Estimating the global flux of methane into the atmosphere and its seasonal variations

A new method of estimating the global fluxes of methane into the Earth’s atmosphere is proposed. This method allows one to take into account the whole spectrum of methane sources irrespectively of their location and calculate seasonal variations in methane fluxes. The results of numerical calculations of the amount of methane emitted into the atmosphere on the basis of this method are supported by data obtained from field measurements. In the Northern Hemisphere (NH), during fall, maximum concentrations of CH₄ are due to methane sources in the arctic region which have not been taken into account before. For the condition of balance between the emission and sink of methane to be fulfilled, the total capacity of its sources amounts to no less than ～530 Tg/year for the NH and ～470 Tg/year for the Southern Hemisphere (SH). The results of our calculations and an analysis of the behavior of the concentration and mass of methane in the Earth’s hemispheres show that the global flux of methane from the surfaces of the lithosphere and ocean into the atmosphere may amount to more than ～1000 Tg/year.     

Modeling the variability of gas and aerosol components in the stratosphere of polar regions

A thermodynamics-microphysics model of the formation and evolution of stratospheric clouds is developed. This model was integrated into the global chemistry-climate model of the lower and middle atmosphere. Model experiments on the study of the evolution of the gas and aerosol compositions of the Arctic and Antarctic atmosphere were performed. The results of an investigation into the observed differences of changes in the contents of gaseous impurities and aerosol in polar regions showed that the presence of nitrification in the Antarctic and its absence in the Arctic are the main factors controlling distinctions between the formation of a full-value ozone hole in the Antarctic and only occasional “mini-holes” in the Arctic.     

Variation in the intensity of tropical cyclones in connection with global warming

In connection with global warming, the growth in the intensity of tropical hurricanes is predicted. The onset of this intensification is partially illustrated by the western Atlantic cyclonic zone [1]. It is noted in [1]that, due to global warming, the sea-surface temperature (SST) over the entire world has increased by 0.6°C since 1970. Since the SST basically determines the energy of tropical hurricanes, it is inferred that global warming will lead to an enhancement in their intensity. This publication presents a plot of the dynamics of SST annual mean anomalies for the northwestern Atlantic and pays special attention to significant excess mean temperatures since 1994. The anomalies are determined with respect to the mean temperature calculated from SSTs over 1901–1970. The same plot also shows that the SST at the end of the 1940s and during the 1950s exceeded the mean temperature by about 0.3 or even 0.4°C, decreasing gradually to negative anomalies (?0.3°C) in 1973. After that, the temperature started to increase again. Figure 1 shows a detail of this plot, which relates to the period 1950–2000.     

全球变暖背景下最近40年太平洋海温变化数值模拟

用Non-Boussinesq POP模式和1960—1999年NCEP的1 000 hPa大气温度和风场资料,模拟了最近40 a太平洋海温的变化,通过与实际观测结果比较,得出模拟结果是可信的,并且得到了一些有意义的结果:在海面,太平洋最大的增温发生在赤道中东太平洋,即Niño1-Niño4区内,最大的降温在中纬度南北太平洋中部,除了北半球太平洋西岸40°N附近为降温外,在北半球太平洋沿岸基本上为升温,但太平洋东海岸的升温幅度要远大于西海岸;在太平洋0~483 m深度垂直方向,除了赤道中太平洋区域海温的变化在海面为上升,在169 m处为下降,在483 m处又转为上升外,其他区域海温的变化在垂直方向基本上为线性变化。在全球增暖的背景下,虽然El Niño现象在20世纪90年代以后表现出增强的趋势,但是反映在赤道表面以下的次表层西太平洋暖池中的异常暖中心,在由西向东移动过程中其强度却是减弱的。     

热带大西洋对全球变暖的响应

与太平洋和印度洋不同，全球变暖下热带大西洋变化的研究较少。本文使用地球系统模型CESM（Community Earth System Model），发现全球变暖后热带大西洋在秋季的升温类似大西洋尼诺（Atlantic Niño）的正位相，即大西洋西部增暖幅度小于东部；在夏季类似大西洋尼诺的负位相，即大西洋西部增暖幅度大于东部。利用覆盖（overriding）技术，分离了风应力、风速和CO₂的直接热效应对海洋升温的作用，探讨了大西洋尼诺本身和全球变暖作用下类似大西洋尼诺正位相（下文简称“类大西洋尼诺升温”）的形成机制。结果表明，这两种情况下的形成机制基本相同，风应力的变化是导致大西洋东部暖异常的主要机制。但两者之间也存在区别：1）全球变暖下海表温度的季节变化振幅减小，而大西洋尼诺时变化不大；2）全球变暖下西风异常主要集中在大西洋东部，而大西洋尼诺时主要集中在大西洋中部；3）除风应力外，CO₂的热效应对类尼诺升温的变化也有一定影响。     

全球变暖与东北地区气温变化研究

本文利用东北地区1951～2002年气温资料,分析了东北地区平均气温年和各季的气温变化.结果表明:在全球气候变暖的背景下,东北地区的气温也在升高,而且从90年代以来增温十分明显.东北地区1951～2000年50年的平均气温以0.38℃/10a的倾向率上升,1991～2000年气温上升加剧,倾向率达到0.55℃/10a,明显高于全国平均水平.     

Response of the North Pacific subtropical countercurrent and its variability to global warming

Response of the North Pacific subtropical countercurrent (STCC) and its variability to global warming is examined in a state-of-the-art coupled model that is forced by increasing greenhouse gas concentrations. Compared with the present climate, the upper ocean is more stratified, and the mixed layer depth (MLD) shoals in warmer climate. The maximum change of winter MLD appears in the Kuroshio–Oyashio extension (KOE) region, where the mean MLD is the deepest in the North Pacific. This weakens the MLD front and reduces lateral induction. As a result of the reduced subduction rate and a decrease in sea surface density in KOE, mode waters form on lighter isopycnals with reduced thickness. Advected southward, the weakened mode waters decelerate the STCC. On decadal timescales, the dominant mode of sea surface height in the central subtropical gyre represents STCC variability. This STCC mode decays as CO₂ concentrations double in the twenty-first century, owing both to weakened mode waters in the mean state and to reduced variability in mode waters. The reduced mode-water variability can be traced upstream to reduced variations in winter MLD front and subduction in the KOE region where mode water forms.     

Satellite monitoring of trace gas and aerosol emissions during wildfires in Russia

Peculiarities of the formation of carbon gas and fine aerosol emissions into the atmosphere during wildfires are analyzed. A prompt satellite monitoring system and technique for the assessment of burnt areas and volumes of CO₂, CO, and PM_2.5 emissions from wildfires are described. The results of satellite monitoring of the Russian Federation and some Russian regions for different months over 2010–2014 are given; burnt areas and volumes of carbon gas and aerosol emissions throughout the entire territory are assessed. The peculiarities of seasonal frequencies of wildfires and volumes of hazardous gas and fine aerosol emissions in the regions under study are identified.     

Simulation of climate change induced by injection of sulfur compounds into the stratosphere

An atmosphere-ocean general circulation model including the atmospheric chemistry and carbon cycle was used to perform numerical experiments to simulate the consequences of geoengineering. Out of the five emission scenarios considered here, the scenario where the injection of sulfur compounds occurs near the equator at an altitude between 22 and 24 km can be considered the most efficient in the sense of a maximum decrease in globally averaged surface temperature. We consider the equilibrium distribution of the sulfate aerosol and changes in temperature at the Earth’s surface and at different altitudes, in precipitation, in ozone concentration, and in primary plant productivity caused by geoengineering.     

Estimating the effects of technological efficiency on the European fishing fleet

By comparing the real reductions in fishing capacity of the European Union (EU) and the effects of technological efficiency, this paper presents the first comprehensive analysis since the creation of the Common Fisheries Policy (CFP). Using a standard methodology and a conservative value of ±4.4% for annual technological progress, the results obtained for tonnage indicated that the EU-13 fleet's fishing capacity was reduced by >4% for only three years (1991, 2004, and 2006) in the 1987–2006 period.     

关键海区潜沉率对全球变暖停滞的可能影响

本文从潜沉率入手,探究了潜沉率在全球变暖停滞过程中可能发挥的作用。本文利用SODA资料首先分析了全球潜沉率的时空分布特征,然后基于EOF分解明确了北大西洋翻转流区域和南极绕极流区域是潜沉率变率较大的两个海区,在此基础上选出了4个关键海区研究了局地潜沉率变化与全球海表温度异常之间的相关关系,最后对关键区潜沉率变化的原因进行了初步探索。结果表明,北大西洋翻转流和南极绕极流范围内的关键区域与全球变暖停滞之间存在超前10年的相关关系,潜沉过程可能是北大西洋翻转流和南极绕极流对全球变暖停滞产生作用的一种机制。平流项在这些关键区域的潜沉率变化中起主导作用。在南极绕极流地区,海面风应力的大小与该区域的潜沉变化密切相关。     

Changes of cooling near mesopause under global warming from observations and model simulations

The results of joint analysis of temperature variations near mesopause from long-term measurements at the Zvenigorod Scientific Station of the Obukhov Institute of Atmospheric Physics RAS in 1960–2015 and variations of surface air temperature characterizing global climate change. Together with variations of temperature at the mesopause T _ms from measurements of the hydroxyl emissions we analyzed the temperature variations near mesopause T _m reduced to the same level of solar activity. The observed strong decrease in temperature near mesopause during last decades, particularly in winter, with its tendency to slow down since the 1980’s is was detected against the background of general increase in the surface air temperature of the Northern Hemisphere T _NHs and the Earth as a whole. It was revealed a sharp drop in winter temperature near mesopause in 1970s. and its synchronicity with the shift in climatic features at the surface associated with changes in formation of El Nino events and their impact on the global climate. The general significant negative correlation of temperature variations near mesopause and T _NHs detected from 56-year observational data was not accompanied by any significant coherence between the most long-period temperature variations from the cross-wavelet analysis. To assess the possible manifestation of this coherence the results of numerical simulations with a global climate model were used. According to model simulations for the 20–21 centuries taking into account anthropogenic forcings for significant coherence between long-term variations T _m and T _NHs the prolonged observations are required for temperature near mesopause–about a century or more.     

Response of the mixed layer depth and subduction rate in the subtropical Northeast Pacific to global warming

The response of the mixed layer depth(MLD) and subduction rate in the subtropical Northeast Pacific to global warming is investigated based on 9 CMIP5 models. Compared with the present climate in the 9 models, the response of the MLD in the subtropical Northeast Pacific to the increased radiation forcing is spatially nonuniform, with the maximum shoaling about 50 m in the ensemble mean result. The inter-model differences of MLD change are non-negligible, which depend on the various dominated mechanisms. On the north of the MLD front, MLD shallows largely and is influenced by Ekman pumping, heat flux, and upper-ocean cold advection changes. On the south of the MLD front, MLD changes a little in the warmer climate, which is mainly due to the upper-ocean warm advection change. As a result, the MLD front intensity weakens obviously from 0.24 m/km to0.15 m/km(about 33.9%) in the ensemble mean, not only due to the maximum of MLD shoaling but also dependent on the MLD non-uniform spatial variability. The spatially non-uniform decrease of the subduction rate is primarily dominated by the lateral induction reduction(about 85% in ensemble mean) due to the significant weakening of the MLD front. This research indicates that the ocean advection change impacts the MLD spatially non-uniform change greatly, and then plays an important role in the response of the MLD front and the subduction process to global warming.     

Early Turonian global warming in the Atlantic and Indian Oceans according to the data of the Foraminifera analysis

In the article, my own data on the species composition of the shells of planktonic Foraminifera (PF) from the Early Turonian sediments of the Atlantic and Indian Ocean and from a number of the cross sections of Australia have been analyzed. In addition, literature materials on the epicontinental basins of the northern hemisphere were also studied. The foraminifera species (PF) are grouped, and four types of thanatocoenoses are distinguished according to their relationship. A climatic zonality map for the early Turonian was constructed on the basis of the spatial distribution of these types. The reconstruction obtained was compared with the climatic maps compiled earlier for the later time intervals of the Late Cretaceous. It was established that the Turonian was characterized by the warmest climate. The tendency for global warming was the most clearly manifested in the Early Turonian.     

On the effectiveness of the ocean's biological pump in global CO2 scenarios

An evaluation is made of the effectiveness of the ocean's biological pump in driving the deep-sea excess CO₂ from the atmosphere. It is based on sediment-trap data available in the literature and on estimates of present and future inputs of anthropogenic nitrogen and phosphorous. The fraction of annual CO₂ production from fossil fuel combustion going into this sink turns out to be insignificant in the total budget of man-made CO₂. A discussion is presented on the formation of macroflocs under oceanic conditions, a process that has been believed to be important for the effectiveness of the biological pump.     

不同气候情景下中国滨海城市海岸极值水位重现期预估

气候变化背景下,海平面上升叠加台风—风暴潮、天文大潮等产生的海岸极值水位事件趋多增强,对我国滨海城市社会经济可持发展构成了严重威胁。为认识未来我国滨海城市海岸极值水位危害性（强度和频率）的变化,本文首先采用第五次国际耦合模式比较计划（CMIP5）数据,分析了不同气候情景下（RCP2.6, 4.5, 8.5,简称为RCPs）下,未来不同年代（2030年、2050年和2100年）我国滨海城市沿岸海平面变化幅度;其次,基于沿海验潮站的历史观测资料和文献数据,分析了未来热带气旋强度变化对海岸极值水位的影响;最后,利用皮尔逊Ⅲ型（P-Ⅲ）水文概率曲线方法,预估了不同气候（RCPs）情景下未来不同年代（2030年、2050年和2100年）我国9个滨海城市海岸极值水位重现期的变化。结果表明：（1）在不同气候情景下,我国滨海城市沿海平均海平面均呈现上升趋势,其中,到21世纪末,长三角地区沿海海平面上升幅度最大,上升速度比全国平均高出约30%;（2）热带气旋的强度与台风—风暴潮的增水幅度存在正相关关系。预计到21世纪末,热带气旋的整体强度很可能将增强,热带气旋引发的台风—风暴潮的增水幅度较当前很可能有明显提高。（3）未来我国滨海城市沿海极值水位将有显著增高的趋势,当前极值水位的重现期将明显缩短。到21世纪末,我国滨海城市当前百年一遇的极值水位,重现期几乎都将缩短至20年一遇以下,其中,大连、青岛、上海和厦门等城市海岸极值水位重现期很可能缩短为（或低于）1年一遇。本文虽在一定程度上反映了不同气候情景下海岸洪水危害性的变化,但对于未来热带气旋的变化及其影响的研究尚有待进一步深入。     

全球变暖和海洋酸化背景下珊瑚礁生态响应的研究进展

生物礁是由珊瑚虫、藻类等造礁生物组成、具有抗浪结构的海相碳酸盐岩,是全球主要碳库之一,也是观察热带海洋影响中-高纬度环境过程的重要窗口。近二、三十年以来,伴随着海洋水体的显著酸化和增温,全球热带海洋生物礁的主体——珊瑚礁系统遭受了不同程度的影响。其中,对于高温强迫而言,海水温度上升诱发珊瑚白化、抑制珊瑚的自我修复;海洋酸化可以显著改变珊瑚钙化率、抑制珊瑚幼虫发育、引发珊瑚礁的溶解;两大因素均可改变珊瑚礁的群落结构。针对这些环境要素的改变,珊瑚自身可以通过共生藻的种类转换以及调控基因表达等手段在一定程度上抵抗高温胁迫;但若温室气体的排放不受控制,绝大多数珊瑚礁到21世纪末都将遭受灾难性打击。为应对未来不同场景下的珊瑚礁变化,还需要对高温、酸化等关键因子响应特征进行更深入的研究;珊瑚礁长序列研究有可能为珊瑚的长周期演化特征提供关键认识,也为现代观测提供有益补充。