Transient climate response to increasing atmospheric carbon dioxide

The ocean's role in the delayed response of climate to increasing atmospheric carbon dioxide has been studied by means of a detailed three-dimensional climate model. A near-equilibrium state is perturbed by a fourfold, stepfunction increase in atmospheric carbon dioxide. The rise in the sea surface temperature was initially much more rapid in the tropics than at high latitudes. However, the fractional response, as normalized on the basis of the total difference between the high carbon dioxide and normal carbon dioxide climates, becomes almost uniform at all latitudes after 25 years. Because of the influence of a more rapid response over continents, the normalized response of the zonally averaged surface air temperature is faster and becomes nearly uniform with respect to latitude after only 10 years.     

Atmospheric carbon dioxide and aerosols: effects of large increases on global climate

Effects on the global temperature of large increases in carbon dioxide and aerosol densities in the atmosphere of Earth have been computed. It is found that, although the addition of carbon dioxide in the atmosphere does increase the surface temperature, the rate of temperature increase diminishes with increasing carbon dioxide in the atmosphere. For aerosols, however, the net effect of increase in density is to reduce the surface temperature of Earth. Because of the exponential dependence of the backscattering, the rate of temperature decrease is augmented with increasing aerosol content. An increase by only a factor of 4 in global aerosol background concentration may be sufficient to reduce the surface temperature by as much as 3.5 degrees K. If sustained over a period of several years, such a temperature decrease over the whole globe is believed to be sufficient to trigger an ice age.     

秸秆生物反应堆技术在北方保护地生产中应用

论述了北方保护地蔬菜冬春茬栽培中应用秸秆生物反应堆技术,可提高地温3.0～7.0℃,提高棚内温度1.5～2.5℃,同时秸秆在分解时产生的二氧化碳,可增加温室内二氧化碳的浓度。使番茄提早上市7-15d,提高番茄产量18%,生产出的番茄果个头均匀、色泽艳丽、果实硬度好、品质佳。摄氏度     

The Climatological Significance of a Doubling of Earth's Atmospheric Carbon Dioxide Concentration

The mean global increase in thermal radiation received at the surface of the earth as a consequence of a doubling of the atmospheric carbon dioxide content is calculated to be 2.28 watts per square meter. Multiplying this forcing function by the atmosphere's surface air temperature response function, which has recently been determined by three independent experimental analyses to have a mean global value of 0.113 K per watt per square meter, yields a value of 相似文献   

Carbon dioxide partial pressure in the columbia river

Columbia River water is supersaturated with respect to atmospheric carbon dioxide by 200 to 870 parts per million. An equilibrium exists between the carbon dioxide partial pressure and pH, and Henry's law is obeyed in this natural water. The carbon dioxide pressure can be calculated by a determination of the pH, total carbon dioxide, and temperature.     

Mid-depth circulation of the subpolar north atlantic during the last glacial maximum

Holocene and glacial carbon isotope data of benthic foraminifera from shallow to mid-depth cores from the northeastern subpolar Atlantic show that this region was strongly stratified, with carbon-13-enriched glacial North Atlantic intermediate water (GNAIW) overlying carbon-13-depleted Southern Ocean water (SOW). The data suggest that GNAIW originated north of the polar front and define GNAIW end-member carbon isotope values for studies of water-mass mixing in the open Atlantic. Identical carbon isotope values in the core of GNAIW and below the subtropical thermocline are consistent with rapid cycling of GNAIW through the northern Atlantic. The high carbon isotope values below the thermocline indicate that enhanced nutrient leakage in response to increased ventilation may have extended into intermediate waters. Geochemical box models show that the atmospheric carbon dioxide response to nutrient leakage that results from an increase in ventilation rate may be greater than the response to nutrient redistribution by conversion of North Atlantic deep water into GNAIW. These results underscore the potential rule of Atlantic Ocean circulation changes in influencing past atmospheric carbon dioxide values.     

碳钢二氧化碳腐蚀研究现状

二氧化碳腐蚀是油气中的二氧化碳（ＣＯ２）溶解于水后生成碳酸后引起的腐蚀。综述了在二氧化碳环境中,碳钢金属表面有产物膜和无产物膜存在的情况下腐蚀机理。分析了温度、二氧化碳分压、流速、ｐＨ值及腐蚀产物膜对二氧化碳腐蚀的影响。认为碳钢的二氧化碳腐蚀机理因金属是否形成碳酸铁（ＦｅＣＯ３）膜而不同,二氧化碳分压和洗速影响着腐蚀的阴极过程,而温度主要是影响腐蚀产物膜的形成条件。在局部腐蚀领域内开展基础性和应用     

Reduction in summer soil wetness induced by an increase in atmospheric carbon dioxide

The geographical distribution of the change in soil wetness in response to an increase in atmospheric carbon dioxide was investigated by using a mathematical model of climate. Responding to the increase in carbon dioxide, soil moisture in the model would be reduced in summer over extensive regions of the middle and high latitudes, such as the North American Great Plains, western Europe, northern Canada, and Siberia. These results were obtained from the model with predicted cloud cover and are qualitatively similar to the results from several numerical experiments conducted earlier with prescribed cloud cover.     

不同浓度二氧化碳杀虫效果比较

通过在不同条件下 (包括处理时间、CO2 浓度、粮食水分、粮食温度 )对于米象和赤拟谷盗的成虫进行CO2 气体处理的实验 ,结果表明CO2 能起到好的杀虫效果。玉米象对CO2 的敏感较强。 1 0 0 %浓度的CO2 对玉米象短期的杀虫效果几乎为零     

秸秆生物反应堆对温室气温和二氧化碳浓度的影响

[目的]研究秸秆生物反应堆技术的应用对茄子温室内气温和二氧化碳浓度的影响。[方法]以茄子温室为研究对象,通过栽培试验和室内测定分析方法相结合,对玉米秸秆反应堆技术应用过程中的温室内外二氧化碳浓度进行跟踪观测。[结果]秸秆生物反应堆对棚内气温有明显的提高,平均提高1.5～2.3℃,最高可以提高温室温度4℃。应用秸秆生物反应堆可以明显提高棚内二氧化碳浓度。[结论]秸秆生物反应堆技术能够明显改善温室的生态环境,解决日光温室CO2不足的矛盾,为温室蔬菜增产提供基础保证。     

花生二氧化碳充气包装贮藏技术研究

为了延长花生的贮藏期并使二氧化碳充气包装在花生贮藏中更好地推广使用,以赣花7号为供试花生品种,研究二氧化碳充气包装花生吸附结块的条件及在加速氧化贮藏期间其品质的变化情况。结果表明:花生吸附结块与花生质量呈正相关性,与气体含量呈负相关性,在常温条件下二氧化碳气体量与花生质量的最佳配比为0.11mL/g;而且二氧化碳充气处理结块组花生的贮藏品质劣变速率缓慢,其过氧化值和酸价显著低于未结块处理组和对照组,由此可见,二氧化碳充气处理结块花生更适合贮藏。     

超临界二氧化碳萃取三孢布拉霉中的番茄红素

[目的]介绍三孢布拉霉中番茄红素的萃取新工艺。[方法]采用超临界二氧化碳流体萃取技术萃取三孢布拉霉中的番茄红素,研究萃取时间、萃取温度、萃取压力及二氧化碳流量对萃取率的影响。[结果]过滤后的发酵液用95%乙醇预处理后萃取3 h时番茄红素的萃取率最高;萃取温度为45℃时番茄红素的萃取率最高,之后随温度升高番茄红素的萃取率下降;最佳萃取压力为45 MPa;最佳二氧化碳流量为20 L/h。[结论]超临界二氧化碳萃取三孢布拉霉中番茄红素的最佳工艺为：压力45 MPa,温度45℃,二氧化碳流量20L/h,此条件下番茄红素的得率可达76%。     

Stability of the martian atmosphere

A detailed chemical dynamic model is presented for a moist martian atmosphere. Recombination of carbon dioxide is catalyzed by trace amounts of water. The abundances of carbon monoxide and molecular oxygen should vary in response to changes in atmospheric water and atmospheric mixing.     

Climate impact of increasing atmospheric carbon dioxide

The global temperature rose by 0.2 degrees C between the middle 1960's and 1980, yielding a warming of 0.4 degrees C in the past century. This temperature increase is consistent with the calculated greenhouse effect due to measured increases of atmospheric carbon dioxide. Variations of volcanic aerosols and possibly solar luminosity appear to be primary causes of observed fluctuations about the mean trend of increasing temperature. It is shown that the anthropogenic carbon dioxide warming should emerge from the noise level of natural climate variability by the end of the century, and there is a high probability of warming in the 1980's. Potential effects on climate in the 21st century include the creation of drought-prone regions in North America and central Asia as part of a shifting of climatic zones, erosion of the West Antarctic ice sheet with a consequent worldwide rise in sea level, and opening of the fabled Northwest Passage.     

Variations in the isotopic composition of carbon in urban atmospheric carbon dioxide

Measurement of the abundance of atmospheric carbon dioxide as an indicator of air pollution has been of very limited value because of variations in urban areas in the substantial concentration of natural carbon dioxide produced from combustion and noncombustion (natural) sources. A solution to this problem is the use of precise isotopic assay of ratios of carbon-13 to carbon-12 in atmospheric carbon dioxide. There is very little variation of carbon isotopic composition in samples taken over rural or urban areas where rapid mixing and diffusion of gaseous combustion products is possible. Significant differences in this composition in samples taken at centrally located points at street level in the lower Manhattan business district show an increase in concentration of atmospheric carbon dioxide of roughly 20 percent produced primarily by automobile exhaust.     

Enhanced open ocean storage of CO2 from shelf sea pumping

Seasonal field observations show that the North Sea, a Northern European shelf sea, is highly efficient in pumping carbon dioxide from the atmosphere to the North Atlantic Ocean. The bottom topography-controlled stratification separates production and respiration processes in the North Sea, causing a carbon dioxide increase in the subsurface layer that is ultimately exported to the North Atlantic Ocean. Globally extrapolated, the net uptake of carbon dioxide by coastal and marginal seas is about 20% of the world ocean's uptake of anthropogenic carbon dioxide, thus enhancing substantially the open ocean carbon dioxide storage.     

Climatic change: are we on the brink of a pronounced global warming?

If man-made dust is unimportant as a major cause of climatic change, then a strong case can be made that the present cooling trend will, within a decade or so, give way to a pronounced warming induced by carbon dioxide. By analogy with similar events in the past, the natural climatic cooling which, since 1940, has more than compensated for the carbon dioxide effect, will soon bottom out. Once this happens, the exponential rise in the atmospheric carbon dioxide content will tend to become a significant factor and by early in the next century will have driven the mean planetary temperature beyond the limits experienced during the last 1000 years.     

The 100,000-year ice-Age cycle identified and found to lag temperature, carbon dioxide, and orbital eccentricity

The deep-sea sediment oxygen isotopic composition (delta(18)O) record is dominated by a 100,000-year cyclicity that is universally interpreted as the main ice-age rhythm. Here, the ice volume component of this delta(18)O signal was extracted by using the record of delta(18)O in atmospheric oxygen trapped in Antarctic ice at Vostok, precisely orbitally tuned. The benthic marine delta(18)O record is heavily contaminated by the effect of deep-water temperature variability, but by using the Vostok record, the delta(18)O signals of ice volume, deep-water temperature, and additional processes affecting air delta(18)O (that is, a varying Dole effect) were separated. At the 100,000-year period, atmospheric carbon dioxide, Vostok air temperature, and deep-water temperature are in phase with orbital eccentricity, whereas ice volume lags these three variables. Hence, the 100,000-year cycle does not arise from ice sheet dynamics; instead, it is probably the response of the global carbon cycle that generates the eccentricity signal by causing changes in atmospheric carbon dioxide concentration.     

响应面法优化超临界CO2萃取当归挥发油工艺及抑菌活性研究

[目的]采用响应面法对超临界CO2萃取当归油的工艺进行优化,同时对当归挥发油的抑制活性进行研究。[方法]在单因素试验基础上,采用Box-Behnken试验设计,考察萃取压力、萃取温度和萃取时间对挥发油提取率的影响,并采用纸片扩散法对提取的挥发油对的抑菌效果进行考察。[结果]当归挥发油的最优提取工艺为:萃取温度44.4℃、萃取压力32.37 MPa、萃取时间1.48 h;在此条件下,萃取率可达2.083 3%。当归挥发油对部分常见的细菌和真菌具有较好的抑菌活性,MIC值在1.25～5.00 mg/ml范围内。[结论]超临界CO2萃取当归油工艺稳定,提取率较高;当归油具有明显的抑菌活性,将为当归挥发油在抑菌制剂中的应用提供一定的理论依据。     

响应面法优化南瓜籽芽蛋白粉的碱法制备工艺

为有效利用蛋白质资源,研究将经过发芽处理的南瓜籽利用超临界CO2脱脂后,采用碱溶酸沉法提取蛋白质。采用响应面分析法,研究提取温度、液料比、提取时间、提取液pH对蛋白纯度的影响,以优化碱溶酸沉法制备南瓜籽芽蛋白粉的工艺条件。实验结果表明：制备南瓜籽芽分离蛋白的最佳条件为液料比40∶1、提取温度43℃、提取时间2 h、pH 10.6。该条件下预测蛋白纯度达到96.64%,实际测得蛋白纯度为94.79%。