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内蒙古地区典型草原下垫面CO2通量变化特征及影响因素

白美兰孟玉婧董祝雷李喜仓   

  1. 内蒙古自治区气候中心,内蒙古呼和浩特010051
  • 出版日期:2018-04-30 发布日期:2018-04-30
  • 作者简介:白美兰(1963—),女,正研级高级工程师,硕士,研究方向为气候变化及影响评估.E-mail:nmghrq@sina.com。
  • 基金资助:

    地方财政专项“内蒙古适应气候变化战略研究"和“全区气候服务创新团队”共同资助

Variation Characteristics of CO2 Flux and Its Influence Factors in Typical Grassland Area of Inner Mongolia

BAI Meilan, MENG Yujing, DONG Zhulei, LI Xicang   

  1. Climate Center of Inner Mongolia Autonomous Region, Hohhot 010051, China
  • Online:2018-04-30 Published:2018-04-30

摘要:

基于内蒙古典型草原腹地锡林浩特国家气候观象台2007—2016年CO2通量逐30 min观测数据及同时段气温、降水等资料,利用WPL方法对CO2通量资料进行修正的基础上,对典型草原牧草不同时期CO2通量的变化特征及影响因素进行统计分析。结果表明:(1)内蒙古典型草原CO2通量存在明显的年际、季节和日变化特征,且表现为碳汇特征,尤以牧草生长季最为明显;CO2通量呈夜间弱排放、白天强吸收的“U”型日变化,其中09:00—10:00最大;全年及生长季CO2通量以吸收为主,夏季吸收最大,春季和秋季次之,冬季最小,甚至表现为弱排放。(2)牧草不同生长期气候要素对CO2通量影响不同,其中返青期热量因子与CO2通量呈负相关,水分因子为正贡献;开花期和枯黄期正相反,热量因子对CO2通量为正贡献,水分因子为负贡献,且开花期热量与水分因子对CO2通量贡献最显著。(3)生长季牧草NDVI与CO2通量表现为负相关,且7、8月二者的相关性极高。

关键词: 典型草原, CO2通量, 变化特征, 碳汇, 影响因素

Abstract:

Based on the 30-minutely CO2 flux observation data during 2007-2016 in Xilinhot national climate observatory in typical grassland area of Inner Mongolia and contemporaneous temperature, precipitation, etc., the CO2 flux data were corrected by using WPL method. And on this basis the variation characteristics of CO2 flux and its influence factors in typical grassland of Inner Mongolia in different periods were analyzed statistically. The results are as follows: (1) The CO2 flux in typical grassland of Inner Mongolia had obvious annual, seasonal and diurnal variation characteristics, and the typical grassland presented carbon sinks characteristic, especially in the growing season of pasture. The CO2 flux presented an obvious diurnal variation with ‘U’ shape, and CO2 was emitted at night and absorbed in the daytime, the CO2 flux reached the maximum between 09:00 and 10:00. The pasture mainly absorbed CO2 in the whole year and growing season, the value of CO2 flux was negative, and the absorption was most in summer, followed by spring and autumn, while it was lowest in winter. (2) The effects of climate elements on CO2 flux in different growth periods of pasture were different. The CO2 flux in the green up period of pasture was negative correlated with heat factors and moisture factors had a positive contribution. On the contrary, the CO2 flux in the flowering and withering period of pasture was positive related to heat factors and moisture factors had a negative contribution, and the contribution of heat and moisture factors to CO2 flux was most significant in the flowering period. (3) NDVI was negative correlated with CO2 flux in the growing season of pasture (from May to September), and the correlation between them was highly significant in July and August.

Key words: typical grassland, CO2 flux, variation characteristics, carbon sinks, effect factors

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