中国西南—东南季风交汇区降水时空格局变化及其对食物产量的影响

全球气候变化背景下,降水格局改变食物供给将是人类当前和未来所面临的重大挑战,但很少有研究揭示食物供给随降水格局变化的关系。研究中国西南、东南季风共同作用区的降水与食物供给变化,对厘清该区降水与食物供给的动态关系、实现区域粮食安全、保障西南边疆稳定、落实区域民族政策、建成全面小康社会等具有重要意义。文章以中国西南地区的云南省为例,刻画了1988—2018年降水变化格局,并探讨了其对食物产量的影响。结果表明：① 云南省降水时间格局分为：Ⅰ降水丰沛期（1988—2004年）、Ⅱ降水偏少期（2005—2015年）、Ⅲ降水恢复期（2016—2018年）等3个降水时段;② 第Ⅰ~Ⅱ时段,全省降水发生显著变化区域为15.07%,第Ⅱ~Ⅲ时段为13.87%,第Ⅰ~Ⅲ时段为16.53%;③ 全省水平上,降水与食物产量具有显著正相关关系（p<0.01）,且粮食产量与各时间段降水相关系数高于肉奶产量;④ 当降水≥1500 mm时降水量快速下降,粮食产量保持稳定、700~1500 mm时降水量与粮食产量同为小幅下降、≤ 700 mm时降水量小幅下降,粮食产量大幅波动下降。总体而言,1988—2018年云南省降水格局发生了明显的变化,且在不同区域对食物供给产生了显著影响,故亟待划分全省范围的食物产量对降水响应的空间区划,以此来应对日益加剧的降水格局变化。

Spatiotemporal patterns of precipitation changes and their impacts on food supply in Southwest China from 1988 to 2018:A case study in Yunnan Province

As the effects of climate change become more devastating, the changes of precipitation patterns and food supply are and will be major challenges facing mankind nowadays and in the future. But the interannual relationship between the precipitation patterns and the food yields is still unclear. Studying changes in food yields and precipitation in those areas where the southwest and southeast monsoons interact is significant to revealing the dynamic correlation of food and precipitation, achieving regional food security, ensuring the stability of the southwestern frontier, implementing regional ethnic policies, and building a harmonious well-off society. The paper takes Yunnan Province in Southwest China as an example to describe the pattern of precipitation changes from 1988 to 2018 and discusses its impact on food production. The results suggested that: (1) The precipitation patterns of Yunnan are classified into three periods: Ⅰ abundance period (1988-2004), Ⅱ shortage period (2005-2015), and Ⅲ recovery period (2016-2018). (2) Areas with significant changes account for 15.07% of the whole province in periods I-Ⅱ to 13.87% in periods II-Ⅲ and to 16.53% in periods I-Ⅲ. (3) There is a significant positive relationship between precipitation and food supply (p < 0.01) across the province. The correlation index between crops yields and precipitation of the three periods is higher than that between precipitation and meat-and-dairy products. (4) In three precipitation value (d) zones, food yields had different responses to changes in precipitation. When d ≥ 1500 mm, the precipitation plummets while the food yield remains stable. When 1500 > d > 700 mm, the two values will decrease simultaneously. When d < 700 mm, a small decrease in precipitation will cause a large decrease in food yields. All in all, the precipitation pattern in Yunnan has undergone significant changes in the past 30 years, which has an essential impact on the food yields in different regions. Therefore, sorting out the grain-precipitation spatial region of the province can help us combat the increasing precipitation pattern changes.