scholarly journals Sea level trends in Southeast Asian seas

2015 ◽  
Vol 11 (5) ◽  
pp. 743-750 ◽  
Author(s):  
M. W. Strassburg ◽  
B. D. Hamlington ◽  
R. R. Leben ◽  
P. Manurung ◽  
J. Lumban Gaol ◽  
...  
Keyword(s):  
Sea Level ◽  
Pacific Decadal Oscillation ◽  
Decadal Variability ◽  
Southeast Asian ◽  
Global Ocean ◽  
Satellite Altimeter ◽  
Trade Winds ◽  
The Past ◽  
The Pacific ◽  
Regional Sea Level

Abstract. Southeast Asian seas span the largest archipelago in the global ocean and provide a complex oceanic pathway connecting the Pacific and Indian oceans. The Southeast Asian sea regional sea level trends are some of the highest observed in the modern satellite altimeter record that now spans almost 2 decades. Initial comparisons of global sea level reconstructions find that 17-year sea level trends over the past 60 years exhibit good agreement with decadal variability associated with the Pacific Decadal Oscillation and related fluctuations of trade winds in the region. The Southeast Asian sea region exhibits sea level trends that vary dramatically over the studied time period. This historical variation suggests that the strong regional sea level trends observed during the modern satellite altimeter record will abate as trade winds fluctuate on decadal and longer timescales. Furthermore, after removing the contribution of the Pacific Decadal Oscillation (PDO) to sea level trends in the past 20 years, the rate of sea level rise is greatly reduced in the Southeast Asian sea region. As a result of the influence of the PDO, the Southeast Asian sea regional sea level trends during the 2010s and 2020s are likely to be less than the global mean sea level (GMSL) trend if the observed oscillations in wind forcing and sea level persist. Nevertheless, long-term sea level trends in the Southeast Asian seas will continue to be affected by GMSL rise occurring now and in the future.

scholarly journals Sea level trends in South East Asian Seas (SEAS)

2014 ◽  
Vol 10 (5) ◽  
pp. 4129-4148 ◽  
Author(s):  
M. W. Strassburg ◽  
B. D. Hamlington ◽  
R. R. Leben ◽  
P. Manurung ◽  
J. Lumban Gaol ◽  
...  
Keyword(s):  
Sea Level ◽  
Decadal Variability ◽  
Low Frequency ◽  
Global Ocean ◽  
Satellite Altimeter ◽  
Trade Winds ◽  
The Past ◽  
The Pacific ◽  
Regional Sea Level ◽  
Historical Variation

Abstract. Southeast Asian Seas (SEAS) span the largest archipelago in the global ocean and provide a complex oceanic pathway connecting the Pacific and Indian Oceans. The SEAS regional sea level trends are some of the highest observed in the modern satellite altimeter record that now spans almost two decades. Initial comparisons of global sea level reconstructions find that 17 year sea level trends over the past 60 years exhibit good agreement in areas and at times of strong signal to noise associated decadal variability forced by low frequency variations in Pacific trade winds. The SEAS region exhibits sea level trends that vary dramatically over the studied time period. This historical variation suggests that the strong regional sea level trends observed during the modern satellite altimeter record will abate as trade winds fluctuate on decadal and longer time scales. Furthermore, after removing the contribution of the Pacific Decadal Oscillation (PDO) to sea level trends in the past twenty years, the rate of sea level rise is greatly reduced in the SEAS region. As a result of the influence of the PDO, the SEAS regional sea level trends during 2010s and 2020s are likely to be less than the global mean sea level (GMSL) trend if the observed oscillations in wind forcing and sea level persist. Nevertheless, long-term sea level trends in the SEAS will continue to be affected by GMSL rise occurring now and in the future.

scholarly journals Wind- versus Eddy-Forced Regional Sea Level Trends and Variability in the North Pacific Ocean

2015 ◽  
Vol 28 (4) ◽  
pp. 1561-1577 ◽  
Author(s):  
Bo Qiu ◽  
Shuiming Chen ◽  
Lixin Wu ◽  
Shinichiro Kida
Keyword(s):  
Pacific Ocean ◽  
Sea Level ◽  
Momentum Flux ◽  
North Pacific Ocean ◽  
Kuroshio Extension ◽  
The Past ◽  
The North ◽  
The Pacific ◽  
Regional Sea Level ◽  
Sea Level Trend

Abstract Regional sea level trend and variability in the Pacific Ocean have often been considered to be induced by low-frequency surface wind changes. This study demonstrates that significant sea level trend and variability can also be generated by eddy momentum flux forcing due to time-varying instability of the background oceanic circulation. Compared to the broad gyre-scale wind-forced variability, the eddy-forced sea level changes tend to have subgyre scales and, in the North Pacific Ocean, they are largely confined to the Kuroshio Extension region (30°–40°N, 140°–175°E) and the Subtropical Countercurrent (STCC) region (18°–28°N, 130°–175°E). Using a two-layer primitive equation model driven by the ECMWF wind stress data and the eddy momentum fluxes specified by the AVISO sea surface height anomaly data, the relative importance of the wind- and eddy-forced regional sea level trends in the past two decades is quantified. It is found that the increasing (decreasing) trend south (north) of the Kuroshio Extension is due to strengthening of the regional eddy forcing over the past two decades. On the other hand, the decreasing (increasing) sea level trend south (north) of the STCC is caused by the decadal weakening of the regional eddy momentum flux forcing. These decadal eddy momentum flux changes are caused by the background Kuroshio Extension and STCC changes in connection with the Pacific decadal oscillation (PDO) wind pattern shifting from a positive to a negative phase over the past two decades.

scholarly journals Changing Expendable Bathythermograph Fall Rates and Their Impact on Estimates of Thermosteric Sea Level Rise

2008 ◽  
Vol 21 (21) ◽  
pp. 5657-5672 ◽  
Author(s):  
Susan E. Wijffels ◽  
Josh Willis ◽  
Catia M. Domingues ◽  
Paul Barker ◽  
Neil J. White ◽  
...  
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Decadal Variability ◽  
Heat Content ◽  
Time History ◽  
Global Ocean ◽  
Fall Rate ◽  
Rate Minimum ◽  
Fall Rates

Abstract A time-varying warm bias in the global XBT data archive is demonstrated to be largely due to changes in the fall rate of XBT probes likely associated with small manufacturing changes at the factory. Deep-reaching XBTs have a different fall rate history than shallow XBTs. Fall rates were fastest in the early 1970s, reached a minimum between 1975 and 1985, reached another maximum in the late 1980s and early 1990s, and have been declining since. Field XBT/CTD intercomparisons and a pseudoprofile technique based on satellite altimetry largely confirm this time history. A global correction is presented and applied to estimates of the thermosteric component of sea level rise. The XBT fall rate minimum from 1975 to 1985 appears as a 10-yr “warm period” in the global ocean in thermosteric sea level and heat content estimates using uncorrected data. Upon correction, the thermosteric sea level curve has reduced decadal variability and a larger, steadier long-term trend.

scholarly journals Contribution of the Pacific Decadal Oscillation to global mean sea level trends

2013 ◽  
Vol 40 (19) ◽  
pp. 5171-5175 ◽  
Author(s):  
B. D. Hamlington ◽  
R. R. Leben ◽  
M. W. Strassburg ◽  
R. S. Nerem ◽  
K.‐Y. Kim
Keyword(s):  
Sea Level ◽  
Pacific Decadal Oscillation ◽  
Mean Sea Level ◽  
The Pacific ◽  
Global Mean Sea Level ◽  
Global Mean

scholarly journals Pacific Decadal Oscillation Causes Fewer Near-Equatorial Cyclones in North Indian Ocean

2021 ◽  
Author(s):  
Shinto Roose ◽  
Ajayamohan Ravindran ◽  
Pallav Ray ◽  
Shang-Ping Xie ◽  
Cherumadanakadan Thelliyil Sabeerali ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Tropical Cyclones ◽  
Pacific Decadal Oscillation ◽  
North Indian Ocean ◽  
Mitigation Strategies ◽  
The Past ◽  
The North ◽  
The Pacific ◽  
Low Latitudes ◽  
Cyclone Frequency

Abstract Tropical cyclones do not form easily near the equator but can intensify rapidly, leaving little time for preparation. We investigated the number of near-equatorial (originating between 5°N and 11°N) tropical cyclones over the north Indian Ocean during post-monsoon seasons (October to December) over the past 60 years. A marked 43% decline in the number of such cyclones was detected in recent decades (1981-2010) compared to earlier (1951-1980). This decline in tropical cyclone frequency is primarily due to the weakened low-level vorticity modulated by the Pacific Decadal Oscillation (PDO). In the presence of basin-wide warming at low latitudes, and a favorable phase of the PDO, both the intensity and frequency of such cyclones is expected to increase. Such dramatic and unique changes in tropical cyclonic activity due to the interplay between natural variability and climate change call for appropriate planning and mitigation strategies.

scholarly journals Pacific Sea Levels Rising Very Slowly and Not Accelerating

2019 ◽  
Vol 38 (1) ◽  
pp. 179-184 ◽  
Author(s):  
Albert Parker ◽  
Clifford Ollier
Keyword(s):  
Pacific Ocean ◽  
Sea Level ◽  
Relative Rate ◽  
Tide Gauges ◽  
Sea Levels ◽  
The Past ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Long Term Trend

AbstractOver the past decades, detailed surveys of the Pacific Ocean atoll islands show no sign of drowning because of accelerated sea-level rise. Data reveal that no atoll lost land area, 88.6% of islands were either stable or increased in area, and only 11.4% of islands contracted. The Pacific Atolls are not being inundated because the sea level is rising much less than was thought. The average relative rate of rise and acceleration of the 29 long-term-trend (LTT) tide gauges of Japan, Oceania and West Coast of North America, are both negative, −0.02139 mm yr−1and −0.00007 mm yr−2respectively. Since the start of the 1900s, the sea levels of the Pacific Ocean have been remarkably stable.

scholarly journals Geological stories from the journey of mollusks fossils in Java

2021 ◽  
Vol 47 (3) ◽  
pp. 73-74
Author(s):  
Aswan Aswan
Keyword(s):  
Sea Level ◽  
Middle Miocene ◽  
Transition Period ◽  
Early Pleistocene ◽  
Late Pliocene ◽  
Central Java ◽  
The Pacific ◽  
Restricted Environment ◽  
Regional Sea Level ◽  
Almost All

The journey began in the Eocene with the presence of mollusk fossil in the Nanggulan Formation (near Yogyakarta) in Central Java. Many experts believe this was the early part of the Tethys system which might still be connected to the Tethys system in Europe.The oldest mollusk fossils type locality after Nanggulan is the Early Miocene Jonggrangan Formation in Kulon Progo near the city of Yogyakarta, which is dominated by the gastropod Haustator specimen. Molluscan paleontological studies of this type of locality reflect a restricted environment with less influence of the Tethyan system. Haustator are considered as the ancestor of the Turritellidae group, which is found mostly on Java Island, during the younger Tertiary to Quaternary Periods.The story continued to the Middle Miocene where the Tethyan realms indication was clearly observed by the presence of some typical Tethys species such as Volema and Babylonia from Nyalindung Formation, West Java. The regional sea level rise in this epoch (around 12 Ma) that was indicated by the presence of Vicarya as an index fossil, which occurrence was due to land submerging to become mangroves area. The fossil then quickly become extinct when the sea level dropped back.Late Miocene to Pliocene was like the transition period from the Tethyan realm to the Pacific realm, where the Tethyan fauna was no longer present. Only evolutional traces of the Middle Miocene mollusk fossils were observed. This continuous evolution is most clearly seen in Turritella cramatensis (late Miocene), Turritella acuticarinata (early Pliocene) and Turritella cikumpaiensis (late Pliocene) which was interpreted to have originated from Turritella angulata as their ancestors.Earth cooling environment that happened in the late Pliocene/early Pleistocene has led the diversity and evolution of a new group of mollusks, most clearly observed from the abundance of Turritella bantamensis in the Bojong Formation, Banten. The new Turritella group has a curved whorl that different from its predecessor with an angled whorl shape.Plio-Pleistocene tectonics event has ended the period of Java marine mollusks domination, then only freshwater mollusk fossils can be found in almost all Quaternary mollusks-bearing deposits. 

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