scholarly journals Temporal variance of the ice navigation conditions within the Northern Sea Route

2021 ◽  
Vol 937 (4) ◽  
pp. 042095
Author(s):  
V Yu Tretyakov ◽  
A V Egovtseva ◽  
V V Dmitriev
Keyword(s):  
Buffer Zone ◽  
Ice Age ◽  
Yamal Peninsula ◽  
Integral Parameter ◽  
Bering Strait ◽  
Statistical Homogeneity ◽  
Temporal Variance ◽  
Partial Concentration ◽  
Ice Navigation ◽  
The One

Abstract Recognition of satellite images, composition of them and vectorization is used in AARI for ice charts production. There is discussed methodology and results of the ice charts processing by means of computer programs, which were elaborated by Dr. Tretyakov in Python. The paper demonstrates results of analysis of temporal variance of ice navigation circumstances within the buffer zone of the marine transport system from the Sabetta Port (the Yamal Peninsula, Russia) up to the Bering Strait. There are considered the variance for April and May from 1998 up to 2020. This intra-annual interval is the one with the heaviest ice circumstances for shipping. We used conditional length of various age and age and form gradations of the sea ice for the route as a whole, as an integral parameter for estimation of the navigation hardships of ice navigation. The conditional length of an ice age (thickness) diapason is result of multiplication of the diapason partial concentration at the length of the route leg with homogeneous ice characteristics. There were produced series of the conditional lengths for each ten-day periods during April and May. Then statistical homogeneity of the series was tested by various methods.

scholarly journals Arctic Ocean stratification set by sea level and freshwater inputs since the last ice age

2021 ◽  
Author(s):  
Jesse R. Farmer ◽  
Daniel M. Sigman ◽  
Julie Granger ◽  
Ona M. Underwood ◽  
François Fripiat ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Surface Waters ◽  
Ice Age ◽  
The Arctic ◽  
Bering Strait ◽  
Central Arctic Ocean ◽  
Phytoplankton Productivity ◽  
Nitrate Consumption ◽  
Western Arctic ◽  
Last Ice Age

AbstractSalinity-driven density stratification of the upper Arctic Ocean isolates sea-ice cover and cold, nutrient-poor surface waters from underlying warmer, nutrient-rich waters. Recently, stratification has strengthened in the western Arctic but has weakened in the eastern Arctic; it is unknown if these trends will continue. Here we present foraminifera-bound nitrogen isotopes from Arctic Ocean sediments since 35,000 years ago to reconstruct past changes in nutrient sources and the degree of nutrient consumption in surface waters, the latter reflecting stratification. During the last ice age and early deglaciation, the Arctic was dominated by Atlantic-sourced nitrate and incomplete nitrate consumption, indicating weaker stratification. Starting at 11,000 years ago in the western Arctic, there is a clear isotopic signal of Pacific-sourced nitrate and complete nitrate consumption associated with the flooding of the Bering Strait. These changes reveal that the strong stratification of the western Arctic relies on low-salinity inflow through the Bering Strait. In the central Arctic, nitrate consumption was complete during the early Holocene, then declined after 5,000 years ago as summer insolation decreased. This sequence suggests that precipitation and riverine freshwater fluxes control the stratification of the central Arctic Ocean. Based on these findings, ongoing warming will cause strong stratification to expand into the central Arctic, slowing the nutrient supply to surface waters and thus limiting future phytoplankton productivity.

The impact of snow products on detecting trends in sea ice thickness during the CryoSat-2 era

2020 ◽  
Author(s):  
Heidi Sallila ◽  
Samantha Buzzard ◽  
Eero Rinne ◽  
Michel Tsamados
Keyword(s):  
Sea Ice ◽  
Snow Depth ◽  
Ice Age ◽  
Ice Thickness ◽  
Sea Ice Thickness ◽  
Seasonal Snow ◽  
Uncertainty Estimates ◽  
The One ◽  
The Impact ◽  
First Time

<p>Retrieval of sea ice depth from satellite altimetry relies on knowledge of snow depth in the conversion of freeboard measurements to sea ice thickness. This remains the largest source of uncertainty in calculating sea ice thickness. In order to go beyond the use of a seasonal snow climatology, namely the one by Warren created from measurements collected during the drifting stations in 1937 and 1954–1991, we have developed as part of an ESA Arctic+ project several novel snow on sea ice pan-Arctic products, with the ultimate goal to resolve for the first time inter-annual and seasonal snow variability.</p><p><span>Our products are inter-compared and calibrated with each other to guarantee multi-decadal continuity, and also compared with other recently developed snow on sea ice modelling </span><span>and satellite based </span><span>products. Quality assessment and uncertainty estimates are provided at a gridded level and as a function of sea ice cover characteristics such as sea ice age, and sea ice type.</span></p><p>We investigate the impact of the spatially and temporally varying snow products on current satellite estimates of sea ice thickness and provide an update on the sea ice thickness uncertainties. We pay particular attention to potential biases of the seasonal ice growth and inter-annual trends.</p>

scholarly journals Aproximación a la correspondencia como fuente para el estudio del clima: la necesidad de un análisis léxico

2019 ◽  
pp. 13-36
Author(s):  
Irene Andreu Candela
Keyword(s):  
Eighteenth Century ◽  
Content Analysis ◽  
Little Ice Age ◽  
Ice Age ◽  
Climate Research ◽  
Private Correspondence ◽  
The One ◽  
As Stress ◽  
Carlos Iii ◽  
Different Sources

RESUMENLos epistolarios se han convertido en los últimos años en una de las diversas fuentes utilizadas en el estudio del clima del pasado, sin embargo, han sido pocos los estudios dedicados a este tipo de información a pesar del potencial que tienen. Este artículo pretende demostrar las posibilidades investigadoras de la correspondencia privada, en este caso la mantenida entre Carlos III y Bernardo Tanucci, comprobando en qué contexto aparecen estas referencias e incidiendo en la importancia de estudiar el lenguaje utilizado para describir los fenómenos meteorológicos.PALABRAS CLAVECorrespondencia, clima, Pequeña Edad del Hielo, análisis de contenido, Carlos III. TITLEAn approach to correspondence as a source for climate research: the need of a lexical analysisABSTRACTThe correspondence has become in recent years one of the different sources used in climate research, however, few studies have been dedicated to this kind of information contained in the letters despite the potential they have. This article aims to demonstrate the investigative possibilities of private correspondence, in this case the one maintained between Carlos III and Bernardo Tanucci, checking in what context these references appear in the eighteenth-century epistolary exchanges, as well as stress the importance of studying the language used to describe meteorological phenomena.KEY WORDSCorrespondence, climate, Little Ice Age, content analysis, Carlos III.

Arctic Nomadic Design (The Nenets Case)

2020 ◽  
Vol 24 (1) ◽  
pp. 111-142
Author(s):  
Andrei V. Golovnev
Keyword(s):  
Extreme Environment ◽  
Space Time ◽  
3D Modelling ◽  
The Other ◽  
The Arctic ◽  
Yamal Peninsula ◽  
Gps Tracking ◽  
New Methods ◽  
Movement Effect ◽  
The One

The nomadic technologies of reindeer herders from Yamal Peninsula, in their multidimensional complexity – from the space-time continuity of mobile camps on the open tundra to multi-functionality of material things – enable and facilitate mobility in the extreme environment of the Arctic. The nomadic tradition contains a whole array of concepts (or principles), which, on the one hand, are ultimately practical and, on the other, deserve a theoretical projection. These include: nomadic transformer, mobile module, movement effect, techno-animation, material austerity, space-time continuity, arctic aesthetics. A study of nomadic design implies the usage of new methods of movement recording – MTA (mapping–tracking–acting), including visual data such as UAV mapping, GPS-tracking and 3D-modelling.

7. The Arctic carbon vault

2021 ◽  
pp. 125-136
Author(s):  
Klaus Dodds ◽  
Jamie Woodward
Keyword(s):  
Organic Carbon ◽  
Carbon Sink ◽  
Ice Age ◽  
The Arctic ◽  
Yamal Peninsula ◽  
Frozen Ground ◽  
Global Soil ◽  
Shelf Sea ◽  
Thawing Permafrost ◽  
Bodies Of Water

‘The Arctic carbon vault’ describes the large share of Earth's organic carbon sequestered in the frozen ground and within the shelf sea sediments of the Arctic Ocean. The organic carbon stock of the permafrost is roughly equivalent to half of total global soil carbon. A cold Arctic with extensive permafrost is an effective long-term carbon sink as carbon is safely locked away as long as permafrost is maintained. Giant craters appeared on the Yamal peninsula. The thawing permafrost leads to the formation of thermokarst lakes, which are frozen bodies of water held in subsidence depressions created by the thawing of ground ice. Well-preserved carcasses of extinct ice age beasts, including woolly mammoths and cave bears, have been recovered from the thawing permafrost.

Effect of reindeer overgrazing on vegetation and animals of tundra ecosystems of the Yamal peninsula

2012 ◽  
Vol 2 (2) ◽  
pp. 80-91 ◽  
Author(s):  
Mikhail G. Golovatin ◽  
Ludmila M. Morozova ◽  
Svetlana N. Ektova
Keyword(s):  
Yamal Peninsula ◽  
Animal Populations ◽  
Key Points ◽  
Tundra Ecosystem ◽  
Reindeer Population ◽  
The One ◽  
The Impact ◽  
Rapid Transformation ◽  
The Yamal Peninsula

Currently, 380 000 domestic reindeers are grazed on 106000 km2 of the Yamal peninsula. This unique situation was analyzed from a view of an ecosystem role of indigenous people. Attention was paied to two key points: the impact of overgrazing on (1) vegetation and (2) vertebrates. The results of our 30-years investigations were compared with the published vegetation data from the 1930-ies. In our paper, it is demonstrated, that overgrazing has resulted in a substantial transformation of vegetation, mostly in lichen tundra. Recent situation is close to total extinction of lichen pastures on the Yamal peninsula. Due to overgrazing, total availability of grasses and shrubs have also decreased, in grasses by 1.5-2.0 times, low shrubs - almost 8 times, tall shrubs – 2.0 times. The degradation of vegetation leads to desertification of the peninsula. The area of ​​sandy spots with no vegetation is on average about 5.5% of the peninsula land, however, it could reach up to 19% locally. Overgrazing affected the animal populations too. Since 1990, the peaks of lemmings have never reached former high values and become locally-limited and patchy. This has led to a decrease in the number of predators. The number of other tundra birds decreased as well. The decrease reached almost 2 times lower numbers in geese, 3 times in hygrophillous waders, 5.5 times in Lapland bunting, and 2 times in long-tailed Duck and Willow grouse on watershed. The Nenets themselves can not control reindeer population because of rigid social and psychological attitudes based on their traditions. The main aim of the Nenets reindeer-farming is not to create marketable products for a profit, but increasing the reindeer number of itself. A situation has formed, that, on the one hand, the Nenets are not economically dependent upon the society, and on the other hand, the society contributes to preservation of their traditional farming. The Nenets reindeer-farming, thus become an important factor contributing to rapid transformation of tundra ecosystem.

scholarly journals Vessel movement velocity as the integral parameter of ice navigation conditions

2021 ◽  
Vol 625 ◽  
pp. 012021
Author(s):  
V Yu Tretyakov ◽  
M I Sarafanov ◽  
V E Fediakov ◽  
S V Frolov
Keyword(s):  
Integral Parameter ◽  
Movement Velocity ◽  
Ice Navigation

IV.—The Supposed Glacial Origin of Carboniferous Terraces

1877 ◽  
Vol 4 (1) ◽  
pp. 17-19
Author(s):  
J. R. Dakyns
Keyword(s):  
Ice Sheet ◽  
The Other ◽  
Ice Age ◽  
Glacial Origin ◽  
Good For ◽  
The One

There is a homely saying, “Sauce for the goose is sauce for the gander.” Mr. Goodchild, with that ingenuity for which he is remarkable, has written an elaborate paper to prove that the terraces of the Yorkshire Limestone dales are all the work of the Great Ice Sheet. This paper will doubtless call forth a number of equally elaborate answers: and this is well. But if Mr. Goodchild has a fine goose fattened on the Limestone terraces of Wensleydale, I have an equally fine gander reared on Gritstone terraces in Derbyshire: and if a frozen sauce of regelated snow from wintry storms of the Great Ice Age is good for one, it is equally good for the other. Dropping metaphor, there is no difference between terraces, mainly of limestone, in Wensleydale, and other terraces, chiefly of grit, that are found over all the Millstone Grit area of South Yorkshire and Derbyshire, saving that while limestone predominates in the one, beds of grit do in the other.

scholarly journals A Homogeneity Test for Comparing Gridded-Spatial-Point Patterns of Human Caused Fires

Forests ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 454
Author(s):  
M. Alba-Fernández ◽  
Francisco Ariza-López
Keyword(s):  
Wildland Fire ◽  
Homogeneity Test ◽  
Statistical Tool ◽  
Specific Test ◽  
Space Filling Curve ◽  
Statistical Homogeneity ◽  
Point Patterns ◽  
Spatial Point ◽  
Spatial Point Patterns ◽  
The One

The statistical evaluation of the spatial similarity of human caused fire patterns is an important issue for wildland fire analysis. This paper proposes a method based on observed data and on a statistical tool (homogeneity test) that is based on non-explicit spatial distribution hypothesis for the human caused fire events. If a tessellation coming from a space filling curve is superimposed on the spatial point patterns, and a linearization mechanism applied, the statistical problem of testing the similarity between the spatial point patterns is equivalent to the one of testing the homogeneity between the two multinomial distributions obtained by modeling the proportions of cases on each cell of the tessellation. This way of comparing spatial point patterns is free of any hypothesis on any spatial point process. Because data are spatially over-dispersed, the existence of many cells of the grid without any count is a problem for classical statistical homogeneity tests. Our work overcomes this problem by applying specific test statistics based on the square Hellinger distance. Simulations and actual data are used in order to tune the process and to demonstrate the capabilities of the proposal. Results indicate that a new and robust method for comparing spatial point patterns of human caused fires is available.

scholarly journals Current state of glaciers in the tropical Andes: a multi-century perspective on glacier evolution and climate change

2013 ◽  
Vol 7 (1) ◽  
pp. 81-102 ◽  
Author(s):  
A. Rabatel ◽  
B. Francou ◽  
A. Soruco ◽  
J. Gomez ◽  
B. Cáceres ◽  
...  
Keyword(s):  
Climate Change ◽  
Mass Balance ◽  
18Th Century ◽  
Break Point ◽  
Global Scale ◽  
Ice Age ◽  
Current Status ◽  
Tropical Andes ◽  
Comprehensive Overview ◽  
The One

Abstract. The aim of this paper is to provide the community with a comprehensive overview of the studies of glaciers in the tropical Andes conducted in recent decades leading to the current status of the glaciers in the context of climate change. In terms of changes in surface area and length, we show that the glacier retreat in the tropical Andes over the last three decades is unprecedented since the maximum extension of the Little Ice Age (LIA, mid-17th–early 18th century). In terms of changes in mass balance, although there have been some sporadic gains on several glaciers, we show that the trend has been quite negative over the past 50 yr, with a mean mass balance deficit for glaciers in the tropical Andes that is slightly more negative than the one computed on a global scale. A break point in the trend appeared in the late 1970s with mean annual mass balance per year decreasing from −0.2 m w.e. in the period 1964–1975 to −0.76 m w.e. in the period 1976–2010. In addition, even if glaciers are currently retreating everywhere in the tropical Andes, it should be noted that this is much more pronounced on small glaciers at low altitudes that do not have a permanent accumulation zone, and which could disappear in the coming years/decades. Monthly mass balance measurements performed in Bolivia, Ecuador and Colombia show that variability of the surface temperature of the Pacific Ocean is the main factor governing variability of the mass balance at the decadal timescale. Precipitation did not display a significant trend in the tropical Andes in the 20th century, and consequently cannot explain the glacier recession. On the other hand, temperature increased at a significant rate of 0.10 °C decade−1 in the last 70 yr. The higher frequency of El Niño events and changes in its spatial and temporal occurrence since the late 1970s together with a warming troposphere over the tropical Andes may thus explain much of the recent dramatic shrinkage of glaciers in this part of the world.

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