青藏高原高寒湿地生态系统能量分配和CO2通量的初步研究

NWIPB OpenIR

	青藏高原高寒湿地生态系统能量分配和CO2通量的初步研究
其他题名	Carbon dioxide and Energy partitioning from the alpine wetland
	张法伟
学位类型	硕士
导师	李英年
	2007-06-08
学位授予单位	中国科学院西北高原生物研究所
学位授予地点	西北高原生物研究所
关键词	涡度相关高寒湿地能量分配 Co2通量回归分析主成份分析青藏高原
摘要	利用微气象～涡度相关技术（Eddy Covariance Method）观测系统，对青藏高原东北隅海北高寒湿地（Alpine Wetland）进行了水热通量和CO2通量的观测研究。通过对2005年连续观测的通量数据和环境、生物因子的分析，得出以下主要结论： 1、海北高寒湿地生态系统2005年通量数据的能量闭合率（Energy Balance Ratio）(未观测土壤热通量)为54%，呈现一定的二次曲线变化趋势（-0.0000124x2+0.00598x-0.0319, R2=0.27），即生长季略高于非生长季。通过对摩擦速度U*（Friction Velocity）进行步长划分和T检验，得出海北高寒湿地生态2005年摩擦速度的阈值为0.15m•s-1。 2、海北高寒湿地生态系统的水热通量在不同的季节中均表现出明显的单峰式日变化特征。即在夜间基本维持0值左右，而在14:00（北京时间，BST）升至最大。而日变化中，潜热通量（Latent Heat Flux, LE）为最大能量消耗者。 3、海北高寒湿地生态系统水热通量的季节变化较为复杂。净辐射（Net Radiation, Rn）呈现单峰式季节特征，年均为125.0 Wm-2，波动范围在23.0～443.0 Wm-2。LE的年均值为49.0 Wm-2，变化范围在-24.6～188.3 Wm-2，也呈现出单峰式规律。显热通量（Sensible Heat flux, H）的年均值为17.6 Wm-2，其值在-15.3～72.1 Wm-2变化。其季节变化规律较复杂，表现出一定的双峰式。LE在能量分配中占有主要位置，在7月其比例达到最大值（54.0%）。 4、海北高寒湿地生态系统的CO2通量日变化在植物生长季中振幅较大，夜间基本保持CO2净排放状态，白天出现吸收，高峰期出现在中午12:00左右。在植物非生长季，CO2通量日变化振幅较小，生态系统基本维持碳排放状态。最大吸收、排放值分别为0.45±0.0012和0.11±0.0082 mgCO2m-2s-1，分别出现在7月和5月。 5、海北高寒湿地生态系统在2005年生长季吸收230.16 gCO2m-2，非生长季排放排放546.18 gCO2m-2，全年生态系统净交换量（Net Eosystem Exchange, NEE）316.02 gCO2m-2，总体表现为碳源。5月份是全年的排放高峰，日平均排放5.85 gCO2m-2；7月份为碳吸收高峰，日平均吸收6.12 gCO2m-2。全年生态系统呼吸（Ecosystem Respiration, Res）和总初级生产力（Gross Primary Production, GPP）分别为2573.76和2257.74 gCO2m-2。 6、海北高寒湿地生态系统水热通量的日变化在各个季节受控因子不同，1月Rn、LE和H的分别为光合有效辐射（Photosynthetically Active Radiation, PAR）（R2=0.986）、2.5m空气湿度（R2=0.933）和降水量（R2=0.589）；4月Rn、LE和H的分别为PAR（R2=0.999）、地面长波辐射（R2=0.962）和地面反射辐射（R2=0.937）；7月Rn、LE和H的分别为太阳总辐射（R2=0.958）、PAR（R2=0.944）和太阳总辐射（R2=0.971）；10月Rn、LE和H的分别为太阳总辐射（R2=0.989）、地面反射辐射（R2=0.880）和太阳总辐射（R2=0.916）。至于季节变化，在生长季中，Rn、H均主要受控于太阳总辐射（R2 = 0.996，R2 = 0.216），LE的主要影响因子为降水量（R2 = 0.584）。非生长季中，Rn受控于1.1m水气饱和亏（R2 = 0.629），LE为1.1m水气压（R2 = 0.536）而H则为40cm地温（R2 = 0.520）。 7、海北高寒湿地生态系统CO2通量的日变化在各个季节受控因子不同，1月NEE、Res和GPP的均为5cm地温（R2=0.740，R2=1.00，R2=0.860）；4月的主控因子和1月相同，但相关系数均有所下降，R2分别为0.356、0.978和0.323；7月NEE、Res和GPP的分别为地表反射辐射（R2=0.971）、5cm地温（R2=0.999）和地表反射辐射（R2=0.970）；10月的受控因子和7月相同，相关系数变化不大，分别为0.891、1.000和0.880。至于季节变化，在生长季中，NEE、GPP均主要受控于冠层温度（R2 = 0.361，R2 = 0.701），Res的主要影响因子为5cm地温（R2 = 0.963）。非生长季中，NEE受控于降水量和地表反射辐射（R2=0.117），Res为10cm地温（R2 = 0.962）而GPP则为40cm地温（R2 = 0.192）。 8、对环境、生物因子进行主成份分析（区分生长季与非生长季），得出4个主成份，生长季和非生长季的累计贡献率分别为89.6%和91.7%。而在与水热通量和CO2通量的回归分析并不优于单因子的结果。
其他摘要	Based on the Microclimate Observation System and Eddy Covariance Method, the Carbon dioxide and energy flux of an alpine wetland were measured and discussed, in the northeast of the Qinghai-Tibetan Plateau. The results were summarized as follows: 1. The Energy Balance Ratio of the alpine wetland was 54%, absence of the information of soil heat flux. Its seasonal dynamic was conic (-0.0000124x2+0.00598x-0.0319, R2=0.27), which meant it was bigger in growing season than that of non-growing season. The threshold of friction velocity was 0.15 m•s-1 in the alpine wetland in 2005, by the methods of T-test. 2. The diurnal dynamics of energy flux showed the single-peak variations no matter what the season. They were kept 0 in nocturnal time and climbed its maximum in 14:00 (Beijing Standard Time, BST). The latent heat flux (LE) was the biggest consumer in diurnal change. 3. The seasonal dynamics of energy flux were a few complicated. The variations of net radiation (Rn) were single-peak, and its annual mean value was 125.0 Wm-2， ranged from 23.0 ~ 443.0 Wm-2. The average year value of LE was 49.0 Wm-2，ranged from -24.6 ~ 188.3 Wm-2，whose variations also was single-peak. The sensible heat flux ranged from -15.3 ~ 72.1 Wm-2, whose annual mean value was 17.6 Wm-2 and seasonal dynamics were double-peak. As to the energy partitioning, LE was primary. 4. The fluctuations of the alpine wetland ecosystem CO2 flux were larger in growing season than that of non-growing season. The ecosystem emitted CO2 in night of respiration while absorbed CO2 in daytime by photosynthesis，and its maximum occurred about 12:00. The maximum rate of absorption and emission was 0.45±0.0012 mgCO2m-2s-1 in July and 0.11±0.0082 mgCO2m-2s-1 in May, respectively. 5. The alpine wetland ecosystem emitted 316.02 g CO2m-2 and acted as the carbon source in 2005, which released 546.18 g CO2m-2 in non-growing season and absorbed 230.16 g CO2m-2 from the atmosphere in growing season. The monthly maximum rate of release and absorption was 5.85 g CO2m-2d-1 in May and 6.12 g CO2m-2d-1 in July, respectively. The accumulative sum of ecosystem respiration (Res) and gross primary production (GPP) was 2573.76 and 2257.74 gCO2m-2。 6. The primary factors on energy flux diurnal dynamic were different with the season. As to those factors on Rn, LE and H, they were photosynthetically active radiation (PAR) (R2=0.986), 2.5m air humidity (R2=0.933) and precipitation (R2=0.589) in January; PAR (R2=0.999), ground surface long-wave radiation (R2=0.962) and ground surface reflected radiation (R2=0.937) in April; total solar radiation (R2=0.958), PAR (R2=0.944) and total solar radiation (R2=0.971) in July; and total solar radiation (R2=0.989), ground surface reflected radiation (R2=0.880) and total solar radiation (R2=0.916) in October, respectively. The factors on Rn, LE and H were total solar radiation (R2=0.996), precipitation (R2=0.584) and total solar radiation (R2=0.216) in growing season variations while were 1.1m vapor pressure deficit (R2=0.629), 1.1m water vapor pressure (R2=0.536) and 40cm soil temperature (R2=0.520). 7. The primary factors on CO2 flux diurnal dynamic were different with the season. As to those factors on NEE, Res and GPP, they all were 5cm soil temperature (R2=0.740, R2=1.000 and R2=0.860) in January; 5cm soil temperature (R2=0.356, R2=0.978 and R2=0.323)in April; ground surface reflected radiation (R2=0.971), 5cm soil temperature (R2=0.999) and ground surface reflected radiation (R2=0.970) in July; and ground surface reflected radiation (R2=0.891), 5cm soil temperature (R2=1.000) and ground surface reflected radiation (R2=0.880) in October, respectively. The factors on NEE, Res and GPP were canopy temperature (R2=0.361), 5cm soil temperature (R2=0.963) and canopy temperature (R2=0.701) in growing season variations while were rainfall and ground surface reflected radiation (R2=0.117), 10cm soil temperature (R2=0.962) and 40cm soil temperature (R2=0.192). 8. Those microclimatic and biological factors were analyzed by the Principal Component Analysis, and four principal components were obtained. Their cumulative variances were up to 89.6% and 91.7% in growing season and non-growing season, respectively. However, the regression results suggested that the principal components weren’t better than the single factors in explaining the change of Carbon dioxide and energy flux.
页数	61
语种	中文
文献类型	学位论文
条目标识符	http://210.75.249.4/handle/363003/3128
专题	中国科学院西北高原生物研究所
推荐引用方式 GB/T 7714	张法伟. 青藏高原高寒湿地生态系统能量分配和CO2通量的初步研究[D]. 西北高原生物研究所. 中国科学院西北高原生物研究所,2007.

条目包含的文件
文件名称/大小	文献类型	版本类型	开放类型	使用许可
10001_20042801221501（3726KB）			开放获取	--	请求全文