Связь между переносом метана в атмосферу и разрушением ледяного покрова Карского моря: спутниковые данные за 2003–2019 гг.

Satellite spectrometers operating on the outgoing long-wave IR (thermal) radiation of the Earth and placed in sunsynchronous polar orbits provide a wealth of information about Arctic methane (CH4) year-round, day and night. Their data are unique for estimating methane emissions from the warming Arctic, both for land and sea. The article analyzes concentrations of methane obtained by the AIRS spectrometer in conjunction with microwave satellite measurements of sea ice concentration. The data were filtered for cases of sufficiently high temperature contrast in the lower atmosphere. The focus is on the Kara Sea during autumn-early winter season between 2003 and January 2019. This sea underwent dramatic decline in the ice cover. This shelf zone is characterized by huge reserves of oil and natural gas (~90% methane), as well as presence of sub-seabed permafrost and methane hydrates. Seasonal cycle of atmospheric methane has a minimum in early summer and a maximum in early winter. During last 16 years both summer and winter concentrations were increasing, but with different rates. Positive summer trends over the Kara Sea and over Atlantic control area were close one to another. In winter the Kara Sea methane was growing faster than over Atlantic. The methane seasonal cycle amplitude tripled from 2003 to 2019. This phenomenon was considered in terms of growing methane flux from the sea. This high trend was induced by a fast decay of the sea ice in this area with ice concentrations dropped from 95 to 20%. If the current Arctic sea cover would decline further and open water area would grow then further increase of methane concentration over the ocean may be foreseen.Проанализированы ИК спутниковые данные о концентрации метана в слое атмосферы 0–4 км над Карским и Баренцевым морями в сравнении с микроволновыми спутниковыми измерениями ледяного покрова Карского моря. За последние 16 лет амплитуда сезонных вариаций метана над северной частью Карского моря выросла в 3 раза, а площадь поверхности того же района, свободная от льда, увеличилась в 4 раза. Сделан вывод о значительной роли ледяного покрова в экранировании потока метана в атмосферу

Analysis of global and regional CO burdens measured from space between 2000 and 2009 and validated by ground-based solar tracking spectrometers

Interannual variations in AIRS and MOPITT retrieved CO burdens are validated, corrected, and compared with CO emissions from wild fires from the Global Fire Emission Dataset (GFED2) inventory. Validation of daily mean CO total column (TC) retrievals from MOPITT version 3 and AIRS version 5 is performed through comparisons with archived TC data from the Network for Detection of Atmospheric Composition Change (NDACC) ground-based Fourier Transform Spectrometers (FTS) between March 2000 and December 2007. MOPITT V3 retrievals exhibit an increasing temporal bias with a rate of 1.4–1.8% per year; thus far, AIRS retrievals appear to be more stable. For the lowest CO values in the Southern Hemisphere (SH), AIRS TC retrievals overestimate FTS TC by 20%. MOPITT's bias and standard deviation do not depend on CO TC absolute values. Empirical corrections are derived for AIRS and MOPITT retrievals based on the observed annually averaged bias versus the FTS TC. Recently published MOPITT V4 is found to be in a good agreement with MOPITT V3 corrected by us (with exception of 2000–2001 period). With these corrections, CO burdens from AIRS V5 and MOPITT V3 (as well as MOPITT V4) come into good agreement in the mid-latitudes of the Northern Hemisphere (NH) and in the tropical belt. In the SH, agreement between AIRS and MOPITT CO burdens is better for the larger CO TC in austral winter and worse in austral summer when CO TC are smaller. Before July 2008, all variations in retrieved CO burden can be explained by changes in fire emissions. After July 2008, global and tropical CO burdens decreased until October before recovering by the beginning of 2009. The NH CO burden also decreased but reached a minimum in January 2009 before starting to recover. The decrease in tropical CO burdens is explained by lower than usual fire emissions in South America and Indonesia. This decrease in tropical emissions also accounts for most of the change in the global CO burden. However, no such diminution of NH biomass burning is indicated by GFED2. Thus, the CO burden decrease in the NH could result from a combination of lower fossil fuel emissions during the global economic recession and transport of CO-poor air from the tropics. More extensive modeling will be required to fully resolve this issue

Increase in Arctic Oscillations explains most interannual variability in Russia’s wildfires

Over the past two decades, the escalating emissions of greenhouse gases from boreal wildfires in the Northern Hemisphere have drawn significant attention, underscoring an unprecedented wildfire season in 2021. Our calculations indicate that between 2002 and 2020, wildfires in Russia released approximately 726 ± 280 Tg CO2eqv yr−1. This aligns closely with similar estimates derived from remote sensing data, far surpassing the earlier approximations found in the Russian National Inventory Report (NIR) by a factor of 2 to 3. Notably, in 2021 alone, Russia’s wildfires emitted an exceptionally high amount of 1,700 Tg CO2eqv, exceeding the carbon emissions from the country’s fossil fuel consumption. Consequently, this situation led to an almost complete counterbalance of carbon assimilation by Russian forests. Our analysis attributes over 50% of the variation in wildfire frequency between 2002 and 2021 to shifts in the Arctic Oscillation (AO). This suggests a potential for utilizing AO as a predictive variable for wildfires. It’s noteworthy that the AO itself is influenced by the sustained regression of Arctic sea-ice. From this, it can be inferred that in the foreseeable future, Russian forests might undergo a transition from their role as carbon sinks to the potential net contributors of carbon to the atmosphere

Ocean stratification and sea-ice cover in Barents and Kara seas modulate sea-air methane flux: satellite data

The diverse range of mechanisms driving the Arctic amplification and global climate are not completely understood and, in particular, the role of the greenhouse gas methane (CH4) in the Arctic warming remains unclear. Strong sources of methane at the ocean seabed in the Barents Sea and other polar regions are well documented. Nevertheless, some of those publications suggest that negligible amounts of methane fluxed from the seabed enter the atmosphere, with roughly 90% of the methane consumed by bacteria. Most in situ observations are taken during summer, which is favorable for collecting data but also characterized by a stratified water column. We present perennial observations of three Thermal IR space-borne spectrometers in the Arctic between 2002 and 2020. According to estimates derived from the data synthesis ECCO (Estimating the Circulation and Climate of the Ocean), in the ice-free Barents Sea the stratification in winter weakens after the summer strong stability. The convection, storms, and turbulent diffusion mix the full-depth water column. CH4 excess over a control area in North Atlantic, measured by three sounders, and the oceanic Mixed Layer Depth (MLD) both maximize in winter. A significant seasonal increase of sea-air exchange in ice-free seas is assumed. The amplitude of the seasonal methane cycle for the Kara Sea significantly increased since the beginning of the century. This may be explained by a decline of ice concentration there. The annual CH4 emission from the Arctic seas is estimated as 2/3 of land emission. The Barents/Kara seas contribute between 1/3 and 1/2 into the Arctic seas annual emission

Carbon monoxide mixing ratios over Oklahoma between 2002 and 2009 retrieved from Atmospheric Emitted Radiance Interferometer spectra

CO mixing ratios for the lowermost 2-km atmospheric layer were retrieved from downwelling infrared (IR) radiance spectra of the clear sky measured between 2002 and 2009 by a zenith-viewing Atmospheric Emitted Radiance Interferometer (AERI) deployed at the Southern Great Plains (SGP) observatory of the Atmospheric Radiation Measurements (ARM) Program near Lamont, Oklahoma. A version of a published earlier retrieval algorithm was improved and validated. Archived temperature and water vapor profiles retrieved from the same AERI spectra through automated ARM processing were used as input data for the CO retrievals. We found the archived water vapor profiles required additional constraint using SGP Microwave Radiometer retrievals of total precipitable water vapor. A correction for scattered solar light was developed as well. The retrieved CO was validated using simultaneous independently measured CO profiles from an aircraft. These tropospheric CO profiles were measured from the surface to altitudes of 4572 m a.s.l. once or twice a week between March 2006 and December 2008. The aircraft measurements were supplemented with ground-based CO measurements using a non-dispersive infrared gas correlation instrument at the SGP and retrievals from the Atmospheric IR Sounder (AIRS) above 5 km to create full tropospheric CO profiles. Comparison of the profiles convolved with averaging kernels to the AERI CO retrievals found a squared correlation coefficient of 0.57, a standard deviation of ±11.7 ppbv, a bias of -16 ppbv, and a slope of 0.92. Averaged seasonal and diurnal cycles measured by the AERI are compared with those measured continuously in situ at the SGP in the boundary layer. Monthly mean CO values measured by the AERI between 2002 and 2009 are compared with those measured by the AIRS over North America, the Northern Hemisphere mid-latitudes, and over the tropics

Method of determining the optimal settings of automatic excitation regulators of synchronous machines in EPS

The stability of the electric power system can be improved by forming of the correct settings of automatic exciting regulators. Currently, there is no unified methodology of automatic exciting regulators, so analysis of their impact is still an urgent task. The article describes the approach to solving above-mentioned problem, which combines several methods. Research based on Hybrid Real Time Simulator of EPS developed in Tomsk Polytechnic University

Seasonal variation of carbon monoxide in northern Japan: Fourier transform IR measurements and source-labeled model calculations

Tropospheric carbon monoxide (CO) was measured throughout 2001 using groundbased Fourier transform IR (FTIR) spectrometers at Moshiri 44.4N and Rikubetsu 43.5N) observatories in northern Japan, which are separated by 150 km. Seasonal and day-to-day variations of CO are studied using these data, and contributions from various CO sources are evaluated using three-dimensional global chemistry transport model (GEOS-CHEM) calculations. Seasonal maximum and minimum FTIR-derived tropospheric CO amounts occurred in April and September, respectively. The ratio of partial column amounts between the 0–4 and 0–12 km altitude ranges is found to be slightly greater in early spring. The GEOS-CHEM model calculations generally reproduce these observed features. Source-labeled CO model calculations suggest that the observed seasonal variation is caused by seasonal contributions from various sources, in addition to a seasonal change in chemical CO loss by OH. Changes in meteorological fields largely control the relative importance of various source contributions. The contributions from fossil fuel (FF) combustion in Asia and photochemical CO production have the greatest yearly averaged contribution at 1 km among the CO sources (31% each). The Asian FF contribution increases from winter to summer, because weak southwesterly wind in summer brings more Asian pollutants to the observation sites. The seasonal variation from photochemical CO production is small (±17% at 1 km), likely because of concurrent increases (decreases) of photochemical production and loss rates in summer (winter), with the largest contribution between August and December. The contribution from intercontinental transport of European FF combustion CO is found to be comparable to that of Asian FF sources in winter. Northwesterly wind around the Siberian high in this season brings pollutants from Europe directly to Japan, in addition to southward transport of accumulated pollution from higher latitudes. The influences are generally greater at lower altitudes, resulting in a vertical gradient in the CO profile during winter. The model underestimates total CO by 12–14% between March and June. Satellite-derived fire-count data and the relationship between FTIR-derived HCN and CO amounts are generally consistent with biomass burning influences, which could have been underestimated by the model calculations

СРЕДСТВА УЧЕТА ОБЪЕМНОГО И МАССОВОГО РАСХОДА, ЭКСПЛУАТИРУЕМЫЕ В РЕСПУБЛИКЕ БЕЛАРУСЬ. ОПЫТ ПОВЕРКИ И КАЛИБРОВКИ НА УСТАНОВКЕ «ЭТАЛОН»

One of the major technical problems of industry of the Republic of Belarus is the measurement of mass and volume flow rate, as the basis for technological consideration in energy-saving and resource-saving technologies. To solve this task many measuring instruments subject to metrological control are developed. This article provides an analysis of the main types of means of discharge measurements, which are used at the industrial enterprises of the Republic of Belarus, the modern requirements for flow meters, as well as assessment of the metrological reliability in time for some types of flowmeters.Одной из важнейших технических задач промышленности Республики Беларусь является измерение массового и объемного расхода как основы для обеспечения технологического учета в энергосберегающих и ресурсосберегающих технологиях. Для решения этой задачи разрабатывается множество средств измерений, которые подлежат обязательному метрологическому контролю. В данной статье приводятся анализ основных типов средств измерений расхода, которые применяются на промышленных предприятиях Республики Беларусь, современные требования, предъявляемые к расходомерам, а также оценка метрологической надежности во времени для некоторых типов расходомеров.