Vegetation and climate

Over the last two centuries, man's activities have caused a 30% increase in the atmospheric concentration of CO₂, with continued increases seeming inevitable. This change in CO₂ concentration will act on vegetation, both directly and indirectly through global climatic change. It is well established that, on a global scale, patterns of vegetation and climate are closely correlated. Such correlations indicate that climatic change will cause the distribution of vegetation to change. However, the use of correlations for predicting vegetation responses to climatic change is fundamentally unreliable because correlations have no mechanistic underpinning of causation. This paper outlines a mechanistic model for predicting the equilibrium state between current climate and vegetation. It is also used to indicate the sensitivity of global vegetation to the changed climate associated with a doubled CO₂—greenhouse scenario. The interpretation of this static model is discussed in terms of rates and patterns of vegetation change.     

The global carbon cycle and possible disturbances due to man's interventions

Global atmospheric CO₂ concentration has increased since the beginning of reliable monitoring in 1958 at a mean rate of about 0.9 ppm CO₂/yr. Now, atmospheric CO₂ concentration is at 330 ppm. From about 1860 up to 1974, man's intervention in the global carbon cycle caused a likely increase of 76.6 × 10¹⁵ gC, corresponding to 36 ppm CO₂ in the atmosphere, if a preindustrial content of 294 ppm CO₂ or 625.3 × 10¹⁵ g C is adopted to be valid. A further rise of atmospheric CO₂ seems to be inevitable and probably will be responsible for a climatic warming in the next several decades; therefore, a global examination of carbon reservoirs and carbon fluxes has been undertaken to determine their storage capacity for excess carbon which orginated mainly from burning fossil fuels and from land clearing. During 1860–1974 about 136 × 10¹⁵ g C have ben emitted into the atmosphere by fossil fuel combustion and cement production. At present, the emission rate is about 5 × 10¹⁵ g C/yr. The worldwide examination of carbon release, primarily by deforestation and soil cultivation since 1860, is estimated to be about 120 × 10¹⁵ g C. The net transfer of carbon to the atmosphere owing to man's interference with the biosphere is now believed to be about 2.4 × 10¹⁵ g C/yr. An oceanic uptake of roughly 179 × 10¹⁵ g C since 1860 is open to discussion. According to the chemical buffering of sea surface water only about 35.5 × 10¹⁵ g C could have been absorbed. It is argued, however, that oceanic circulations might have been more effective in removing atmospheric excess carbon of anthropogenic origin.     

The influence of ventilation on indoor/outdoor air contaminants in an office building

The air quality in a newly built preschool was investigated in a longitudinal study. Typical air contaminants emanating from building materials were determined, their variation over time (0–18 months) was measured, and the influence of the ventilation system (81%–91% recirculation of return air) on contaminant concentrations was studied. Volatile organic compounds were sampled by adsorption on porous polymer, analysed by a GC/FID system, and identified by MS. A spatial build-up in concentration (ppb or μg/m³ levels) is evident for all the organic compounds, as well as for CO₂, from the outdoor air, through the ventilation system, and through the rooms to the exhaust air. The longitudinal comparison over time shows that all the organic compounds decline in concentration mainly within the first 6 months of occupancy: 1-butanol 4–14 times, toluene and pentanal + hexanal 2–4 times, while formaldehyde remained at a constant low level of 90 ppb (110 μg/m³). It is difficult to believe that the problems of poor air quality in 100 preschools in Stockholm are caused by the organic compounds alone unless interactions occur. A preschool building needs to be gassed off during the first 6 months after its construction with no recirculation of return air allowed (outdoor air rate approx 4–5 ach). During at least 1–2 additional years, it is desired that the recirculation rate of return air is restricted, perhaps to 50%.     

鄱阳湖流域1960～2018年极端气温变化及其与大气环流的关系

为进一步揭示鄱阳湖流域极端气温事件变化及其影响因素,基于鄱阳湖流域24个气象站点连续59年观测资料,选取8个极端气温指数,分析鄱阳湖流域极端气温动态变化,并探讨了大气环流与极端气温变化的联系.结果表明:(1)鄱阳湖流域极端气温暖指数(暖昼天数、暖夜天数和夏日天数)及极值指数(日最低气温最小值和日最高气温最大值)均呈增加趋势;冷指数(冷昼天数、冷夜天数和霜冻天数)均呈逐渐减少趋势.(2)从空间分布来看,极端气温空间变化趋势与年际变化一致,极端气温暖指数和极值指数呈增加趋势,冷指数均呈减少趋势,但在不同地区变化趋势存在差异.流域各站点霜冻天数和冷昼天数均呈显著下降趋势,但在赣北地区下降趋势最显著.大部分站点(23/24)暖夜天数、夏日天数和日最低气温最小值均呈显著增加趋势;(3)鄱阳湖流域极端气温指数的变化与大气环流的变化存在相关性,其中西太平洋副高强度指数、夏季东亚季风指数、亚洲区极涡强度指数和北极涛动指数对极端气温事件影响显著.研究结果可为极端气候风险评估、灾害预警提供参考.     

Soil organic carbon dynamics of croplands in European Russia: estimates from the “model of humus balance”

The Model of Humus Balance was used to estimate the influence of climate effects and changing agricultural practices on carbon (C) levels in soddy–podzolic soils in the Russian Federation for the years 2000–2050. The model was linked with a spatial database containing soil, climate and farming management layers for identification of spatial change of C sequestration potential. Analysis of relationships between C, soil texture and climate indicated that compared with a business-as-usual scenario, adaptation measures could increase the number of polygons storing soil organic carbon (SOC) by 2010–2020. The rate of possible C loss is sensitive to the different climate scenarios, with a maximum potential for SOC accumulation expected in 2030–2040, thereafter decreasing to 2050. The effect is most pronounced for the arid part of the study area under the emission scenario with the highest rate of increase in atmospheric CO₂ concentration, supporting findings from the dynamic SOC model, RothC. C sequestration during the study period was permanent for clay and clay loam soils with a C content of more than 2%, suggesting that C sequestration should be focused on highly fertile, fine-textured soils. We also show that spatial heterogeneity of soil texture can be a source of uncertainty for estimates of SOC dynamics at the regional scale. Figures in color are available at     

北京、上海两地2004和2005年大气污染特征对比分析

为了解北京、上海两市大气污染的变化及其影响因素之间的关系,根据2004、2005年大气质量监测数据,分析了北京、上海两地大气污染特征和两地主要大气污染物的变化规律.结果表明,2004、2005年北京市的PM10最大值是最小值的63.7倍,北京市的变化幅度较上海市的变化幅度大;2004、2005年北京市的SO2最大值是最小值的46.7倍,上海市的SO2最大值是最小值的13.1倍,上海市的SO2污染的因素变化幅度较小;两市的NO2浓度都较高,且季节变化不太明显;两市NO2浓度年平均值满足国家空气质量二级标准,但质量浓度都较高,这与两市的机动车尾气污染有关;两市SO2浓度年平均值除上海市2005年外均满足国家空气质量二级标准,上海市SO2污染严重与上海市消耗大量煤炭有关,北京市SO2污染物浓度年度变化剧烈与冬季取暖烧煤有关;两市可吸入颗粒物污染比较严重,北京市PM10浓度年平均值超过国家空气质量二级标准,上海市PM10浓度年平均值达到国家空气质量二级标准.总体上上海市的大气质量要好于北京市.两地大气主要污染物随时间的变化规律与两地的污染物来源、地理、气候等条件有关.     

Some characteristics of plutonium distribution in the atmospheric air and plants in the zone surrounding the Mayak Production Association

The results of long-term studies on plutonium distribution in the atmospheric air and plants in the area surrounding the Mayak Production Association in the years 1976–1995 are summarized. Data are presented on the changes in plutonium concentration in the air overtime at some points located in the survey zone and the impact zone of the industrial enterprise as compared to those in the control region. In addition, data on the changes in air plutonium concentration depending on the season and direction of wind are presented; the ratios between plutonium concentrations in the air and the fallout are analyzed.Translated from Ekologiya, No. 1, 2005, pp. 20–25.Original Russian Text Copyright © 2005 by Chudin, Shcherbakova, Maslovskii, Kocheva, Iovlev, Denisenko, Demin, Mamin, Chebotina.     

National and regional trends in ambient ozone measurements, 1975–1981

Long-term (1975–1981) and short-term (1980–1981) national and regional trends in ozone (O₃) are examined. The data used in this paper come from the U.S. Environmental Protection Agency's National Aerometric Data Bank (NADB). Air quality trends are presented for both the National Air Monitoring Sites (NAMS) and all other sites meeting the historical and data completeness criteria. Nationally, the composite average of the second-highest daily maximum 1-h O₃ values recorded at 209 sites decreased 14% between 1975 and 1981. An even greater improvement was observed in the estimated number of exceedances in the ozone season (July–September), which decreased 42%. Volatile organic compound (VOC) emissions decreased 9% during the same time period. The greater improvement observed in ozone levels appears to be a combination of reductions in VOC emissions and the change in the calibration procedure which took place between 1978 and 1979. Between 1980 and 1981, the majority of the 159 monitoring sites with data in both years decreased with a median rate of improvement of 8%. This is consistent with the 7% drop in VOC emissions during this period.     

北京、上海两地2004和2005年大气污染特征对比分析

为了解北京、上海两市大气污染的变化及其影响因素之间的关系，根据2004、2005年大气质量监测数据，分析了北京、上海两地大气污染特征和两地主要大气污染物的变化规律。结果表明，2004、2005年北京市的PM10最大值是最小值的637倍，北京市的变化幅度较上海市的变化幅度大；2004、2005年北京市的SO2最大值是最小值的467倍，上海市的SO2最大值是最小值的131倍，上海市的SO2污染的因素变化幅度较小；两市的NO2浓度都较高，且季节变化不太明显；两市NO2浓度年平均值满足国家空气质量二级标准，但质量浓度都较高，这与两市的机动车尾气污染有关；两市SO2浓度年平均值除上海市2005年外均满足国家空气质量二级标准，上海市SO2污染严重与上海市消耗大量煤炭有关，北京市SO2污染物浓度年度变化剧烈与冬季取暖烧煤有关；两市可吸入颗粒物污染比较严重，北京市PM10浓度年平均值超过国家空气质量二级标准，上海市PM10浓度年平均值达到国家空气质量二级标准。总体上上海市的大气质量要好于北京市。两地大气主要污染物随时间的变化规律与两地的污染物来源、地理、气候等条件有关。     

The Hungarian national climate change strategy: its principles, assignments, and a special case study on maize production

Efficient protection against global climate change requires international emission reduction measures. Before these ones are decided, the individual states should make arrangements within their own scope of authority for preventing and mitigating the adverse impacts of climate change already in progress as a consequence of carbon dioxide emissions done so far. In spring 2008 Hungary—among the very first ones in the international stage—passed a middle-term National Climate Change Strategy, which determines both the national tasks in order to reduce greenhouse gas emissions, and sectoral tasks of the adaptation to the ongoing climate change for the period of 2008–2025. As a concrete case study we investigated the possible impacts of the regional change in atmospheric carbon dioxide concentration, temperature and precipitation conditions of the Carpathian Basin on the cultivation conditions of maize, based on the downscaled IPCC 2007 scenarios. Temperatures of each scenarios increased significantly to basic run (1961–1990). This change suppressed the positive influence of elevated CO₂ on carbon assimilation. Serious depression may be waited during extreme hot days at Keszthely, Hungary.     

Carbon dioxide and climate: an astrophysical perspective

In this survey the earth is viewed from the astrophysical perspective, i.e. using global mean values of environmental parameters. The role of carbon dioxide is described in the processes of energy transfer from the earth's surface to space, which determine “global climate” as measured by the mean surface temperature. Analogies and differences between the problems of the terrestrial atmosphere and those of the solar and stellar atmospheres are examines, both in the computation of model atmosphere and in remote sensing of atmospheric temperature and composition. Subsequently, the temporal astrophysical perspective, with a review of the evolution of CO₂ abundance and climate on astrophysical or geological time scales, on earth as on Venus (the runaway greenhouse) and on Mars is introduced. Variation of CO₂ may have been critical to the maintenance of an environment in which life could originate and evolve, and may itself have been affected by life. On human time scales, the recent and continuing increase in atmospheric CO₂ raises new problems, which are briefly surveyed. It is argued, that the differential greenhouse effect of increased CO₂ in the earth's atmosphere is essentially identical to the “blanketing effect” of spectral lines on the temperature structure of stellar atmospheres. The methods used by astrophysicists in such studies are reviewed and compared with those used to evaluate the differential greenhouse effect of CO₂ in radiative-convective models of the earth's atmosphere. The latter methods remain relatively crude, but recent results by different authors are in reasonably good agreement; however, the astrophysical perspective, i.e. the use of one-dimensional global mean models, remains a gross simplification of the real complexity of the earth's climate system, which is also true in stellar atmospheres.     

On the Classification of Aquatic Communities: An Example of Zooplanktonic Cenoses of Karst Lakes in the North of European Russia

Nine lakes in the Arkhangelsk oblast were analyzed with respect to their morphometry, hydrology, and hydrochemistry, and their zooplankton was studied for three years. The data on zooplankton abundance, biomass, the ratio of filter-feeders and predators, the Shannon index of species diversity, and average individual weight of zooplankters were obtained. Differences in the structure of zooplanktonic cenoses were revealed in lakes differing in morphometric parameters, prevailing ions (HCO₃ ^–, SO₄ ^2–), and their concentration.     

Indoor climate in low-ventilated day-care institutions

Measurements of indoor atmospheric environment were carried out in a day nursery and a kindergarten, in which natural air infiltration supplied the rooms with only 1–2 m³ fresh air per person and hour under the prescribed occupancy. The exposure situation from the field was duplicated under controlled conditions in a climate chamber. The results indicate unacceptably high concentrations of carbon dioxide, and emphasize the need for more elaborate building design in airtight buildings.     

The Potential of Soil Carbon Sequestration Through Improved Management Practices in Norway

The study was conducted to assess the potential of Norwegian agricultural ecosystems to sequester carbon (C) based on the data from some long-term agronomic and land use experiments. The total emission of CO₂ in Norway in 1998 was 41.4 million metric ton (MMT), of which agriculture contributed only 0.157 MMT, or <0.4% of the total emissions. With regards to methane (CH₄) and nitrous oxide (N₂O) gases, however, agricultural activities contributed 32.5% and 51.3% of their respective emissions in Norway. The soil organic carbon (SOC) losses associated with accelerated soil erosion in Norway are estimated at 0.475 MMTC yr^–1. Land use changes and soil/crop management practices with potential for SOC sequestration include conservation tillage methods, judicious use of fertilizers and manures, use of crop residues, diverse crop rotations, and erosion control measures. The potential for SOC sequestration is 0.146 MMTC yr^–1 for adopting conservation tillage, 0.011–0.035 MMTC yr^–1 for crop residue management, 0.026 MMTC yr^–1 for judicious use of mineral fertilizer, 0.016–0.135 MMTC yr^–1 for manure application, and 0.036 MMTC yr^–1 for adopting crop rotations. The overall potential of these practices for SOC sequestration ranges from 0.591 to 1.022 MMTC yr^–1 with an average value of 0.806 MMTC yr^–1. Of the total potential, 59% is due to adoption of erosion control measures, 5.8% to restoration of peat lands, 21% to conversion to conservation tillage and residue management, and 14% to adoption of improved cropping systems. Enhancing SOC sequestration and improving soil quality, through adoption of judicious land use and improved system of soil and crop management, are prudent strategies for sustainable management of soil, water and environment resources.Readers should send their comments on this paper to: bhaskarn ath@aol.com within 3 months of publication of this issue.     

The influence of air temperature on the perception of body odor

Ambient temperature may influence both the emission and the perception of human odor. This paper studies how human odor is perceived at different temperatures. The intensity of human odor in an auditorium was judged by an odor panel in an adjacent space. The ventilation rate of the occupied auditorium was 5–17 L/sec person. A continuous sample of odorous air was exhausted from the auditorium through a glass tube to an odor test station. One-half of the air flow was heated 1–7 K, and the other half was unheated. The odor panel was asked to compare the odor intensity of the two air flows. The air flow judged to have the strongest odor was stepwise dilluted with clean air (air temperature difference maintained). The dilution required to provide the same odor intensity in the two air flows was estimated. At air temperatures 23–32 °C no significant influence of temperature on perceived intensity of body odor was found. The ventillation requirement in auditoria and similar spaces is likely to be independent of the temperature level, provided that the occupants are kept thermally neutral or cooler, so that little or no perspiration occurs.     

Atmospheric radon in Hong Kong

For the first time in Hong Kong, atmospheric radon concentration was continuously monitored between November 2007 and October 2008. This paper presents the results obtained during the 12-month period. The annual mean atmospheric radon concentration in Hong Kong was found to be 9.3 Bq m⁻³ which was close to the level at neighbouring places like Guangdong and Taiwan. An estimation of the dose arising from atmospheric radon to the Hong Kong population was made. The meteorological effects on the variation of atmospheric radon concentration were discussed. It was found that the origin of the airmass and stability of the local atmosphere played vital roles in the seasonal and diurnal variations respectively, whereas precipitation caused abrupt changes in rainy days. An attempt was also made to find out the contribution of atmospheric radon to the ambient gamma dose rate.     

Effects of radionuclide and rainfall characteristics on field loss parameters of grass

The decrease of foliar activity in vegetation after its initial contamination by foliar deposition is termed “field loss” (Chamberlain, 1970). This work investigated further laboratory data concerning field loss of ¹³⁴Cs, ¹³⁷Cs, ⁸⁵Sr, ¹³³Ba and ^123mTe deposited on grassland (Madoz-Escande et al., 2005). Treatments consisted in rainfall scenarios cumulating 14 mm per week, combining two levels of intensity (8 or 30 mm/h) and two levels of frequency/precocity (late once or early twice-a-week). The time course of field loss was monitored in the edible tissues which were sampled by mowing between the rainfalls. Data were analyzed with an offset exponential loss model which is applicable to chronic contamination and is consistent with approaches adopted in radiological assessment models. Its parameters were estimated by the maximum-likelihood method, and their accuracy was determined by nonparametric boostrap. Radionuclide and rainfall conditions significantly affected the estimated rate (λ₁) and extent (A₁) of field loss. Field loss rate (λ₁) and nonentrainable fraction (1 − A₁) varied by a factor 1.5–3. Cesium was very mobile but persistent. On the contrary Tellerium was found less labile, but eventually was almost completely eliminated. Strontium and Barium had intermediate behaviors. Field loss was more efficient for moderate late once-a-week rainfalls (8 mm/h). Higher rainfall intensity reduced more the radionuclides losses than higher rainfall frequency/precocity. This paper reports statistically relevant effects that should be considered for more realistic assessments.     

Dynamic simulation of radon daughter concentrations in apartments using solar rockbed heat storage

In solar rockbed storage systems, heat is transferred during the day from the collector to a bed of pebbles, and released at night to warm the living space. When the rocks used for storage contain significant concentrations of uranium, ²²²Rn and its daughters may be released to the living area. A microcomputer model was used to simulate variations in air filtration rate and source strength through several days of operation. Source strengths were estimated from theoretical considerations and literature data. Resulting ²²²Rn and daughter concentrations were computed by solving system equations by fourth-order Runge-Kutta integration. During the day, when the living space is isolated from the radon source, interior ²²²Rn concentrations approach those of the outdoors. A nighttime steady-state concentration is approached about 6 h after heat discharge begins. Due to the dynamic nature of the simulation, equilibrium between ²²²Rn and its daughters is not reached. Time-weighted average nighttime exposures (6 p.m.–8 a.m.) for 10 simulation runs varied from 0.001 to 0.018 working level (WL). Comparison with one set of measurement data showed the model to overpredict concentrations but to approximate the ²²²Rn buildup rate well. Combinations of source strength, infiltration rate, and exterior radon concentration which would lead to exposures exceeding 0.02 WL were calculated.     

Ecophysiological Responses of Larix sibiricaLedeb. and Pinus sibiricaDu Tour Undergrowth to Climate Change

The effects of probable climate change—an increase in atmospheric CO₂(by two times), air temperature, precipitation—on CO₂exchange and temperature dependence of net photosynthesis in the larch and Siberian stone pine undergrowth formed in the light larch forests of West Siberia were studied in chambers with an artificial climate. The change of the aforementioned ecological factors caused an increase in the temperature optima of photosynthesis and the range of optimum temperatures (in the case of Siberian stone pine, to a slightly greater degree). Therefore, the ranges of both species may broaden, and the Siberian stone pine can expand to the north, displacing larch tree stands.     

西南地区近50年来气温变化特征研究

通过对中国西南地区1951~2000年的平均气温、日最高气温、日最低气温随时间变化特征的分析发现：在全球气候变暖的背景下,西南地区年平均气温、年平均日最高气温、年平均日最低气温自20世纪80年代中期以来呈升温态势,在1998年达到50年来最高值;中国西南地区近50年来日最高气温呈降温态势,其年际变化大于平均气温和日最低气温;日最高气温的下降对平均气温影响大;日最低气温总体上呈升温态势,冬季1月升温比夏季7月显著;冬季气温在80年代为暖期;夏季气温在50年代为暖期。