Using a radiative-convective model to estimate the temperature potential of greenhouse gases

A comprehensive approach is proposed to the construction of an equilibrium global warming potential with the use of a radiative-convective model of climate and the line-by-line calculations of the characteristics of radiative transfer in the atmosphere on the basis of analysis and comparison of different methods of estimating emission metrics. The studies conducted in the past decade have demonstrated that a widely used method of calculating the global warming potential for methane and other trace greenhouse gases is applicable only to relatively small time horizons (within 100 years). The proposed equilibrium global warming potential makes it possible to consider a set of equilibrium states of the Earth’s climate system under variations in the contents of greenhouse gases in the atmosphere and to estimate the parameters of the system’s response to such variations for arbitrary time intervals. Analysis of a set of different equilibrium states makes it possible to assess a relative contribution of different anthropogenic pollutants to radiation balance and, hence, to a change in the Earth’s climatic regime.     

The millennium eruption of Hekla in February 2000

The 18th historic eruption of Hekla started on 26 February, 2000. It was a short-lived but intense event, emitting basaltic andesitic (55.5 wt% SiO₂) pyroclastic fragments and lava. During the course of the eruption, monitoring was done by both instruments and direct observations, together providing unique insight into the current activity of Hekla. During the 12-day eruption, a total of 0.189 km³ DRE of magma was emitted. The eruptive fissure split into five segments. The segments at the highest altitude were active during the first hours, while the segments at lower altitude continued throughout the eruption. The eruption started in a highly explosive manner giving rise to a Subplinian eruptive column and consequent basaltic pyroclastic flows fed by column collapses. After the explosive phase reached its maximum, the eruption went through three more phases, namely fire-fountaining, Strombolian bursts and lava effusion. In this paper, we describe the course of events of the eruption of Hekla and the origin of its magma, and then show that the discharge rate can be linked to different style of eruptive activity, which are controlled by fissure geometry. We also show that the eruption phases observed at Hekla can be linked with inferred magma chamber overpressure prior to the eruption.     

Dependence of the Anthropogenic Heat Flux on Air Temperature (Using St. Petersburg as an Example)

Izvestiya, Atmospheric and Oceanic Physics - The anthropogenic heat flux associated with energy consumption for heating buildings has a significant impact on the heat balance of urbanized areas and...     

Climate-driven changes in water level: a decadal scale multi-proxy study recording the 8.2-ka event and ecosystem responses in Lake Sarup (Denmark)

A two-stage change in lake level during the 8.2-ka event was identified in Lake Sarup, Denmark (55°N), using a multiproxy approach on precise radiocarbon wiggle-matched annually laminated sediments deposited 8740–8060 cal. yr BP. Changes in δ¹³C and δ¹⁸O indicated closed lake hydrology driven by precipitation. The isotopic, sedimentary and plant macrofossil records suggested that the lake level started to decrease around 8400 cal. yr BP, the decrease accelerating during 8350–8260 before an abrupt increase during 8260–8210. This pattern shows that the climate anomaly started ~150 years before the onset of the 8.2-ka cooling event registered in Greenland ice cores, but was synchronous with hydrologic change in the North American Lake Agassiz drainage. The lake level decrease was accompanied by a higher accumulation rate of inorganic matter and lower accumulation rates of cladoceran subfossils and algal pigments, possibly due to increased turbidity and reduced nutrient input during this drier period. Pigment analysis also showed added importance of diatoms and cryptophytes during this climate anomaly, while cyanobacteria became more important when the water level rose. Moreover, Nymphaeaceae trichosclereids were abundant during the period of algal enrichment. Cladoceran taxa associated with floating leaved plants or benthic habitats responded in a complex way to changes in water level, but the cladoceran assemblages generally reflected deep lake conditions throughout the period. The lake did not return to its pre-8.2-ka event status during the period of analysis, but remained more productive for centuries after the climatic anomaly as judged from the pigment accumulation and assemblage composition. The change to more eutrophic conditions may have been triggered by erosion of marginal deposits. Together, these data confirm the chronology of hydrologic changes and suggest, for the first time, that lake levels exhibited both a decline and an increase in rapid succession in response to the 8.2-ka event in southern Scandinavia.     

Variability of Surface Methane Concentration in Moscow at Different Time Scales

Izvestiya, Atmospheric and Oceanic Physics - The variability of surface methane (СН4) concentration in Moscow at different time scales is analyzed using long-term regular measurements...     

Emission of carbon-bearing gases and aerosols from natural fires on the territory of Russia based on space monitoring

The results of the space monitoring of natural fires during the period 2010–2014 to estimate the areas destroyed by fire, volumes of the emissions of greenhouse gases, and fine particulate aerosols over the entire territory of Russia and its individual regions are presented. The methods of research, the regularities of the seasonal recurrence of fires distinguished in different regions, as well as the peculiarities of emissions of small gas components and aerosols in different months are described.     

Spatial and spectral characteristics of oscillations of offshore oil and gas production platforms caused by earthquakes and other impacts

The results of analysis of oscillations of an offshore oil and gas production platform, caused by seismic and other impacts (ice-field motion, storm wave impact, ship impact on platform supports, mechanism operations, etc.) are given. The analysis has been based on mathematical modeling of various impacts. Specific features of the inducement of platform mechanical oscillations as a function of the type of impact have been revealed, and the qualitative distinctions of platform oscillations under different impacts are described, allowing one to determine accelerometer-mounting sites for revealing seismic events by changes in acceleration on the platform.     

Regional air temperature maxima and the possibility of their simple energy-balance estimates

The record high temperatures during the summer of 2010 in the central part of the European territory of Russia (ETR) raised great interest in the question of whether these temperatures are the maximum possible ones and whether these maxima can be estimated from energy-balance considerations. The gigantic anticyclone was long lasting and stable, allowing the maximum air temperatures to be estimated with the help of simple energy-balance considerations. This situation can be considered an equilibrium state if a stable meteorological situation persists for quite a long time. In this case these equilibrium temperatures can be estimated using energy-balance equations in the atmosphere and on the Earth’s surface. The simple energy-balance estimates presented in this paper show that the maximum daytime air temperatures recorded in the summer of 2010 in the central part of the ETR are close to the maximum theoretically possible values.