我国已经进入拉尼娜状态

Group 1 - The core viewpoint of the article discusses the current La Niña state in China, which is characterized by a significant and sustained cooling of sea surface temperatures in the eastern and central equatorial Pacific. The article highlights that while China has entered a La Niña state as of October, this does not equate to a La Niña event, which requires the NINO 3.4 index to remain below -0.5 degrees Celsius for five consecutive months [1][4][19] - The article explains that a "double La Niña" refers to the occurrence of La Niña events in consecutive winters, rather than two events within the same year. The probability of a double La Niña event occurring this winter is considered low, although the ongoing La Niña state will still impact China's climate [4][19][21] - The direct impact of La Niña includes the development of a cyclonic circulation anomaly over the Northwest Pacific and the South China Sea, leading to prevailing northeast winds that suppress moisture transport. This is expected to result in below-average precipitation in eastern and southern China, with predictions of winter-spring droughts in regions like East and South China [6][19] Group 2 - The article provides a detailed explanation of freezing rain, a common winter weather phenomenon that occurs when supercooled water droplets freeze upon contact with surfaces below 0 degrees Celsius. The formation of freezing rain requires two key conditions: sufficiently low temperatures near the ground and the presence of precipitation [7][11] - It distinguishes between freezing rain and rime ice, noting that while freezing rain is a specific type of precipitation, rime ice is a result of freezing rain. The potential for freezing rain to cause damage is significantly higher than that of rime ice due to its weight and the conditions under which it forms [12][14] - The article identifies Guizhou as the province most affected by freezing rain in China, with the highest frequency and severity of occurrences. It notes that the winter months from December to February are peak periods for freezing rain, and despite the La Niña state, the probability of widespread freezing rain in Guizhou this winter is expected to be relatively low [16][21]