Prediction of atmospheric rivers over the North Pacific and its connection to ENSO in the North American multi-model ensemble (NMME)

2017 ◽  
Vol 51 (5-6) ◽  
pp. 1623-1637 ◽  
Author(s):  
Yang Zhou ◽  
Hye-Mi Kim
Keyword(s):  
North American ◽  
North Pacific ◽  
Model Ensemble ◽  
Atmospheric Rivers ◽  
The North ◽  
The North Pacific

scholarly journals Contrastive Influence of ENSO and PNA on Variability and Predictability of North American Winter Precipitation

2019 ◽  
Vol 32 (19) ◽  
pp. 6271-6284 ◽  
Author(s):  
Xiaofan Li ◽  
Zeng-Zhen Hu ◽  
Ping Liang ◽  
Jieshun Zhu
Keyword(s):  
North America ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
North American ◽  
North Pacific ◽  
Winter Precipitation ◽  
Sea Surface ◽  
The North ◽  
Remote Forcing ◽  
The North Pacific

Abstract In this work, the roles of El Niño–Southern Oscillation (ENSO) in the variability and predictability of the Pacific–North American (PNA) pattern and precipitation in North America in winter are examined. It is noted that statistically about 29% of the variance of PNA is linearly linked to ENSO, while the remaining 71% of the variance of PNA might be explained by other processes, including atmospheric internal dynamics and sea surface temperature variations in the North Pacific. The ENSO impact is mainly meridional from the tropics to the mid–high latitudes, while a major fraction of the non-ENSO variability associated with PNA is confined in the zonal direction from the North Pacific to the North American continent. Such interferential connection on PNA as well as on North American climate variability may reflect a competition between local internal dynamical processes (unpredictable fraction) and remote forcing (predictable fraction). Model responses to observed sea surface temperature and model forecasts confirm that the remote forcing is mainly associated with ENSO and it is the major source of predictability of PNA and winter precipitation in North America.

The North Pacific Experiment (NORPEX-98): Targeted Observations for Improved North American Weather Forecasts

1999 ◽  
Vol 80 (7) ◽  
pp. 1363-1384 ◽  
Author(s):  
R. H. Langland ◽  
Z. Toth ◽  
R. Gelaro ◽  
I. Szunyogh ◽  
M. A. Shapiro ◽  
...  
Keyword(s):  
North American ◽  
North Pacific ◽  
Weather Forecasts ◽  
The North ◽  
Targeted Observations ◽  
The North Pacific

Key Role of the North Pacific Oscillation–West Pacific Pattern in Generating the Extreme 2013/14 North American Winter

2015 ◽  
Vol 28 (20) ◽  
pp. 8109-8117 ◽  
Author(s):  
Stephen Baxter ◽  
Sumant Nigam
Keyword(s):  
North America ◽  
North American ◽  
North Pacific ◽  
Eastern North America ◽  
North Pacific Oscillation ◽  
Winter Climate ◽  
West Pacific ◽  
The North ◽  
The Tropics ◽  
The North Pacific

Abstract The 2013/14 boreal winter (December 2013–February 2014) brought extended periods of anomalously cold weather to central and eastern North America. The authors show that a leading pattern of extratropical variability, whose sea level pressure footprint is the North Pacific Oscillation (NPO) and circulation footprint the West Pacific (WP) teleconnection—together, the NPO–WP—exhibited extreme and persistent amplitude in this winter. Reconstruction of the 850-hPa temperature, 200-hPa geopotential height, and precipitation reveals that the NPO–WP was the leading contributor to the winter climate anomaly over large swaths of North America. This analysis, furthermore, indicates that NPO–WP variability explains the most variance of monthly winter temperature over central-eastern North America since, at least, 1979. Analysis of the NPO–WP related thermal advection provides physical insight on the generation of the cold temperature anomalies over North America. Although NPO–WP’s origin and development remain to be elucidated, its concurrent links to tropical SSTs are tenuous. These findings suggest that notable winter climate anomalies in the Pacific–North American sector need not originate, directly, from the tropics. More broadly, the attribution of the severe 2013/14 winter to the flexing of an extratropical variability pattern is cautionary given the propensity to implicate the tropics, following several decades of focus on El Niño–Southern Oscillation and its regional and far-field impacts.

scholarly journals A Comparison of Northern Hemisphere Atmospheric Rivers Detected by a New Image-Processing Based Method and Magnitude-Thresholding Based Methods

Atmosphere ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 628 ◽  
Author(s):  
Guangzhi Xu ◽  
Xiaohui Ma ◽  
Ping Chang ◽  
Lin Wang
Keyword(s):  
Image Processing ◽  
North Atlantic ◽  
North Pacific ◽  
Detection Method ◽  
New Method ◽  
Detection Methods ◽  
Image Processing Algorithm ◽  
Atmospheric Rivers ◽  
The North ◽  
The North Pacific

A majority of the existing atmospheric rivers (ARs) detection methods is based on magnitude thresholding on either the integrated water vapor (IWV) or integrated vapor transport (IVT). One disadvantage of such an approach is that the predetermined threshold does not have the flexibility to adjust to the fast changing conditions where ARs are embedded. To address this issue, a new AR detection method is derived from an image-processing algorithm that makes the detection independent of AR magnitude. In this study, we compare the North Pacific and Atlantic ARs tracked by the new detection method and two widely used magnitude thresholding methods in the present day climate. The results show considerable sensitivities of the detected AR number, shape, intensities and their accounted IVT accumulations to different methods. In many aspects, ARs detected by the new method lie between those from the two magnitude thresholding methods, but stand out with a greater number of AR tracks, longer track durations, and stronger AR-related moisture transport in the AR tracks. North Pacific and North Atlantic ARs identified by the new method account for around 100–120 ×   10 3 kg/m/s IVT within the AR track regions, about 50 % more than the other two methods. This is primarily due to the fact that the new method captures the strong IVT signals more effectively.

scholarly journals Combined Influences on North American Winter Air Temperature Variability from North Pacific Blocking and the North Atlantic Oscillation: Subseasonal and Interannual Time Scales

2020 ◽  
Vol 33 (16) ◽  
pp. 7101-7123 ◽  
Author(s):  
Binhe Luo ◽  
Dehai Luo ◽  
Aiguo Dai ◽  
I. Simmonds ◽  
Lixin Wu
Keyword(s):  
North America ◽  
Air Temperature ◽  
North Atlantic ◽  
North American ◽  
North Pacific ◽  
Eastern North America ◽  
The North ◽  
The North Atlantic ◽  
The North Atlantic Oscillation ◽  
The North Pacific

AbstractWinter surface air temperature (SAT) over North America exhibits pronounced variability on subseasonal, interannual, decadal, and interdecadal time scales. Here, reanalysis data from 1950–2017 are analyzed to investigate the atmospheric and surface ocean conditions associated with its subseasonal to interannual variability. Detrended daily SAT data reveal a known warm west/cold east (WWCE) dipole over midlatitude North America and a cold north/warm south (CNWS) dipole over eastern North America. It is found that while the North Pacific blocking (PB) is important for the WWCE and CNWS dipoles, they also depend on the phase of the North Atlantic Oscillation (NAO). When a negative-phase NAO (NAO−) coincides with PB, the WWCE dipole is enhanced (compared with the PB alone case) and it also leads to a warm north/cold south dipole anomaly in eastern North America; but when PB occurs with a positive-phase NAO (NAO+), the WWCE dipole weakens and the CNWS dipole is enhanced. The PB events concurrent with the NAO− (NAO+) and SAT WWCE (CNWS) dipole are favored by the Pacific El Niño–like (La Niña–like) sea surface temperature mode and the positive (negative) North Pacific mode. The PB-NAO+ has a larger component projecting onto the SAT WWCE dipole during the La Niña winter than during the El Niño winter because a more zonal wave train is formed. Strong North American SAT WWCE dipoles and enhanced projections of PB-NAO+ events onto the SAT WWCE dipole component are also readily seen for the positive North Pacific mode. The North Pacific mode seems to play a bigger role in the North American SAT variability than ENSO.

THE IDENTITY OF THE SPECIES OF LEPEOPHTHEIRUS (COPEPODA) PARASITIC ON PACIFIC SALMON (GENUS ONCORHYNCHUS) AND ATLANTIC SALMON (SALMO SALAR)

1958 ◽  
Vol 36 (6) ◽  
pp. 889-892 ◽  
Author(s):  
L. Margolis
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
North American ◽  
North Pacific ◽  
Pacific Salmon ◽  
Distinct Species ◽  
Atlantic Salmon Salmo Salar ◽  
The North ◽  
Wide Range ◽  
The North Pacific

A review of existing descriptions of Lepeophtheirus from salmonids, based on specimens collected mainly from Salmo salar in the European and North American Atlantic and from Oncorhynchus spp. in the Asiatic and North American Pacific, coupled with observations by the author on material from S. salar from England and from Oncorhynchus spp. from a wide range of localities in the North Pacific, suggest that L. salmonis (Krøyer, 1838) is the only species found on salmonids from both oceans. The differentiation of L. uenoi Yamaguti, 1939 as a distinct species on Pacific salmon seems to be the result of incorrect or inadequate early descriptions of L. salmonis.

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