Seasonality of soil CO2 efflux in a temperate forest: Biophysical effects of snowpack and spring freeze–thaw cycles

Wang, Chuankuan; Han, Youngho; Chen, Jiquan; Wang, Xingchang; Zhang, Quan‐Zhi; Bond‐Lamberty, Ben

doi:10.1016/j.agrformet.2013.04.008

Cited by 71 publications

(60 citation statements)

References 62 publications

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“…The mean (1989-2009) annual precipitation is 629 mm, of which ~50% falls between June and August. The mean annual air temperature is 3.1 °C, and mean January and July air temperature are −18.5 °C and +22.0 °C, respectively [40]. The frost-free period is between 120 and 140 days with early frosts in September and late frosts in May.…”

Section: Site Descriptionmentioning

confidence: 99%

“…For example, the height of wind velocity maximum on the low-angle (1.6°) side-wall of the floor of Utah's Salt Lake Valley occurred at 10 to 15 m height [20], but could reach 40 m in another slope in the same valley [48]. Most studies in forest sites reported that the drainage flows were restricted in the subcanopy layer, which characterized with relative open canopy and insignificant understory vegetation [8,13,21], or at the upper part of a long slope [39,40], or very gentle slope [39]. We did not detect the possible subcanopy wind maximum as many previous studies [13,28,31,41,42] due to only one observation point below canopy.…”

Section: Horizontal Wind Velocitymentioning

confidence: 99%

“…In valley topography, significant interplays between the flows on side-wall and the flows along the valley axis, down-valley flows differ dramatically from down-slope flows on isolated mountains [15]. When the observation was conducted at upper slope, the depth of nocturnal drainage flow was often limited to the first few meters above the ground in the trunk-space e.g., [8,13,39,40]. On the side-wall of a valley, the down-slope flow often started before sunset [23,49], and then speeded up and increased in depth with down-slope distance before mid-night [18,19,23].…”

Section: Horizontal Wind Velocitymentioning

confidence: 99%

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Wind Regimes above and below a Temperate Deciduous Forest Canopy in Complex Terrain: Interactions between Slope and Valley Winds

Wang

2014

Atmosphere

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Abstract:The thermally driven wind over mountainous terrains challenges the estimation of CO2 exchange between forests and the atmosphere when using the eddy covariance technique. In this study, the wind regimes were investigated in a temperate deciduous forested valley at the Maoershan site, Northeast China. The wind direction above the canopy was preferentially up-valley in the daytime and down-valley in the nighttime, corresponding to the diurnal patterns of above-canopy temperature gradient and stability parameter. In both leaf-on and -off nighttime, a down-valley flow with a maximum velocity of 1~3 m•s −1 was often developed at 42 m above the ground (2.3-fold of the canopy height). However, the below-canopy prevailing wind was down-slope in the night, contrast to the below-canopy temperature lapse and unstable conditions. This substantial directional shear illustrated shallow slope winds were superimposed on larger-scale valley winds. As a consequence, the valley-wind component becomes stronger with increasing height, indicating a clear confluence of drainage flow to the valley center. In the daytime, the below-canopy wind was predominated down-slope due to the temperature inversion and stable conditions in the leaf-on season, and was mainly up-valley or down-slope in the leaf-off season. The isolation of momentum flux and OPEN ACCESSAtmosphere 2015, 6 61 radiation by the dense canopy played a key role in the formation of the below-canopy unaligned wind and inverse stability. Significant lateral kinematic momentum fluxes were detected due to the directional shear. These findings suggested a significant interaction between slope and valley winds at this site. The frequent vertical convergence / divergence above the canopy and horizontal divergence/convergence below the canopy in the nighttime / daytime is likely to induce significant advections of trace gases and energy flux.

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Section: Site Descriptionmentioning

confidence: 99%

Section: Horizontal Wind Velocitymentioning

confidence: 99%

Section: Horizontal Wind Velocitymentioning

confidence: 99%

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Wind Regimes above and below a Temperate Deciduous Forest Canopy in Complex Terrain: Interactions between Slope and Valley Winds

Wang

2014

Atmosphere

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“…The climate is a continental monsoon climate with a windy and dry spring, a warm and humid summer, and a dry and cold winter (Wang et al, 2013a). The mean annual air temperature is 3.1 • C, and the mean January and July air temperatures are −18.5 • C and +22.0 • C, respectively.…”

Section: Site Descriptionmentioning

confidence: 99%

Improving the CO2 storage measurements with a single profile system in a tall-dense-canopy temperate forest

Wang

Guo

et al. 2016

Agricultural and Forest Meteorology

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a b s t r a c tThe CO 2 storage (F s ) measurement can contribute significantly to the estimation of the net ecosystem exchange of CO 2 (NEE) especially in tall-canopy forest ecosystems. The F s is often measured with a profile of CO 2 concentration or with an eddy covariance system at the tower top, but few studies investigated potential errors in the F s measurements. We assessed the errors in F s relevant to the vertical distribution of sampling levels and window sizes of averaging time of CO 2 mixing ratio and their effects on NEE in a temperate deciduous forest site in Northeast China using the standardized major axis method. The CO 2 storage per unit height typically decreased with the height increasing, suggesting that the below-canopy layer need a higher spatial resolution. CO 2 storage could be underestimated by up to one third based only on the tower-top measurement. The uncertainty (standard deviation) of the F s decreased with the length of the averaging time window increasing. However, taking time averaging of CO 2 mixing ratio caused significant underestimate of F s , and consequently led to significant underestimates of CO 2 uptake and release at a 30-min time scale. Our results highlight that appropriately combining spatial resolution and temporal resolution (response time for a whole sampling of all levels) is essential to improving the F s estimates with the existing CO 2 profile systems in forest ecosystems. Since the systematic bias and random error in F s estimate with a single profile system are irreconcilable, there is an urgent need to develop a fast response planar-averaging profile or measure the instantaneous vertical-mean concentration to improve the accuracy of F s measurement.

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“…Jansson & Prosser, 2013)。运用生态化学计量学理论 (Sterner & Elser, 2002) 和代谢理论(Brown et al, 2004)研究土壤微生物, 不但可以提升我们对土壤微生物生态过程和机理的认识, 而且有助于生态学理论的发展与完善 (Sterner & Elser, 2002;Brown et al, 2004;Sinsabaugh & Follstad Shah, 2011;Manzoni et al, 2012;Mooshammer et al, 2014;Buchkowski et al, 2015;Zechmeister-Boltenstern et al, 2015 (Högberg et al, 2001;Bond-Lamberty et al, 2004;Wang & Yang, 2007;Wang et al, 2013), 但可能由于对微生物生理代谢机制认识不足 (Allison et al, 2010;Buchkowski et al, 2015;Steinauer et al, 2015) (Vitousek & Howarth, 1991;Vitousek et al, 2010 et al, 2004;Yuan & Chen, 2009;Reed et al, 2012;Vergutz et al, 2012;Han et al, 2013) Mechanisms of microbial response and regulation on substrate stoichiometry. C:X, substrate carbon to nutrient (nitrogen and phosphor) ratios; BG, β-1,4-glucosidase; NAG, β-1,4-N-acetylglucosaminidase; AP, phosphatase, EEA, extracellular enzymatic activity; RAT, resource allocation theory; TER, threshold elemental ratio; GRH, growth rate hypothesis; CNR, consumer-driven nutrient recycling; OM, overflow metabolism; CUE, carbon use efficiency; NUE, nitrogen use efficiency; PUE, phosphor use efficiency; qMB, fraction of total substrate carbon in microbe; qCO 2 , microbial respiration rate per unit biomass carbon; N min , nitrogen mineralization; P min , phosphor mineralization.…”

mentioning

confidence: 99%

Responses and regulation mechanisms of microbial decomposers to substrate carbon, nitro-gen, and phosphorus stoichiometry

Zhou¹,

Wang²

2016

Chinese Journal of Plant Ecology

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Seasonality of soil CO2 efflux in a temperate forest: Biophysical effects of snowpack and spring freeze–thaw cycles

Cited by 71 publications

References 62 publications

Wind Regimes above and below a Temperate Deciduous Forest Canopy in Complex Terrain: Interactions between Slope and Valley Winds

Wind Regimes above and below a Temperate Deciduous Forest Canopy in Complex Terrain: Interactions between Slope and Valley Winds

Improving the CO2 storage measurements with a single profile system in a tall-dense-canopy temperate forest

Responses and regulation mechanisms of microbial decomposers to substrate carbon, nitro-gen, and phosphorus stoichiometry

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