亚热带人工针叶林储热量的变化特征及其影响因素

论文总字数：15159字

目 录

目录 1

1.引言 4

2.研究方法 4

2.1研究地概况 4

2.2观测方法 5

2.3能量平衡方程 5

2.4 能量平衡闭合评价 6

3 .研究结果和分析 6

3.1 气象要素的变化特征 6

3.1.1净辐射的月变化和日变化特征 6

3.1.2 气温的月变化和日变化特征 6

3.1.3 5cm土壤温度的月变化和日变化特征 7

3.1.4 降水量变化特征 7

3.2空气储热量的时间变化及影响因素 8

3.2.1潜热储量的时间变化特征 8

3.2.2潜热热储量的影响因素及特征分析 9

3.2.3显热储量的时间变化特征 10

3.2.4显热变化的影响因素及特征分析 11

3.2.4土壤热通量的时间变化特征 12

3.2.5土壤热通量变化的影响因素及特征分析 13

3.3 热储量占净辐射的比值 13

3.4 土壤热通量占净辐射的比值 14

3.5能量闭合分析 14

参考文献 18

亚热带人工针叶林储热量的变化特征及其影响因素

庞业

，China

Abstract Studying the change of the heat storage of the forest can help to evaluate the ecosystem energy balance and the accuracy of eddy covariance measurement. Based on the meteorological factors observed in subtropical planted coniferous forest at Qianyanzhou from January 2003 to December 2006, the latent heat storage and sensible heat storage was calculated. And, the variation characteristics of different heat storage term and their influencing factors were analyzed. Moreover, the latent heat and sensible heat flux data were used to evaluate the energy balance of the ecosystem. The results showed that the latent heat storage showed the type of "double peak and double grain " dynamic. The sensible heat and the soil heat flux showed "single peak" variation. Monthly total sensible heat storage, latent heat storage, and soil heat flux reached the maximum in January, October and July, respectively, with the value of 14.06MJ · m^-2, 20.52MJ · m^-2, and 14.58MJ · m^-2. And, Monthly total sensible heat storage, latent heat storage, and soil heat flux were the smallest in September, September, December, respectively, with the value of -9.13MJ · m^-2, -18.42MJ · m^-2, and -20.25MJ · m^-2. The latent heat and sensible heat storage correlated negatively with temperature. And, the latent heat storage negatively correlated with wind speed. Significant correlation between heat storage and wind speed was positive. Soil heat flux positively correlated with soil water content and soil temperature. The ratio of latent heat storage, sensible heat storage to net radiation reached the maximum before 10:00 am, then decreased with time. The ratio of soil heat flux to net radiation was the highest after 12:00 due to the lag of soil temperature change to air temperature. Considering the heat storage, the energy closure rate of each season was improved. The EBR was about 0.7. The result indicated that the heat storage can improve the energy balance. This study can promote understanding the process of energy exchange of subtropical forests and provide a reference for the study of energy balance closure in subtropical forests.

Key word：Heat storage; Energy balance; Qianyanzhou; Subtropical planted coniferous forest

1.引言

森林是人类生存环境中不可缺少的生态系统，具有调节大气CO₂的作用，即绿色植被通过光合作用吸收大气中的CO₂成为大气CO₂的汇，又能通过动物等生物的呼吸作用成为大气CO₂的源，由此可见，森林在全世界的大气环境变化中起到不可小觑的重要作用^[1,2]。

为了更好地了解森林生态系统与大气之间能量和物质的交换过程，全球广泛采用涡度相关方法获得森林与大气之间的二氧化碳、潜热、显热等物质和能量的交换量^[3,4]。但由于涡度相关法所要求的观测条件苛刻，许多天气、下垫面条件都会影响到观测值的准确性，如：观测地的植被冠层特征、大气稳定度、地面的平坦程度、仪器的响应速度和仪器的安装高度等因素。因此，通量观测的可靠性需要进行评价，而生态系统能量闭合程度是评价通量观测可靠性的重要判据^[5,6]。

储热项是能量平衡方程中的一项，但在以往生态系统能量闭合的研究中常因储热量较小而被忽略，造成能量不闭合现象的出现^[1,3,7]。大量研究发现，不同下垫面和气候区，这些储热量有明显的差异。对长白山温带针阔叶混交林、西双版纳热带季节雨林生态系统的研究发现，储热量白天为正值，夜晚为负值，在能量平衡的各分量日变化中储热量变化相对较小，6月到10月储热量是正值的持续时间逐渐缩短，负值持续时间相应变长。储热量平均最大值范围为27～44W·m^-2，夜间平均最小值变化范围为-10～-26W·m^-2。对高山草甸生态系统的研究发现，储热量变化特征为夜间总平均值为-5.5W·m^-2，白天总平均值为13.2W·m^-2。对比发现，森林与亚高山草甸有相似的日变化特征，但森林的热储量明显大于亚高山草甸的热储量。所以，在森林生态系统系统的能量闭合评价中，了解热储量变化特征尤为重要^[3,7,8,9]。

我国长江以南的亚热带地区分布着大量的人工林，千烟洲亚热带人工针叶林是该地区典型的森林生态系统类型，研究该森林生态系统储热量变化特征及其影响要素，以及储热量对该森林生态系统能量闭合的影响，可为该地区同类研究提供重要参考。

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