中国农业气象 ›› 2021, Vol. 42 ›› Issue (10): 845-858.doi: 10.3969/j.issn.1000-6362.2021.10.004

• 农业生物气象栏目 • 上一篇    下一篇

未来气候变暖对羌塘自然保护区高寒草地牧草青草期的影响

杜军,周刊社,高佳佳,次旺顿珠   

  1. 1.西藏高原大气环境科学研究所,拉萨 850001;2.西藏高原大气环境研究重点实验室,拉萨 850001;3.西藏自治区气候中心,拉萨 850001
  • 收稿日期:2021-03-02 出版日期:2021-10-20 发布日期:2021-10-15
  • 作者简介:杜军,E-mail:dujun0891@163.com
  • 基金资助:
    国家自然科学基金项目(41765011);第二次青藏高原综合科学考察研究项目(2019QZKK0106);2020年西藏自治区科技重点研发计划(XZ202001ZY0023N);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”

Influence of Climate Warming in Future on the Green Grass Season for Alpine Grassland in Qiangtang Nature Reserve of Tibet

DU Jun, ZHOU Kan-she, GAO Jia-jia, Tsewangthondup   

  1. 1.Tibet Institute of Plateau Atmospheric and Environmental Science Research, Lhasa 850001, China;2.Tibet Key Laboratory of Plateau Atmospheric and Environmental Science Research, Lhasa 850001;3.Tibet Autonomous Region Climate Centre, Lhasa 850001
  • Received:2021-03-02 Online:2021-10-20 Published:2021-10-15

摘要: 基于5℃界限温度指标,利用羌塘自然保护区附近站点1971−2019年逐日平均气温、降水量和日照时数等资料,采用线性回归、Mann-Kendall检验方法和R/S分析等方法,分析了近49a自然保护区高寒草地牧草青草期及其水热气候资源的变化特征;预估了在RCP2.6、RCP4.5和RCP8.5三种排放情景下,未来80a(2021−2100年)牧草青草期的变化,以期了解和预测高寒草地生态系统的动态变化。结果表明:(1)近49a自然保护区平均每10a牧草青草期开始日提早2.81d,终止日推迟2.74d,天数延长5.56d;青草期积温、降水量和日照时数均表现为显著增加趋势,增幅分别为75.86℃·d·10a−1、15.84mm·10a−1和27.58h·10a−1。(2)在年代际变化特征上,20世纪70−90年代各站青草期开始日晚、终止日早、持续天数短、水热条件偏差;21世纪00−10年代截然相反,青草期开始日早、终止日晚、持续天数长、水热资源充沛。(3)M-K法检验显示,青草期开始日、终止日和天数的突变时间分别出现在2006年、1991年和1988年;青草期积温、降水量和日照时数分别在1988年、1999年和1981年也发生了由偏少变偏多的突变。(4)青草期要素的Hurst指数均大于0.5,表明未来青草期开始日提早、终止日推迟、天数延长,积温、降水量和日照时数均增加的变化趋势仍将持续。(5)在RCP4.5排放情景下,未来80a自然保护区牧草青草期开始日提早10d、终止日推迟9d、天数延长17d,这有利于牧草生长,牲畜抓膘,对牧业生产、草地生态系统恢复十分重要。

关键词: 青草期, ≥5℃积温, 降水量, 日照时数, 气候变化, CMIP5预估

Abstract: The daily meteorological variables observed at weather stations in the Qiangtang Nature Reserve of Tibet (QNRT), including average temperature, precipitation, and sunshine duration from 1971 to 2019, were analyzed with the criteria on the 5℃ threshold temperature. Based on the variation characteristics of the green grass seasons(GGS) of alpine grasslands and their hydrothermal climate conditions in the recent 49 years were revealed with the support of the statistical analyses of the linear regression, the Mann-Kendall test method and the R/S method. In addition, the possible changes of the GGS were also assessed under RCP2.6, RCP4.5 and RCP8.5 emission scenarios, in order to well understand and accurately predict the dynamic change of the terrestrial ecosystems in the future. The study results indicate that the start date of GGS has been advanced at a rate of 2.81d·10y−1 while the end date has been delayed with a rate of 2.74d·10y−1, which has contributed to an increase in duration by 5.56 days per decade. The increasing trends in cumulative temperature, precipitation, and sunshine duration were significant, with the rates of 75.86℃·d·10y−1, 15.84mm·10y−1 and 27.58h·10y−1, respectively. In terms of the decadal variation characteristics, the start dates were late while the end dates were early at all stations from 1970s to 1990s, leading to the shorter duration of GGS and the unfavorable hydrothermal conditions. In contrast, the start dates were early while the end dates were late at all stations from 2000s to 2010s, which contributed to the longer duration of GGS and the abundant hydrothermal resource. It was detected by M-K methods that the abrupt changes of start date, end date, and duration of GGS occurred in 2006, 1991, and 1988, respectively. In addition, the abrupt increases in cumulative temperature, precipitation, and sunshine duration of GGS were also detected in 1988, 1999, and 1981, respectively. All values of H were larger than 0.5, indicating that the trends in early start date, late end date, longer duration will continue, and the increases in cumulative temperature, precipitation, and sunshine duration will remain unchanged in the future. Under RCP4.5 emission scenario, the start date of GGS will be advanced by 10 days, while the end date will be delayed by 9 days, and the duration of GGS will prolonged by 17 days in QNRT in the next 80 years, which will be beneficial to pasture growth and livestock fattening, and also play a positive role in pasture production and restoration of the grassland ecosystem in this highland region.

Key words: Green grass season, Accumulated temperature above 5℃, Precipitation, Sunshine duration, Climate change, CMIP5 prediction