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1.
A global mean ocean model including atmospheric heating, heat capacity of the mixed layer ocean, and vertical thermal diffusivity in the lower ocean, proposed by Cess and Goldenberg (1981), is used in this paper to study the sen-sitivity of global warming to the vertical diffusivity. The results suggest that the behaviour of upper ocean tempera-ture is mainly determined by the magnitude of upper layer diffusivity and an ocean with a larger diffusivity leads to a less increase of sea surface temperature and a longer time delay for the global warming induced by increasing CO2 than that with smaller one. The global warming relative to four scenarios of CO2 emission assumed by Intergovernmental Panel of Climate Change (IPCC) is also estimated by using the model with two kinds of thermal diffusivities. The result shows that for various combinations of the CO2 emission scenarios and the diffusivities, the oceanic time delay to the global warming varies from 15 years to 70 years. 相似文献
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印度洋二维碳循环模式中表层CO2分压分布对物理和生化过程的敏感性试验 总被引：1，自引：0，他引：1
利用二维印度洋碳循环模式的模拟结果,集中对表层海洋中的CO2分压分布及其控制因子、海洋生物对海气CO2交换的影响、海洋营养物含量的改变和海洋环流的改变对大气CO2浓度的影响等进行了深入的分析和讨论,并与实际的GEOSECS观测数据的分析结果做比较;研究了与表层海洋CO2分压相关的海洋条件,较详细讨论了形成海洋表层CO2源与汇系统的决定因素及其相对重要性,得到了海洋热力因子和海洋环流对海洋表层的CO2化学过程起着决定性作用而生物过程仅处于次要地位的重要结论。此外,还利用建立的海洋碳模式进行了一些有意义的数值试验,详细讨论了海洋的物理化学因子改变对大气CO2浓度的可能影响。
相似文献
4.
把建好的海洋碳模式应用于印度洋区域，模拟得到了印度洋中与碳有关各化学量的表层分布、垂直分布和沿子午线面的等值线分布。与实测的GEOSECS(Geochemical Ocean－Section Study)数据作对比，模式较好地再现了印度洋上营养盐浓度、总碳浓度、总碱度和溶解氧的二维分布。通过模拟还发现，在稳定状态下，大气和海洋中总碳含量的分布依赖于发生在海洋中的各种物理化学过程及边界条件，水平扩散系数Kh和光合作用常数率Kg对各化学量的分布有较大影响(以前有学者认为不太重要，如Baes[1])；南印度洋中纬地区10°S至30°S是14C的重要向下渗透区域，人为排放的CO2可通过这片渗透区从海洋的表层输入海洋的深层。 相似文献
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海洋对人为CO2吸收的三维模式研究 总被引：4，自引：0，他引：4
文中用包含海洋化学过程和一个简单生物过程的三维碳循环模式模拟了海洋对大气CO2 的吸收 ,并分析了碳吸收的纬度分布。模拟工业革命以来海洋对大气 CO2 的吸收表明 :海洋碳吸收再加上大气 CO2 的增加只占由化石燃料燃烧、森林砍伐和土地利用的变化而释放到大气中的 CO2 的 2 /3。1 980～ 1 989年期间海洋年平均吸收 2 .0 5Gt C。海洋人为 CO2 的吸收有明显的纬度特征。模式计算的海洋 CO2 的吸收在总量与纬度分布上与观测结果比较相符。 相似文献
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Ocean-circulation model of the carbon cycle 总被引：8，自引：0，他引：8
A three-dimensional model of the natural carbon cycle in the oceans is described. The model is an extension of the inorganic ocean-circulation carbon cycle model of Maier-Reimer and Hasselmann (1987) to include the effect of the ocean biota. It is based on a dynamic, general circulation model of the world oceans. Chemical species important to the carbon cycle are advected by the current field of the general circulation model. Mixing occurs through numerical diffusivity (related to finite box size), a small explicit horizontal diffusivity, and a convective adjustment. An atmospheric box exchanges CO2 with the surface ocean. There is no land biota provided in the present version of the model. The effect of the ocean biota on ocean chemistry is represented in a simple way and model distributions of chemical species are compared with distributions observed during the GEOSECS and other expeditions.
Offprint requests to: R Bacastow 相似文献
7.
利用一个全球海洋动力学环流模式所模拟的海洋环流场,建立了一个全面的二维海洋碳循环模式。此模式摒弃了传统箱模式的缺陷,充分考虑了诸如大气与海洋间的碳交换、光合作用和氧化分解、碳酸钙的产生和溶解、悬浮颗粒物的下沉等过程,尤其是在模式中耦合进了以往甚少考虑的海洋生物过程对碳循环的影响,引入了详尽合理的参数化方案。通过模拟发现：在稳定状态下,大气和海洋中总碳含量分布依赖于发生在海洋中的各种物理化学过程及边界条件,水平扩散系数和光合作用常数率对各化学量的分布有很大影响。 相似文献
8.
CHEN Zhao-Hui 《大气和海洋科学快报》2011,4(2):70-74
The seasonal cycle of atmospheric CO2 at surface observation stations in the northern hemisphere is driven primarily by net ecosystem production (NEP) fluxes from terrestrial ecosystems. In addition to NEP from terrestrial ecosystems, surface fluxes from fossil fuel combustion and ocean exchange also contribute to the seasonal cycle of atmospheric CO2. Here the authors use the Goddard Earth Observing System-Chemistry (GEOS-Chem) model (version 8-02-01), with modifications, to assess the impact of these fluxes on the seasonal cycle of atmospheric CO2 in 2005. Modifications include monthly fossil and ocean emission inventories. CO2 simulations with monthly varying and annual emission inventories were carried out separately. The sources and sinks of monthly averaged net surface flux are different from those of annual emission inventories for every month. Results indicate that changes in monthly averaged net surface flux have a greater impact on the average concentration of atmospheric CO2 in the northern hemisphere than on the average concentration for latitudes 30-90°S in July. The concentration values differ little between both emission inventories over the latitudinal range from the equator to 30°S in January and July. The accumulated impacts of the monthly averaged fossil and ocean emissions contribute to an increase of the total global monthly average of CO2 from May to December.An apparent discrepancy for global average CO2 concentration between model results and observation was because the observation stations were not sufficiently representative. More accurate values for monthly varying net surface flux will be necessary in future to run the CO2 simulation. 相似文献
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本文用一个全球碳循环的一维模式重建了1860年以来的大气二氧化碳浓度。结果表明:(1) 模拟结果与冒纳罗亚（Mauna Loa）的观测结果之间存在极好的一致性；(2) 海洋虽然是人类活动释放的CO2的最重要的汇，但其作为碳汇的能力受到海洋缓冲效应的限制。海洋吸收CO2的速率还与某些响应过程密切相关；(3) 在全球碳循环中，生态系统的作用是双重的:人类活动对它的破坏使它成为CO2的源，而其对过量CO2的响应又使其成为CO2的一个汇。工业革命以来，人类对生态系统的破坏与其自身的恢复大致是同量级的；(4) 陆地生物圈缩短了整个碳循环系统对人为扰动的响应时间。 相似文献
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海洋中碳及营养物自然分布的数值模拟 总被引：1，自引：1，他引：0
用海洋生物化学环流模式（Ｂ－ ＧＣＭ） 模拟了工业化前碳及营养物在海洋中的分布, 并得到了较为合理的结果。模式考虑了海洋表面化学和一个简单的生物过程。模式的主要预报变量有总ＣＯ２ 、碱度和磷酸盐。决定生物化学物质分布的三个参数的取值为： ＰＯＣ 通量的垂直廓线的指数ａ 取观测值０－８５８ 、生物生产效率ｒ ＝ ２／ 年和下落比Ｒ＝ ０－０６ 。用Ｂ－ＧＣＭ 模拟出的结果与ＧＥＯＳＥＣＳ观测值基本相符。 相似文献
11.
Changes in Earth's temperature have significant impacts on the global carbon cycle that vary at different time scales, yet to quantify such impacts with a simple scheme is traditionally deemed difficult. Here, we show that, by incorporating a temperature sensitivity parameter(1.64 ppm yr~(-1) ?C~(-1)) into a simple linear carbon-cycle model, we can accurately characterize the dynamic responses of atmospheric carbon dioxide(CO_2) concentration to anthropogenic carbon emissions and global temperature changes between 1850 and 2010(r~2 0.96 and the root-mean-square error 1 ppm for the period from 1960onward). Analytical analysis also indicates that the multiplication of the parameter with the response time of the atmospheric carbon reservoir(～12 year) approximates the long-term temperature sensitivity of global atmospheric CO_2concentration(～15 ppm?C~(-1)), generally consistent with previous estimates based on reconstructed CO_2 and climate records over the Little Ice Age. Our results suggest that recent increases in global surface temperatures, which accelerate the release of carbon from the surface reservoirs into the atmosphere, have partially offset surface carbon uptakes enhanced by the elevated atmospheric CO_2 concentration and slowed the net rate of atmospheric CO_2 sequestration by global land and oceans by ～30%since the 1960 s. The linear modeling framework outlined in this paper thus provides a useful tool to diagnose the observed atmospheric CO_2 dynamics and monitor their future changes. 相似文献
12.
Global and regional ocean carbon uptake and climate change: sensitivity to a substantial mitigation scenario 总被引：1，自引：0，他引：1
Marcello Vichi Elisa Manzini Pier Giuseppe Fogli Andrea Alessandri Lavinia Patara Enrico Scoccimarro Simona Masina Antonio Navarra 《Climate Dynamics》2011,37(9-10):1929-1947
Under future scenarios of business-as-usual emissions, the ocean storage of anthropogenic carbon is anticipated to decrease because of ocean chemistry constraints and positive feedbacks in the carbon-climate dynamics, whereas it is still unknown how the oceanic carbon cycle will respond to more substantial mitigation scenarios. To evaluate the natural system response to prescribed atmospheric ??target?? concentrations and assess the response of the ocean carbon pool to these values, 2 centennial projection simulations have been performed with an Earth System Model that includes a fully coupled carbon cycle, forced in one case with a mitigation scenario and the other with the SRES A1B scenario. End of century ocean uptake with the mitigation scenario is projected to return to the same magnitude of carbon fluxes as simulated in 1960 in the Pacific Ocean and to lower values in the Atlantic. With A1B, the major ocean basins are instead projected to decrease the capacity for carbon uptake globally as found with simpler carbon cycle models, while at the regional level the response is contrasting. The model indicates that the equatorial Pacific may increase the carbon uptake rates in both scenarios, owing to enhancement of the biological carbon pump evidenced by an increase in Net Community Production (NCP) following changes in the subsurface equatorial circulation and enhanced iron availability from extratropical regions. NCP is a proxy of the bulk organic carbon made available to the higher trophic levels and potentially exportable from the surface layers. The model results indicate that, besides the localized increase in the equatorial Pacific, the NCP of lower trophic levels in the northern Pacific and Atlantic oceans is projected to be halved with respect to the current climate under a substantial mitigation scenario at the end of the twenty-first century. It is thus suggested that changes due to cumulative carbon emissions up to present and the projected concentration pathways of aerosol in the next decades control the evolution of surface ocean biogeochemistry in the second half of this century more than the specific pathways of atmospheric CO2 concentrations. 相似文献
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二维的大气CO2——大西洋碳循环模式 总被引：5，自引：1，他引：5
本文描述了一个二维（纬度×深度）的大西洋碳循环模式，模拟了大气和海洋间CO2的交换以及碳在海洋中的输送过程。模式在运行时使用了一个12层的三维动力学模拟的海洋环流的结果。大西洋被划分成397个网格箱，每个箱子中各种形式的碳的含量、总碱度、溶解的无机营养物和溶解氧的浓度以及几种14C(碳14)同位素的值分别得到求解。模式稳定状态的计算采用解大型稀疏线性方程组的直接解法。计算结果与“地球化学的海洋研究（GEOSECS）”的实际观测数据对比，表明模式较好地再现了实际大西洋中几种化学量的分布。 相似文献
14.
Inorganic carbon in the ocean is modelled as a passive tracer advected by a three-dimensional current field computed from a dynamical global ocean circulation model. The carbon exchange between the ocean and atmosphere is determined directly from the (temperature-dependent) chemical interaction rates in the mixed layer, using a standard CO2 flux relation at the air-sea interface. The carbon cycle is closed by coupling the ocean to a one-layer, horizontally diffusive atmosphere. Biological sources and sinks are not included. In this form the ocean carbon model contains essentially no free tuning parameters. The model may be regarded as a reference for interpreting numerical experiments with extended versions of the model including biological processes in the ocean (Bacastow R and Maier-Reimer E in prep.) and on land (Esser G et al in prep.). Qualitatively, the model reproduces the principal features of the observed CO2 distribution bution in the surface ocean. However, the amplitudes of surface pCO2 are underestimated in upwelling regions by a factor of the order of 1.5 due to the missing biological pump. The model without biota may, nevertheless, be applied to compute the storage capacity of the ocean to first order for anthropogenic CO2 emissions. In the linear regime, the response of the model may be represented by an impulse response function which can be approximated by a superposition of exponentials with different amplitudes and time constants. This provides a simple reference for comparison with box models. The largest-amplitude (0.35) exponential has a time constant of 300 years. The effective storage capacity of the oceans is strongly dependent on the time history of the anthropogenic input, as found also in earlier box model studies. 相似文献
15.
1. Introduction14C is a radioactive isotope of carbon, whose halftime is about 5730 yr. Under natural circumstance,14C comes into being in the stratosphere because of thenitrogen explosion of cosmic radial. 14C is mixed inthe atmosphere, absorbed by oceans, and then trans-ported into deep ocean. 14C radioactively reduces asits age increases. The reduction process of 14C canuncover the evolvement process of sea water's age andrenewal time.14 C content is usually described with one in athousan… 相似文献
16.
A GCM study of Antarctic glaciation 总被引：1，自引：0，他引：1
Robert J Oglesby 《Climate Dynamics》1989,3(3):135-156
An atmospheric general circulation model, the NCAR CCM, has been used to investigate the possible effects of two specific tectonic mechanisms on Antarctic glaciation. These two mechanisms are: (1) closing the Drake Passage (connecting South America with Antarctica), which is assumed to effectively represent an increased meridional heat transport by the ocean; and (2) changing the elevation of Antarctica. Perpetual season (summer and winter) and seasonal cycle simulations with warmer sea-surface temperatures and no sea ice prescribed for mid- to high-latitude southern oceans have been made with both present-day (high) Antarctic elevations and with low Antarctic elevations (all points 200 m). The results suggest a relatively minor role for oceanic heat transport in the formation/elimination of Antarctic glaciation. That is, under the warmer conditions inferred to have prevailed prior to the opening of the Drake Passage, conditions would still have been favorable for the maintenance of an Antarctic ice-sheet. If anything, a moderate ocean warming would promote glaciation, by increasing snowfall. Lowering the elevation of Antarctica has a larger effect on the model simulations, reducing the likelihood of glacial conditions. In the absence of snowcover, summer temperatures over Antarctica can warm considerably, leading to a monsoon-like circulation. However, it may be difficult to achieve such snow-free conditions, even with greatly increased atmospheric carbon dioxide. A tundra-like climate is the closest the model has come to representing a non-glacial climate, even when both seasurface temperatures and elevations are maximally varied. 相似文献
17.
IPCC确定的几种未来大气CO2浓度水平对人为CO2排放的限制 总被引：1，自引：0，他引：1
用三维海洋碳循环模式和一个简单的陆地生物圈模式计算了IPCC(政府间气候变化委员会)未来大气CO2情景中海洋和生物圈的吸收,并结合土地变化的资料得出燃料的排放值。结果表明：尽管在所有的构想下,为了使大气中CO2浓度达到稳定必须减少排放,但对应不同的IPCC未来大气CO2情景,对人为CO2排放的限制是很不相同的。 相似文献
18.
The CO2-seawaler system and the method for calculating the partial pressure of CO2 (pCO3) in seawater are stu-died. The buffer capability of the ocean to increasing atmospheric CO2, is expressed in terms of the differential buffer factor and buffer index. Dissolutions of aragonite and calcite have a significant influence on the differential buffer factor. The trend of change in the buffer factor is obtained by a box model. 相似文献
19.
Probabilistic climate change projections using neural networks 总被引：5，自引：0，他引：5
Anticipated future warming of the climate system increases the need for accurate climate projections. A central problem are the large uncertainties associated with these model projections, and that uncertainty estimates are often based on expert judgment rather than objective quantitative methods. Further, important climate model parameters are still given as poorly constrained ranges that are partly inconsistent with the observed warming during the industrial period. Here we present a neural network based climate model substitute that increases the efficiency of large climate model ensembles by at least an order of magnitude. Using the observed surface warming over the industrial period and estimates of global ocean heat uptake as constraints for the ensemble, this method estimates ranges for climate sensitivity and radiative forcing that are consistent with observations. In particular, negative values for the uncertain indirect aerosol forcing exceeding –1.2 Wm–2 can be excluded with high confidence. A parameterization to account for the uncertainty in the future carbon cycle is introduced, derived separately from a carbon cycle model. This allows us to quantify the effect of the feedback between oceanic and terrestrial carbon uptake and global warming on global temperature projections. Finally, probability density functions for the surface warming until year 2100 for two illustrative emission scenarios are calculated, taking into account uncertainties in the carbon cycle, radiative forcing, climate sensitivity, model parameters and the observed temperature records. We find that warming exceeds the surface warming range projected by IPCC for almost half of the ensemble members. Projection uncertainties are only consistent with IPCC if a model-derived upper limit of about 5 K is assumed for climate sensitivity. 相似文献
20.
生物泵在海洋碳循环中的作用 总被引：11，自引：1，他引：11
生物过程在海洋碳的自然分布中起着重要的作用,它使海洋中碳的储量大大增加.作者用包含海洋化学过程和一个简单生物过程的三维碳循环模式模拟了生物泵在海洋碳循环中的作用.模式计算的结果表明:生物过程产生的海-气通量的量级非常大;在高纬度和赤道它的量级与因溶解度泵产生的碳的海-气通量差不多.在高纬度地区这两个通量符号相反,使组合模式中的通量大小比只有溶解度泵时的通量小,而在赤道两者的符号相同,使组合模式在赤道的通量大于只有溶解度泵时的通量.在稳态条件下生物泵对海洋吸收人为CO2的直接影响很小. 相似文献