High-resolution IP25-based reconstruction of sea-ice variability in the western North Pacific and Bering Sea during the past 18,000 years

2015 ◽  
Vol 36 (2) ◽  
pp. 101-111 ◽  
Author(s):  
Marie Méheust ◽  
Ruediger Stein ◽  
Kirsten Fahl ◽  
Lars Max ◽  
Jan-Rainer Riethdorf
Keyword(s):  
High Resolution ◽  
Sea Ice ◽  
Bering Sea ◽  
North Pacific ◽  
Western North Pacific ◽  
The Past

scholarly journals How Does the Arctic Sea Ice Affect the Interannual Variability of Tropical Cyclone Activity Over the Western North Pacific?

2021 ◽  
Vol 9 ◽  
Author(s):  
Hao Fu ◽  
Ruifen Zhan ◽  
Zhiwei Wu ◽  
Yuqing Wang ◽  
Jiuwei Zhao
Keyword(s):  
Sea Ice ◽  
Bering Sea ◽  
North Pacific ◽  
Western North Pacific ◽  
Japan Sea ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Arctic Sea ◽  
The Japan Sea ◽  
The Bering Sea

Although many studies have revealed that Arctic sea ice may impose a great impact on the global climate system, including the tropical cyclone (TC) genesis frequency over the western North Pacific (WNP), it is unknown whether the Arctic sea ice could have any significant effects on other aspects of TCs; and if so, what are the involved physical mechanisms. This study investigates the impact of spring (April-May) sea ice concentration (SIC) in the Bering Sea on interannual variability of TC activity in terms of the accumulated cyclone energy (ACE) over the WNP in the TC season (June-September) during 1981–2018. A statistical analysis indicates that the spring SIC in the Bering Sea is negatively correlated with the TC season ACE over the WNP. Further analyses demonstrate that the reduction of the spring SIC can lead to the westward shift and intensification of the Aleutian low, which strengthens the southward cold-air intrusion, increases low clouds, and reduces surface shortwave radiation flux, leading to cold sea surface temperature (SST) anomaly in the Japan Sea and its adjacent regions. This local cloud-radiation-SST feedback induces the persistent increasing cooling in SST (and also the atmosphere above) in the Japan Sea through the TC season. This leads to a strengthening and southward shift of the subtropical westerly jet (SWJ) over the East Asia, followed by an anomalous upper-level anticyclone, low-level cyclonic circulation anomalies, increased convective available potential energy, and reduced vertical wind shear over the tropical WNP. These all are favorable for the increased ACE over the WNP. The opposite is true for the excessive spring SIC. The finding not only has an important implication for seasonal TC forecasts but also suggests a strengthened future TC activity potentially resulting from the rapid decline of Arctic sea ice.

scholarly journals High-Resolution Seeded Simulations of Western North Pacific Ocean Tropical Cyclones in Two Future Extreme Climates

2018 ◽  
Vol 32 (2) ◽  
pp. 309-334
Author(s):  
J. G. McLay ◽  
E. A. Hendricks ◽  
J. Moskaitis
Keyword(s):  
High Resolution ◽  
Pacific Ocean ◽  
Tropical Cyclones ◽  
North Pacific ◽  
Western North Pacific ◽  
North Pacific Ocean ◽  
Weather Prediction ◽  
Bootstrap Analysis ◽  
Western North Pacific Ocean ◽  
The Future

ABSTRACT A variant of downscaling is devised to explore the properties of tropical cyclones (TCs) that originate in the open ocean of the western North Pacific Ocean (WestPac) region under extreme climates. This variant applies a seeding strategy in large-scale environments simulated by phase 5 of the Coupled Model Intercomparison Project (CMIP5) climate-model integrations together with embedded integrations of Coupled Ocean–Atmosphere Mesoscale Prediction System for Tropical Cyclones (COAMPS-TC), an operational, high-resolution, nonhydrostatic, convection-permitting numerical weather prediction (NWP) model. Test periods for the present day and late twenty-first century are sampled from two different integrations for the representative concentration pathway (RCP) 8.5 forcing scenario. Then seeded simulations for the present-day period are contrasted with similar seeded simulations for the future period. Reinforcing other downscaling studies, the seeding results suggest that the future environments are notably more conducive to high-intensity TC activity in the WestPac. Specifically, the future simulations yield considerably more TCs that exceed 96-kt (1 kt ≈ 0.5144 m s−1) intensity, and these TCs exhibit notably greater average life cycle maximum intensity and tend to spend more time above the 96-kt intensity threshold. Also, the future simulations yield more TCs that make landfall at >64-kt intensity, and the average landfall intensity of these storms is appreciably greater. These findings are supported by statistical bootstrap analysis as well as by a supplemental sensitivity analysis. Accounting for COAMPS-TC intensity forecast bias using a quantile-matching approach, the seeded simulations suggest that the potential maximum western North Pacific TC intensities in the future extreme climate may be approximately 190 kt.

scholarly journals Ventilation changes in the western North Pacific since the last glacial period

2011 ◽  
Vol 7 (4) ◽  
pp. 2719-2739 ◽  
Author(s):  
Y. Okazaki ◽  
T. Sagawa ◽  
H. Asahi ◽  
K. Horikawa ◽  
J. Onodera
Keyword(s):  
Sedimentation Rate ◽  
North Pacific ◽  
Western North Pacific ◽  
Glacial Period ◽  
High Quality ◽  
Last Glacial Period ◽  
The Past ◽  
High Sedimentation ◽  
The Last Glacial

Abstract. We reconstructed the ventilation record of deep water at 2100 m depth in the mid-latitude western North Pacific over the past 25 kyr from radiocarbon measurements of coexisting planktic and benthic foraminiferal shells in sediment with a high sedimentation rate. The 14C data on fragile and robust planktic foraminiferal shells were concordant with each other, ensuring high quality of the reconstructed ventilation record. The radiocarbon activity changes were consistent with the atmospheric record, suggesting that no massive mixing of old carbon from the abyssal reservoir occurred throughout the glacial to deglacial periods.

scholarly journals Improved Simulation of Tropical Cyclone Responses to ENSO in the Western North Pacific in the High-Resolution GFDL HiFLOR Coupled Climate Model*

2016 ◽  
Vol 29 (4) ◽  
pp. 1391-1415 ◽  
Author(s):  
Wei Zhang ◽  
Gabriel A. Vecchi ◽  
Hiroyuki Murakami ◽  
Thomas Delworth ◽  
Andrew T. Wittenberg ◽  
...  
Keyword(s):  
High Resolution ◽  
Tropical Cyclone ◽  
El Niño ◽  
North Pacific ◽  
Western North Pacific ◽  
El Nino ◽  
Walker Circulation ◽  
La Niña ◽  
Sea Surface ◽  
La Nina

Abstract This study aims to assess whether, and the extent to which, an increase in atmospheric resolution of the Geophysical Fluid Dynamics Laboratory (GFDL) Forecast-Oriented Low Ocean Resolution version of CM2.5 (FLOR) with 50-km resolution and the High-Resolution FLOR (HiFLOR) with 25-km resolution improves the simulation of the El Niño–Southern Oscillation (ENSO)–tropical cyclone (TC) connections in the western North Pacific (WNP). HiFLOR simulates better ENSO–TC connections in the WNP including TC track density, genesis, and landfall than FLOR in both long-term control experiments and sea surface temperature (SST)- and sea surface salinity (SSS)-restoring historical runs (1971–2012). Restoring experiments are performed with SSS and SST restored to observational estimates of climatological SSS and interannually varying monthly SST. In the control experiments of HiFLOR, an improved simulation of the Walker circulation arising from more realistic SST and precipitation is largely responsible for its better performance in simulating ENSO–TC connections in the WNP. In the SST-restoring experiments of HiFLOR, more realistic Walker circulation and steering flow during El Niño and La Niña are responsible for the improved simulation of ENSO–TC connections in the WNP. The improved simulation of ENSO–TC connections with HiFLOR arises from a better representation of SST and better responses of environmental large-scale circulation to SST anomalies associated with El Niño or La Niña. A better representation of ENSO–TC connections in HiFLOR can benefit the seasonal forecasting of TC genesis, track, and landfall; improve understanding of the interannual variation of TC activity; and provide better projection of TC activity under climate change.

2000 years of marine primary productivity in the Eastern Tropical North Pacific

2020 ◽  
Author(s):  
Christina Treinen-Crespo ◽  
Jose Carriquiry ◽  
Julio Villaescusa ◽  
Elisabet Repiso-Terrones
Keyword(s):  
High Resolution ◽  
Climate Variability ◽  
Primary Productivity ◽  
North Pacific ◽  
Biogenic Silica ◽  
Change Scenario ◽  
The Past ◽  
Past 2000 Years ◽  
Increasing Trend ◽  
Marine Primary Productivity

<p>Changes in marine primary productivity (MPP) over the 21st century are expected to occur under the prevailing climate change scenario. For better understanding of past climate variability, we reconstructed MPP at high resolution (~1-2 years) for the past 2000 years analyzing biogenic silica and total organic carbon (TOC %) on a sediment core collected from Soledad Basin (25°N, 112°W), Baja  California, Mexico. Located in the Eastern Tropical North Pacific, this suboxic basin is ideal for palaeoceanographic reconstructions due to its high sedimentation rate (2 mm/year), which allow us to reconstruct past changes in the ocean and climate at high resolution. Our results show an increasing trend in the variability of MPP for the past 2000 years: biogenic silica content does not show a well-defined trend, but rather it is dominated by strong multidecadal and prominent centennial-scale cycles while TOC (%) shows a slight increasing trend towards the present, starting at least 2000 years ago. Spectral analysis confirms the presence of multidecadal to centennial cycles. These results will be discussed in the context of the Anthropocene and natural climate variability.</p>

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