scholarly journals Interdecadal Relationships between the Asian-Pacific Oscillation and Summer Climate Anomalies over Asian, North Pacific and North America during Recent 100 Years

2011 ◽  
pp. 110415071529000 ◽  
Author(s):  
PING ZHAO ◽  
SONG YANG ◽  
HUIJUN WANG ◽  
QIANG ZHANG
Keyword(s):  
North America ◽  
North Pacific ◽  
Climate Anomalies ◽  
Summer Climate ◽  
Asian Pacific

scholarly journals Interdecadal Relationships between the Asian–Pacific Oscillation and Summer Climate Anomalies over Asia, North Pacific, and North America during a Recent 100 Years

2011 ◽  
Vol 24 (18) ◽  
pp. 4793-4799 ◽  
Author(s):  
Ping Zhao ◽  
Song Yang ◽  
Huijun Wang ◽  
Qiang Zhang
Keyword(s):  
North America ◽  
North Pacific ◽  
Asian Monsoon ◽  
Asian Monsoon Region ◽  
Climate Anomalies ◽  
Summer Climate ◽  
The North ◽  
The Pacific ◽  
Asian Pacific ◽  
The North Pacific

Abstract Summertime relationships between the Asian–Pacific Oscillation (APO) and climate anomalies over Asia, the North Pacific, and North America are examined on an interdecadal time scale. The values of APO were low from the 1880s to the mid-1910s and high from the 1920s to the 1940s. When the APO was higher, tropospheric temperatures were higher over Asia and lower over the Pacific and North America. From the low-APO decades to the high-APO decades, both upper-tropospheric highs and lower-tropospheric low pressure systems strengthened over South Asia and weakened over North America. As a result, anomalous southerly–southwesterly flow prevailed over the Asian monsoon region, meaning stronger moisture transport over Asia. On the contrary, the weakened upper-tropospheric high and lower-tropospheric low over North America caused anomalous sinking motion over the region. As a result, rainfall generally enhanced over the Asian monsoon regions and decreased over North America.

scholarly journals Simulation and Dynamical Prediction of the Summer Asian–Pacific Oscillation and Associated Climate Anomalies by the NCEP CFSv2

2013 ◽  
Vol 26 (11) ◽  
pp. 3644-3656 ◽  
Author(s):  
Junming Chen ◽  
Ping Zhao ◽  
Song Yang ◽  
Ge Liu ◽  
Xiuji Zhou
Keyword(s):  
North America ◽  
South America ◽  
South Asian ◽  
North Africa ◽  
South Asian High ◽  
Tropospheric Temperature ◽  
Climate Anomalies ◽  
The North ◽  
Asian Pacific ◽  
Tropical South America

Abstract The Asian–Pacific Oscillation (APO) is a dominant teleconnection pattern linking the climate anomalies over Asia, the North Pacific, and other regions including North America. The National Centers for Environmental Prediction (NCEP) Climate Forecast System version 2 (CFSv2) successfully simulates many summer-mean features of the upper-tropospheric temperature, the South Asian high, the westerly and easterly jet streams, and the regional monsoons over Asia and Africa. It also well simulates the interannual variability of the APO and associated anomalies in atmospheric circulation, precipitation, surface air temperature (SAT), and sea surface temperature (SST). Associated with a positive APO are a strengthened South Asian high; a weakened extratropical upper-tropospheric westerly jet stream over North America; strengthened subtropical anticyclones over the Northern Hemisphere oceans; and strengthened monsoons over North Africa, India, and East Asia. Meanwhile, increased precipitation is found over tropical North Africa, South Asia, northern China, and tropical South America; decreased precipitation is seen over subtropical North Africa, the Middle East, central Asia, southern China, Japan, and extratropical North America. Low SAT occurs in North Africa, India, and tropical South America and high SAT appears in extratropical Eurasia and North America. SST increases in the extratropical Pacific and the North Atlantic but decreases in the tropical Pacific. The summer APO and many of the associated climate anomalies can be predicted by the NCEP CFSv2 by up to 5 months in advance. However, the CFSv2 skill of predicting the SAT in the East Asian monsoon region is low.

scholarly journals Relative Controls of Asian–Pacific Summer Climate by Asian Land and Tropical–North Pacific Sea Surface Temperature

2011 ◽  
Vol 24 (15) ◽  
pp. 4165-4188 ◽  
Author(s):  
Ping Zhao ◽  
Song Yang ◽  
Maoqiu Jian ◽  
Junming Chen
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Atmospheric Circulation ◽  
North Pacific ◽  
Sea Surface ◽  
Tropospheric Temperature ◽  
Climate Anomalies ◽  
Sensitivity Experiments ◽  
The Pacific ◽  
Asian Pacific

Abstract The dominant pattern of summertime tropical and North Pacific sea surface temperature (SST) is characterized by an out-of-phase relationship between the tropics and the extratropics. This pattern, defined as the tropical–North Pacific mode (TNPM) in this study, is closely correlated with the variability of climate over Asia and the Pacific Ocean. A high TNPM index, with positive (negative) SST anomalies over the extratropics (tropics) of the Pacific, is linked to deep negative anomalies of tropospheric temperature over the extratropical Pacific, with shallow positive anomalies in the lower troposphere, and is also linked to deep positive temperature over Asia. It is also found that these anomalies of tropospheric temperature and SST are significantly related to the Asian–Pacific Oscillation (APO), an extratropical zonal–vertical atmospheric pattern connecting Asia and the Pacific. Indeed, when the variability of APO is removed, the above-described climate anomalies weaken significantly. Although the above relationships observed between atmospheric circulation and SST can be captured by general circulation models, sensitivity experiments show that the variations of summertime Asian–Pacific atmospheric circulation may not be mainly forced by the Pacific SST. Instead, the Asian land elevated heating seems to play a more important role in generating the climate anomalies, as shown by model-sensitivity experiments in which changes in topographic height are included. Moreover, the relative importance of Asian land and Pacific SST for the variations of Asian–Pacific climate in summer and winter is compared in this study. In winter the most dominant mode of Pacific SST exerts a stronger impact on the Asian–Pacific climate.

scholarly journals Effects of the Tibetan High and the North Pacific High on the Occurrence of Hot or Cool Summers in Japan

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 307
Author(s):  
Makoto Inoue ◽  
Atsushi Ugajin ◽  
Osamu Kiguchi ◽  
Yousuke Yamashita ◽  
Masashi Komine ◽  
...  
Keyword(s):  
High Pressure ◽  
North Pacific ◽  
Lower Stratosphere ◽  
The Other ◽  
Summer Climate ◽  
The North ◽  
Several Variables ◽  
Western Japan ◽  
Cool Summer ◽  
The North Pacific

In this study, we investigated the effects of the Tibetan High near the tropopause and the North Pacific High in the troposphere on occurrences of hot or cool summers in Japan. We first classified Japan into six regions and identified hot and cool summer years in these regions from a 38-year sample (1980–2017) based on the monthly air temperature. To investigate the features of circulation fields over Asia during hot and cool summers in Japan, we calculated the composite differences (hot summer years minus cool summer years) of several variables such as geopotential height, which indicated significant high-pressure anomalies in the troposphere and lower stratosphere. These results suggest that both the North Pacific and the Tibetan Highs tend to extend to Japan during hot summer years, while cool summers seem to be associated with the weakening of these highs. We found that extension of the Tibetan High to the Japanese mainland can lead to hot summers in Northern, Eastern, and Western Japan. On the other hand, hot summers in the Southwestern Islands may be due to extension of the Tibetan High to the south. Similarly, the latitudinal direction of extension of the North Pacific High is profoundly connected with the summer climate in respective regions.

Interannual Variability of North American Winter Temperature Extremes and Its Associated Circulation Anomalies in Observations and CMIP5 Simulations

2020 ◽  
Vol 33 (3) ◽  
pp. 847-865 ◽  
Author(s):  
B. Yu ◽  
H. Lin ◽  
V. V. Kharin ◽  
X. L. Wang
Keyword(s):  
North America ◽  
Surface Temperature ◽  
Atmospheric Circulation ◽  
North American ◽  
North Pacific ◽  
Large Scale ◽  
Temperature Extremes ◽  
Temperature Extreme ◽  
Central Canada ◽  
Leading Mode

AbstractThe interannual variability of wintertime North American surface temperature extremes and its generation and maintenance are analyzed in this study. The leading mode of the temperature extreme anomalies, revealed by empirical orthogonal function (EOF) analyses of December–February mean temperature extreme indices over North America, is characterized by an anomalous center of action over western-central Canada. In association with the leading mode of temperature extreme variability, the large-scale atmospheric circulation features an anomalous Pacific–North American (PNA)-like pattern from the preceding fall to winter, which has important implications for seasonal prediction of North American temperature extremes. A positive PNA pattern leads to more warm and fewer cold extremes over western-central Canada. The anomalous circulation over the PNA sector drives thermal advection that contributes to temperature anomalies over North America, as well as a Pacific decadal oscillation (PDO)-like sea surface temperature (SST) anomaly pattern in the midlatitude North Pacific. The PNA-like circulation anomaly tends to be supported by SST warming in the tropical central-eastern Pacific and a positive synoptic-scale eddy vorticity forcing feedback on the large-scale circulation over the PNA sector. The leading extreme mode–associated atmospheric circulation patterns obtained from the observational and reanalysis data, together with the anomalous SST and synoptic eddy activities, are reasonably well simulated in most CMIP5 models and in the multimodel mean. For most models considered, the simulated patterns of atmospheric circulation, SST, and synoptic eddy activities have lower spatial variances than the corresponding observational and reanalysis patterns over the PNA sector, especially over the North Pacific.

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