共查询到20条相似文献，搜索用时 296 毫秒
1.
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
2.
The authors propose a new “three-layer” conceptual model for the air-sea exchange of organic gases, which includes a dynamic surface microlayer with photochemical and biological processes. A parameterization of this three-layer model is presented, which was used to calculate the air-sea fluxes of acetone over the Pacific Ocean. The air-sea fluxes of acetone calculated by the three-layer model are in the same direction but possess half the magnitude of the fluxes calculated by the traditional two-layer model in the absence of photochemical and biological processes. However, photochemical and biological processes impacting acetone in the microlayer can greatly vary the calculated fluxes in the three-layer model, even reversing their direction under favorable conditions. Our model may help explain the discrepancies between measured and calculated acetone fluxes in previous studies. More measurements are needed to validate our conceptual model and provide constraints on the model parameters. 相似文献
3.
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
4.
Ingrid H. Ellingsen Padmini Dalpadado Dag Slagstad Harald Loeng 《Climatic change》2008,87(1-2):155-175
The Barents Sea is a high latitude ecosystem and is an important nursery and feeding area for commercial fish stocks such
as cod, capelin and herring. There is a large inter-annual variability both in physical and biological conditions in the Barents
Sea. Understanding and predicting changes in the system requires insight into the coupled nature of the physical and biological
interactions. A coupled physical and biological ocean model is used to study the impact of postulated future atmospheric changes
on the physical and biological conditions in the Barents Sea. Results from this simulation not only show that there is a large
variability in the physical conditions on a wide range of time scales, but also that the temperature in the Barents Sea is
increasing. The corresponding ice cover decrease is most noticeable in the summer months. The changes in physical properties
will most likely have an impact on the biotope. On average, the primary production increases slightly over a 65 year long
period, about 8%, partly due to an increased production in the northern Barents Sea. The model further simulates that the
production of Atlantic zooplankton species increases approximately 20% and becomes more abundant in the east. The Arctic zooplankton
biomass decreases significantly (50%) causing the total simulated production to decrease. 相似文献
5.
Eugenia Paulescu Nicoleta Stefu Paul Gravila Remus Stefan Boata Nicolina Pop Marius Paulescu 《Theoretical and Applied Climatology》2012,109(3-4):323-332
In order to perform calculations of biologically effective irradiance, the usual procedure is to modulate the ground-measured spectral solar irradiance with a specific biological action function. The inconvenience is that only a few meteorological stations worldwide are equipped to measure the spectral solar irradiance in the ultraviolet range. This motivates the search for a numerical substitute, which constitutes the subject of this report. An innovative approach based on generalized mean is used to infer the effective atmospheric transmittance. Its illustration resulted in a new parametric model for computing the biological dose under clear sky. The action spectrum for the growth response of plants, as a carrier of biological effects, is encapsulated into the atmospheric transmittance, leading to the calculation of the effective irradiance by simple algebra. The overall results indicate that the new parametric model performs accurately enough to be routinely used in practice. The procedure is general; therefore, it is described in detail to guide potential users in developing similar models incorporating other biological action spectra as needed. For speed-intensive applications, an executable file intended to run on any PC, which computes the effective irradiance with the proposed model, is provided. 相似文献
6.
东亚飞蝗发生程度与气象条件关系密切,该文使用1980-2008年的飞蝗资料和气象资料,选择了环渤海4种典型(沿海、水库、洼淀、内涝)蝗区,利用秩相关系数法筛选影响飞蝗发生程度的气象因子,确定了影响不同蝗区夏蝗发生程度的气象因子指标集。利用权重修正气象距离法,建立了气象距离指标预报模型;依据飞蝗自身生物学特性,建立了生物学预报模型。在此基础上,基于蝗虫生物学和气象条件影响的共同作用,建立了夏蝗发生程度的生物一气象集成长期预报模型。结果表明:在环渤海飞蝗区域,不同类型蝗区影响气象因子有一定差别,集成预报模型趋势预报准确率高于其他模型。 相似文献
7.
豫北多时效归一化棉铃虫气象预报模式 总被引：4，自引：0，他引：4
按照棉铃虫繁育规律,将棉铃虫周年活动期划分为秋季预蛹期、越冬期、春季羽化期、夏季危害期4个阶段,分阶段选取有昆虫学、统计学意义的气象因子,通过归一化处理和加权组合,组成棉铃虫气象指数,建立多时效、归一化棉铃虫气象预报模式和分析、评价指标。结果显示：气象条件与棉铃虫发生程度密切相关,各时段预报模式的复相关系数达0.7780~0.8780,回代拟合率为96.7%,回归效果极显著。经试报应用,取得较好效果。结论认为：将诸多气象因子作无量纲化处理,不但便于因子间相互组合,还可提高模式的预报精度;将棉铃虫周年繁育期划分为秋季预蛹期、越冬期、春季羽化期、夏季危害期,突出了阶段性特点,分阶段组建预报模式,预报效果较好。对组合因子的生物学意义,有待生物学试验认定。 相似文献
8.
海洋生物过程在海洋吸收大气二氧化碳中的作用 总被引：5，自引：0，他引：5
使用一个包括浮游生物（植物、动物和细菌）和无生命氮（有机碎片、溶解有机氮、硝酸盐和铵）的食物网来描述发生在海洋上层的生物过程。并将该生物模式分别用在佛罗里达海峡的一个固定位置和从佛罗里达海峡（２４°Ｎ,８０°Ｗ）流经挪威海（６８°Ｎ,１０°Ｅ）（扩展湾流体系,ＥＧＳＳ）的一个水块中,研究了海洋中上述的生物过程对水块吸收大气二氧化碳的影响。水块模式的结果十分明显地表明了海洋中的水华季,比包括浮游植物－浮游动物－硝酸盐体系得到的峰陡,结果更合理。扩展湾流体系中平均净初级生产力为４３ｇＣｍ－２ａ－１,小于观测值。模拟的总碱度,总二氧化碳和二氧化碳分压落在观测值的范围内,在水块吸收大气ＣＯ２的总量中生物泵的作用约占１６％。 相似文献
9.
气候系统具有非平稳特征,根本原因在于其外强迫随时间发生改变,因此外部驱动力的分析对于理解气候系统的动力学特征至关重要,而如何有效提取系统外部驱动信息是一个亟待解决的前沿科学问题。最近几年,在生物神经学领域中应用的一种提取非平稳信号中外强迫信息的方法——慢特征分析法(Slow Feature Analysis,SFA),在气象领域中也得到了初步成功的尝试,结果显示出此方法对气候系统的外强迫信息分析及有关动力学机制的探究有较好的应用前景。本文主要介绍SFA方法的理论思想及实施步骤,并通过一个理想的非平稳时间序列检验其提取外强迫信息的能力,结果证明在衰减的Logistic模型中,可利用SFA算法提取出模型中的外强迫,且与真实外强迫的相关系数可达0.99;此外,还介绍将该方法应用于Arosa臭氧时间序列,分析其提取的外强迫信息的动力学特征;并介绍了在气候时间序列建模中引入外强迫因子的预测效果。 相似文献
10.
Based on a coupled physical-biogeochemical model of the Yellow and East China Seas (YECS), the influence of biological activity on the seasonal variation of the air–sea CO2 flux is evaluated. The solution of a sensitivity experiment that excludes biological activity is compared with that of a reference experiment that includes the full processes. The comparison reveals that biological activity results in a much stronger seasonal variation of surface dissolved inorganic carbon (DIC) and, hence, the ratio of total alkalinity to DIC in the northern parts of the YECS. The increased ratio resulting from biological DIC consumption contributes to the undersaturated partial pressure of CO2 at the sea surface with respect to the atmosphere, causing the central Yellow Sea in summer and autumn to shift from being a CO2 source to a sink; this same shift also occurs over the Changjiang Bank in summer. In the southern YECS, the biological effect is relatively weak. The comparison further reveals that low water temperature, instead of biological activity, is the dominant factor causing the YECS to become a carbon sink in spring. The biological effect on the variation of DIC (both at the surface and in the water column) differs greatly among the three representative regions of the YECS because of differences in primary production and hydrodynamic conditions. Particle-tracking simulations quantify the regional difference in horizontal advection. In the northern region, weaker horizontal advection causes the longer residence time of low DIC water induced by biological consumption. Over the entire YECS, biological activity contributes to about one-third of the total annual absorption of atmospheric CO2. 相似文献
11.
12.
Arne Eide 《Climatic change》2008,87(1-2):251-262
The Barents Sea area is characterised by a highly fluctuating physical environment causing substantial variations in the ecosystems
and fisheries depending upon this. Simulations assuming different management regimes have been carried out to study how physical
and biological effects of global warming influence the Barents Sea cod fisheries. A regional, high-resolution representation
of the B2 world region (OECD90) scenario from the Intergovernmental Panel on Climate Change was used to calculate water temperatures
and plankton biomasses by hydrodynamic modelling. These results were included in simulations performed by a multi-fleet, multi-species
model, by which a fully integrated model linking to the global circulation model to the Barents Sea fisheries through a regional
downscaling to the Barents Sea area is constructed. One factor of particular importance for the natural annual biological
variations is the occasional inflow of young herring into the Barents Sea area. The herring inflow is difficult to predict
and links to dynamical systems outside the Barents Sea area, complex recruitment mechanisms and oceanographic conditions.
These processes are in the study represented by a stochastic representation of herring inflow based on historical observations.
According to the performed simulations the biomass fluctuations may slightly increase over the next 25 years, possibly caused
by changes in temperature patterns. Six different management regimes have been included in the study and the results support
earlier studies claiming that the choice of management regime potentially has a greater importance for biological and economic
performance in the Barents Sea fisheries than impacts which derive from global warming over the next 25 years. A basic assumption
for this conclusion is however that the Barents Sea ecosystem essentially preserves its structure and composition of today.
Possible, unpredictable significant shifts in the ecosystem structure are not considered. 相似文献
13.
14.
冬小麦生长发育的模拟模式 总被引：3，自引：0，他引：3
根据冬小麦生长发育及其与环境条件关系的机理研究,建立了模拟冬小麦发育阶段和各器官生物量变化的动态模式。其中包括3个环境要素子模式,分别计算温度、辐射和水分,5个生物学过程子模式,分别模拟冬小麦的发育、光合、呼吸、同化物分配和叶面积系数。用镇江和海安共8个播期的实测资料对模式进行验证,并对模式进行了初步数值试验应用。 相似文献
15.
Models of the climatic perturbation caused by a large scale extraterrestrial impact predict an injection of dust into the stratosphere. This would cause the onset of environmental conditions whose two principal characteristics are a prolonged period of darkness and reduced global temperatures. Similar scenarios follow large scale volcanic eruptions, wildfires and they are predicted for a nuclear winter following a protracted nuclear exchange. A significant drop in temperature and solar insolation are also characteristics of the polar winter. In this paper the onset and emergence from the polar winter is examined as a potential biological framework for studying immediate biological effects following transition into and out of a dark/cold catastrophe. Limitations of the conceptual model, particularly with respect to the fact that polar organisms are well adapted to a regular and severe dark/cold climatic change (which the rest of the Earth's biota is not) are discussed. The model has implications for the poles as an extinction refuge during such climatic changes. 相似文献
16.
小麦作物光合生产模拟研究 总被引：14，自引：0，他引：14
以生物学原理为基础，建立了小麦干物质增长的动态模式。该模式考虑了小麦株型、群体光分布、群体光合作用、呼吸作用及同化物分配。输入简单易测的因子，可计算得到光合速率值、群体光分布特征值、群体光合量、呼吸作用速率以及分部位干物重量等，其计算值与这关测值较吻合。 相似文献
17.
该文考虑生命活动与物质交换和能量流动的关系,从热力学出发,引入一维能量模型。在一维能量模型的基础上,将水稻对外界能量的摄取能力与水稻生长季中的气温变化规律联系起来,建立在气温变化条件下水稻的生长模型。结合气温增长率、水稻最适气温和不同阶段的生物量,以徐士良单形调优算法为基础,利用Forcal二维方程参数拟合,得到关于水稻自然增长率、气温波幅和初始值等参数的最优拟合。将最优拟合数据代入水稻的生长模型,拟合得到水稻的生长曲线和水稻生长随气温的变化趋势。以水稻的生长模型为基础,定性分析水稻的临界气温和最大生长率出现时间。通过分析发现,水稻生长季的临界气温与气温增长率无关;水稻的最大生长率出现时间为水稻分蘖后期、孕穗期。为考虑异常气温对水稻生长的影响,利用Matlab对水稻分蘖期低温和生殖生长期高温的水稻生长进行模拟,结果表明:水稻后期高温对产量影响比前期受低温影响严重。 相似文献
18.
AN AGROMETEOROLOGICAL MODEL OF PHYSIOLOGICAL THERMAL INDEX FOR WINTER WHEAT DEVELOPMENT IN EARLY STAGE 总被引：2，自引：0，他引：2
Liu Jiandong Fu Baopu Jin Zhiqing Cao Weixing Yu Qiang 《Acta Meteorologica Sinica》1997,11(4):503-512
Based on full consideration of the winter wheat biological characters,an agrometeorologicalmodel of physiological thermal index of winter wheat including vernalization and photoperiodresponse is established,in which the influence of diurnal variation of temperature,effectivetemperature and daylength on the development of winter wheat during the period from emergenceto elongation are comprehensively considered.Validation of the model using the data taken fromthe experiments of wheat ecology in China shows that the model behaves well with mean error lessthan 3 days. 相似文献
19.
Abstract Total alkalinity and total carbonate determinations together with salinity and temperature are used to characterize water masses in Foxe Basin, Hudson Bay and Hudson Strait. From these measurements, we are able to infer the amounts of fresh water from river runoff and from sea‐ice meltwater. The average ice cover is estimated to be 1.9 m, and the residence time of river runoff in Hudson Bay is 3—4 years. Estimates of biological productivity were made by “correcting” total carbonate measurements for effects of biological processes, giving a value of 24 gC m a for new production. 相似文献
20.
Primary biological aerosol particles including pollen, spores, plant debris, epithelial cells, bacteria, algae, protozoa and viruses, are an ubiquitous component of the atmospheric aerosol, they are most probably present in all size ranges. Besides their effects on air hygiene and health, biological particles play an important role in cloud physics, for example some bacteria are able to accumulate water and act as ice nuclei. To sample aerosols a two-stage-slit-impactor and a wing-impactor are used to collect particles for a following single particle analysis. The coarse particles are sampled on dyed glycerine jelly. The biological particles become stained and can be distinguished in contrast to the non-dyed particles using a light microscope.The small particles are examined in a scanning-electron-microscope equipped with an energy dispersive X-ray spectrometer after sampling on graphitic foils. Three criteria were used to characterize the particles: the morphology, the elemental composition and the behaviour during the microanalysis.With this method the size distributions of the primary biological aerosol particles were determined in an urban/rural influenced region. Considering all measurements we calculated a mean number concentration of 1.9 cm−3 of biological aerosol particles ≈30% of the total aerosol particles. The mean volume concentration was about 15% of the total volume. A model size distribution for primary biological aerosol particles was obtained by performing a non-linear fitting procedure. 相似文献