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Possible Impacts of Winter Arctic Oscillation on Siberian High, the East Asian Winter Monsoon and Sea-Ice Extent
冬季北极涛动对西伯利亚高压、东亚冬季风以及海冰范围的可能影响

Wu Bingyi,Wang Jia,
Wu Bingyi
,Wang Jia

大气科学进展 , 2002,
Abstract: Using the NCEP/NCAR reanalysis dataset covering a 40-year period from January 1958 to December 1997, sea surface temperature (1950-1992), and monthly sea-ice concentration dataset for the period from 1953to 1995, we investigate connections between winter Arctic Oscillation (AO) and Siberian high (SH), the East Asian winter monsoon (EAWM), and winter sea-ice extent in the Barents Sea. The results indicate that winter AO not only influences climate variations in the Arctic and the North Atlantic sector, but also shows possible effects on winter SH, and further influences EAWM. When winter AO is in its positive phase, both of winter SH and the EAWM are weaker than normal, and air temperature from near the surface to the middle troposphere is about 0.S-2°C higher than normal in the southeastern Siberia and the East Asian coast, including eastern China,Korea, and Japan. When AO reaches its negative phase, an opposite scenario can be observed. The results also indicate that winter SH has no significant effects on climate variations in Arctic and the ture in contrast to AO. This study further reveals the possible mechanism of how the winter AO is related to winter SH. It is found that winter SH variation is closely related to both dynamic processes and air temperature variations from the surface to the middle troposphere. The western SH variation mainly depends on dynamic processes, while its eastern part is more closely related to air temperature variation. The maintaining of winter SH mainly depends on downward motion of airflow of the nearly entire troposphere. The airflow originates from the North Atlantic sector, whose variation is influenced by the AO. When AO is in its positive (negative) phase,downward motion remarkably weakened (strengthened), which further influences winter SH. In addition, winter AO exhibits significant influences on the simultaneous sea-ice extent in the Barents Sea.
The combined effects of the ENSO and the Arctic Oscillation on the winter climate anomalies in East Asia
Wen Chen,XiaoQing Lan,Lin Wang,Yin Ma
Chinese Science Bulletin , 2013, DOI: 10.1007/s11434-012-5654-5
Abstract: With the warm/cold phases of the El Ni o and Southern Oscillation (ENSO) as a background, the impacts of monthly variation in the Arctic Oscillation (AO) on the winter climate anomalies in East Asia are studied with the NCEP/DOE Reanalysis 2 data and the Chinese station data regarding temperature and rainfall. The combined effects of ENSO and the AO indicate that the winter climate anomalies are mainly influenced by the AO in northern China and the ENSO in southern China, when an El Ni o couples with a negative AO month or a La Ni a couples with a positive AO month. These climate anomalies in China are consistent with the mechanisms proposed in previous studies. However, most of China presents a different pattern of climate anomalies if an El Ni o couples with a positive AO month or a La Ni a couples with a negative AO month, with the exception of the temperature anomalies in northern China, which are still affected dominantly by the AO. Further analysis suggests that the causes are attributed to the differences in both the stratosphere-troposphere interaction and the extratropics-tropics interaction. In the former cases, zonal symmetric circulation prevails in the winter and the extratropics-tropics interaction is weakened. Thus, the influences of the ENSO and the AO on the East Asian climate mainly present linear combination effects. On the contrary, an annular mode of atmospheric circulation is not favored in the latter cases and the extratropics-tropics interaction is strong. Hence, the combined effects of the ENSO and the AO on the winter climate in East Asia present nonlinear characteristics.
Influence of Arctic Oscillation on winter climate over China

GONG Daoyi,WANG Shaowu,

地理学报 , 2003,
Abstract: In this study the relationship between the Arctic Oscillation (AO) and climate in China in boreal winter are investigated. Correlation analysis for the last 41 years shows that the winter temperature and precipitation in China change in phase with AO. High positive correlation (>0.4) between temperature and AO appears in the northern China. High correlation coefficients between precipitation and AO cover the southern China (close to the South China Sea) and the central China (between 30o-40oN and east of ~100oE), with the values varying between +0.3 and +0.4. It is found that during the past several decades the precipitation was strongly affected by AO, but for the temperature the Siberian High plays a more important role. At the interdecadal time scale the AO has significant influence on both temperature and precipitation. Multivariate regression analysis demonstrates that AO and the Siberian High related variance in temperature and precipitation is 35% and 11% respectively. For precipitation, however the portion is rather low, implying that some other factors may be responsible for the changes in precipitation, in addition to AO and the Siberian High.
Arctic Oscillation influence on daily temperature variance in winter over China
Daoyi Gong,Shaowu Wang,Jinhong Zhu
Chinese Science Bulletin , 2004, DOI: 10.1360/03wd0481
Abstract: The relationship between the Arctic Oscillation (AO) and daily temperature variance of 150 Chinese stations are investigated in the present study for wintertime (1November through 31 March) in the period of 1954–2001. Results show that the temperature variance significantly decreases during the high AO years, and increases in low AO cases. A key factor connecting them is the Siberian High, particularly the high-frequency fluctuations of the High. Within the seasonal time scale, the frequency of low-temperature extremes (daily temperature anomaly below 2σ, σ is the standard deviation of daily temperature for a given winter and a given station) displays an odd relation to the variance: a larger (smaller) variance is found to be associated with smaller (greater) frequency of low-temperature events. That is due to the non-normal distribution of the temperatures, and also influenced by the phases of AO. During the last 50 years or so, AO experiences a significant increasing trend, meanwhile the variance of daily sea level pressure (SLP) in the central region of Siberian High has decreased at a rate of 10.7%/10 a. These result in a significant weakening of the daily temperature variance in China with a trend of 4.1%/10 a, and a significant increase in the intra-seasonal low-temperature extremes at a rate of 0.16d/10 a.
Arctic Oscillation influence on daily temperature variance in winter over China
Daoyi Gong,Shaowu Wang,Jinhong Zhu,
GONGDaoyi
,WANGShaowu,ZHUJinhong

科学通报(英文版) , 2004,
Abstract: The relationship between the Arctic Oscillation (AO) and daily temperature variance of 150 Chinese stations are investigated in the present study for wintertime (1November through 31 March) in the period of 1954–2001. Results show that the temperature variance significantly decreases during the high AO years, and increases in low AO cases. A key factor connecting them is the Siberian High, particularly the high-frequency fluctuations of the High. Within the seasonal time scale, the frequency of low-temperature extremes (daily temperature anomaly below 2σ, σ is the standard deviation of daily temperature for a given winter and a given station) displays an odd relation to the variance: a larger (smaller) variance is found to be associated with smaller (greater) frequency of low-temperature events. That is due to the non-normal distribution of the temperatures, and also influenced by the phases of AO. During the last 50 years or so, AO experiences a significant increasing trend, meanwhile the variance of daily sea level pressure (SLP) in the central region of Siberian High has decreased at a rate of 10.7%/10 a. These result in a significant weakening of the daily temperature variance in China with a trend of 4.1%/10 a, and a significant increase in the intra-seasonal low-temperature extremes at a rate of 0.16d/10 a.
Modulation of the Arctic Oscillation and the East Asian Winter Climate Relationships by the 11-year Solar Cycle

CHEN Wen,ZHOU Qun,

大气科学进展 , 2012,
Abstract: The modulation of the relationship between the Arctic Oscillation (AO) and the East Asian winter climate by the 11-year solar cycle was investigated. During winters with high solar activity (HS), robust warming appeared in northern Asia in a positive AO phase. This result corresponded to an enhanced anticyclonic flow at 850 hPa over northeastern Asia and a weakened East Asian trough (EAT) at 500 hPa. However, during winters with low solar activity (LS), both the surface warming and the intensities of the anticyclonic flow and the EAT were much less in the presence of a positive AO phase. The possible atmospheric processes for this 11-year solar-cycle modulation may be attributed to the indirect influence that solar activity induces in the structural changes of AO. During HS winters, the sea level pressure oscillation associated with the AO became stronger, with the significant influence of AO extending to East Asia. In the meantime, the AO-related zonal-mean zonal winds tended to extend more into the stratosphere during HS winters, which implies a stronger coupling to the stratosphere. These trends may have led to an enhanced AO phase difference; thus the associated East Asian climate anomalies became larger and more significant. The situation tended to reverse during LS winters. Further analyses revealed that the relationship between the winter AO and surface-climate anomalies in the following spring is also modulated by the 11-year solar cycle, with significant signals appearing only during HS phases. Solar-cycle variation should be taken into consideration when the AO is used to predict winter and spring climate anomalies over East Asia.
Interannual variability of winter precipitation in the European Alps: relations with the North Atlantic Oscillation.
E. Bartolini, P. Claps,P. D'Odorico
Hydrology and Earth System Sciences (HESS) & Discussions (HESSD) , 2009,
Abstract: The European Alps rely on winter precipitation for various needs in terms of hydropower and other water uses. Major European rivers originate from the Alps and depend on winter precipitation and the consequent spring snow melt for their summer base flows. Understanding the fluctuations in winter rainfall in this region is crucially important to the study of changes in hydrologic regime in river basins, as well as to the management of their water resources. Despite the recognized relevance of winter precipitation to the water resources of the Alps and surrounding regions, the magnitude and mechanistic explanation of interannual precipitation variability in the Alpine region remains unclear and poorly investigated. Here we use gridded precipitation data from the CRU TS 1.2 to study the interannual variability of winter alpine precipitation. We found that the Alps are the region with the highest interannual variability in winter precipitation in Europe. This variability cannot be explained by large scale climate patterns such as the Arctic Oscillation (AO), North Atlantic Oscillation (NAO) or the East Atlantic/West Russia (EA/WR), even though regions below and above the Alps demonstrate connections with these patterns. Significant trends were detected only in small regions located in the Eastern part of the Alps.
Interannual Variation of the Onset of Yunnan’s Rainy Season and Its Relationships with the Arctic Oscillation of the Preceding Winter  [PDF]
Yan Chen, Shichang Guo, Yu Liu, Jianhua Ju, Juzhang Ren
Atmospheric and Climate Sciences (ACS) , 2017, DOI: 10.4236/acs.2017.72015
Abstract: Based on an analysis of the circulation in May associated with the interannual variation of the onset of Yunnan’s rainy season, this study examined the rela-tionship between Arctic Oscillation (AO) and the onset timing of the rainy sea-son by using the NCEP/NCAR reanalysis and observational precipitation data for 1961-2010. The results indicated that, on an interannual time scale, intense Asian summer monsoon and an active EU-pattern wave train circulation in its positive phase, associated with a cold cyclonic cell covering the western part of the East Asian subtropical westerly jet (EASWJ), jointly contributed to the onset of the rainy season in May. Otherwise, the onset might be suppressed. The cold cyclonic cell over East Asia likely led to the southward shift and enhancement of EASWJ as well as its secondary circulation around the jet entrance, which could provide a favorable dynamic and thermal condition for rainfalls in Yunnan as was revealed in previous studies on 10 - 30-day time scale. Further examination showed that the preceding wintertime AO played a significant role in the timing of the onset of the rainy season before the mid-1980s’ by mostly modulating the wave-train-like circulation over East Asia in May. During that time period, when the AO index of the previous winter was positive (negative), Yunnan’s rainy season tended to begin earlier (later) than normal. Correspond-ingly, the precipitation in May was also closely linked to wintertime AO.
Correlations between North Atlantic Oscillation Index in winter and eastern China Flood/Drought Index in summer in the last 530 years
Congbin Fu,Zhaomei Zeng
Chinese Science Bulletin , 2005, DOI: 10.1007/BF03183642
Abstract: The time series of winter North Atlantic Oscillation Index (NAOI) in the period of 1429–1983 developed by Glueck and summer Flood/Drought Index (FDI) of eastern China in the period of 1470–1999 from 100 stations are used in this paper to study the potential impact of North Atlantic Oscillation on the climate in China. The analysis has explored some significant lag correlations between FDI and NAOL The maximum positive correlation coefficients between NAOI and area-mean FDI in eastern and northern China lagging 2–3 years reach at 0.001 significance level, and while there are also negative correlation between NAOI and FDI in central and southern China at significance level of 0.05–0.01. The correlation between FDI and NAOI is time-dependent, i.e. the correlation coefficients between two indices vary from period to period. The highest correlation appeared in the period of 1636–1742, around the Little Ice Age, with the significant level of far above 0.001. The second significant period was from 1951 to 1999, at the level of 0.005–0.002. Both the power spectrum analysis and Morlet wavelet transformation have presented an interesting phenomenon: the area-mean FDIs in eastern and northern China share almost the same oscillation periods with NAOI in the inter-annual, decadal and centurial scales’ oscillations, i.e. 4–5, about 10, 20–30, around 50 and 80–100 years, etc. The Mann-Kendall Rank Statistic test reveals the significant trend and decadal abrupt changes in the series of area-mean FDIs in eastern and northern China in the past 530 years, while the NAOI in the past 400 years, did not show such trend at the significance level, but presented more frequent changes than those of FDI in China. This difference is perhaps due to the fact that the amplitude of the extremes of reconstructed NAOI series is less than that from instrumental records.
Influence of Arctic Oscillation on Winter Climate over China
近百年北极涛动对中国冬季气候的影响

GONG Daoyi,WANG Shaowu,
龚道溢
,王绍武

地理学报 , 2003,
Abstract: In this study the relationships between the Arctic Oscillation and climate in China in boreal winter are investigated. The data used in this study include NCEP/NCAR Reanalysis monthly mean sea level pressure, 500 hPa geopotential heights, two Arctic Oscillation indices, and the observed temperature and precipitation. Correlation analysis for the last 41 years shows that the winter temperature and precipitation in China change in phase with AO. High positive correlation between temperature and AO is above +0.4 and appears in the northern China. High correlation coefficients between precipitation and AO cover the southern China (close to the South China Sea) and the central China (between 30o-40oN and east of ~100oE), with the values varying between +0.3 and +0.4. The correlation between the 160-station average temperature and the simultaneous sea level pressure show that the winter temperature of China is strongly connected to the sea level pressure over the high latitudes of Eurasia continent. The center is located in Siberia with values lower than -0.6. The partial correlation between the intensity of Siberian High and averaged temperature in China remains -0.58, when AO keeps constant. But the partial correlation between temperature and AO is only 0.14 when the influence of Siberian High is excluded. The relationship between AO and precipitation is also significant. The partial correlation between AO and mean precipitation of 160 stations is 0.36. But when the AO's influence is excluded, the partial correlation between the intensity of Siberian High and precipitation is only -0.16. This suggests that during the past several decades the precipitation was strongly affected by AO, but for the temperature the Siberian High plays a more important role. AO and the Siberian High correlate at -0.51, according to the data for the period 1958/59-1994/95. The possible dynamical connection between AO and the Siberian High needs further study. Using the long-term series of AO and the Siberian High spanning 1899/1900-1994/1995, their connections to climate in China are analyzed too. At the interdecadal time scale the AO shows significant influence on both temperature and precipitation. Partial correlation between AO and temperature is 0.66. For precipitation the correlation coefficient is 0.70.
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