scholarly journals Thermal growing season and timing of biospheric carbon uptake across the Northern Hemisphere

2012 ◽  
Vol 26 (4) ◽  
pp. n/a-n/a ◽  
Author(s):  
J. Barichivich ◽  
K. R. Briffa ◽  
T. J. Osborn ◽  
T. M. Melvin ◽  
J. Caesar
Keyword(s):  
Northern Hemisphere ◽  
Growing Season ◽  
Carbon Uptake

scholarly journals Continued increase in atmospheric CO<sub>2</sub> seasonal amplitude in the 21st century projected by the CMIP5 Earth system models

2014 ◽  
Vol 5 (2) ◽  
pp. 423-439 ◽  
Author(s):  
F. Zhao ◽  
N. Zeng
Keyword(s):  
Northern Hemisphere ◽  
21St Century ◽  
Seasonal Cycle ◽  
Co2 Concentration ◽  
Growing Season ◽  
Carbon Uptake ◽  
Earth System ◽  
System Models ◽  
Amplitude Increase ◽  
Earth System Models

Abstract. In the Northern Hemisphere, atmospheric CO2 concentration declines in spring and summer, and rises in fall and winter. Ground-based and aircraft-based observation records indicate that the amplitude of this seasonal cycle has increased in the past. Will this trend continue in the future? In this paper, we analyzed simulations for historical (1850–2005) and future (RCP8.5, 2006–2100) periods produced by 10 Earth system models participating in the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Our results present a model consensus that the increase of CO2 seasonal amplitude continues throughout the 21st century. Multi-model ensemble relative amplitude of detrended global mean CO2 seasonal cycle increases by 62 ± 19% in 2081–2090, compared to 1961–1970. This amplitude increase corresponds to a 68 ± 25% increase in net biosphere production (NBP). The results show that the increase of NBP amplitude mainly comes from enhanced ecosystem uptake during Northern Hemisphere growing season under future CO2 and temperature conditions. Separate analyses on net primary production (NPP) and respiration reveal that enhanced ecosystem carbon uptake contributes about 75% of the amplitude increase. Stimulated by higher CO2 concentration and high-latitude warming, enhanced NPP likely outcompetes increased respiration at higher temperature, resulting in a higher net uptake during the northern growing season. The zonal distribution and spatial pattern of NBP change suggest that regions north of 45° N dominate the amplitude increase. Models that simulate a stronger carbon uptake also tend to show a larger increase of NBP seasonal amplitude, and the cross-model correlation is significant (R=0.73, p< 0.05).

scholarly journals Seasonal biological carryover dominates northern vegetation growth

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xu Lian ◽  
Shilong Piao ◽  
Anping Chen ◽  
Kai Wang ◽  
Xiangyi Li ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Growing Season ◽  
Ecosystem Dynamics ◽  
Environmental Drivers ◽  
Subsequent Growth ◽  
Ecosystem Models ◽  
Carryover Effect ◽  
Vegetation Growth ◽  
Sequestration Potential ◽  
Future Warming

AbstractThe state of ecosystems is influenced strongly by their past, and describing this carryover effect is important to accurately forecast their future behaviors. However, the strength and persistence of this carryover effect on ecosystem dynamics in comparison to that of simultaneous environmental drivers are still poorly understood. Here, we show that vegetation growth carryover (VGC), defined as the effect of present states of vegetation on subsequent growth, exerts strong positive impacts on seasonal vegetation growth over the Northern Hemisphere. In particular, this VGC of early growing-season vegetation growth is even stronger than past and co-occurring climate on determining peak-to-late season vegetation growth, and is the primary contributor to the recently observed annual greening trend. The effect of seasonal VGC persists into the subsequent year but not further. Current process-based ecosystem models greatly underestimate the VGC effect, and may therefore underestimate the CO2 sequestration potential of northern vegetation under future warming.

scholarly journals Comparison of Phenology Models for Predicting the Onset of Growing Season over the Northern Hemisphere

PLoS ONE ◽  
2014 ◽  
Vol 9 (10) ◽  
pp. e109544 ◽  
Author(s):  
Yang Fu ◽  
Haicheng Zhang ◽  
Wenjie Dong ◽  
Wenping Yuan
Keyword(s):  
Northern Hemisphere ◽  
Growing Season

The use of multi-tracer flask-measurements to understand changes in the land-surface processes.

2021 ◽  
Author(s):  
Theertha Kariyathan ◽  
Wouter Peters ◽  
Julia Marshall ◽  
Ana Bastos ◽  
Markus Reichstein
Keyword(s):  
Northern Hemisphere ◽  
Land Surface ◽  
Seasonal Cycle ◽  
Growing Season ◽  
Plant Productivity ◽  
Surface Processes ◽  
Terrestrial Biosphere ◽  
Land Surface Processes ◽  
Species Analysis

&lt;p&gt;Carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;)&amp;#160;is an important greenhouse gas, and it accounts for about 20% of the present-day anthropogenic greenhouse effect. Atmospheric CO&lt;sub&gt;2&lt;/sub&gt; is cycled between the terrestrial biosphere and the atmosphere through various land-surface processes and thus links the atmosphere and terrestrial biosphere through positive and negative feedback. Since multiple trace gas elements are linked by common biogeochemical processes, multi-species analysis is useful for reinforcing our understanding and can help in partitioning CO&lt;sub&gt;2&lt;/sub&gt; fluxes. For example,&amp;#160;in the northern hemisphere, CO&lt;sub&gt;2&lt;/sub&gt; has a distinct seasonal cycle mainly regulated by plant photosynthesis and respiration and it&amp;#160;has a distinct negative correlation with the&amp;#160;seasonal cycle of the &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C isotope of CO&lt;sub&gt;2&lt;/sub&gt;,&amp;#160;due to a stronger isotopic fractionation&amp;#160;associated with terrestrial photosynthesis.&amp;#160;Therefore, multi-species flask-data measurements are useful for the long-term analysis of various green-house gases. Here we try to&amp;#160;infer the complex interaction between the atmosphere and the terrestrial biosphere by&amp;#160;multi-species analysis using&amp;#160;atmospheric flask measurement data from different NOAA flask measurement sites across the northern hemisphere.&lt;/p&gt;&lt;p&gt;This study focuses on the long-term changes in the seasonal cycle of CO&lt;sub&gt;2&lt;/sub&gt; over the northern hemisphere and tries to attribute the observed changes to driving land-surface processes through a combined analysis of the &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C seasonal cycle. For this we generate metrics of different parameters of the CO&lt;sub&gt;2&lt;/sub&gt;&amp;#160;and &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C&amp;#160;seasonal cycle like the seasonal cycle amplitude given by the peak-to-peak difference of the cycle (indicative of the amount of CO&lt;sub&gt;2&lt;/sub&gt; taken up by terrestrial uptake),&amp;#160; the intensity of plant productivity inferred from the slope of the seasonal cycle during the growing season , length of growing season and the start of the growing season. We analyze the inter-relation between these metrics and how they change across latitude and over time.&amp;#160;We hypothesize that the CO&lt;sub&gt;2 &lt;/sub&gt;seasonal cycle amplitude is controlled both by the intensity of plant productivity and period of the active growing season and that the timing of the growing season can affect the intensity of plant productivity. We then quantify these relationships, including their variation over time and latitudes and describe the effects of an earlier start of the growing season on the intensity of plant productivity and the CO&lt;sub&gt;2&lt;/sub&gt;&amp;#160;uptake by plants.&lt;/p&gt;

scholarly journals Changes in the Response of the Northern Hemisphere Carbon Uptake to Temperature Over the Last Three Decades

2018 ◽  
Vol 45 (9) ◽  
pp. 4371-4380 ◽  
Author(s):  
Yi Yin ◽  
Philippe Ciais ◽  
Frederic Chevallier ◽  
Wei Li ◽  
Ana Bastos ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Carbon Uptake

scholarly journals Spatio-Temporal Variation of Drought within the Vegetation Growing Season in North Hemisphere (1982–2015)

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2146 ◽  
Author(s):  
Zhaoqi Zeng ◽  
Yamei Li ◽  
Wenxiang Wu ◽  
Yang Zhou ◽  
Xiaoyue Wang ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Gross Primary Production ◽  
Coniferous Forest ◽  
Critical Time ◽  
Growing Season ◽  
Well Being ◽  
Estimation Methods ◽  
Drought Risk ◽  
Drought Characteristics ◽  
The Impact

Drought disasters jeopardize the production of vegetation and are expected to exert impacts on human well-being in the context of global climate change. However, spatiotemporal variations in drought characteristics (including the drought duration, intensity, and frequency), specifically for vegetation areas within a growing season, remain largely unknown. Here, we first constructed a normalized difference vegetation index to estimate the length of the growing season for each pixel (8 km) by four widely used phenology estimation methods; second, we analyzed the temporal and spatial patterns of climate factors and drought characteristics (in terms of the Standardized Precipitation Evapotranspiration Index (SPEI)), within a growing season over vegetation areas of the northern hemisphere before and after the critical time point of 1998, which was marked by the onset of a global warming hiatus. Finally, we extracted the highly drought-vulnerable areas of vegetation by examining the sensitivity of the gross primary production to the SPEI to explore the underlying effects of drought variation on vegetation. The results revealed, first, that significant (p < 0.05) increases in precipitation, temperature, and the SPEI (a wetting trend) occurred from 1982 to 2015. The growing season temperature increased even more statistically significant after 1998 than before. Second, the duration and frequency of droughts changed abruptly and decreased considerably from 1998 to 2015; and this wetting trend was located mainly in high-latitude areas. Third, at the biome level, the wetting areas occurred mainly in the tundra, boreal forest or taiga, and temperate coniferous forest biomes, whereas the highly drought-vulnerable areas were mainly located in the desert and xeric shrubland (43.5%) biomes. Our results highlight the fact that although the drought events within a growing season decreased significantly in the northern hemisphere from 1998 to 2015, the very existence of a mismatch between a reduction in drought areas and an increase in highly drought-vulnerable areas makes the impact of drought on vegetation nonnegligible. This work provides valuable information for designing coping measures to reduce the vegetative drought risk in the Northern Hemisphere.

The relative importance of environmental factors on the interannual variability of carbon fluxes in the boreal forest

2020 ◽  
Author(s):  
Mariam El-Amine ◽  
Alexandre Roy ◽  
Pierre Legendre ◽  
Oliver Sonnentag
Keyword(s):  
Environmental Factors ◽  
Boreal Forest ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Carbon Sink ◽  
Growing Season ◽  
Carbon Uptake ◽  
Net Ecosystem Productivity ◽  
Ecosystem Productivity ◽  
Environmental Controls

&lt;p&gt;As climate change will cause a more pronounced rise of air temperature in northern high latitudes than in other parts of the world, it is expected that the strength of the boreal forest carbon sink will be altered. To better understand and quantify these changes, we studied the influence of different environmental controls (e.g., air and soil temperatures, soil water content, photosynthetically active radiation, normalized difference vegetation index) on the timing of the start and end of the boreal forest growing season and the net carbon uptake period in Canada. The influence of these factors on the growing season carbon exchanges between the atmosphere and the boreal forest were also evaluated. There is a need to improve the understanding of the role of the length of the growing season and the net carbon uptake period on the strength of the boreal forest carbon sink, as an extension of these periods might not necessarily result in a stronger carbon sink if other environmental factors are not optimal for carbon sequestration or enhance respiration.&lt;/p&gt;&lt;p&gt;Here, we used 31 site-years of observation over three Canadian boreal forest stands: Eastern, Northern and Southern Old Black Spruce in Qu&amp;#233;bec, Manitoba and Saskatchewan, respectively. Redundancy analyses were used to highlight the environmental controls that correlate the most with the annual net ecosystem productivity and the start and end of the growing season and the net carbon uptake period. Preliminary results show that the timing at which the air temperature becomes positive correlates the most strongly with the start of the net carbon uptake period (r = 0.70, p &lt; 0.001) and the start of the growing season (r = 0.55, p &lt; 0.01). Although the increase of the normalized difference vegetation index also correlates with the start of these periods, a thorough examination of this result shows that the latter happens well before the former. No dependency between any environmental control and the end of the net carbon uptake period was identified. Also, the annual net ecosystem productivity is highly correlated with the length of the net carbon uptake period (r = 0.54, p &lt; 0.01). Other environmental controls such as annual precipitations, the mean annual soil temperature or the maximum yearly normalized difference vegetation index have a smaller impact on the annual net ecosystem productivity. By extending the dataset to include forest stands that represent a wider climate and permafrost variability, we will examine the generalizability of these results.&lt;/p&gt;

scholarly journals The imprint of surface fluxes and transport on variations in total column carbon dioxide

2011 ◽  
Vol 8 (4) ◽  
pp. 7475-7524 ◽  
Author(s):  
G. Keppel-Aleks ◽  
P. O. Wennberg ◽  
R. A. Washenfelder ◽  
D. Wunch ◽  
T. Schneider ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Large Scale ◽  
Carbon Sink ◽  
Potential Temperature ◽  
Surface Flux ◽  
Growing Season ◽  
Temporal Variations ◽  
Surface Fluxes ◽  
Synoptic Scale ◽  
Meridional Gradient

Abstract. New observations of the vertically integrated CO2 mixing ratio, ⟨CO2⟩, from ground-based remote sensing show that variations in ⟨CO2⟩ are primarily determined by large-scale flux patterns. They therefore provide fundamentally different information than observations made within the boundary layer, which reflect the combined influence of large scale and local fluxes. Observations of both ⟨CO2⟩ and CO2 concentrations in the free troposphere show that large-scale spatial gradients induce synoptic-scale temporal variations in ⟨CO2⟩ in the Northern Hemisphere midlatitudes through horizontal advection. Rather than obscure the signature of surface fluxes on atmospheric CO2, these synoptic-scale variations provide useful information that can be used to reveal the meridional flux distribution. We estimate the meridional gradient in ⟨CO2⟩ from covariations in ⟨CO2⟩ and potential temperature, θ, a dynamical tracer, on synoptic timescales to evaluate surface flux estimates commonly used in carbon cycle models. We find that Carnegie Ames Stanford Approach (CASA) biospheric fluxes underestimate both the ⟨CO2⟩ seasonal cycle amplitude throughout the Northern Hemisphere midlatitudes as well as the meridional gradient during the growing season. Simulations using CASA net ecosystem exchange (NEE) with increased and phase-shifted boreal fluxes better reflect the observations. Our simulations suggest that boreal growing season NEE (between 45–65° N) is underestimated by ~40 % in CASA. We describe the implications for this large seasonal exchange on inference of the net Northern Hemisphere terrestrial carbon sink.

scholarly journals Competing effects of nitrogen deposition and ozone exposure on Northern hemispheric terrestrial carbon uptake and storage, 1850–2099

2020 ◽  
Author(s):  
Martina Franz ◽  
Sönke Zaehle
Keyword(s):  
Air Pollution ◽  
East Asia ◽  
Nitrogen Deposition ◽  
Carbon Storage ◽  
Northern Hemisphere ◽  
21St Century ◽  
Ozone Exposure ◽  
Carbon Uptake ◽  
Northern Hemispheric ◽  
And Storage

Abstract. Tropospheric ozone and nitrogen deposition affect vegetation growth and thus the ability of the land biosphere to store carbon. However, the magnitude of this effect on the contemporary and future terrestrial carbon balance is insufficiently understood. Here, we apply an extended version of the O-CN terrestrial biosphere model that simulates the atmosphere to canopy transport of O3, its surface and stomatal uptake, as well as the ozone-induced leaf injury. We use this model to simulate past and future impacts of air pollution (ozone and nitrogen deposition) against a background of concurrent changes in climate and carbon dioxide concentrations (CO2) for two contrasting representative concentration pathways (RCP) scenarios (RCP2.6 and RCP8.5). The simulations show that O3-related damage considerably reduced Northern hemispheric gross primary production (GPP) and long-term carbon storage between 1850 and the 2010s. The ozone effect on GPP in the Northern hemisphere peaks at the end of the 20th century with reductions of 4 %, causing a reduction in the Northern hemispheric carbon sink of 0.4 Pg C yr−1. During the 21st century, ozone-induced reductions in GPP and carbon storage is projected to decline through a combination of air pollution control methods that reduce tropospheric O3 and the indirect effects of rising atmospheric CO2, which reduces stomatal uptake of ozone concurrent with increases of leaf-level water-use efficiency. However, in hotspot regions such as East Asia, the model simulations suggest a sustained decrease of GPP by more than 8 % during the 21st century. Regionally, ozone exposure reduces carbon storage at the end of the 21st century by up to 15 % in parts of Europe, the US and East Asia. These estimates are lower compared to previous studies, which partially results from the explicit representation of non-stomatal ozone destruction, which considerably reduces simulated ozone uptake by leaves and incurred injury. Our simulations suggest that ozone damage largely offsets the growth stimulating effect induced by nitrogen deposition in the Northern hemisphere until the 2050s. Thus, accounting for the stimulating effects of nitrogen deposition but omitting the detrimental effect of O3 might lead to an over estimation of carbon uptake and storage.

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