Dune systems in relation to rising seas

2009 ◽  
Author(s):  
Anwar Maun ◽  
Dianne Fahselt
Keyword(s):  
Plant Cover ◽  
Personal Communication ◽  
Sea Levels ◽  
Dune Systems ◽  
The North ◽  
The Indian Ocean ◽  
Tide Gage ◽  
Natural Dune ◽  
Global Mean

Beaches and associated dunes are constituted of unconsolidated materials, such as sand, and thus are low-strength land forms less robust than rocky cliffs (van der Meulen et al. 1991). It is estimated that 70% of sand-based coastlines in the world are presently subject to erosion (Bird 1985; Wind and Peerbolte 1993). However, natural dune systems are inclined to adjust after stress without permanent damage (Brown and McLachlin 2002), and when stabilized by plant cover they offer a first line of coastal defence against assault from wave action (Wind and Peerbolte 1993; Broadus 1993; De Ronde 1993). Natural self-sustaining dune systems interact with the sea and closely reflect changes in sea levels. At any given time no single sea level characterizes all oceans, that is, the resting position of the ocean surface, or geoid, is not uniformly elevated over the earth. Eustatic sea levels, free of influence from tides, waves and storms, thus vary from place to place as well as over time. Satellite altimetry, which permits more accurate as well as more numerous observations than older tide-gage methods of measuring sea levels, shows that the ocean is actually a spheroid modified by depressions and elevations. For example, in parts of the Indian Ocean sea levels are as much as 70 m lower than the global mean and in the North Atlantic 80 m higher (Carter 1988). Climate is governed by long-term periodic variations in the earth’s orbit that effect changes in solar radiation and, consequently, also in sea levels (Bartlein and Prentice 1989; Woodroffe 2002). As a result, ice ages repeatedly alternate with periods of interglacial warming in which ice masses contract and sea levels increase. Most of the time that has passed since the Cambrian period—approximately 500 million years—sea levels, although fluctuating on several timescales, have been higher than they are today. Because of the difficulties in documenting conditions so far in the distant past estimates of these sea levels vary considerably, but those shown in Fig. 13.1, based on different kinds of evidence, are representative of attempts at reconstruction (personal communication RA Rohde 2008).

In memory of Vera Antonovna Martynenko (1936-2018)

2018 ◽  
pp. 149-154
Keyword(s):  
Vascular Plants ◽  
Ussr Academy ◽  
Vascular Plant ◽  
Plant Cover ◽  
Komi Republic ◽  
Great Contribution ◽  
North East ◽  
The North ◽  
Natural Flora

Vera Antonovna Martynenko (17.02.1936–06.01.2018) — famous specialist in the field of studying vascular plant flora and vegetation of the Far North, the Honored worker of the Komi Republic (2006), The Komi Republic State Scientific Award winner (2000). She was born in the town Likhoslavl of the Kali­nin (Tver) region. In 1959, Vera Antonovna graduated from the faculty of soil and biology of the Leningrad State University and then moved to the Komi Branch of USSR Academy of Science (Syktyvkar). From 1969 to 1973 she passed correspondence postgraduate courses of the Komi Branch of USSR Academy of ­Science. In 1974, she received the degree of candidate of biology (PhD) by the theme «Comparative analysis of the boreal flora at the Northeast European USSR» in the Botanical Institute (St. Petersburg). In 1996, Vera Antonovna received the degree of doctor of biology in the Institute of plant and animal ecology (Ekaterinburg) «Flora of the northern and mid subzones of the taiga of the European North-East». The study and conservation of species and coenotical diversity of the plant world, namely the vascular plants flora of the Komi Republic and revealing its transformation under the anthropogenic influence, was in the field of V. A. Martynenko’ scientific interests. She made great contribution to the study of the Komi Republic meadow flora and the pool of medi­cinal plants. She performed inventorying and mapping the meadows of several agricultural enterprises of the Republic, revealed the species composition and places for harvesting medicinal plants and studied their productivity in the natural flora of the boreal zone. The results of her long-term studies were used for making the NPA system and the Red Book of the Komi Republic (1998 and 2009). Vera Antonovna participated in the research of the influence of placer gold mining and oil development on the natural ecosystems of the North, and developed the method of long-term monitoring of plant cover. Results of these works are of high practical value. V. A. Martynenko is an author and coauthor of more than 130 scientific publications. The most important jnes are «Flora of Northeast European USSR» (1974, 1976, and 1977), «Floristic composition of fodder lands of the Northeast Europe» (1989), «The forests of the Komi Republic» (1999), «Forestry of forest resources of the Komi Republic» (2000), «The list of flora of the Yugyd va national park» (2003), «The guide for vascular plants of the Syktyvkar and its vicinities» (2005), «Vascular plants of the Komi Republic» (2008), and «Resources of the natural flora of the Komi Republic» (2014). She also was an author of «Encyclopedia of the Komi Republic» (1997, 1999, and 2000), «Historical and cultural atlas of the Komi Republic» (1997), «Atlas of the Komi Republic» (2001, 2011). V. A. Martynenko made a great contribution to the development of the botanical investigations in the North. Since 1982, during more than 10 years, she was the head of the Department of the Institute of Biology. Three Ph. D. theses have been completed under her leadership. Many years, she worked actively in the Dissertation Council of the Institute of biology Komi Scientific Centre UrB RAS.  The death of Vera Antonovna Martynenko is a heavy and irretrievable loss for the staff of the Institute of Biology. The memory of Vera Antonovna will live in her numerous scientific works, the hearts of students and colleagues.

scholarly journals The long-term variability of extreme sea levels in the German Bight

Ocean Science ◽  
2019 ◽  
Vol 15 (3) ◽  
pp. 651-668 ◽  
Author(s):  
Andreas Lang ◽  
Uwe Mikolajewicz
Keyword(s):  
Sea Level ◽  
German Bight ◽  
Large Scale ◽  
Internal Variability ◽  
Climate System ◽  
System Model ◽  
Tide Gauge Record ◽  
Sea Levels ◽  
The North

Abstract. Extreme high sea levels (ESLs) caused by storm floods constitute a major hazard for coastal regions. We here quantify their long-term variability in the southern German Bight using simulations covering the last 1000 years. To this end, global earth system model simulations from the PMIP3 past1000 project are dynamically scaled down with a regionally coupled climate system model focusing on the North Sea. This approach provides an unprecedented long high-resolution data record that can extend the knowledge of ESL variability based on observations, and allows for the identification of associated large-scale forcing mechanisms in the climate system. While the statistics of simulated ESLs compare well with observations from the tide gauge record at Cuxhaven, we find that simulated ESLs show large variations on interannual to centennial timescales without preferred oscillation periods. As a result of this high internal variability, ESL variations appear to a large extent decoupled from those of the background sea level, and mask any potential signals from solar or volcanic forcing. Comparison with large-scale climate variability shows that periods of high ESL are associated with a sea level pressure dipole between northeastern Scandinavia and the Gulf of Biscay. While this large-scale circulation regime applies to enhanced ESL in the wider region, it differs from the North Atlantic Oscillation pattern that has often been linked to periods of elevated background sea level. The high internal variability with large multidecadal to centennial variations emphasizes the inherent uncertainties related to traditional extreme value estimates based on short data subsets, which fail to account for such long-term variations. We conclude that ESL variations as well as existing estimates of future changes are likely to be dominated by internal variability rather than climate change signals. Thus, larger ensemble simulations will be required to assess future flood risks.

scholarly journals Climate change in Victoria: trends, predictions and impacts

2013 ◽  
Vol 125 (1) ◽  
pp. 5 ◽  
Author(s):  
Lesley Hughes ◽  
Will Steffen
Keyword(s):  
Global Trends ◽  
Sea Levels ◽  
North West ◽  
Average Temperature ◽  
The Past ◽  
The North ◽  
Hot Days ◽  
National Trends ◽  
Do So

Australia’s climate is changing, consistent with global trends. Continental average temperatures have increased nearly 1°C since the early 20th century, with warming accelerating since the 1950s. The number of extreme hot days is increasing, whereas the number of cold days and frosts is decreasing. With an average temperature over 1.0°C above the long-term mean, 2005 was Australia’s warmest year on record; 2009 was the second warmest year on record. The decade 2000–2009 was Australia’s warmest. Rainfall has been decreasing in the south-west and south-east of Australia, but increasing in the north-west. The ocean is warming and sea levels are rising, consistent with global averages. Consistent with global and national trends, Victoria’s climate is already changing and will continue to do so, posing significant risks to the State. Over the past few decades Victoria has become hotter and drier, and these trends are likely to continue, together with an increasing intensity and/or frequency of extreme events, such as heatwaves, droughts, bushfires and floods, posing significant risks to the State’s infrastructure, coasts, ecosystems, agriculture and health.

scholarly journals Cenozoic sea-level and cryospheric evolution from deep-sea geochemical and continental margin records

2020 ◽  
Vol 6 (20) ◽  
pp. eaaz1346 ◽  
Author(s):  
Kenneth G. Miller ◽  
James V. Browning ◽  
W. John Schmelz ◽  
Robert E. Kopp ◽  
Gregory S. Mountain ◽  
...  
Keyword(s):  
Sea Level ◽  
Ice Sheets ◽  
Milankovitch Cycles ◽  
Continental Margins ◽  
Sea Levels ◽  
Continental Scale ◽  
Global Mean Sea Level ◽  
Thermal Subsidence ◽  
Global Mean

Using Pacific benthic foraminiferal δ18O and Mg/Ca records, we derive a Cenozoic (66 Ma) global mean sea level (GMSL) estimate that records evolution from an ice-free Early Eocene to Quaternary bipolar ice sheets. These GMSL estimates are statistically similar to “backstripped” estimates from continental margins accounting for compaction, loading, and thermal subsidence. Peak warmth, elevated GMSL, high CO2, and ice-free “Hothouse” conditions (56 to 48 Ma) were followed by “Cool Greenhouse” (48 to 34 Ma) ice sheets (10 to 30 m changes). Continental-scale ice sheets (“Icehouse”) began ~34 Ma (>50 m changes), permanent East Antarctic ice sheets at 12.8 Ma, and bipolar glaciation at 2.5 Ma. The largest GMSL fall (27 to 20 ka; ~130 m) was followed by a >40 mm/yr rise (19 to 10 ka), a slowing (10 to 2 ka), and a stillstand until ~1900 CE, when rates began to rise. High long-term CO2 caused warm climates and high sea levels, with sea-level variability dominated by periodic Milankovitch cycles.

scholarly journals Analysis of Segmented Sea level Time Series

2020 ◽  
Vol 10 (2) ◽  
pp. 625
Author(s):  
Alberto Boretti
Keyword(s):  
Data Mining ◽  
Time Series ◽  
Indian Ocean ◽  
Break Point ◽  
Tide Gauges ◽  
Sea Levels ◽  
Term Trend ◽  
The Indian Ocean ◽  
Long Term Trend

Records of measurements of sea levels from tide gauges are often “segmented”, i.e., obtained by composing segments originating from the same or different instruments, in the same or different locations, or suffering from other biases that prevent the coupling. A technique is proposed, based on data mining, the application of break-point alignment techniques, and similarity with other segmented and non-segmented records for the same water basin, to quality flag the segmented records. This prevents the inference of incorrect trends for the rate of rise and the acceleration of the sea levels for these segmented records. The technique is applied to the four long-term trend tide gauges of the Indian Ocean, Aden, Karachi, Mumbai, and Fremantle, with three of them segmented.

scholarly journals The long-term variability of extreme sea levels in the German Bight

2019 ◽  
Author(s):  
Andreas Lang ◽  
Uwe Mikolajewicz
Keyword(s):  
Sea Level ◽  
North Sea ◽  
German Bight ◽  
Large Scale ◽  
Climate System ◽  
Tide Gauge Record ◽  
Sea Levels ◽  
The North ◽  
The North Sea

Abstract. We investigate the long-term variability of extreme high sea levels (ESL) in the southern German Bight and associated large-scale forcing mechanisms in the climate system using simulations covering the last 1000 years. To this end, global MPI-ESM simulations from the PMIP3 past1000 project are dynamically scaled-down with a regionally coupled climate system model focusing on the North Sea. We find that the statistics of simulated ESL compare well with observations from the tide gauge record at Cuxhaven but show large variations on interannual to centennial timescales. ESL arise independent of preferred systematic oscillations and are to a large extent decoupled from variations of the background sea level (BSL). Large scale circulation regimes associated with periods of high ESL are regionally consistent and similar to those associated with elevated BSL, but the location of the respective centers of action of the governing sea level pressure (SLP) dipole differs. While BSL variations correlate well with the wintertime North Atlantic Oscillation (NAO), ESL variations are rather associated with a dipole between northeastern Scandinavia and the Gulf of Biscay, leading to a stronger local north-westerly wind component in the North Sea. Potential links with solar or volcanic forcing are masked due to the high ESL variability. The high internal variability stresses the irreducible uncertainties related to traditional extreme value estimates based on shorter subsets which fail to account for long-term variations. Existing estimates of future changes in ESL may be dominated by natural variability rather than climate change signals, thus requiring larger ensemble simulations to assess future flood risks.

Subalternity across the Indian Ocean: the Sidis of Gujarat

2020 ◽  
Vol 8 (1) ◽  
pp. 61-82
Author(s):  
Rosa Maria Perez
Keyword(s):  
Indian Ocean ◽  
African Diaspora ◽  
North Atlantic ◽  
The Other ◽  
Indian Society ◽  
The North ◽  
The World ◽  
The Indian Ocean ◽  
The One

Abstract In Gujarat, as in other states of India, the Sidis illustrate the long-term African existence in India, which was dominantly analyzed through Eurocentric categories substantiated either by the semantics of slavery or, more recently, by the paradigm of the African diaspora in the world. Both were mainly produced in and for the North Atlantic realm. This article aims at identifying the intersection between the two margins of the Indian Ocean grounded on an ethnohistory of the Sidis of Gir, in Saurashtra. As an anthropologist, it is at the level of contemporary Indian society within the dialectic and dialogic framework of relationships between the Sidis and the other groups that I observed them, being aware of the discontinuities existing within this category on the one hand and, on the other, of a common idiom through which the Sidis communicate their “Africanness.”

Long-term Cyclic Variations of Prominences, Green and Red Coronae over Solar Cycles

2000 ◽  
Vol 179 ◽  
pp. 201-204
Author(s):  
Vojtech Rušin ◽  
Milan Minarovjech ◽  
Milan Rybanský
Keyword(s):  
Emission Lines ◽  
High Latitudes ◽  
Green Line ◽  
Solar Cycles ◽  
The South ◽  
Coronal Emission ◽  
Local Maxima ◽  
The North ◽  
Cyclic Variations

AbstractLong-term cyclic variations in the distribution of prominences and intensities of green (530.3 nm) and red (637.4 nm) coronal emission lines over solar cycles 18–23 are presented. Polar prominence branches will reach the poles at different epochs in cycle 23: the north branch at the beginning in 2002 and the south branch a year later (2003), respectively. The local maxima of intensities in the green line show both poleward- and equatorward-migrating branches. The poleward branches will reach the poles around cycle maxima like prominences, while the equatorward branches show a duration of 18 years and will end in cycle minima (2007). The red corona shows mostly equatorward branches. The possibility that these branches begin to develop at high latitudes in the preceding cycles cannot be excluded.

Mafias on the Move

2011 ◽  
Author(s):  
Federico Varese
Keyword(s):  
United States ◽  
New York ◽  
Organized Crime ◽  
The United States ◽  
The West ◽  
Market Expansion ◽  
The North ◽  
Economic Transformations ◽  
At Will

Organized crime is spreading like a global virus as mobs take advantage of open borders to establish local franchises at will. That at least is the fear, inspired by stories of Russian mobsters in New York, Chinese triads in London, and Italian mafias throughout the West. As this book explains, the truth is more complicated. The author has spent years researching mafia groups in Italy, Russia, the United States, and China, and argues that mafiosi often find themselves abroad against their will, rather than through a strategic plan to colonize new territories. Once there, they do not always succeed in establishing themselves. The book spells out the conditions that lead to their long-term success, namely sudden market expansion that is neither exploited by local rivals nor blocked by authorities. Ultimately the inability of the state to govern economic transformations gives mafias their opportunity. In a series of matched comparisons, the book charts the attempts of the Calabrese 'Ndrangheta to move to the north of Italy, and shows how the Sicilian mafia expanded to early twentieth-century New York, but failed around the same time to find a niche in Argentina. The book explains why the Russian mafia failed to penetrate Rome but succeeded in Hungary. A pioneering chapter on China examines the challenges that triads from Taiwan and Hong Kong find in branching out to the mainland. This book is both a compelling read and a sober assessment of the risks posed by globalization and immigration for the spread of mafias.

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