scholarly journals Seasonal and Long-Term Coupling between Wintertime Storm Tracks and Sea Surface Temperature in the North Pacific

2013 ◽  
Vol 26 (16) ◽  
pp. 6123-6136 ◽  
Author(s):  
Bolan Gan ◽  
Lixin Wu
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
North Pacific ◽  
Storm Track ◽  
Sea Surface ◽  
Storm Tracks ◽  
The North ◽  
The North Pacific ◽  
Sst Anomalies

Abstract In this study, a lagged maximum covariance analysis (MCA) of the wintertime storm-track and sea surface temperature (SST) anomalies derived from the reanalysis datasets shows significant seasonal and long-term relationships between storm tracks and SST variations in the North Pacific. At seasonal time scales, it is found that the midlatitude warm (cold) SST anomalies in the preceding fall, which are expected to change the tropospheric baroclinicity, can significantly reduce (enhance) the storm-track activities in early winter. The storm-track response pattern, however, is in sharp contrast to the forcing pattern, with warm (cold) SST anomalies in the western–central North Pacific corresponding to a poleward (equatorward) shift of storm tracks. At interannual-to-decadal time scales, it is found that the wintertime SST and storm-track anomalies are mutually reinforced up to 3 yr, which is characterized by PDO-like SST anomalies with warming in the western–central domain coupled with basin-scale positive storm-track anomalies extending along 50°N.

Recent intensified influence of the winter North Pacific sea surface temperature on the withdrawal date of Meiyu

2021 ◽  
pp. 1-53
Author(s):  
Hua Li ◽  
Shengping He ◽  
Ke Fan ◽  
Yong Liu ◽  
Xing Yuan
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Interannual Variability ◽  
North Pacific ◽  
North Pacific Ocean ◽  
Sea Surface ◽  
The North ◽  
Time Period ◽  
The North Pacific ◽  
Sst Anomalies

AbstractThe Meiyu withdrawal date (MWD) is a crucial indicator of flood/drought conditions over East Asia. It is characterized by a strong interannual variability, but its underlying mechanism remains unknown. We investigated the possible effects of the winter sea surface temperature (SST) in the North Pacific Ocean on the MWD on interannual to interdecadal timescales. Both our observations and model results suggest that the winter SST anomalies associated with the MWD are mainly contributed by a combination of the first two leading modes of the winter SST in the North Pacific, which have a horseshoe shape (the NPSST). The statistical results indicate that the intimate linkage between the NPSST and the MWD has intensified since the early 1990s. During the time period 1990–2016, the NPSST-related SST anomalies persisted from winter to the following seasons and affected the SST over the tropical Pacific in July. Subsequently, the SST anomalies throughout the North Pacific strengthened the southward migration of the East Asian jet stream (EAJS) and the southward and westward replacement of the western North Pacific subtropical high (WPSH), leading to an increase in Meiyu rainfall from July 1 to 20. More convincingly, the anomalous EAJS and WPSH induced by the SST anomalies can be reproduced well by numerical simulations. By contrast, the influence of the NPSST on the EASJ and WPSH were not clear between 1961 and 1985. This study further illustrates that the enhanced interannual variability of the NPSST may be attributed to the more persistent SST anomalies during the time period 1990–2016.

scholarly journals Feedbacks of Sea Surface Temperature to Wintertime Storm Tracks in the North Atlantic

2014 ◽  
Vol 28 (1) ◽  
pp. 306-323 ◽  
Author(s):  
Bolan Gan ◽  
Lixin Wu
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
North Atlantic ◽  
Storm Track ◽  
Early Spring ◽  
Sea Surface ◽  
Storm Tracks ◽  
The North ◽  
The North Atlantic ◽  
Sst Anomalies

Abstract In this study, the lagged maximum covariance analysis is performed on winter storm-track anomalies, represented by the meridional heat flux by synoptic-scale (2–8 days) transient eddies and sea surface temperature (SST) anomalies in the North Atlantic, which are both derived from reanalysis datasets spanning the twentieth century. The analysis shows significant seasonal and interannual coupling between storm-track and SST variations. On seasonal time scales, it is found that SST anomalies in the preceding early winter (November–December), which are expected to change the lower-tropospheric baroclinicity, can significantly influence storm tracks in early spring (March); that is, an intensification and slight northward shift of storm tracks in response to a midlatitude SST dipole, with a cold pole centered to the southeast of Newfoundland and a warm pole in the western subtropical Atlantic. This storm-track response pattern is similar to the storm-track forcing pattern in early spring, which resembles the dominant mode of storm tracks. At interannual time scales, it is found that the wintertime (January–March) storm-track and SST anomalies are mutually reinforced, manifesting as a zonal-dipole-like pattern in storm-track anomalies (with dominant negative anomalies in the downstream) coupled with a midlatitude SST monopole (with warm anomalies centered to the south and east of Newfoundland).

scholarly journals Summertime Evolution of Decadal Sea Surface Temperature Anomalies in the Midlatitude North Pacific

2008 ◽  
Vol 21 (7) ◽  
pp. 1569-1588 ◽  
Author(s):  
Takashi Mochizuki ◽  
Toshiyuki Awaji
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
North Pacific ◽  
Radiation Flux ◽  
Sea Surface ◽  
Shortwave Radiation ◽  
The North ◽  
Sst Anomaly ◽  
The North Pacific ◽  
Sst Anomalies

Abstract To clarify the summertime evolution of decadal sea surface temperature (SST) anomalies and related physical processes in the midlatitudes of the North Pacific, numerical solutions of a three-dimensional bulk mixed layer model are analyzed, focusing on the contribution of the net shortwave radiative forcing at the sea surface. A quantitative heat budget analysis for the ocean mixed layer relating to late-1980s decadal SST change reveals that the decadal SST anomalies decay from late spring to early summer over the entire midlatitudes of the North Pacific. This quasi-seasonal decay of the decadal SST anomalies is controlled by an anomalous local thermal damping (i.e., anomalous surface heat fluxes). From midsummer to early autumn the anomalous net shortwave radiation flux associated with a meridional shift of the storm track acts to induce strong seasonal damping of the decadal SST anomaly in the northern Kuroshio–Oyashio Extension region. In contrast, in the north of the subtropical frontal region, the net shortwave radiation flux anomaly, which results from changes in low-level stratiform cloud cover, plays a major role in seasonally enhancing the decadal SST anomaly. Consequently, the SST anomalies formed by these radiative forcings cause significant variations in the local thermal damping rate at the sea surface over the period from late summer to early autumn.

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.

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