On The Variable Rules, Air Circulation Backgrounds And Tele-connections With Arctic Sea-ice Areas Of Spring Sand-storm's Occurrence Times In Ningxia

Based on sand-storm's occurrence times data in Ningxia, Arctic sea-ice area index data, height and wind fields data of NCAR/NCAR reanalysis, the basic variable rules and anomalous air circulation background fields of spring sand-storm's occurrence times in Ningxia are systematically analyzed. More attention was paid on studying the tele-connections between arctic sea-ice areas and spring sand-storm's occurrence times in Ningxia, and impossible affecting process of Greenland sea-ice areas' anomalies on sand-storm's occurrence times. The results are as follows:1. The variable of spring sand-storm's occurrence times in Ningxia is decreased totally with significantly interannual and chronological features. It suddenly changes in 1984 and has periodic variation of 10 and about 7 years.2. There are significant difference between more and less period's air circulation backgrounds relating to chronological variable of spring sand-storm's occurrence times in Ningxia During more (less) period, 500hPa and 850hPa height fields are lower (higher) and wind fields are cyclonic (anticyclonic) circulation in areas such as Mongolia, Lake Baikal and west Siberian, which are the key areas affecting Ningxia's weather, and northwest winds are significant stronger (weaker) in areas from Ningxia to Xinjiang. The air circulation fields, which are related to interannual variable of spring sand-storm's occurrence times in Ningxia, are different during the two periods of before and after the sudden change year, which are from 1960 to 1984 and from 1985 to 2000. The chronological variable has more important effect on the sand-storm's occurrence times.3. The correlations are significant between sea-ice area index of Kara Barents and Greenland seas ,which locate on the north of the continent of Europe and Asian, and spring sand-storm's occurrence times in Ningxia. The anomaly of Greenland sea-ice area can affect sand-storm's occurrence times in Ningxia (North of China)in later through affecting air circulation backgrounds. When autumn Greenland sea-ice area increases (decreases), the next spring 500hPa and 850hPa height fields from Mongolia to Siberian will become lower (higher) and the wind fields will have cyclonic (anticyclonic) anomalies, west winds from Ningxia to Xingjiang will be significant stronger (weaker), which suggests the activities of cold air are more (less), corresponding the spring sand-storm's occurrence times in Ningxia are more(less).4. The global temperature increase is one of the possible reasons for the total decrease trend of sand-storm's occurrence times in Ningxia(North of China).