Journal of Geographical Sciences >
Activity of cold vortex in northeastern China and its connection with the characteristics of precipitation and circulation during 1960-2012
Received date: 2015-03-17
Accepted date: 2015-06-26
Online published: 2015-12-31
Supported by
National Natural Science Foundation of China, No.41375078, No.41405094, No.41175083, No.41275096.Science and technology development plan in Jilin Province of China, No.20150204023SF
Copyright
Based on the daily reanalysis data released by NCEP/NCAR and the daily precipitation of 753 Chinese stations from May to August during the period of 1960 to 2012, the statistical characteristics of the cold vortex in northeastern China were analyzed. In addition, the strength index, which described the characteristics of the vortex consistently and frequently, and the geographical distribution were given by continuous anomalies of circulation. Based on this index, the activity routines of the cold vortex, characteristics of atmospheric circulation, and their effects on precipitation in northeastern China were analyzed. The results show that: the activities of the cold vortex exhibit remarkable features of annual and interdecadal oscillation, and the vortex high frequency and its characteristics of atmospheric circulation are described more accurately by the strength index of the cold vortex, which shows a high correspondence with the vortex precipitation during early summer and midsummer in the northeast. In strong (weak) vortex years, the general circulation in the middle and high latitudes of Eurasia is to the advantage (disadvantage) of the formation, development and maintenance of the cold vortex, thus it is easy (difficult) to form the circulation which is beneficial to transmit vapor from south to north during the period of July to August. Blocking over the Ural Mountains prevails (does not prevail) in early summer, and blocking over the Sea of Okhotsk prevails (does not prevail) in midsummer. Areas where the subtropical high is too small (large) and moves toward the north too late (early) are better (worse) for the maintenance of the cold vortex in northeastern China.
Key words: northeast cold vortex; index of strength; circulation; subtropical high
LIU Gang , FENG Guolin , QIN Yulin , CAO Ling , YAO Hongwei , LIU Ziqi . Activity of cold vortex in northeastern China and its connection with the characteristics of precipitation and circulation during 1960-2012[J]. Journal of Geographical Sciences, 2015 , 25(12) : 1423 -1438 . DOI: 10.1007/s11442-015-1243-2
Figure 1 The distribution of area of northeast cold vortex activity from 1960 to 2012.a. May-June; b. July-August |
Table 1 The contrast between the generalized “cold vortex” and northeast cold vortex during 1960-2012 |
Num | The generalized “cold vortex” | Northeast cold vortex | ||||
---|---|---|---|---|---|---|
Year | Day 1 | Start time | End time | Day 2 | Frequency | |
1 | 1969 | 40 | May 10th | June 18th | 16 | 5 |
2 | 1972 | 24 | June 7th | June 30th | 16 | 4 |
3 | 1974 | 22 | June 9th | June 30th | 19 | 5 |
4 | 1964 | 19 | June 10th | June 28th | 10 | 3 |
5 | 1983 | 19 | May 31st | June 18th | 10 | 3 |
6 | 1986 | 19 | May 7th | May 25th | 12 | 2 |
7 | 1961 | 18 | May 7th | May 24th | 4 | 1 |
8 | 1976 | 18 | May 20th | June 6th | 10 | 3 |
9 | 2009 | 18 | June 9th | June 26th | 13 | 3 |
10 | 1999 | 16 | May 1st | May 16th | 7 | 1 |
11 | 1992 | 15 | June 3th | June 17th | 15 | 1 |
12 | 1995 | 15 | May 19th | June 2nd | 8 | 2 |
13 | 1996 | 15 | Jun 1st | June 25th | 15 | 2 |
14 | 2011 | 15 | May 31st | June 14th | 13 | 2 |
Notes: Day 1 represents the lasting time of the generalized “cold vortex” process; Day 2 represents days (number) of northeast cold vortex occurred during the generalized “cold vortex” process (day) |
Figure 1 The contrast between the value and the rainy days of precipitation in the northeast during “cold vortex” in May-June from 1960 to 2012 Note: the percentage of precipitation represents the ratio of precipitation leading to the generalized “cold vortex” and total precipitation; ratio of the number of days 1 represents the ratio of rainy days in “cold vortex” days and the total rainy days; ratio of the number of days 2 represents the ratio of days in the process of the cold vortex and the total days; broken lines represent 3 years of moving average. |
Figure 3 The distribution of percentage of precipitation days and precipitation during the generalized “cold vortex” from 1960 to 2012 a1 and a2 represent May-June; b1 and b2 represent July-August; a1 and b1 represent percentage of precipitation days; a2 and b2 represent percentage of precipitation |
Figure 4 The contrast between NCVSI and days of the generalized “cold vortex” (standardization) (a1 and b1) and wavelet analysis of NCVSI (a2 and b2) from 1960 to 2012 a1 and a2 represent May-June; b1 and b2 represent July-August |
Figure 5 The correlation of NCVSI with meteorological elements field from 1960 to 2012 a. May-June; b. July-August (correlation coefficients are shown in the figure), color shadows represent relative humidity, red contours represent temperature, black contours represent geopotential height) |
Table 2 The top ten of NCVSI active years, inactive years and normal years from 1960 to 2012 |
Num | May and June | July and August | ||||
---|---|---|---|---|---|---|
Active years | Inactive years | Normal years | Active years | Inactive years | Normal years | |
1 | 1969 | 2003 | 1973 | 1972 | 1998 | 1993 |
2 | 1976 | 2010 | 1992 | 1965 | 2008 | 1986 |
3 | 1965 | 2000 | 2011 | 1961 | 1974 | 1990 |
4 | 1972 | 2012 | 2005 | 1971 | 1980 | 1995 |
5 | 1960 | 1970 | 1998 | 1981 | 1996 | 1989 |
6 | 1974 | 1996 | 1964 | 1966 | 2002 | 1975 |
7 | 1995 | 1968 | 1986 | 1964 | 2001 | 2000 |
8 | 1961 | 1985 | 1993 | 1987 | 2006 | 1973 |
9 | 1963 | 2007 | 1987 | 1978 | 1999 | 2009 |
10 | 2009 | 1978 | 1997 | 1976 | 2005 | 1969 |
Figure 6 The distribution of synthesize of meteorological elements anomaly during different NCVSI years (5 years respectively) from 1960 to 2012 1 represents May-June; 2 represents June-August; a represents week years; b represents strong years; c represents normal years; shadows represent relative humidity, vector arrows represent wind speed, black contours represent geopotential height, red contours represent temperature) |
Table 3 The contrast between NCVSI and subtropical high's characteristic features from 1960 to 2012 |
May and June | Subtropical high’s characteristic | July and August | Subtropical high’s characteristic | ||||
---|---|---|---|---|---|---|---|
Time of the first northward jump | Ridge line | Area | Time of the second northward jump | Ridge line | Area | ||
The most active 10 years | 7 years later 2 years earlier 1 year normal | 5 years northerly 5 years southerly | 2 years larger 8 years less | The most active 10 years | 8 years later 2 years earlier | 6 years northerly 4 years southerly | 3 years larger 7 years less |
The most inactive 10 years | 2 years later 5 years earlier 3 year normal | 4 years northerly 6 years southerly | 5 years larger 5 years less | The most inactive 10 years | 2 years later 4 years earlier 4 year normal | 4 years northerly 6 years southerly | 8 years larger 2 years less |
The normal 10 years | 1 years later 9 years earlier | 3 years northerly 7 years southerly | 6 years larger 4 years less | The normal 10 years | 7 years later 2 years earlier 1 year normal | 5 years northerly 5 years southerly | 3 years larger 7 years less |
The authors have declared that no competing interests exist.
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