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古尔班通古特沙漠南缘梭梭树干液流特征与林分蒸腾规律
李浩
Subtype硕士
Thesis Advisor胡顺军
2017-05-01
Degree Grantor中国科学院大学
Place of Conferral新疆乌鲁木齐
Degree Discipline理学硕士
Keyword古尔班通古特沙漠 树干液流 热扩散茎流计 环境因子 林分蒸腾 Gurbantunggut desert the stem sap flow TDP(thermal dissipation probe) environmental factors stand transpiration
AbstractThe transpiration water consumption of Haloxylon ammodendron is an importantphysiological index, and its variation law is influenced by many environmental factorscomprehensively. The transpiration water consumption of individual trees could beaccurately measured by investigating the characteristics of sap flow andenvironmental factors, and the transpiration of single-tree also could be predicted withthe help of environmental indicators by building the modeling with the sap flow andenvironmental factors. Combined with automatic weather stations, thermal dissipationprobe (TDP) was continuously used to measure the sap flow dynamics andenvironmental factors of Haloxylon ammodendron in the southern marginal zone ofthe Gurbantunggut desert, the sap flow velocity response to the environmentalelements were analyzed and the stem sap flow of Haloxylon ammodendron weresimulated based on the potential evapotranspiration and transpiration requirementindex . The results showed that:(1) The change of sap flow velocity mainly presented single peak or occasionallyappeared double peak curve in summer. The amplitude of daily variation and sap flowpeak in summer were greater than in the spring and autumn and presented asignificant differences with the sap-flow velocity during different seasons. Thestarting and peak times of sap flow were earlier and had a weak sap flow at night insummer. (2) In the growing season, net radiation, air temperature and saturated vapor pressuredeficit were the key factors of leading to the instantaneous changes. The instantaneoussap-flow of Haloxylon ammodendron was positively correlated with wind speed, netradiation, saturated vapor pressure deficit and air temperature, and negativelycorrelated with the actual water vapor pressure and air humidity. The net radiation, saturated vapor pressure deficit and air temperature were the key factor affectting theseasonal change of sap flow velocity. The daily average flow rate was positivelycorrelated with the net radiation, air temperature,saturated vapor pressure (3) deficit,actual water vapor pressure, soil water content and soil temperature, and asignificant negatively correlated with the air humidity. (4) There were different degrees of correlation between environmental factors, Thefirst three axes of principal component analysis (PCA) explained 47%, 20%, 17.6% ofvariances in the environmental data sets, while the first principal component includingRH, Ta, VPD, ET0 and Rn could explain 47% of environmental information changes, the second principal component with Ts and ea could explain 20% of environmentinformation, the third principal component given priority to HS and u2 could explain17.6% of the environment change information. The first principal component reflectsthe needs of the atmosphere transpiration, and the second and third principalcomponents reflect the effect of soil environmental conditions on transpiration rate. (4) The accuracy of sigmoid based on potential evapotranspiration in spring andsummer was higher, and the polynomial model was better than the ET0 model inautumn. (5)The hysteresis between velocity of sap flow and environmental factors wererevealed, presented significant differences during different seasons. In spring andautumn, the relationship between the velocity of sap flow and VPD was clockwise, while the relationship between the velocity of sap flow and the net radiation or thepotential evapotranspiration presented a counterclockwise trend. As in the spring andautumn seasons, the relationship between the sap flow velocity and VPD alsopresented a trend of clockwise during summer, however, the relationship between thesap flow velocity and the net radiation or potential evapotranspiration presented aclockwise as figure 8. (6)The daily transpiration of Haloxylon ammodendron forest was 0.35 mm/d, totaltranspiration was 53.35 mm during the whole study period, The daily transpirationwas increased from April to July, then began to decrease until the end of the growingperiod.
Other Abstract为了揭示古尔班通古特沙漠南缘原生梭梭衰败机制,指导荒漠植被的经营管理,利用 TDP 热扩散式茎流计结合波文比气象观测系统,对古尔班通古特沙漠南缘原生梭梭的树干液流及环境因子进行连续监测,分析了梭梭树干液流对环境要素的响应;基于潜在蒸散发和蒸腾需求指数对梭梭茎干液流进行了模拟;以梭梭基茎为空间纯量,利用尺度扩展法估算了梭梭群落的日、季耗水量。结果表明:(1)梭梭树干液流在晴天的日变化呈单峰曲线,液流速率上升阶段时间短于下降阶段时间,与气象因素的日变化规律不一致。不同季节梭梭树干液流速率日变化规律存在差异,夏季液流与春季、秋季相比,启动早,停止晚,峰值更大且发生更早。(2)环境要素间存在着不同程度的相关性;梭梭树干瞬时液流速率与风速、净辐射、空气温度、饱和水汽压亏缺值因素呈显著正相关,与实际水汽压和空气湿度呈极显著负相关,影响梭梭树干瞬时液流速率变化的关键因子是净辐射和饱和水汽压亏缺值;梭梭树干日均液流速率与净辐射、空气温度、实际水汽压、土壤含水率和土壤温度等呈极显著正相关,与空气湿度呈极显著负相关,影响梭梭日均液流速率变化的关键因子是净辐射、饱和水汽压亏缺和空气温度。(3)环境要素间存在着不同程度的相关性,主成分分析前 3 个主成分分别能解释 47%、20%和 17.6%的环境信息变化,第一主成分反映了大气的蒸腾需求,第二、三主成分反映了土壤环境条件对蒸腾速率的影响。(4)在春季和夏季基于潜在蒸散发的模拟梭梭液流速率的 S 型模型精度更高,在秋季基于蒸腾需求指数的模拟梭梭液流速率的多项式模型优于基于潜在蒸散发的 S 型模型。(5)梭梭树干液流速率与大气水分亏缺、净辐射、潜在蒸散发之间存在非对称响应,且不同季节间的响应规律存在差异。在春季和秋季,液流速率与 VPD呈顺时针状,与净辐射、潜在蒸散发呈逆时针状;在夏季,液流速率与 VPD 呈顺时针状,与净辐射、潜在蒸散发呈斜 8 字顺时针状。(6) 整个生长季林分的日蒸腾呈先增大后减小的趋势,日均蒸腾量 0.35mm/d,梭梭生长季 152 d 总蒸腾量是 53.35 mm。
Subject Area生态学
Language中文
Document Type学位论文
Identifierhttp://ir.xjlas.org/handle/365004/14882
Collection研究系统_荒漠环境研究室
Affiliation中国科学院新疆生态与地理研究所
First Author Affilication中国科学院新疆生态与地理研究所
Recommended Citation
GB/T 7714
李浩. 古尔班通古特沙漠南缘梭梭树干液流特征与林分蒸腾规律[D]. 新疆乌鲁木齐. 中国科学院大学,2017.
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