scholarly journals The Global Spatiotemporal Distribution of the Mid-Tropospheric CO2 Concentration and Analysis of the Controlling Factors

2019 ◽  
Vol 11 (1) ◽  
pp. 94 ◽  
Author(s):  
Liangzhong Cao ◽  
Xi Chen ◽  
Chi Zhang ◽  
Alishir Kurban ◽  
Jin Qian ◽  
...  
Keyword(s):  
Average Rate ◽  
Co2 Concentration ◽  
Controlling Factors ◽  
Empirical Orthogonal Functions ◽  
Spatiotemporal Distribution ◽  
Orthogonal Functions ◽  
High Co2 ◽  
Co2 Concentrations ◽  
Observation Network ◽  
Rate Of Increase

The atmospheric infrared sounder (AIRS) provides a robust and accurate data source to investigate the variability of mid-tropospheric CO2 globally. In this paper, we use the AIRS CO2 product and other auxiliary data to survey the spatiotemporal distribution characteristics of mid-tropospheric CO2 and the controlling factors using linear regression, empirical orthogonal functions (EOFs), geostatistical analysis, and correlation analysis. The results show that areas with low mid-tropospheric CO2 concentrations (20°S–5°N) (384.2 ppm) are formed as a result of subsidence in the atmosphere, the presence of the Amazon rainforest, and the lack of high CO2 emission areas. The areas with high mid-tropospheric CO2 concentrations (30°N–70°N) (382.1 ppm) are formed due to high CO2 emissions. The global mid-tropospheric CO2 concentrations increased gradually (the annual average rate of increase in CO2 concentration is 2.11 ppm/a), with the highest concentration occurring in spring (384.0 ppm) and the lowest value in winter (382.5 ppm). The amplitude of the seasonal variation retrieved from AIRS (average: 1.38 ppm) is consistent with that of comprehensive observation network for trace gases (CONTRAIL), but smaller than the surface ground stations, which is related to altitude and coverage. These results contribute to a comprehensive understanding of the spatiotemporal distribution of mid-tropospheric CO2 and related mechanisms.

Stomatal Limitation of Photosynthesis in Abscisic Acid-Treated and in Water-Stressed Leaves Measured at Elevated CO2

1988 ◽  
Vol 15 (4) ◽  
pp. 495 ◽  
Author(s):  
SP Robinson ◽  
WJR Grant ◽  
BR Loveys
Keyword(s):  
Abscisic Acid ◽  
Stomatal Conductance ◽  
Quantum Yield ◽  
Oxygen Evolution ◽  
Stomatal Closure ◽  
Co2 Concentration ◽  
Assimilation Rate ◽  
High Co2 ◽  
Co2 Concentrations ◽  
Ambient Co2

Feeding 10-5M (�)-abscisic acid (ABA) via the petioles of detached leaves of apricot (Prunus armeniaca) or sunflower (Helianthus annuus) decreased stomatal conductance and assimilation rate but not the calculated intercellular CO2 concentration (Ci) suggesting non-stomatal as well as stomatal inhibition of photosynthesis. Evidence for non-stomatal inhibition was not observed in spinach (Spinacia oleracea). There was no significant decrease in rates of electron transport nor ribulosebisphosphate carboxylase (Rubisco) activity in intact chloroplasts isolated from ABA-treated sunflower leaves. Oxygen evolution by leaf discs with 3% CO2 in the gas phase was inhibited in ABA- treated sunflower and apricot leaves but not in spinach; the inhibition was only half as great as the inhibition of assimilation rate at ambient CO2. The quantum yield of oxygen evolution decreased in ABA-treated sunflower leaves in proportion to the decrease in the light-saturated rate. There was no significant difference in room temperature chlorophyll fluorescence of ABA-treated leaves compared to controls. Stomatal conductance of sunflower leaves decreased by more than 90% when the CO2 concentration was increased from 340 ppm to 1000 ppm but at much higher CO2 concentrations the stomata appeared to reopen. Stomatal conductance at 2-3% CO2 (20 000-30 000 ppm) was 50% that at ambient CO2. This reopening of stomata at high CO2 was inhibited in previously water-stressed or ABA-treated plants. In unstressed leaves, the maximum rate of oxygen evolution occurred at 0.5-2% CO2 but in ABA-treated leaves 10-15% CO2 was required for maximum rates. It is suggested that stomatal closure may limit photosynthesis in ABA-treated or previously water-stressed leaves even at the relatively high CO2 concentrations normally used in the leaf disc oxygen electrode. The inhibition of photosynthesis by ABA is largely overcome at saturating CO2. The apparent non-stomatal inhibition suggested by gas exchange measurements and the decreased quantum yield could be explained by patchy stomatal closure in response to ABA.

scholarly journals Evidence of Adaptation to Recent Changes in Atmospheric CO2 in Four Weedy Species

2018 ◽  
Author(s):  
James Bunce
Keyword(s):  
Co2 Concentration ◽  
Dry Mass ◽  
Atmospheric Co2 ◽  
Agricultural Fields ◽  
Down Regulation ◽  
High Co2 ◽  
Co2 Concentrations ◽  
C3 Species ◽  
Weedy Species ◽  
Atmospheric Co2 Concentrations

Seeds of three C3 and one C4 annual weedy species were collected from agricultural fields in Beltsville, Maryland in 1966 and 2006, when atmospheric CO2 concentrations averaged about 320 and 380 mmol mol-1, respectively.  Plants from each collection year were grown over a range of CO2 concentrations to test for adaptation of these weedy species to recent changes in atmospheric CO2.  In all three of the C3 species, the increase in CO2 concentration from 320 to 380 mmol mol-1 increased total dry mass at 24 days in plants from seeds collected in 2006, but not in plants from seeds collected in 1966.  Shoot and seed dry mass at maturity was greater at the higher growth CO2 in plants collected in 2006 than in 1966 in two of the species.  Down regulation of photosynthetic carboxylation capacity during growth at high CO2 was less in the newer seed lots than in the older in two of the species.  Overall, the results indicate that adaptation to recent changes in atmospheric CO2 has occurred in some of these weedy species.

Empirical Methods in Short-Term Climate Prediction

2006 ◽  
Author(s):  
Huug van den Dool
Keyword(s):  
Climate Prediction ◽  
Empirical Orthogonal Functions ◽  
Data Sets ◽  
Seasonal Forecasts ◽  
Short Term ◽  
Orthogonal Functions ◽  
Ocean Atmosphere Interaction ◽  
Global Coverage ◽  
Atmosphere Interaction ◽  
Global Data

This clear and accessible text describes the methods underlying short-term climate prediction at time scales of 2 weeks to a year. Although a difficult range to forecast accurately, there have been several important advances in the last ten years, most notably in understanding ocean-atmosphere interaction (El Nino for example), the release of global coverage data sets, and in prediction methods themselves. With an emphasis on the empirical approach, the text covers in detail empirical wave propagation, teleconnections, empirical orthogonal functions, and constructed analogue. It also provides a detailed description of nearly all methods used operationally in long-lead seasonal forecasts, with new examples and illustrations. The challenges of making a real time forecast are discussed, including protocol, format, and perceptions about users. Based where possible on global data sets, illustrations are not limited to the Northern Hemisphere, but include several examples from the Southern Hemisphere.

Experimental and kinetic study of NO-reburning by syngas under high CO2 concentration in a jet stirred reactor

Fuel ◽  
2021 ◽  
Vol 304 ◽  
pp. 121403
Author(s):  
Fan Hu ◽  
Pengfei Li ◽  
Wenhao Li ◽  
Cuijiao Ding ◽  
Junjun Guo ◽  
...  
Keyword(s):  
Kinetic Study ◽  
Co2 Concentration ◽  
High Co2 ◽  
Stirred Reactor ◽  
High Co2 Concentration

scholarly journals Effects of Climatic Conditions, Season and Environmental Factors on CO2 Concentrations in Naturally Ventilated Primary Schools in Chile

2021 ◽  
Vol 13 (8) ◽  
pp. 4139
Author(s):  
Muriel Diaz ◽  
Mario Cools ◽  
Maureen Trebilcock ◽  
Beatriz Piderit-Moreno ◽  
Shady Attia
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Primary Schools ◽  
Co2 Concentration ◽  
Building Design ◽  
Climatic Conditions ◽  
Indoor Environmental Quality ◽  
Co2 Concentrations ◽  
The Impact

Between the ages of 6 and 18, children spend between 30 and 42 h a week at school, mostly indoors, where indoor environmental quality is usually deficient and does not favor learning. The difficulty of delivering indoor air quality (IAQ) in learning facilities is related to high occupancy rates and low interaction levels with windows. In non-industrialized countries, as in the cases presented, most classrooms have no mechanical ventilation, due to energy poverty and lack of normative requirements. This fact heavily impacts the indoor air quality and students’ learning outcomes. The aim of the paper is to identify the factors that determine acceptable CO2 concentrations. Therefore, it studies air quality in free-running and naturally ventilated primary schools in Chile, aiming to identify the impact of contextual, occupant, and building design factors, using CO2 concentration as a proxy for IAQ. The monitoring of CO2, temperature, and humidity revealed that indoor air CO2 concentration is above 1400 ppm most of the time, with peaks of 5000 ppm during the day, especially in winter. The statistical analysis indicates that CO2 is dependent on climate, seasonality, and indoor temperature, while it is independent of outside temperature in heated classrooms. The odds of having acceptable concentrations of CO2 are bigger when indoor temperatures are high, and there is a need to ventilate for cooling.

scholarly journals Spatio-Temporal Patterns of Mass Changes in Himalayan Glaciated Region from EOF Analyses of GRACE Data

2021 ◽  
Vol 13 (2) ◽  
pp. 265
Author(s):  
Harika Munagapati ◽  
Virendra M. Tiwari
Keyword(s):  
Temperature Anomaly ◽  
Mass Gain ◽  
Snow Accumulation ◽  
Empirical Orthogonal Functions ◽  
Total Water ◽  
Orthogonal Functions ◽  
Grace Data ◽  
Grace Satellite ◽  
Spatio Temporal ◽  
Gravity Recovery

The nature of hydrological seasonality over the Himalayan Glaciated Region (HGR) is complex due to varied precipitation patterns. The present study attempts to exemplify the spatio-temporal variation of hydrological mass over the HGR using time-variable gravity from the Gravity Recovery and Climate Experiment (GRACE) satellite for the period of 2002–2016 on seasonal and interannual timescales. The mass signal derived from GRACE data is decomposed using empirical orthogonal functions (EOFs), allowing us to identify the three broad divisions of HGR, i.e., western, central, and eastern, based on the seasonal mass gain or loss that corresponds to prevailing climatic changes. Further, causative relationships between climatic variables and the EOF decomposed signals are explored using the Granger causality algorithm. It appears that a causal relationship exists between total precipitation and total water storage from GRACE. EOF modes also indicate certain regional anomalies such as the Karakoram mass gain, which represents ongoing snow accumulation. Our causality result suggests that the excessive snowfall in 2005–2008 has initiated this mass gain. However, as our results indicate, despite the dampening of snowfall rates after 2008, mass has been steadily increasing in the Karakorum, which is attributed to the flattening of the temperature anomaly curve and subsequent lower melting after 2008.

Overview of Axial Compression Technology for Direct Capture of CO2

2013 ◽  
Vol 744 ◽  
pp. 392-395 ◽  
Author(s):  
Hao Xian Malcolm Chan ◽  
Eng Hwa Yap ◽  
Jee Hou Ho
Keyword(s):  
Axial Compression ◽  
Carbon Capture ◽  
Carbon Capture And Storage ◽  
Co2 Concentration ◽  
Point Sources ◽  
Direct Capture ◽  
Rate Of Increase ◽  
Air Capture ◽  
Key Issues ◽  
And Storage

Carbon Capture and Storage (CCS) is one of the global leading methods that could potentially retard the speed of climate change. However, CCS on point sources can only slowdown the rate of increase of atmospheric CO2 concentration. In order to mitigate CO2 released by previous emissions, a more proactive alternative is proposed where CO2 is directly extracted and captured from air Direct Air Capture (DAC). This paper presents a technical overview from our current research of a novel DAC concept which features a phase of axial compression to adapt pre-capture atmospheric air to a level suitable for carbon capture. Also detailed in the paper is the feasibility study addressing several key issues: the energy consumption and overall capturing efficiency of the proposed DAC system.

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