veenendaal et al, 2004).…”

Section: Methodsmentioning

confidence: 99%

“…Eddy flux calculations were performed online but were later corrected to account for flux losses due to the gas-analysers' imperfect performance in the high-frequency domain, or dampening of the signal while air was travelling along the tube (O. Kolle, unpublished;Eugster and Senn, 1995;Arneth et al, 2002a;Lloyd et al, 2002;Röser et al, 2002;Tchebakova et al, 2002;Veenendaal et al, 2004). The half-hourly fluxes thus derived were screened, and corrected for possibly dubious values encountered during stable conditions at night by applying a stationarity test or a u*-threshold, with the thresholds being: >0.2 ms −1 at the birch forest, >0.1 ms −1 at the Mopane woodland, 0.055 at the wetland, and >0.15 ms −1 at the pine forest (Arneth et al, 2002a;Lloyd et al, 2002;Röser et al, 2002;Veenendaal et al, 2004).…”

Section: Methodsmentioning

confidence: 99%

“…Maximum leaf area of this nearly monospecific forest was 2.6 by late August. A more detailed description of the three ecosystems can be found elsewhere (Arneth et al, 2002a;Lloyd et al, 2002;Röser et al, 2002;Tchebakova et al, 2002).…”

Section: Boreal Forests and Wetlands Central Siberiamentioning

confidence: 99%

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Water use strategies and ecosystem-atmosphere exchange of CO2 in two highly seasonal environments

et al. 2006

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Abstract.We compare assimilation and respiration rates, and water use strategies in four divergent ecosystems located in cold-continental central Siberia and in semi-arid southern Africa. These seemingly unrelated systems have in common a harsh and highly seasonal environment with a very sharp transition between the dormant and the active season, with vegetation facing dry air and soil conditions for at least part of the year. Moreover, the northern high latitudes and the semi-arid tropics will likely experience changes in key environmental parameters (e.g., air temperature and precipitation) in the future; indeed, in some regions marked climate trends have already been observed over the last decade or so.The magnitude of instantaneous or daily assimilation and respiration rates, derived from one to two years of eddy covariance measurements in each of the four ecosystems, was not related to the growth environment. For instance, respiration rates were clearly highest in the two deciduous systems included in the analysis (a Mopane woodland in northern Botswana and a Downy birch forest in Siberia; >300 mmol m −2 d −1 ), while assimilation rates in the Mopane woodland were relatively similar to a Siberian Scots pine canopy for a large part of the active season (ca. 420 mmol m −2 d −1 ). Acknowledging the limited number of ecosystems compared here, these data nevertheless demonstrate that factors like vegetation type, canopy phenology or ecosystem age can override larger-scale climate differences in terms of their effects on carbon assimilation and respiration rates.By far the highest rates of assimilation were observed in Downy birch, an early successional species. These were achieved at a rather conservative water use, as indicated by relatively low levels of λ, the marginal water cost of plant Correspondence to: A. Arneth (almut.arneth@nateko.lu.se) carbon gain. Surprisingly, the Mopane woodland growing in the semi-arid environment had significantly higher values of λ. However, its water use strategy included a very plastic response to intermittently dry periods, and values of λ were much more conservative overall during a rainy season with low precipitation and high air saturation deficits. Our comparison demonstrates that forest ecosystems can respond very dynamically in terms of water use strategy, both on interannual and much shorter time scales. But it remains to be evaluated whether and in which ecosystems this plasticity is mainly due to a short-term stomatal response, or alternatively goes hand in hand with changes in canopy photosynthetic capacity.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Water use strategies and ecosystem-atmosphere exchange of CO2 in two highly seasonal environments

et al. 2006

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“…An analysis of two years of measurements over a Central Siberian pine forest by Tchebakova et al (2002) found evaporation rates of 1.5 to 2 mm day −1 with a three year average for the growing season of 1.5 mm day −1 . Generally these low evaporation rates, typically using up to only 20% of the available energy, are associated with high Bowen ratios, well above 1, even when the forest are well supplied with water.…”

Section: Introductionmentioning

confidence: 99%

Net ecosystem exchange of carbon dioxide and water of far eastern Siberian Larch (Larix cajanderii) on permafrost

Dolman

Maximov²,

Moors

et al. 2004

Biogeosciences

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Abstract.Observations of the net ecosystem exchange of water and CO 2 were made during two seasons in 2000 and 2001 above a Larch forest in Far East Siberia (Yakutsk). The measurements were obtained by eddy correlation. There is a very sharply pronounced growing season of 100 days when the forest is leaved. Maximum half hourly uptake rates are 18 µmol m −2 s −1 ; maximum respiration rates are 5 µmol m −2 s −1 . Net annual sequestration of carbon was estimated at 160 gCm −2 in 2001. Applying no correction for low friction velocities added 60 g C m −2 . The net carbon exchange of the forest was extremely sensitive to small changes in weather that may switch the forest easily from a sink to a source, even in summer. June was the month with highest uptake in 2001.The average evaporation rate of the forest approached 1.46 mm day −1 during the growing season, with peak values of 3 mm day −1 with an estimated annual evaporation of 213 mm, closely approaching the average annual rainfall amount. 2001 was a drier year than 2000 and this is reflected in lower evaporation rates in 2001 than in 2000.The surface conductance of the forest shows a marked response to increasing atmospheric humidity deficits. This affects the CO 2 uptake and evaporation in a different manner, with the CO 2 uptake being more affected. There appears to be no change in the relation between surface conductance and net ecosystem uptake normalized by the atmospheric humidity deficit at the monthly time scale. The response to atmospheric humidity deficit is an efficient mechanism to prevent severe water loss during the short intense growing season. The associated cost to the sequestration of carbon may be another explanation for the slow growth of these forests in this environment.

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“…However, studies dedicated to heat and radiative fluxes investigation over ATR, especially during last decades, do not provide complete information for the territory, only for local regions (Zotino, Yakutsk) and these studies are connected with solution of specific problems (Meroni et al, 2002;Tchebakova et al, 2002), for the regions of the North and wetlands (Meroni et al, 2002;Iwahana et al, 2005;Boike et al, 2008).…”

Section: E V Kharyutkina Et Al: the Variability Of Radiative Balanmentioning

confidence: 99%

The variability of radiative balance elements and air temperature over the Asian region of Russia

2012

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Abstract. The variability of spatial-temporal distribution of temperature and heat balance elements is investigated for the Asian territory of Russia (45-80 • N, 60-180 • E) using JRA-25, NCEP/DOE AMIP-II reanalysis data and observational data for the period of global warming 1979-2008. It is shown that temperature trend over the territory is 1.4 • C for the period under study according to reanalysis data. Since the beginning of 90s of 20th century the increase of back earth-atmosphere shortwave radiation is observed. Such tendency is in conformity with the cloud cover distribution and downward shortwave radiation at the surface. Regression model describing temperature variability with variability of heat balance elements was presented. We conclude that possible applications for the model include the convenient estimate of temperature variability according to reanalysis data.

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Inter-annual and seasonal variations of energy and water vapour fluxes above a <i>Pinus sylvestris</i> forest in the Siberian middle taiga

Cited by 25 publications

References 15 publications

Water use strategies and ecosystem-atmosphere exchange of CO<sub>2</sub> in two highly seasonal environments

Water use strategies and ecosystem-atmosphere exchange of CO<sub>2</sub> in two highly seasonal environments

Net ecosystem exchange of carbon dioxide and water of far eastern Siberian Larch (<I>Larix cajanderii</I>) on permafrost

The variability of radiative balance elements and air temperature over the Asian region of Russia

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Inter-annual and seasonal variations of energy and water vapour fluxes above a <i>Pinus sylvestris</i> forest in the Siberian middle taiga

Cited by 25 publications

References 15 publications

Water use strategies and ecosystem-atmosphere exchange of CO&lt;sub&gt;2&lt;/sub&gt; in two highly seasonal environments

Water use strategies and ecosystem-atmosphere exchange of CO&lt;sub&gt;2&lt;/sub&gt; in two highly seasonal environments

Net ecosystem exchange of carbon dioxide and water of far eastern Siberian Larch (&lt;I&gt;Larix cajanderii&lt;/I&gt;) on permafrost

The variability of radiative balance elements and air temperature over the Asian region of Russia

Contact Info

Product

Resources

About

Water use strategies and ecosystem-atmosphere exchange of CO<sub>2</sub> in two highly seasonal environments

Water use strategies and ecosystem-atmosphere exchange of CO<sub>2</sub> in two highly seasonal environments

Net ecosystem exchange of carbon dioxide and water of far eastern Siberian Larch (<I>Larix cajanderii</I>) on permafrost