1981—2020年西藏“一江两河”主要农区负积温的时空变化特征  

Spatial-temporal Change of Negative Accumulated Temperature in the Main Agricultural Regions of the Yarlung Zangbo River and Its Two Tributaries of Tibet During 1981-2020

作　　者：次旺顿珠 杜军 次旺 平措桑旦 Tsewang Thondup;DU Jun;Tsewang;Phuntsok Samten(Tibet Autonomous Region Climate Centre,Lhasa 850001;Tibet Institute of Plateau Atmospheric and Environmental Science Research,Lhasa 850001;Tibet Key Laboratory of Plateau Atmospheric and Environmental Science Research,Lhasa 850001)

机构地区：[1]西藏自治区气候中心,拉萨850001 [2]西藏高原大气环境科学研究所,拉萨850001 [3]西藏高原大气环境研究重点实验室,拉萨850001

出　　处：《中国农学通报》2022年第5期99-105,共7页Chinese Agricultural Science Bulletin

基　　金：第二次青藏高原综合科学考察研究项目“西风-季风协同作用下青藏高原植被环境野外科考及气候控制机制”(2019QZKK0106);2019年西藏自治区科技重点研发计划“西藏主要地表特征科学考察及研究”。

摘　　要：利用西藏“一江两河”流域9个气象站点1980—2020年逐日平均气温资料,采用线性回归、MannKendall非参数检验、相关分析等方法,分析了研究期内“一江两河”主要农区负积温的时空分布特征及其与气温、积雪和冻土的关系。结果表明:“一江两河”农区负积温总体上呈自西向东递减分布,并随海拔升高而降低。该农区负积温初日推迟率为3.11 d/10 a,终日平均10年提早2.53天,持续日数缩短率为6.03 d/10 a,负积温以24.93(℃·d)/10 a的速度显著升高。在10年际变化尺度上,负积温表现为逐年代升高的变化特征,其中1980s—1990s偏低,2000s—2010s明显偏高。进入21世纪后,负积温初日推迟、终日提早、持续日数缩短和积温升高的年代际变化特征尤为明显。M-K检验显示,负积温终日突变时间较早,为1993年;初日和持续日数均发生在1996年,负积温出现在1995年;突变后负积温初日推迟9天、终日提早6天、持续日数缩短17天、积温减少68.6℃·d。负积温升高与冬季平均气温上升、积雪日数减少和冻土退化具有较好的一致性。负积温对农业生产的影响有利有弊。Based on the daily mean air temperature at 9 meteorological stations in the Yarlung Zangbo River and its two tributaries(BRTT)of Tibet from 1980 to 2020,the relationships between the spatial-temporal distribution characteristics of the negative accumulated temperature(NAT)and its corresponding factors,including air temperature,snow cover and permafrost,were explored with the methods of linear regression,Mann-Kendall test and correlation analysis.The study results indicated that NAT decreased generally from west to east in BRTT,and it also decreased with altitude decreasing.The initial day of NAT was delayed at a rate of 3.11 d/10 a,while the final day was advanced at a rate of 2.53 d/10 a.The duration days decreased at a rate of 6.03 d/10 a,with the significant increase of NAT at a rate of 24.93(℃·d)/10a.The NAT exhibited an increasing trend at the decadal scale,with a low value in 1980s—1990s and a significant high value in 2000s—2010s.The trends of decadal variation features,such as the delayed initial day,the advanced final day,the shortened duration days and the elevated NAT,had become significant since the beginning of the 21st century.The abrupt changes detected by the M-K mutation test indicated that the abrupt changes of the final day of NAT was earlier,occurred in 1993.The abrupt change of both the initial day and the duration days of NAT occurred simultaneously in 1996,while the abrupt change of NAT was detected in 1995.After the mutation,the initial day of NAT was delayed by 9 days,while the final day was advanced by 6 days.The duration was shortened by 17 days,and the NAT was reduced by 68.6℃·d accordingly.The increase of NAT was in accordance with the increasing mean temperature,decreasing snow cover days in winter and permafrost degradation.The NAT variation had both positive and negative effects on agricultural productions in this highland region.

关 键 词：负积温 变化趋势 气候突变 积雪 冻土 相关性 西藏“一江两河”农区 

分 类 号：S162[农业科学—农业气象学]