Indian monsoon derailed by a North Atlantic wavetrain

The forecast of Indian monsoon droughts has been predicated on the notion of a season-long rainfall deficit linked to a warm equatorial Pacific. Here we show that nearly half of all droughts over the past century differ from this paradigm in that they (i) occur when Pacific temperatures are near-neutral and (ii) are subseasonal phenomena, characterized by an abrupt decline in late-season rainfall. This severe subseasonal rainfall deficit can be associated with a Rossby wave from mid-latitudes. Specifically, we find that the interaction of upper-level winds with an episodic North Atlantic vorticity anomaly results in a wavetrain that curves toward East Asia, disrupting the monsoon. This atmospheric teleconnection offers an avenue for improved predictability of droughts, especially in the absence of telltale signatures in the Pacific.

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A New Metric for Indian Monsoon Rainfall Extremes*

Journal of Climate ◽

10.1175/jcli-d-13-00764.1 ◽

2015 ◽

Vol 28 (7) ◽

pp. 2842-2855 ◽

Cited By ~ 1

Author(s):

Tackseung Jun ◽

Lalith Munasinghe ◽

David H. Rind

Keyword(s):

Monsoon Rainfall ◽

Indian Monsoon ◽

Southern Oscillation ◽

Extreme Rainfall ◽

Past Century ◽

Socioeconomic Impacts ◽

Factors Associated ◽

The Past ◽

The Pacific ◽

Time Patterns

Abstract Extreme monsoon rainfall in India has disastrous consequences, including significant socioeconomic impacts. However, little is known about the overall trends and climate factors associated with extreme rainfall because rainfall greatly varies across India and because few appropriate methods are available to measure extreme rainfall in the context of such heterogeneity. To provide a comprehensive assessment of extreme monsoon rainfall, the authors developed a metric using record rainfall data to measure the changes in the likelihood of extreme high and extreme low rainfall over time; this metric is independent of the characteristics of the underlying rainfall distributions. Hence, the metric is ideally suited to aggregate extreme rainfall information across heterogeneous regions covering India. The authors found that from 1930 to 2013, the likelihood of extreme high and extreme low rainfall increases 2-fold and 4-fold, respectively. These overall trend increases are driven by anomalous increases, particularly in the early 2000s; the likelihood of extreme high and extreme low rainfall increases 5-fold and 18-fold in 2005 and 2002, respectively. These findings imply a broadening of the underlying monsoon rainfall distribution over the past century. The authors also show that the time patterns of the likelihood of extreme rainfall in recent decades are correlated with El Niño–Southern Oscillation, especially when it is in the same phase with the Pacific decadal oscillation and Indian Ocean dipole.

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Good offices: grasping the place of law in conflict

Legal Studies ◽

10.1111/lest.12029 ◽

2014 ◽

Vol 34 (3) ◽

pp. 469-496 ◽

Cited By ~ 2

Author(s):

Aoife O'Donoghue

Keyword(s):

International Law ◽

Past Century ◽

Legal Analysis ◽

International Organisations ◽

The Past ◽

The Pacific ◽

The Subject ◽

Definition Of ◽

Settlement Of Disputes ◽

Violent Conflicts

In the pantheon of approaches open to participants in the pacific settlement of disputes, good offices holds a noteworthy place. The evolution of good offices over the past century is concurrent with a trend of considerable transformation within international law, including – amongst other changes – a move away from a state-led legal order, including in good offices following the emergence of the heads of international organisations as its prime users, and a process of legalisation and specialisation within the subject that has entirely altered its character. These changes have led to a redefinition of good offices that stresses the actor carrying out the role above the form that it takes. To accompany these changes in practice, there is a need for a transformation in the legal analysis and definition of good offices. One potential option in achieving this end is Bell'slex pacificatoria. If good offices is to continue to play a significant role in the settlement of violent conflicts, a fully developed legal analysis is necessary to grasp both its historical development and its potential future role.

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Implications of Radiolarian Assemblages for the Late Quaternary Paleoceanography of the Eastern Equatorial Pacific

Quaternary Research ◽

10.1016/0033-5894(85)90007-9 ◽

1985 ◽

Vol 24 (2) ◽

pp. 204-218 ◽

Cited By ~ 23

Author(s):

Cynthia T. Schramm

Keyword(s):

Surface Water ◽

Late Quaternary ◽

Zonal Flow ◽

Equatorial Pacific ◽

Equatorial Undercurrent ◽

Ice Volume ◽

The Past ◽

Eastern Equatorial Pacific ◽

The Pacific ◽

Radiolarian Assemblages

The distribution of radiolarian assemblages identified by Q-mode factor analysis of radiolarian microfossils in surface sediments from low latitudes in the Pacific Ocean reflects their associations with surface water masses. Downcore fluctuations of these radiolarian assemblages at two sites, RC10-65 and V19–29, indicate changes in circulation in the eastern equatorial Pacific during the past 500,000 yr. Surface-water radiolarian assemblages characteristic of zonal flow have dominated siliceous sedimentation in the eastern equatorial Pacific, except during times of intense upwelling which can occur along the coast of Peru and in the Equatorial Undercurrent. Fluctuations in the importance of this upwelling have not been consistent with glacial/interglacial changes in ice volume throughout the late Quaternary. Intensification of upwelling in the equatorial divergence, however, has consistently coincided with increases in ice volume in the past 500,000 yr. The times at which changes in the nature of the relationship between upwelling and ice volume occur (approximately 240,000 and 380,000 yr B.P.) roughly coincide with times of observed changes in other proxy indicators of oceanographic conditions in the Pacific and Indian oceans.

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Sovereignty over Islands in the Pacific

The American Journal of International Law ◽

10.2307/2192452 ◽

1941 ◽

Vol 35 (3) ◽

pp. 443-461 ◽

Cited By ~ 5

Author(s):

Beatrice Orent ◽

Pauline Reinsch

Keyword(s):

United States ◽

Great Britain ◽

British Empire ◽

The United States ◽

Past Century ◽

Central Pacific ◽

Commercial Aviation ◽

Central Pacific Ocean ◽

The Past ◽

The Pacific

Recently, certain small uninhabited islands in the central Pacific Ocean have assumedsudden importance for the British Empire and the United States. Their value as landing places for commercial aviation and as strategic bases for air and naval forces is being increasingly recognized. Acquired during the past century by Great Britain and the UnitedStates, many of these islands have been the object of conflicting claims to sovereignty by the two nations. To clarify their status, it has been found desirable to review the past practice of these states and to examine those factors which were considered adequateto create sovereign rights over uninhabited islands in the Pacific.

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Pulses of Rapid Ventilation in the North Atlantic Surface Ocean During the Past Century

Science ◽

10.1126/science.275.5305.1454 ◽

1997 ◽

Vol 275 (5305) ◽

pp. 1454-1457 ◽

Cited By ~ 53

Author(s):

E. R. M. Druffel

Keyword(s):

North Atlantic ◽

Past Century ◽

Surface Ocean ◽

The Past ◽

The North ◽

The North Atlantic

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Sea Trials of the SWATH Ship USNS Victorious (T-AGOS 19)

Marine Technology and SNAME News ◽

10.5957/mt1.1994.31.4.245 ◽

1994 ◽

Vol 31 (04) ◽

pp. 245-257

Author(s):

Jim Sandison ◽

Dennis Woolaver ◽

Martin Dipper ◽

Mark Rice

Keyword(s):

North Atlantic ◽

Data Acquisition System ◽

Ship Motions ◽

Past Century ◽

Sea State ◽

Chief Engineer ◽

The Past ◽

The North ◽

Surface Ship ◽

The North Pacific

In 1986 the design of the Navy's first large SWATH (small waterplane area twin hull) ship was completed. Designated the T-AGOS 19 Class, these vessels were designed to operate comfortably in high latitudes during winter months. The T-AGOS 19 and T-AGOS 23 Classes represent one of the greatest departures in naval surface ship design in the past century. In 1989 extensive confirmation sea trials on USNS Victorious (T-AGOS 19) were required by the Chief Engineer of the Navy. T-AGOS 19 was built by McDermott Shipyards in Amelia, Louisiana and was delivered to the Navy in August of 1991. An extensive Core Data Acquisition System (CDAS) was installed to support seakeeping, ship motions, hydrodynamic, structural, and acoustic trials. The trials were continual from the winter of 1991/92 in the North Atlantic through winter of 1992/93 in the North Pacific, and finished with standardization trials off Hawaii in April of 1993. An extensive amount of trials data has been generated, the analysis of which is still in process. This paper is an overview of the trials and a presentation (preliminary) of some of the results. The Victorious has proven to be a very seakindly ship with motions that allow one to comfortably work at a computer station in sea state 7.

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Trends in the climate of the North Atlantic Ocean over the past century

Nature ◽

10.1038/263576a0 ◽

1976 ◽

Vol 263 (5578) ◽

pp. 576-577 ◽

Cited By ~ 26

Author(s):

J. M. COLEBROOK

Keyword(s):

Atlantic Ocean ◽

North Atlantic ◽

North Atlantic Ocean ◽

Past Century ◽

The Past ◽

The North ◽

The North Atlantic

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A multidecadal-scale tropically-driven global teleconnection over the past millennium and its recent strengthening

Journal of Climate ◽

10.1175/jcli-d-20-0216.1 ◽

2020 ◽

pp. 1-51

Author(s):

Xiaofang Feng ◽

Qinghua Ding ◽

Liguang Wu ◽

Charles Jones ◽

Ian Baxter ◽

...

Keyword(s):

Surface Temperature ◽

Eastern Pacific ◽

The Arctic ◽

Boreal Winter ◽

Past Century ◽

Tropical Eastern Pacific ◽

Atmospheric Teleconnection ◽

Temperature Changes ◽

The Past ◽

Circulation Mode

AbstractIn the past 40 years, the global annual mean surface temperature has experienced a non-uniform warming, differing from the spatially uniform warming simulated by the forced responses of large multi-model ensembles to anthropogenic forcing. Rather, it exhibits significant asymmetry between the Arctic and Antarctic, intermittent and spatially varying warming trends along the Northern Hemisphere (NH) mid-latitudes and a slight cooling in the tropical eastern Pacific. In particular, this “wavy” pattern of temperature changes over the NH mid-latitudes features strong cooling over Eurasia in boreal winter. Here, we show that these non-uniform features of surface temperature changes are likely tied together by tropical eastern Pacific sea surface temperatures (SSTs), via a global atmospheric teleconnection. Using six reanalyses, we find that this teleconnection can be consistently obtained as a leading circulation mode in the past century. This tropically-driven teleconnection is associated with a Pacific SST pattern resembling the Interdecadal Pacific Oscillation (IPO), and hereafter referred to as the IPO-related Bipolar Teleconnection (IPO-BT). Further, two paleo-reanalysis reconstruction datasets show that the IPO-BT is a robust recurrent mode over the past 400 and 2000 years. The IPO-BT mode may thus serve as an important internal mode that regulates high-latitude climate variability on multidecadal time scales, favoring a warming (cooling) episode in the Arctic accompanied by cooling (warming) over Eurasia and the Southern Ocean (SO). Thus, the spatial non-uniformity of recent surface temperature trends may be partially explained by the enhanced appearance of the IPO-BT mode by a transition of the IPO toward a cooling phase in the eastern Pacific in the past decades.

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Non-steady behaviour in the Cenozoic polar North Atlantic system: the onset and variability of Northern Hemisphere glaciations

Philosophical Transactions of the Royal Society of London Series A Physical and Engineering Sciences ◽

10.1098/rsta.1995.0077 ◽

1995 ◽

Vol 352 (1699) ◽

pp. 373-385 ◽

Cited By ~ 6

Keyword(s):

Sea Ice ◽

Arctic Ocean ◽

Northern Hemisphere ◽

North Atlantic ◽

Middle Miocene ◽

Ice Cover ◽

The Arctic ◽

Past Century ◽

The Past ◽

The Arctic Ocean

Changes of the extent of the Arctic Ocean sea-ice cover over the past century, the geological record of the Arctic Ocean seafloor of the youngest geological past, as well as the evidence of a pre-Glacial temperate to warm Arctic Ocean during Mesozoic and Palaeogene time are witnesses of dramatic revolutions of the Arctic oceanography. The climate over northwestern Europe on a regional scale as well as the global environment have responded to these revolutions instantly over geological time scales. Results of ocean drilling in the deep northern North Atlantic document an onset of Northern Hemisphere glaciation towards the end of the middle Miocene (10-14 Ma). While the available evidence points to early glaciations of modest extent and intensity centred around southern Greenland, the early to mid-Pliocene intervals record a sudden intensification of ice-rafting in the Labrador and Norwegian Greenland seas as well as in the Arctic Ocean proper. The Greenland ice cap seems to have remained rather stable whereas the northwest European ice shields have experienced rapid and dramatic changes leading to their frequent complete destruction. Many sediment properties seem to suggest that orbital parameters (Milankovitch-frequencies) and their temporal variability control important properties of the deep-sea floor depositional environment. Obliquity (with approximately 40 ka) seems to be dominant in pre-Glacial (middle Miocene) as well as Glacial (post late Miocene) scenarios whereas eccentricity (with approximately 100 ka) only dominated the past 600-800 ka. PlioPleistocene deposits of the Arctic Ocean proper, of the entire Norwegian Greenland and of the Labrador seas have recorded the almost continuous presence of sea-ice cover with only short ‘interglacial’ intervals when the eastern Norwegian Sea was ice-free. The documentation of long-term changes of the oceanographic and climatic properties of the Arctic environments recorded in the sediment cover of the deepsea floors might also serve to explain scenarios which have no modern analog, but which might well develop in the future under the influence of the anthropogenic drift towards warmer global climates.

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