87Sr/86Sr ratio in early paleoproterozoic seawater: Implications for the δ13Ccarb positive anomaly

Regional climate change in Ukraine in recent decades is accompanied by an increase in the repetitiveness of intense waves, both heat and cold; there is a tendency to increase the frequency of warm winters, but sometimes there are periods with significant decreases in temperature. The aim of the study is to determine the specifics of the formation of air temperature anomalies in the cold period 2010–2019. According to the distribution of the average monthly air temperature at the stations Odessa, Kiev, Kharkiv, Lviv investigated positive and negative deviations from the climate norm. In January, the average monthly air temperature in most cases was above normal, except for 1–3 years. The maximum positive anomaly was 4–5°C in Kyiv and Lviv (2015), the largest negative deviations were 3.8°C. In February, the trend continues – only 2–3 years with negative anomalies, the largest deviations to 3–6°C in 2011 and 2012, and positive deviations maximum in 2016. In March, negative temperature anomalies were observed 3–4 years, with a maximum of 2–3°C in 2018, positive anomalies in 4–6°C were observed in 2014, 2017. Temperatures in November were variable, with the prevailing positive anomaly, a high of 6–8°C in 2010. The distribution of air temperature in December was characterized by positive deviations of a maximum of 5–6°C in 2011, 2015, 2017 and 2019. Months of the greatest positive and negative air temperature anomalies over Europe have been highlighted. Among the colder months, the biggest anomaly stood out in January 2010 and February 2012 to 5–6°C. Among the warm months, the temperature anomaly was observed in February 2016, positive deviations from the norm to 8°C. Heat waves formed in winter with a zonal type of circulation, when warm moist air from the Atlantic shifted across the periphery of the Icelandic low. In March, waves of heat formed in low–gradient fields. Powerful waves of cold over the European sector were mainly formed under the influence of “eastern processes” in the spread of the Siberian anticyclone to Europe. In some years, significant cooling over Ukraine is formed in cyclonic systems with a high–altitude thermobaric field characterized by polar or ultrapolar hollow.

Download Full-text

Sr Isotope Chemostratigraphy and Pb–Pb Age of the Riphean Carbonate Deposits of the Kharaulakh Uplift (Northeastern Margin of the Siberian Platform)

Russian Geology and Geophysics ◽

10.2113/rgg20194076 ◽

2021 ◽

Vol 62 (03) ◽

pp. 377-387

Author(s):

B.B. Kochnev ◽

A.B. Kuznetsov ◽

D.R. Sitkina ◽

A.Yu. Kramchaninov

Keyword(s):

Siberian Platform ◽

Sedimentary Cover ◽

Complex Structure ◽

The Arctic ◽

86Sr Ratio ◽

Sr Isotope ◽

Upper Riphean ◽

Carbonate Deposits

Abstract —The least altered limestones of the Ukta and Eselekh formations in the Precambrian section of the Kharaulakh uplift have a minimum 87Sr/86Sr ratio of 0.70673–0.70715. The lowest 87Sr/86Sr ratio of the overlying Neleger and Sietachan formations is 0.70791–0.70817. Based on these data, along with the earlier obtained positive δ13С values (up to 8‰) for the Kharaulakh section, we have estimated the age of the Ukta and Eselekh formations at 800–670 Ma and the age of the Neleger and Sietachan formations at ~640–580 Ma. The Pb–Pb isochron age of the least altered limestones of the Eselekh Formation calculated from eight samples is 720 ± 30 Ma. This age permits us to define the lower part of the Kharaulakh section of the Ukta and Eselekh formations to be the late Tonian of the International Chronostratigraphic Chart or to the Upper Riphean of the General Stratigraphic Scale of Russia. The presence of reliably dated Upper Riphean sediments in the Kharaulakh uplift indicates a more complex structure of the Precambrian sedimentary cover on the Arctic margin of the Siberian Platform than assumed earlier.

Download Full-text

Thermomechanical coupling of ice flow with the bedrock

Annals of Glaciology ◽

10.3189/172756403781815988 ◽

2003 ◽

Vol 37 ◽

pp. 390-396 ◽

Cited By ~ 1

Author(s):

Richard C.A. Hindmarsh

Keyword(s):

Temperature Distribution ◽

Horizontal Velocity ◽

Time Dependent ◽

Thermomechanical Coupling ◽

Positive Anomaly ◽

Thermal Coupling ◽

Steady Temperature ◽

Ice Flow ◽

Time Dependent Problem ◽

Geomorphological Processes

AbstractTwo aspects of thermal coupling with bedrock are considered: the coupled time-dependent problem of co-evolving temperatures in lithosphere and ice; and the influence of basal topography on steady temperature distribution within the ice. The nature of the time-dependent coupling is found to depend on the horizontal velocity. As has been suggested, there is a cooling of steady temperatures on bedrock highs, but this is phase-shifted downstream when horizontal velocities increase. This observation may have consequences for geomorphological processes such as plucking and protection. The effect of bedrock channelling on steady temperature is considered. The positive anomaly of basal temperature due to channelling increases as the transverse wavelength decreases, but not monotonically, reaching a plateau when both the wavelengths of the basal topography are around 100 km.

Download Full-text

Changes in Frequency of Occurrence of Yearly Precipitation Anomalies in the Lublin Region in the Second Half of the 20th Century

Bulletin of Geography Physical Geography Series ◽

10.2478/bgeo-2009-0012 ◽

2009 ◽

Vol 2 (1) ◽

pp. 63-68

Author(s):

Szczepan Mrugała ◽

Krzysztof Siwek

Keyword(s):

20Th Century ◽

Atmospheric Precipitation ◽

Precipitation Anomaly ◽

Frequency Of Occurrence ◽

Positive Anomaly ◽

Precipitation Anomalies ◽

Yearly Precipitation

Abstract The aim of this paper is to characterise changes in frequency of occurrence of anomalous yearly sums of atmospheric precipitation in the Lublin region in the period 1951-2000. In the second half of the 20th century negative precipitation anomaly occurred in a larger number of stations than the positive anomaly. Particularly strong anomalies were observed in two decades (1951-1960 and 1981-1990). However, during two following decades (1961-1970 and 1971-1980) the positive anomaly occurred in more stations.

Download Full-text

Heat flow and presence of oil and gas (the Yamal peninsula, Tomsk region)

Georesursy ◽

10.18599/grs.2019.3.125-135 ◽

2019 ◽

Vol 21 (3) ◽

pp. 125-135

Author(s):

Valery I. Isaev ◽

Galina A. Lobova ◽

Alexander N. Fomin ◽

Valery I. Bulatov ◽

Stanislav G. Kuzmenkov ◽

...

Keyword(s):

Heat Flow ◽

Western Siberia ◽

Oil And Gas ◽

Sedimentary Cover ◽

The Arctic ◽

Yamal Peninsula ◽

Flow Density ◽

Positive Anomaly ◽

Tomsk Region ◽

History Of

The possibilities of Geothermy as a geophysical method are studied to solve forecast and prospecting problems of Petroleum Geology of the Arctic regions and the Paleozoic of Western Siberia. Deep heat flow of Yamal fields, whose oil and gas potential is associated with the Jurassic-Cretaceous formations, and the fields of Tomsk Region, whose geological section contents deposits in the Paleozoic, is studied. The method of paleotemperature modeling was used to calculate the heat flow density from the base of a sedimentary section (by solving the inverse problem of Geothermy). The schematization and mapping of the heat flow were performed, taking into account experimental determinations of the parameter. Besides, the correlation of heat flow features with the localization of deposits was revealed. The conceptual and factual basis of research includes the tectonosedimentary history of sedimentary cover, the Mesozoic-Cenozoic climatic temperature course and the history of cryogenic processes, as well as lithologic and stratigraphic description of the section, results of well testing, thermometry and vitrinite reflectivity data of 20 deep wells of Yamal and 37 wells of Ostanino group of fields of Tomsk region. It was stated that 80 % of known Yamal deposits correlate with anomalous features of the heat flow. Bovanenkovskoe and Arkticheskoe fields are located in positive anomaly zones. 75 % of fields of Ostanino group relate to anomalous features of the heat flow. It is shown that the fields, which are characterized by existence of commercial deposits in the Paleozoic, are associated with the bright gradient zone of the heat flow. The forecast of commercial inflows in the Paleozoic for Pindzhinskoe, Mirnoe and Rybalnoe fields is given. The correlation between the intensity of naftidogenesis and the lateral inhomogeneity of the deep heat flow is characterized as a probable fundamental pattern for Western Siberia.

Download Full-text

The effect of cyclones crossing the Mediterranean region on sea level anomalies at the Mediterranean Sea coast

10.5194/nhess-2019-6 ◽

2019 ◽

Author(s):

Piero Lionello ◽

Dario Conte ◽

Marco Reale

Keyword(s):

Mediterranean Sea ◽

Sea Level ◽

Eastern Mediterranean ◽

Storm Track ◽

Western Mediterranean ◽

Residual Water ◽

Positive Anomaly ◽

Western Basin ◽

Sea Level Anomalies ◽

The Mediterranean

Abstract. Large positive and negative sea level anomalies at the coast of the Mediterranean Sea are linked to intensity and position of cyclones moving along the Mediterranean storm track, with dynamics involving different factors. This analysis is based on a model hindcast and considers nine coastal stations, which are representative of sea level anomalies with different magnitude and characteristics. When a shallow water fetch is present, the wind around the cyclone center is the main cause of sea level positive and negative anomalies, depending on its onshore or offshore direction. The inverse barometer effect produces a positive anomaly at the coast near the cyclone pressure minimum and a negative anomaly at the opposite side of the Mediterranean Sea, because a cross-basin mean sea level pressure gradient is associated to the presence of a cyclone. Further, at some stations, negative sea level anomalies are reinforced by a residual water mass redistribution within the basin, which is associated with a transient response to the atmospheric pressure forcing. Though the link between presence of a cyclone in the Mediterranean has comparable importance for positive and negative anomalies, the relation between cyclone position and intensity is stronger for the magnitude of positive events. Area of cyclogenesis, track of the central minimum and position at the time of the event differ depending on the location where the sea level anomaly occurs and on its sign. The western Mediterranean is the main cyclogenesis area for both positive and negative anomalies, overall. Atlantic cyclones mainly produce positive sea level anomalies in the western basin. At the easternmost stations, positive anomalies are caused by Cyclogenesis in the Eastern Mediterranean. North Africa cyclogeneses are a major source of positive anomalies at the central African coast and negative anomalies at the eastern Mediterranean and North Aegean coast.

Download Full-text

A Study of the Distribution and Variability of Cloud Water Using ISCCP, SSM/I Cloud Product, and Reanalysis Datasets

Journal of Climate ◽

10.1175/jcli-d-13-00031.1 ◽

2014 ◽

Vol 27 (9) ◽

pp. 3114-3128 ◽

Cited By ~ 6

Author(s):

Zhiwei Heng ◽

Yunfei Fu ◽

Guosheng Liu ◽

Renjun Zhou ◽

Yu Wang ◽

...

Keyword(s):

Cloud Water ◽

Positive Anomaly ◽

Liquid Water Path ◽

Water Path ◽

The North ◽

Increasing Trend ◽

Moderate Resolution ◽

Moderate Resolution Imaging Spectroradiometer ◽

Microwave Imager ◽

Ice Water

Abstract In this paper, the global distribution of cloud water based on International Satellite Cloud Climatology Project (ISCCP), Moderate Resolution Imaging Spectroradiometer (MODIS), CloudSat Cloud Profiling Radar (CPR), European Center for Medium-Range Weather Forecasts Interim Re-Analysis (ERA-Interim), and Climate Forecast System Reanalysis (CFSR) datasets is presented, and the variability of cloud water from ISCCP, the Special Sensor Microwave Imager (SSM/I), ERA-Interim, and CFSR data over the time period of 1995 through 2009 is discussed. The results show noticeable differences in cloud water over land and over ocean, as well as latitudinal variations. Large values of cloud water are mainly distributed over the North Pacific and Atlantic Oceans, eastern ITCZ, regions off the west coast of the continents as well as tropical rain forest. Cloud water path (CWP), liquid water path (LWP), and ice water path (IWP) from these datasets show a relatively good agreement in distributions and zonal means. The results of trend analyzing show an increasing trend in CWP, and also a significant increasing trend of LWP can be found in the dataset of ISCCP, ERA-Interim, and CFSR over the ocean. Besides the long-term variation trend, rises of cloud water are found when temperature and water vapor exhibit a positive anomaly. EOF analyses are also applied to the anomalies of cloud water, the first dominate mode of CWP and IWP are similar, and a phase change can be found in the LWP time coefficient around 1999 in ISCCP and CFSR and around 2002 in ERA-Interim.

Download Full-text

The impact of the 2015/2016 El Niño on global photosynthesis using satellite remote sensing

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2017.0409 ◽

2018 ◽

Vol 373 (1760) ◽

pp. 20170409 ◽

Cited By ~ 17

Author(s):

Xiangzhong Luo ◽

Trevor F. Keenan ◽

Joshua B. Fisher ◽

Juan-Carlos Jiménez-Muñoz ◽

Jing M. Chen ◽

...

Keyword(s):

Remote Sensing ◽

Carbon Cycle ◽

El Niño ◽

El Nino ◽

Southern Oscillation ◽

Carbon Sink ◽

Global Climate ◽

Prognostic Models ◽

Positive Anomaly ◽

The Impact

The El Niño-Southern Oscillation exerts a large influence on global climate regimes and on the global carbon cycle. Although El Niño is known to be associated with a reduction of the global total land carbon sink, results based on prognostic models or measurements disagree over the relative contribution of photosynthesis to the reduced sink. Here, we provide an independent remote sensing-based analysis on the impact of the 2015–2016 El Niño on global photosynthesis using six global satellite-based photosynthesis products and a global solar-induced fluorescence (SIF) dataset. An ensemble of satellite-based photosynthesis products showed a negative anomaly of −0.7 ± 1.2 PgC in 2015, but a slight positive anomaly of 0.05 ± 0.89 PgC in 2016, which when combined with observations of the growth rate of atmospheric carbon dioxide concentrations suggests that the reduction of the land residual sink was likely dominated by photosynthesis in 2015 but by respiration in 2016. The six satellite-based products unanimously identified a major photosynthesis reduction of −1.1 ± 0.52 PgC from savannahs in 2015 and 2016, followed by a highly uncertain reduction of −0.22 ± 0.98 PgC from rainforests. Vegetation in the Northern Hemisphere enhanced photosynthesis before and after the peak El Niño, especially in grasslands (0.33 ± 0.13 PgC). The patterns of satellite-based photosynthesis ensemble mean were corroborated by SIF, except in rainforests and South America, where the anomalies of satellite-based photosynthesis products also diverged the most. We found the inter-model variation of photosynthesis estimates was strongly related to the discrepancy between moisture forcings for models. These results highlight the importance of considering multiple photosynthesis proxies when assessing responses to climatic anomalies. This article is part of a discussion meeting issue ‘The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.

Download Full-text

Correction for Geomagnetic Secular Variation Effects: A New Method (Case Study of the Altai Geodynamic Network)

Russian Geology and Geophysics ◽

10.2113/rgg20194056 ◽

2021 ◽

Vol 62 (2) ◽

pp. 255-262

Author(s):

D.A. Kuleshov ◽

P.G. Dyadkov ◽

V.V. Plotkin

Keyword(s):

Secular Variation ◽

Surface Deformation ◽

Liquid Core ◽

New Method ◽

Space Distribution ◽

Main Magnetic Field ◽

Positive Anomaly ◽

Geomagnetic Secular Variation ◽

Using Data ◽

Curie Surface

Abstract ––The study focuses on detection of geomagnetic secular variation and the respective correction of tectonomagnetic data. A new technique is proposed for picking the secular variation component in the Earth’s main magnetic field recorded by precise measurements at 100 to 500 km sites on the surface. Long-period field variations presumably arise from fluid motions in the liquid core, at depths of 3000 km, whereas the sizes of observation networks are within 500 km. The sources of secular variation, irrespective of their configuration, are much deeper than those of tectonomagnetic anomalies located above the Curie surface depths of ~10 to 20 km. Therefore, the surfaces that represent the space distribution of secular variation must be smoother than the respective surfaces for tectonomagnetic anomalies. The problem is thus to separate the regional and local signals from the two types of sources located at different depths. The new method is tested using data of yearly geomagnetic measurements at more than 30 repeat stations of a ~120 km long geodynamic network in Gorny Altai spanning the period from 2004 through 2018. The secular variation pattern is reconstructed by quadratic interpolation. The precise data corrected for secular variation of the main field reveal previously hidden tectonomagnetic anomalies up to 12 nT. The 3 nT positive anomaly falls within the zone of surface deformation caused by the Mw = 7.3 Chuya earthquake of 27 September 2003.

Download Full-text