Traditional Culture Encyclopedia - Weather inquiry - What is the Arctic polar vortex? How did it change?
What is the Arctic polar vortex? How did it change?
Because the Arctic vortex and subtropical high are two main atmospheric circulation entities that affect the weather and climate change in China, they are closely related and have obvious effects on the summer precipitation in North China. Based on NCEP/NCAR reanalysis data, 74 atmospheric circulation factors provided by National Climate Center and monthly precipitation data of China 160 station, the relationship between Arctic vortex and northern hemisphere atmospheric circulation and summer subtropical high is discussed by using the methods of synthetic analysis, correlation analysis and singular value decomposition. The results show that the change of (1) Arctic vortex is closely related not only to the height field at high latitudes, but also to the circulation at middle and low latitudes. When the polar vortex is unusually large and strong, the potential height in the middle and low latitudes is obviously low, the area and intensity of the subtropical high in the northern hemisphere tend to be small, and the northern boundary position tends to be south, in which the intensity of the subtropical high changes the most. (2) The polar vortex factor is negatively correlated with the subtropical high factor, but positively correlated with the northern boundary and ridge position of the western Pacific and South China Sea subtropical high. (3) Polar vortex index, subtropical high ridge line and northern boundary index are mainly positively correlated with precipitation in North China, while subtropical high area and intensity index are basically negatively correlated with precipitation in North China. When the Eurasian polar vortex expands southward abnormally, the subtropical high in North Africa, Atlantic Ocean and North America shrinks significantly, and the subtropical high in the western Pacific Ocean and South China Sea rises northward obviously, the precipitation in North China is easy to increase. Keywords: Arctic vortex; Subtropical high; Classification number of summer precipitation in North China: P466 Document ID: A Date of receipt: 2007-01-29; Date of revision: May 28, 2008 Fund Project: Key Fund of National Natural Science Foundation (40633015); China Meteorological Bureau's New Technology Promotion Project (Impact of Explosive Stratospheric Warming in the Northern Hemisphere and Polar Vortex Activity on East Asian Tropospheric Blockage) * * * Co-sponsored Correspondent: Zhang Hengde, male, from Hanshan, Anhui, Ph.D., mainly engaged in atmospheric dynamics research. E-mail: Zhang De1977 @163.com.1Introduction Arctic vortex and subtropical high (referred to as subtropical high) are two main atmospheric circulation entities that affect the weather and climate change in China [1-3]. However, the effects of polar vortex and subtropical high on weather and climate are not isolated, but cooperate with each other. Polar vortex mainly reflects the circulation characteristics in middle and high latitudes, while subtropical high largely reflects the changes of atmospheric circulation in middle and low latitudes, and they are closely related. Some people link them and analyze their relationship with atmospheric circulation and their impact on the climate and environment. Shi Neng et al. [4] pointed out that the trend of strengthening the two is the direct cause of the long-term trend change and interdecadal change of winter temperature in China. Wu Shangsen et al. [5] established a model to predict the abnormal Leng Yue in winter in South China with polar vortex and subtropical high as two main factors. Liu Chuanfeng and others [6] think that the Asian polar vortex and the western Pacific subtropical high are the main factors of low temperature chilling injury in South China. History [7] thinks that the intensification of polar vortex and subtropical high is the main reason of flood or drought in Jianghuai area. Liang et al. [1] regard the intensity change of polar vortex and subtropical high as the main forecasting factors of drought and flood in Guangdong in the first flood season. Sun Li et al. [8] analyzed the influence of polar vortex in spring and subtropical high in the western Pacific in autumn on the atmospheric circulation in East Asia. Huang Jiayou et al. [9] found that the comprehensive study of their effects on summer precipitation in China has a higher forecast value than the separate study of their respective effects. Peng et al. [10] also found that their changes in April had a significant impact on sandstorms in Ningxia. The above studies all consider the changes of polar vortex and subtropical high in the process of diagnosing and analyzing the evolution of weather, climate and environment, and fail to discuss their interaction. Therefore, it is necessary to explore the relationship between polar vortex and atmospheric circulation and subtropical high in order to better analyze their influence on weather and climate. Precipitation in North China is mainly concentrated in summer, accounting for more than 3/4 of the total precipitation in the whole year. In recent years, people have done a lot of research on summer precipitation in North China, pointing out that monsoon activity [1 1], blocking high [12], western Pacific subtropical high [13] and Arctic oscillation [65438+. These results give some influence mechanisms of summer precipitation in North China, which have certain guiding significance for the prediction of summer drought and flood in North China, but they fail to discuss their influence on summer precipitation in North China by combining polar vortex and subtropical high. Based on the close relationship between polar vortex and subtropical high and its significant influence on the weather and climate in China, combined with the importance of summer precipitation in North China, if we can understand the relationship between polar vortex and atmospheric circulation and subtropical high in summer, and find out the simultaneous influence of polar vortex and subtropical high on summer precipitation in North China, it will be helpful to create PDF with PDFFactory trial version of www.pdffactory.com.
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4 18 Volume 24 of Journal of Tropical Meteorology aims to strengthen the mechanism analysis of atmospheric circulation and summer precipitation anomalies in North China and improve the forecasting ability of summer precipitation in North China. Materials and Methods The main materials used in this paper include: NCEP/NCAR 1950 ~ 2002 monthly reanalysis of 500 hPa height field; Based on 74 atmospheric circulation factors and monthly precipitation data from1951to 2002 provided by National Climate Center of China Meteorological Bureau, Chengde, Beijing, Tianjin, Shijiazhuang, Dezhou, Scaffolding, Anyang, Yantai, Qingdao, Weifang, Jinan, Linyi, Heze, Zhengzhou, Changzhi and Taiyuan were selected. In this paper, the relationship between polar vortex and subtropical high and its influence on precipitation in North China are diagnosed and analyzed by using conventional statistical methods such as synthetic analysis, correlation analysis and SVD[ 18]. The correlation between arctic vortex and atmospheric circulation in summer is shown in figure1a. Except for the weak positive correlation near the polar region (north of 70 N), all other regions have significant negative correlation, and most regions can pass the significance test of 0.0 1. From the distribution of correlation coefficient between polar vortex intensity and 500 hPa potential height (Figure 1b), it can be seen that there is a strong negative correlation in most areas, especially in the middle and low latitudes, the negative correlation coefficient in many areas can reach -0.5, and only a few areas have a weak positive correlation, and the correlation coefficient is only 0. 1. These show that the Arctic vortex has a significant influence on the circulation situation in the middle and low latitudes in summer. When the area and intensity of the Arctic vortex increase abnormally, the potential height in the middle and low latitudes is usually low, and vice versa. The comprehensive analysis of potential height field can further explain the relationship between Arctic vortex and atmospheric circulation in summer. According to the normalized anomaly variation curve of the area and intensity of the Arctic vortex in summer (the figure is omitted), taking the year of normalized anomaly ≥ 1.0 as the maximum year and the year of normalized anomaly ≤- 1.0 as the minimum year, the maximum and minimum years of the area and intensity of the Arctic vortex in summer are obtained respectively (table 1). According to the magnitude and strong and weak years of polar vortex in summer listed in table 1, the potential height fields of 850 hPa, 500 hPa and 200 hPa in summer are synthesized and analyzed into lower troposphere, middle troposphere and upper troposphere respectively, with emphasis on the middle troposphere (500 hPa). Table 1 The maximum and minimum values of polar vortex area and intensity in summer are 1 1 year: 1957, 1958, 1959, 1960 and/kloc, respectively. 1968, 197 1 small area value 10 year: 195 1, 1952,198/kloc-. The biggest strength in 2002 was nine years: 196 1, 1962, 1963, 1964, 1965, 1970,/. 1954, 1977, 1993, 1998, 2000, 200 1 digital1950-2002 summer. As shown in Figures 2a, 2b and 2c, when the Arctic vortex area is at the height of 500 hPa in summer, the difference between them can be seen intuitively, and the height difference between them is very large at the middle and low latitudes. In summer when the polar vortex area is large, the potential height is low, and the area surrounded by the 588 dgpm line representing the subtropical high is small, and it almost disappears in the western Pacific. However, when the polar vortex region is abnormal, the western Pacific subtropical high is strong and moves northward. The geopotential height values in mid-latitude areas are quite different, and the height values in summer with large polar vortex area are much lower (as shown in Figure 2c, the differences in many areas reach 40 gpm or even 60 gpm). For example, the main body of 570 dgpm line is located in the south of 50 N, while the summer 570 dgpm line with small polar vortex area is basically located in the north of 50 N; At high latitudes, there is no significant difference in the circulation situation between them, but the height value is quite different, even exceeding 30 gpm. In addition, from the synthetic distribution of height field anomalies (schematic diagram), it can be further known that in summer when the polar vortex area is large, most areas in the middle and high latitudes are negative anomaly areas, and the center is located in East Asia continent; However, when the polar vortex sheet is active, positive and abnormal centers appear in Eurasia and gulf of alaska, especially in the Urals and the Sea of Okhotsk. The PDFFactory trial version of the PDF created by www.pdffactory.com is used.
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The fourth issue, Zhang Hengde et al.: The relationship between the Arctic vortex and subtropical high in summer and its influence on precipitation in North China 4 19, that is, Eurasia and Alaska are prone to blocking situations. Fig. 2 The large (a) and low (b) arctic vortex area and its difference (c) of 500 hPa northern hemisphere geopotential height in summer and the large (d) and low (e) arctic vortex intensity and its difference (f) of 500 hPa northern hemisphere geopotential height in summer are shown in figs. 2d, 2e and 2f, respectively. In the summer when the polar vortex intensity is high, the potential height in the middle and low latitudes is low, and the range of 588 dgpm line representing the characteristics of subtropical high is much smaller, and the intensity of subtropical high is obviously weakened, and the 588 dgpm line in the western Pacific has disappeared. There is no obvious difference in the mid-latitude circulation situation between them, but the height values are quite different (Figure 2f). In high latitudes, if the polar vortex intensity is unusually high, the potential height is generally low. For example, the area surrounded by the line 546 is much larger, and the center value is lower than the www.pdffactory.com of 540 PDF created with the trial version of PDFFactory.
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420 Journal of Meteorology in Tropical Zones, Volume 24 dgpm shows that the potential height difference between the maximum and minimum polar vortex intensity in summer is above 30 gpm in most high latitudes (Figure 2f). The height anomaly synthesis (schematic diagram) further shows that in the summer when the polar vortex intensity is high, except Canada, the potential height in the northern hemisphere is basically negative anomaly, and in the middle and high latitudes, the central value reaches-30 gpm; When the intensity of polar vortex is low in summer, positive anomalies appear in most parts of the northern hemisphere except northwest Europe, and the average positive anomalies in many areas in the middle and high latitudes are above 20 gpm. Due to the baroclinic of the atmosphere, the results of 850 hPa and 200 hPa heights are different from those of 500 hPa heights, but the overall trend is the same. Therefore, the change of Arctic vortex in summer is closely related not only to the potential height field at high latitudes, but also to the circulation at middle and low latitudes. The area and intensity of the 500 hPa Arctic vortex have a significant influence on the atmospheric circulation in the whole troposphere in the northern hemisphere, especially on the blocking of mid-latitude and the subtropical high in the middle and low latitudes. According to the preliminary results of the comprehensive analysis of the relationship between the Arctic vortex and atmospheric circulation in summer, the following will focus on the analysis of the relationship between the Arctic vortex and the subtropical high. 4 The relationship between the Arctic vortex and the subtropical high in summer According to the geographical location where the subtropical high often occurs, the northern hemisphere subtropical high (5° E ~ 360°) is usually divided into the following parts for international research: Indian subtropical high (65 E ~ 95 E) and western Pacific subtropical high (1/kloc-0 E ~180). North Africa Atlantic subtropical high (165438+20° W ~ 60° W), and the last part can be divided into North America subtropical high (110 ~ 60 w), Atlantic subtropical high (55 ~ 25 W) and North Africa subtropical high (20). That is, the National Climate Center in Zone I (60 ~150 E) and Zone II (150 E) provide the subtropical high index and the Arctic vortex index in the northern hemisphere and its subregions. Each subtropical high index is numbered 1 ~ 45 in this paper, where1~1is the subtropical high area index, which corresponds to the northern hemisphere, North Africa, North America, India, Western Pacific, Eastern Pacific, North America, Atlantic Ocean, South China Sea, North American Atlantic Ocean and Pacific subtropical high in turn. 12 ~ 22 is the intensity index corresponding to the subtropical high; 23 ~ 33 is the corresponding subtropical high ridge index; 34 ~ 44 is the northern boundary index corresponding to subtropical high; 45 is the ridge index of the western Pacific subtropical high. Figure 2 shows that when the area and intensity of the Arctic vortex are unusually large, the area of the subtropical high is small, and the main position moves south; On the contrary, when the area and intensity of the Arctic vortex are abnormally small, the area of the subtropical high tends to be larger and the main position moves northward. Through calculation, it can be found that the area index of the polar vortex in the northern hemisphere in summer is negatively correlated with the area, intensity, ridge line and northern boundary index of the subtropical high, and the coefficients are -0.45, -0.52, -0.43 and -0.49 respectively, which at least reaches the significance test of 99% reliability level. The intensity index of polar vortex in the northern hemisphere is also negatively correlated with the area, intensity, ridge line and northern boundary index of subtropical high, with coefficients of -0.43, -0.5 1, -0.24 and -0.34 respectively, which is slightly weaker than the correlation between polar vortex area and subtropical high. Generally speaking, polar vortex has the most obvious influence on the intensity of subtropical high and the weakest influence on the position of ridge line. This further shows that when the abnormal expansion of the Arctic vortex increases, the subtropical high will contract, weaken and withdraw southward. On the contrary, if the abnormal contraction of the Arctic vortex weakens, the subtropical high will obviously expand, strengthen and move northward. This can generally be explained as follows: when the polar vortex in the northern hemisphere is unusually large in area and obviously strong in intensity, the geopotential height in the middle and high latitudes is obviously low, the characteristic contour line is southerly, the subtropical front area is abnormally southerly, and the geopotential height in the middle and low latitudes is generally low, which means that the main body of the 588 dgpm line reflecting the subtropical high is also small and southerly, that is, the subtropical high in the northern hemisphere is small in area, weak in intensity and southerly; On the contrary, when the subtropical high in the northern hemisphere is unusually large in area and strong in intensity and located in the north, the potential height in the subtropical region, that is, the middle and low latitudes (here,10 ~ 40 N) is relatively high, then the characteristic contour line of the polar vortex in southern Xinjiang in the northern hemisphere is located in the north, and if the potential height in the middle latitudes is too high, the area and intensity of the polar vortex are easy to be small. Due to the difference of land and sea distribution and terrain height, the geopotential height in the northern hemisphere is unevenly distributed in the latitude circle, and the polar vortex and subtropical high in different regions are quite different, which needs to be discussed in different regions. Therefore, the summer polar vortex and subtropical high are decomposed by SVD, so as to fully understand the relationship between polar vortex and subtropical high in different regions. The specific structure of SVD decomposition is as follows: the polar vortex index is taken as the left factor field, and the order of variables is I, II, III, IV, northern hemisphere area, I, II, III, IV and northern hemisphere intensity, which are called polar vortex factor 1 and 2 in turn. Taking the subtropical high index as the right factor field, the order of variables is the 45 subtropical high indexes mentioned above, followed by the subtropical high factor 1, 2, …, 45. Taking the summer polar vortex and subtropical high as singular value decomposition, the variance contribution rates of the first three modes are 90.5, 5. 1 and 1.7 respectively. The variance contribution rate of 1 mode is obviously higher than that of other modes, which is absolutely dominant. 1 mode can basically reflect the relationship between polar vortex and subtropical high. In addition, the correlation coefficients between the time coefficients of the left and right singular vectors of the first three modes are 0.69, 0.63 and 0.40, respectively, which are all above 0.40, indicating that the polar vortex has a strong correlation with the typical variable field of the subtropical high, especially 1 mode. Therefore, the modal results of 1 obtained by SVD can be used for analysis. The left anomaly correlation coefficients of 1 mode obtained by polar vortex index and subtropical high index SVD are -0.58, -0.47, -0.24, -0.3 1, -0.60, -0.54, -0.49, -0.36, -0.27 and-respectively. The signs of these coefficients are consistent, and all of them can pass the significance test of 95% reliability, indicating that all polar vortex factors play an in-phase role in the subtropical high. The two most important factors are the polar vortex area and intensity in the northern hemisphere, followed by the polar vortex area and intensity in region I. According to the correlation coefficient of the right field anisotropy shown in fig. 3, the coefficients of other factors are all positive except the subtropical high factors 27, 3 1, 38, 42 and 45, which are negative (and cannot pass the significance test). The number of subtropical high factors that passed the significance level test of 0. 10, 0.05, 0.0 1, 0.00 1 reached 3 1, 27, 22, 15 respectively, in which the subtropical high factors were 2, 3 and 7. Therefore, combined with the correlation coefficient of left and right anisotropy, we can know that the polar vortex area and intensity in the northern hemisphere and its sub-region are related to the subtropical high area and intensity in the northern hemisphere and its sub-region, and to the www.pdffactory.com of the PDF created by the trial version of PDFFactory.
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Zhang Hengde et al.: The relationship between the Arctic vortex and subtropical high in summer and its influence on precipitation in North China are basically negatively correlated with most factors, such as the ridge and northern boundary of 42 1, that is, when the polar vortex area and intensity in the northern hemisphere and its sub-regions are abnormal, most subtropical high indexes in the northern hemisphere and its sub-regions tend to be large (small), especially between the polar vortex in Asia and the northern hemisphere and the Atlantic subtropical high in North Africa, North America and North America. -0.3-0.2-0.100.10.20.30.40.50.60.713166538+2066546 5 The subtropical high and polar vortex are two in the atmospheric circulation. Therefore, the summer polar vortex, subtropical high factor and precipitation in North China are decomposed by SVD. Specific measures: Take the summer polar vortex factor 1 ~ 10 mentioned in the previous section as the left field factor 1 ~ 10, and the subtropical high factor 1 ~ 45 as the left field factor1~ 55. The correlation coefficients between the time coefficients of the left and right singular vectors of the first three pairs of modes are 0.52, 0.42 and 0.56, respectively, indicating that the overall correlation is strong. The variance contribution percentages of the first three modes are 60.2, 17.7 and 5. 1 respectively, and 1 mode is absolutely dominant, which basically reflects the relationship between polar vortex and subtropical high and summer precipitation in North China. Therefore, the modal results of 1 can be used for analysis. Figure 4 shows the left anomaly correlation coefficient of 1 mode (abscissa 1 ~ 10 corresponds to polar vortex factor 1 ~ 10,1~ 55 corresponds to subtropical high factor1. Generally speaking, the numbers in Figure 4 are 1, 4, 5, 8, 9, 12, 13, 17, 18, 20, 22, 23, 24, 22. Among them, the factors that can pass the significance level test of 0.05 are: polar vortex area in Asia, Europe and northern hemisphere (factor 1, 4, 5), subtropical high area and intensity in northern hemisphere, North Africa and North Africa Atlantic (factor 1 1 2,/kloc). The right field correlation coefficients of 1 modes in Chengde, Beijing, Tianjin, Shijiazhuang, Dezhou, Scaffolding, Anyang, Yantai, Qingdao, Weifang, Jinan, Linyi, Heze, Zhengzhou, Changzhi, Taiyuan and Linfen in North China are 0. 1 1 and 0./kloc-respectively. The signs of this 17 coefficient are all positive, which shows that the interannual variation phase of summer precipitation at North China 17 station is basically the same, and the influence of polar vortex and subtropical high factor is also the same. Combining this 17 coefficient with the left anomaly correlation coefficient shown in Figure 4, we can see that polar vortex, subtropical ridge and northern boundary index are mainly positively correlated with precipitation in North China (except for the main indexes such as the intensity of Zone III, the northern boundary of North Africa subtropical high, the northern boundary of North Africa Atlantic subtropical high and the ridge point of West Pacific subtropical high), and the subtropical high area and intensity index are mostly negatively correlated with precipitation in North China. Therefore, when the polar vortex expands significantly southward and the subtropical high shrinks significantly, especially when the Eurasian polar vortex expands abnormally southward, the subtropical high in North Africa and the Atlantic shrinks significantly, and the subtropical high in the western Pacific Ocean and the South China Sea rises significantly northward, the summer precipitation in North China tends to be more. On the contrary, if the polar vortex contraction weakens and the subtropical high increases, the summer precipitation in North China will be less. -0.5-0.4-0.3-0.2-0.65438+000. 1 0.20.30.416162136.07 station) The influence of summer polar vortex and subtropical high on precipitation in North China can be summarized as follows: the expansion and enhancement of summer polar vortex can usually bring a lot of cold air from high latitudes, which will merge with the warm air mass in North China and easily form a cold front or quasi-static front in North China. If the water vapor is sufficient, it will cause obvious precipitation. In addition, the expansion, enhancement and south pressure of polar vortex are usually accompanied by the contraction, weakening and south withdrawal of subtropical high, which is further beneficial to precipitation in North China. When the subtropical high expands, strengthens and moves northward, North China is controlled by the high pressure, which in itself is not conducive to precipitation in this area. On the other hand, this long-term control of high pressure also inhibits the expansion and southward extension of polar vortex, resulting in insufficient cold air in the south, which is not easy to form a front, which is even more unfavorable to precipitation. 6 summary and discussion polar vortex and subtropical high are two main atmospheric circulation entities that affect the weather and climate change in China. They are closely related, and both have a significant impact on summer precipitation in North China. The change of (1) Arctic vortex is closely related not only to the high latitude potential, but also to the circulation in the middle and low latitudes. When the polar vortex is unusually large and strong, the potential height in these areas is obviously low, the area and intensity of the subtropical high in the northern hemisphere are easy to be small, and the northern boundary position is easy to be southward, in which the intensity of the subtropical high changes the most. PDF created with pdfFactory trial version of www.pdffactory.com.
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422 Journal of Tropical Meteorology, Volume 24 (2) The polar vortex factor is negatively correlated with the subtropical high factor, while the polar vortex factor is positively correlated with the northern boundary and ridge position of the subtropical high in the western Pacific Ocean and the South China Sea. (3) Polar vortex index, subtropical high ridge line and northern boundary index are mainly positively correlated with precipitation in North China, while subtropical high area and intensity index are basically negatively correlated with precipitation in North China. When the Eurasian polar vortex expands southward abnormally, the subtropical high in North Africa, Atlantic Ocean and North America shrinks significantly, and the subtropical high in the western Pacific Ocean and South China Sea rises northward obviously, the precipitation in North China is easy to increase. References: [1] Liang, Wu Shangsen. Discussion on the causes of drought and flood in flood season in Guangdong Province and its early influencing factors [J]. Journal of Tropical Meteorology, 200 1, 17 (2): 97- 108. [2] Bi, Zhang Guocai. 2004, 20(5): 505-5 14.[3] Zhang Hengde, Lu, Ting, et al. Influence of Arctic vortex activity on China's temperature in the same period and later period [J]. Journal of Nanjing Institute of Meteorology, 2006,29 (4): 507-5/KLOC-. Zhu ganggen Long-term trend and interdecadal variation of atmospheric circulation characteristics in the northern hemisphere [J]. Journal of Nanjing Institute of Meteorology, 1996, 19 (3): 283-289. [5] Wu Shangsen, Liang,. Conceptual model 2-Leng Yue prediction of winter anomalies in South China-physical factors such as atmospheric circulation, polar ice and snow. 16(4): 289-296.[6] Liu Chuanfeng, Gao Bo. The low temperature and freezing climate in South China in spring and its atmospheric circulation characteristics [J]. Journal of Tropical Meteorology, 200 1, 17 (2): 179-65433. 1996, 22 (9): 35-38.[8] Sun Li, Study on the anomalous relationship of atmospheric circulation in East Asia in spring and summer [J]. journal of applied meteorological science, 2002, 13 (6): 650-66 1. [2004,28 (4): 5 17-526. Peng, Chen Nan. Comparative analysis of the average circulation characteristics of sandstorms in Ningxia in April [J]. Plateau Meteorology, 2002,21(6): 599-66. Li Chunhui. Relationship between summer monsoon intensity in South China Sea and precipitation in flood season in China [J]. Journal of Tropical Meteorology, 2003, 19 (Suppl.): 25-36. [12] Sun. Relationship between mid-latitude blocking high index and summer precipitation in North China [J]. Journal of Nanjing Institute of Meteorology, 2003,202. Sun zhaobo The relationship between subtropical high in the western Pacific and drought and flood in North China [J]. Journal of Tropical Meteorology, 2004,20 (2): 206-21/. [14] Li Chun, Luo Dehai, Fang Zhifang, et al. Relationship between interdecadal variation of Arctic oscillation and summer precipitation in North China [J] 28 (6): 755-762. Huang Ying, Qian Yongfu. Study on the Relationship between South Asia High and Summer Precipitation in North China [J]. Plateau Meteorology, 2003,22 (6): 602-607. Zhao, Song Zhengshan 27(5): 88 1-893. [17] Yuan,. Relationship between early circulation anomaly in southern hemisphere and summer precipitation anomaly in North China [J]. Journal of Tropical Meteorology, 2005,21(6): 705-578. Comparison of methods for finding coupling models in climatic data [J].j Climate,1992,5 (6): 541-560. The relationship between Arctic vortex and subtropical high in summer and its influence on precipitation in North China. National Meteorological Center of China Meteorological Bureau, Beijing100081; 2. Abstract: Arctic vortex and subtropical high are two important members of the atmospheric circulation that affect the weather and climate change in China. They interact closely and have a great influence on summer precipitation in North China. Based on NCEP reanalysis data, 74 factors of atmospheric circulation and monthly precipitation data of China 160 station provided by National Climate Center (NCC), the relationship between Arctic vortex and atmospheric circulation and subtropical high in summer is discussed by using the methods of composite analysis, correlation analysis and singular value decomposition, and the joint influence of Arctic vortex and subtropical high on precipitation in North China is analyzed. The results show that the activity of Arctic vortex is not only affected by the height of high latitude potential, but also closely related to the circulation in middle and low latitudes. When the area and intensity of polar vortex are unusually large, the potential height in the middle and low latitudes is much lower, so the area and intensity of SH are smaller, and its northern boundary is Vietnam, especially the change of intensity. Most of the polar vortex indices in the northern hemisphere and the transitional zone are negatively correlated with the subtropical high factor, while the polar vortex indices are positively correlated with the northern boundary and ridge index of the subtropical high in the western Pacific Ocean and the South China Sea. Most indexes of polar vortex, northern boundary and ridge line of subtropical high are positively correlated with summer precipitation in North China, while the area and intensity index of subtropical high are negatively correlated with summer precipitation in North China. Especially, when the Eurasian polar vortex expands abnormally, the contraction of subtropical high in North Africa, Atlantic Ocean and North America weakens, and the subtropical high in the western Pacific Ocean and South China Sea jumps northward, the precipitation in North China increases obviously. Keywords: Arctic vortex; Subtropical high; PDF of summer precipitation in North China was created by pdfFactory trial version of www.pdffactory.com.
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