The Effect of Greenland Sea Ice Anomaly in June on the Drought-flood in Upper-middle Reaches of Yellow River in July

By using the relationship between DQ% index of sea ice in 4 regions of Arctic and the precipitation for 160 stations in July over China, the diagnostic study is made. It is pointed out that there is close correlationship between Greenland sea ice anomaly in June and the droughts-floods in upper-middle reaches of Yellow River in July. When Greenland sea ice in June is below (above) normal, the flood (drought) is easily happened in upper-middle reaches of Yellow River in July. The physical mechanism of this correlation is investigated. Based on the significance test of the correlation field, the statistical reliability of the correlation above mentioned is confirmed. It is also found that the correlation between random number series and meteorological element fields sometime can reach high significance level, and that distribution of significance correlation area in the correlation field is not in disorder, but in ordinal area. The article shows that it is necessary to combine the significance test of correlation field with the physical mechanism analysis of causing of it.