Influences of central Pacific warming on synoptic-scale wave intensity over the northwest Pacific

2021 ◽  
Author(s):  
Jingliang Huangfu ◽  
Xi Cao ◽  
Renguang Wu ◽  
Guosen Chen ◽  
Wen Chen
Keyword(s):  
Wave Intensity ◽  
Northwest Pacific ◽  
Synoptic Scale ◽  
Central Pacific ◽  
Central Pacific Warming

scholarly journals Different Pacific Ocean Warming Decaying Types and Northwest Pacific Tropical Cyclone Activity

2013 ◽  
Vol 26 (22) ◽  
pp. 8979-8994 ◽  
Author(s):  
Yao Ha ◽  
Zhong Zhong ◽  
Xiuqun Yang ◽  
Yuan Sun
Keyword(s):  
Tropical Cyclone ◽  
East Asian ◽  
The Philippines ◽  
La Niña ◽  
Eastern Pacific ◽  
Northwest Pacific ◽  
Central Pacific ◽  
East Indian ◽  
La Nina ◽  
Central Pacific Warming

Abstract This study focuses on statistical analysis of anomalous tropical cyclone (TC) activities and the physical mechanisms behind these anomalies. Different patterns of decaying of the warm sea surface temperature anomaly (SSTA) over the equatorial central-eastern Pacific are categorized into three types: eastern Pacific warming decaying to La Niña (EPWDL), eastern Pacific warming decaying to a neutral phase (EPWDN), and a central Pacific warming decaying year (CPWD). Differences in TC activity over the western North Pacific (WNP) corresponding to the above three types are discussed, and possible mechanisms are proposed. For EPWDL, TC genesis shows a significant positive (negative) anomaly over the northwestern (southeastern) WNP and more TCs move westward and make landfall over the southern East Asian coast. This is attributed primarily to the combined modulation of La Niña and the warm equatorial east Indian Ocean SSTA. For EPWDN, enhanced TC genesis is observed over the northeastern WNP, and suppressed TC activity is located mainly in the zonal region extending from the Philippine Sea to the eastern WNP, close to 160°E. Most of the TCs formed over the eastern WNP experience early recurvature east of 140°E, then move northeastward; hence, fewer TCs move northwestward to make landfall over the East Asian coast. For CPWD, the enhanced TC activity appears over the western WNP. This is due to the weak anomalous cyclonic circulation over the Philippines, primarily caused by the weaker, more westward-shifting warm SSTA compared to that in the previous warming year over the central Pacific.

scholarly journals Freshening of Subsurface Waters in the Northwest Pacific Subtropical Gyre: Observations and Dynamics

2013 ◽  
Vol 43 (12) ◽  
pp. 2733-2751 ◽  
Author(s):  
Youfang Yan ◽  
Eric P. Chassignet ◽  
Yiquan Qi ◽  
William K. Dewar
Keyword(s):  
Predictive Model ◽  
Subtropical Gyre ◽  
Northwest Pacific ◽  
Spatial Structures ◽  
Central Pacific ◽  
Dynamical Mechanism ◽  
Salinity Anomaly ◽  
Low Latitudes ◽  
Subsurface Waters ◽  
One Year

Abstract Subsurface salinity anomalies propagating between mid- and low latitudes along isopycnal surfaces have been shown to play an important role in modulating ocean and climate variability. In this study, a sustained freshening and southwestward propagation of subsurface salinity anomalies in the northwest Pacific subtropical gyre and its dynamical mechanism are investigated using observations, numerical outputs, and a predictive model. Analyses of the observations show a pronounced subsurface freshening with salinity decreasing about 0.25 PSU near the 24.5-σθ surface in the northwest Pacific subtropical gyre during 2003–11. This freshening is found to be related to the surface forcing of salinity anomalies in the outcrop zone (25°–35°N, 130°–160°E). A predictive model based on the assumption of salinity conservation along the outcrop isopycnals is derived and used to examine this surface-forcing mechanism. The resemblance between the spatial structures of the subsurface salinity derived from the predictive model and from observations and numerical outputs suggests that subsurface salinity anomalies are ventilated over the outcrop zone. A salinity anomaly with an amplitude of about 0.25 PSU generated by the surface forcing is subducted in the outcrop zone and then propagates southwestward, accompanied by potential vorticity anomalies, to the east of Luzon Strait (~15°N) in roughly one year. When the anomalies reach 15°N, they turn and move gradually eastward toward the central Pacific, associated with an eastward countercurrent on the southern subtropical gyre.

scholarly journals New species of Eurythenes from hadal depths of the Mariana Trench, Pacific Ocean (Crustacea: Amphipoda)

Zootaxa ◽  
2020 ◽  
Vol 4748 (1) ◽  
pp. 163-181 ◽  
Author(s):  
JOHANNA N. J. WESTON ◽  
PRISCILLA CARRILLO-BARRAGAN ◽  
THOMAS D. LINLEY ◽  
WILLIAM D. K. REID ◽  
ALAN J. JAMIESON
Keyword(s):  
Pacific Ocean ◽  
Morphological Characteristics ◽  
Anthropogenic Pollution ◽  
Ocean Basin ◽  
Northwest Pacific ◽  
Central Pacific ◽  
Bathymetric Range ◽  
Northwest Pacific Ocean ◽  
Mariana Trench ◽  
Central Pacific Ocean

Eurythenes S. I. Smith in Scudder, 1882 are one of the largest scavenging deep-sea amphipods (max. 154 mm) and are found in every ocean across an extensive bathymetric range from the shallow polar waters to hadal depths. Recent systematic studies of the genus have illuminated a cryptic species complex and highlighted the benefits of using a combination of morphological and molecular identification approaches. In this study, we present the ninth species, Eurythenes plasticus sp. nov., which was recovered using baited traps between the depths 6010 and 6949 m in the Mariana Trench (Northwest Pacific Ocean) in 2014. This new Eurythenes species was found to have distinct morphological characteristics and be a well-supported clade based on sequence variation at two mitochondrial regions (16S rDNA and COI). While this species is new to science and lives in the remote hadal zone, it is not exempt from the impacts of anthropogenic pollution. Indeed, one individual was found to have a microplastic fibre, 83.74% similar to polyethylene terephthalate (PET), in its hindgut. As this species has a bathymetric range spanning from abyssal to hadal depths in the Central Pacific Ocean basin, it offers further insights into the biogeography of Eurythenes. 

Investigation of Machine Learning using Satellite-Based Advanced Dvorak Technique Analysis Parameters to Estimate Tropical Cyclone Intensity

2021 ◽  
Author(s):  
Timothy Olander ◽  
Anthony Wimmers ◽  
Christopher Velden ◽  
James P. Kossin
Keyword(s):  
Machine Learning ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
North Indian Ocean ◽  
Northwest Pacific ◽  
Data Sets ◽  
Learning Models ◽  
Central Pacific ◽  
Data Set ◽  
Machine Learning Models

AbstractSeveral simple and computationally inexpensive machine learning models are explored that can use Advanced Dvorak Technique (ADT) retrieved features of tropical cyclones (TCs) from satellite imagery to provide improved maximum sustained surface wind speed (MSW) estimates. ADT (Version 9.0) TC analysis parameters and operational TC forecast center Best Track data sets from 2005-2016 are used to train and validate the various models over all TC basins globally and select the best among them. Two independent test sets of TC cases from 2017 and 2018 are used to evaluate the intensity estimates produced by the final selected model called the “artificial intelligence (AI)” enhanced Advanced Dvorak Technique (AiDT). The 2017 and 2018 MSW results demonstrate a global RMSE of 7.7 and 8.2 kt, respectively. Basin-specific MSW RMSEs of 8.4, 6.8, 7.3, 8.0, and 7.5 kt were obtained with the 2017 data set in the North Atlantic, East/Central Pacific, Northwest Pacific, South Pacific/Indian, and North Indian ocean basins, respectively, with MSW RMSE values of 8.9, 6.7, 7.1, 10.4, and 7.7 obtained with the 2018 data set. These represent a 30% and 23% improvement over the corresponding ADT RMSE for the 2017 and 2018 data sets, respectively, with the AiDT error reduction significant to 99% in both sets. The AiDT model represents a notable improvement over the ADT performance and also compares favorably to more computationally expensive and complex machine learning models that interrogate satellite images directly while still preserving the operational familiarity of the ADT.

scholarly journals Intensified impact of the central Pacific warming on the monsoon trough over the western North Pacific since 1984

2018 ◽  
Vol 19 (7) ◽  
pp. e828
Author(s):  
Hongjie Zhang ◽  
Liang Wu ◽  
Ronghui Huang ◽  
Jau-Ming Chen
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Monsoon Trough ◽  
Central Pacific ◽  
Central Pacific Warming

scholarly journals Decadal-Scale SST and Salinity Variations in the Central Tropical Pacific: Signatures of Natural and Anthropogenic Climate Change

2011 ◽  
Vol 24 (13) ◽  
pp. 3294-3308 ◽  
Author(s):  
Intan S. Nurhati ◽  
Kim M. Cobb ◽  
Emanuele Di Lorenzo
Keyword(s):  
Climate Change ◽  
Twentieth Century ◽  
Time Scales ◽  
Tropical Pacific ◽  
Anthropogenic Climate Change ◽  
Central Pacific ◽  
Proxy Record ◽  
Decadal Scale ◽  
Central Pacific Warming ◽  
Salinity Variations

Abstract Accurate projections of future temperature and precipitation patterns in many regions of the world depend on quantifying anthropogenic signatures in tropical Pacific climate against its rich background of natural variability. However, the detection of anthropogenic signatures in the region is hampered by the lack of continuous, century-long instrumental climate records. This study presents coral-based sea surface temperature (SST) and salinity proxy records from Palmyra Island in the central tropical Pacific over the twentieth century, based on coral strontium/calcium and the oxygen isotopic composition of seawater (δ18OSW), respectively. On interannual time scales, the Sr/Ca-based SST record captures both eastern and central Pacific warming “flavors” of El Niño–Southern Oscillation (ENSO) variability (R = 0.65 and 0.67, respectively). On decadal time scales, the SST proxy record is highly correlated to the North Pacific gyre oscillation (NPGO) (R = −0.85), reflecting strong dynamical links between the central Pacific warming mode and extratropical decadal climate variability. Decadal-scale salinity variations implied by the coral-based δ18OSW record are significantly correlated with the Pacific decadal oscillation (PDO) (R = 0.54). The salinity proxy record is dominated by an unprecedented trend toward lighter δ18OSW values since the mid–twentieth century, implying that a significant freshening has taken place in the region, in line with climate model projections showing enhanced hydrological patterns under greenhouse forcing. Taken together, the new coral records suggest that low-frequency SST and salinity variations in the central tropical Pacific are controlled by different sets of dynamics and that recent hydrological trends in this region may be related to anthropogenic climate change.

scholarly journals Inter-Annual Variability of Boreal Summer Intra-Seasonal Oscillation Propagation from the Indian Ocean to the Western Pacific

Atmosphere ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 596
Author(s):  
Zhang ◽  
Wang ◽  
Liu
Keyword(s):  
Indian Ocean ◽  
Equatorial Pacific ◽  
Boreal Summer ◽  
Central Pacific ◽  
Mean Motion ◽  
Annual Variability ◽  
Seasonal Oscillation ◽  
Central Pacific Warming ◽  
The Indian Ocean ◽  
The Western Pacific

The inter-annual variability of boreal summer intra-seasonal oscillation (BSISO) propagation from the Indian Ocean (IO) to the western Pacific (WP) is investigated for the boreal summers (May to September) of 1979–2018. It is shown that the interannual variability of BSISO mainly happens in its evolution, not in its strength over the IO. Here, we classify four distinctive modes for inter-annual variability of BSISO propagation: (i) northeast mode, propagating from the IO to the western equatorial Pacific (WEP) and the western North Pacific (WNP); (ii) north-only mode, only propagating to the WNP; (iii) east-only mode, only propagating to the WEP; and (iv) stationary mode, propagating to neither the WEP nor the WNP. It is found that the Maritime Continent (MC) and WEP are two key regions determining these four modes concerning mean state moisture and vertical motion. Associated with central equatorial Pacific cooling, the BSISO of northeast and north-only modes can reach the WP by passing over the MC due to positive mean moisture anomalies and upward mean motion anomalies over the MC. The strong negative mean moisture anomalies and downward mean motion anomalies over the WEP, related to strong central Pacific cooling, prevents the development of BSISO there, resulting in north-only mode. For the east-only and stationary modes associated with the central Pacific warming, their BSISO can hardly pass the MC due to negative mean moisture anomalies and downward mean motion anomalies. The positive mean moisture anomalies and upward mean motion anomalies over the WEP related to strong central Pacific warming, however, will reinitiate the BSISO in the WEP for the east-only mode.

scholarly journals Genetic and morphological evidence for cryptic species in Macrobrachium australe and resurrection of M. ustulatum (Crustacea, Palaemonidae)

2017 ◽  
Author(s):  
Magalie Castelin ◽  
Valentin De Mazancourt ◽  
Gérard Marquet ◽  
Gabrielle Zimmerman ◽  
Philippe Keith
Keyword(s):  
Pacific Ocean ◽  
Cryptic Species ◽  
Distinct Species ◽  
Morphological Characters ◽  
Morphological Evidence ◽  
Northwest Pacific ◽  
Central Pacific ◽  
Northwest Pacific Ocean ◽  
Southwest Indian Ocean ◽  
Central Pacific Ocean

Macrobrachium australe is an amphidromous prawn living in the insular freshwater systems of the Indo-Pacific. Because it possesses few informative morphological characters, that often vary from one habitat to another, M. australe has produced much taxonomic confusion and has historically been described under eight synonyms. Here, 53 specimens collected throughout the Indo-Pacific under the name M. australe were phylogenetically and morphologically examined. Results revealed that what has been called M. australe belongs to at least two distinct species: M. australe, distributed from the Southwest Indian Ocean to the Central Pacific Ocean, and a cryptic species potentially restricted to the Northwest Pacific Ocean, here identified as M. ustulatum, which until now was considered as a junior synonym. Although they are not quite found in the same habitat (lentic-lotic), the presence of these distinct, and reciprocally monophyletic entities in the same rivers on the islands of Palau and Santo strongly favors the hypothesis of two reproductively isolated entities. Six morphological characters, including the proportions of the joints of the male second pereiopod, the shape of the epistome lobe and the armature of the fourth thoracic sternite, are evidenced as diagnostic. A neotype of M. australe is designated and deposited in the Muséum national d’Histoire naturelle in Paris.

scholarly journals Decadal Variation of the Precipitation Relationship Between June and August over South China and Its Mechanism

2021 ◽  
Author(s):  
shuai li ◽  
Zhiqiang Gong ◽  
Shixuan zhang ◽  
Jie Yang ◽  
Shaobo Qiao ◽  
...  
Keyword(s):  
South China ◽  
Late Summer ◽  
Summer Rainfall ◽  
Feedback Mechanism ◽  
Interdecadal Change ◽  
Northwest Pacific ◽  
Decadal Variation ◽  
Central Pacific ◽  
Anomaly Pattern ◽  
Dipole Pattern

Abstract This paper investigates the characteristics and causes for the interdecadal change in the relationships between early and late summer rainfall over South China (SC). This study finds that the correlations of the precipitation over SC between June and August shift from weakly positive in 1979 – 1995 to obviously negative in 1996-2019. Further analysis demonstrates that the interdecadal variations of monthly SST anomaly (SSTA) and associated air-sea interactions in June and August account for the decadal variations of the precipitation relationships. During the prior period 1979-1995, the tropical West Indian Ocean (WIO) shows a significant positive SSTA in June, which triggers Kevin waves and an anticyclone circulation over the tropical Northwest Pacific (NWP). The warm and wet air transported by the southwest airflow at the north of the anticyclone provides favorable environmental condition to produce more precipitation over SC region in June. In contrast, the SST dipole pattern with the negative SSTAs in the maritime continent (MC) and positive SSTAs in the tropical Central Pacific (CP) is dominant in August. The SST dipole pattern is inconducive to the formation of anticyclone over SC, causing a weak positive precipitation correlation between June and August. During the latter period 1996-2019, the precipitation over SC in June is the same as that in the prior period as there is no significant decadal change in tropical WIO SST and East Asian circulation. However, an opposite phase of the SST dipole anomaly pattern in MC and the tropical CP is dominant in August during the latter period. Accordingly, the positive feedback mechanism of air-sea interaction leads to the enhancement of local convection activities in MC and the meridional Hadley circulations and the NWP subtropical high, leading to a decrease of precipitation over SC in August. Overall, the decadal variation of the SST dipole anomaly pattern in MC and the tropical CP is the key factor affecting the adjustment of the correlations between June and August precipitation in the two periods.

scholarly journals What modulates the intensity of synoptic scale variability over the western North Pacific during boreal summer and fall?

2021 ◽  
pp. 1
Author(s):  
Renguang Wu ◽  
Yuqi Wang ◽  
Xi Cao
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Eastern Pacific ◽  
Propagation Path ◽  
Boreal Summer ◽  
Synoptic Scale ◽  
Mean Flow ◽  
Central Pacific ◽  
Background Fields ◽  
Sst Anomalies

AbstractThe present study investigates the factors that affect the year-to-year change in the intensity of synoptic scale variability (SSV) over the tropical western North Pacific (TWNP) during boreal summer and fall. It is found that the intensity of the TWNP SSV in summer is associated with the equatorial central-eastern Pacific sea surface temperature (SST) anomalies that modulates the background fields through a Rossby wave response both in the source region and along the propagation path of the synoptic scale disturbances. In fall, the intensity of the TWNP SSV is related to an SST anomaly pattern with opposite anomalies in the equatorial central Pacific and TWNP that modulates the background fields from the equatorial central Pacific to TWNP. However, the equatorial central Pacific SST anomalies alone fail to change the intensity of the TWNP SSV as the induced background field changes are limited to the equatorial central Pacific. It is shown that tropical western Pacific SST anomalies may induce notable changes in the intensity of the TWNP SSV. The relation of the TWNP SSV to the equatorial eastern Pacific SST is weak due to opposite SST anomalies in different types of years. Both seasonal mean and intraseasonal flows provide source of barotropic energy for the change in the intensity of the TWNP synoptic scale disturbances in summer. Seasonal mean flow has a main contribution to the barotropic energy conversion for the change in the intensity of the TWNP synoptic scale disturbances in fall.

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