漳河灌区实时灌溉预报研究   总被引：15，自引：1，他引：15       下载免费PDF全文

李远华  杨常武 《水科学进展》1997,8(1):71-77

介绍了逐日参考作物蒸发蒸腾量和实际作物蒸发蒸腾量的分析计算与预测方法,提出了水稻需水量预测和实时灌溉预报的通用模型,并对实时灌溉预报的方法、步骤以及所需的实时资料进行了讨论.所提出的计算机程序手段先进,实用方便,通用性强.  相似文献   

三江平原典型沼泽湿地能量平衡和蒸散发研究   总被引：2，自引：1，他引：1       下载免费PDF全文

孙丽  宋长春 《水科学进展》2008,19(1):43-48

基于涡度相关技术对三江平原典型沼泽湿地的水热通量进行了连续观测,研究沼泽湿地能量平衡和蒸散发的季节变化,确定观测期内沼泽湿地总蒸散量,并通过逐步回归方程估算沼泽湿地水面蒸发和植被蒸腾。结果表明,沼泽湿地的能量平衡具有明显的季节变化特征,总体看来,潜热通量是湿地的主要能量支出项,占净辐射的45.5%,感热通量和存储热通量分别占净辐射的27.9%和26.7%。2006年5~10月份沼泽湿地总蒸散量为310.6mm,月均日蒸散量最高值出现在7月。观测期内沼泽湿地水面蒸发量约为221mm,占总蒸散量的71%左右,植被蒸腾量则约占总蒸散量的29%,湿地蒸散发以水面蒸发为主。  相似文献   

遮荫条件下乌拉苔草(Carex meyeriana)蒸腾特性及其与环境因子的关系   总被引：4，自引：0，他引：4  

徐惠风  刘兴土  高磊  沙箓 《湿地科学》2004,2(1):42-46

通过对不同遮荫下条件乌拉苔草蒸腾特性的研究表明，乌拉苔草蒸腾速率日变化规律是，上午8h出现次峰，18h出现高峰，日变化有“午休”现象，其中光。和光，出现在中午12h，对照和光：出现在下午14h。在上午8h，蒸腾速率的变化不受气孔开闭的影响，是由于时间和环境因子的综合影响所致；中午出现的“午休”现象，是由于气孔闭所至。不同遮荫处理下蒸腾速率变化规律基本一致，遮荫50％对蒸腾速率影响较大，其他处理对蒸腾速率的影响较小，说明乌拉苔草的蒸腾特性不仅由本身的生理特性所决定，并受环境因子综合的影响；另外，不同遮荫对气孔也有直接的影响，遮荫是影响气孔阻力的直接因素。  相似文献   

Modelling forest transpiration from different perspectives     

S. C. Dekker  W. Bouten  J. M. Verstraten 《水文研究》2000,14(2):251-260

Forest transpiration models have been developed in different disciplines such as plant physiology, ecology, meteorology, hydrology and soil science. In the present study, three different types of model perspectives for transpiration control are used: leaf cooling, CO₂ assimilation and the combined energy and water balance. All three process‐orientated models are calibrated on measurements in a Douglas fir stand in the Netherlands. The performances of these models are equally good, although they have different complexities, different numbers of calibration parameters (ranging from 1 to 6) and the models are calibrated on different measurements (eddy correlation at canopy level or CO₂ measurements at leaf level). The resemblance of the model results is caused by the calibration procedure and by the high impact of radiation in all three cases. Significant discrepancies become apparent when differences between model responses are examined and when specific (short) periods are selected when input variables are uncoupled. The main differences between the models are caused by another formulation of leaf area index and vapour pressure deficit (VPD). Considerable differences in simulated transpiration occur in the afternoon as a result of the diurnal hysteresis between VPD and radiation. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

基于茎干液流法和涡度相关法的小叶锦鸡儿(Caragana microphylla)群落蒸散特征     

祁秀娇  刘廷玺  段利民  陈小平  黄天宇 《中国沙漠》2019,(4):73-82

运用Dynamax茎流测量系统、涡度相关系统、气象-土壤环境观测系统进行连续观测,利用基径横截面积对单枝茎干液流进行尺度扩展,得到科尔沁沙地小叶锦鸡儿(Caragana microphylla)群落蒸腾量(T),并与涡度相关系统观测的蒸散发量(ET)进行对比,详细分析了小叶锦鸡儿群落T与ET的变化特征以及群落水分收支状况。结果表明:(1)小叶锦鸡儿群落T、ET日变化趋势基本一致,均值分别为1.61 mm·d-1、2.43 mm·d-1;(2)T、ET日内变化曲线分别呈宽幅单峰型、钟型分布,日累积量均呈"S"型增长趋势;(3)不同天气条件下T、ET日变化峰型各异,峰值及总量变化水平晴天高于阴雨天;(4)不同降水事件中,降雨时间不同导致T启动时间推迟或结束时间提前,ET发生时间降水前后无显著差异;降雨量P≤10 mm或P>20 mm时,雨后T有所降低,10 mm相似文献   

球状星团NGC4147基于依巴谷系统的自行和空间运动     

王家骥  武振宇 《天文学报》1999,40(3):335-336

王家骥等［１］曾得到球状星团ＮＧＣ４１４７的绝对自行为（－２．８２±０．４９,２．３７±０．４３）ｍａｓ／ｙｒ．但是,其中所用的参考星表是Ｂｒｏｓｃｈｅ等［２］１９８５年发表的结果,含有ＡＧＫ３星表的系统误差．在Ｄａｕｐｈｏｌｅ等［３］给出的２６个球状星团轨道远银心距（ａｐｏｇａｌａｃｔｉｃｄｉｓｔａｎｃｅ）与金属度［Ｆｅ／Ｈ］的关系图上,ＮＧＣ４１４７处于一个特殊的位置,即按照它的远银距（５２ｋｐｃ）,它的金属度［Ｆｅ／Ｈ］应该大于－２．０,但实际上只有－１．８３［４］．类似的问题在文［１］的…  相似文献   

Impact of soil conditions on the physiological characteristics of maize plants in an arid region,Northwest China     

LiWen Zhao  ZhiBin He  WenZhi Zhao 《寒旱区科学》2016,8(4):334-342

Overuse of irrigation water to ensure the crop yield of maize plants has caused serious water shortage problems in the middle reach of Heihe River, China. Thus, further research on the physiological characteristics, i.e., photosynthetic rate and leaf transpiration rate, are urgently needed to develop an efficient irrigation management system. In this paper, we selected two common soil textures (sandy loam, sand) and three one-time irrigation volumes (60 mm, 20 mm, 0 mm) in order to analyze the impact of soil conditions on the physiological characteristics of maize plants. Physiological and meteorological factors, soil water content and plant growing parameters were synchronously monitored on Jun. 30, Jul. 25 and Aug. 27 of 2012. The results indicate that sandy loam is better than sand for the growth of maize plants and single irrigation may provide limited influence on the physiological characteristics. Thus, increasing irrigation times and decreasing one-time volume is suggested for an efficient irrigation system.  相似文献   

Seasonal modelling of catchment water balance: A two-levle cascading modification of TOPMODEL to increase the realism of spatio-temporal processes     

BERTRAM OSTENDORF  BERNHARD MANDERSCHEID 《水文研究》1997,11(9):1231-1242

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Subalpine forest water use behaviour and evapotranspiration during two hydrologically contrasting growing seasons in the Canadian Rockies     

Lindsey E. Langs  Richard M. Petrone  John W. Pomeroy 《水文研究》2021,35(5):e14158

Hydrological processes in mountain headwater basins are changing as climate and vegetation change. Interactions between hydrological processes and subalpine forest ecological function are important to mountain water supplies due to their control on evapotranspiration (ET). Improved understanding of the sensitivity of these interactions to seasonal and interannual changes in snowmelt and summer rainfall is needed as these interactions can impact forest growth, succession, health, and susceptibility to wildfire. To better understand this sensitivity, this research examined ET for a sub-alpine forest in the Canadian Rockies over two contrasting growing seasons and quantified the contribution of transpiration (T) from the younger tree population to overall stand ET. The younger population was focused on to permit examination of trees that have grown under the effect of recent climate change and will contribute to treeline migration, and subalpine forest densification and succession. Research sites were located at Fortress Mountain Research Basin, Kananaskis, Alberta, where the subalpine forest examined is composed of Abies lasiocarpa (Subalpine fir) and Picea engelmannii (Engelmann spruce). Seasonal changes in water availability from snowmelt, precipitation, soil moisture reserves yielded stark differences in T and ET between 2016 and 2017. ET was higher in the drier year (2017), which had late snowmelt and lower summer rainfall than in the wetter year (2016) that had lower snowmelt and a rainy summer, highlighting the importance of spring snowmelt recharge of soil moisture. However, stand T of the younger trees (73% of forest population) was greater (64 mm) in 2016 (275 mm summer rainfall) than 2017 (39 mm T, 147 mm summer rainfall), and appears to be sensitive to soil moisture decreases in fall, which are largely a function of summer period rainfall. Relationships between subalpine forest water use and different growing season and antecedent (snowmelt period) hydrological conditions clarify the interactions between forest water use and alpine hydrology, which can lead to better anticipation of the hydrological response of subalpine forest-dominated basins to climate variability and change.  相似文献   

山东省干旱主要原因分析   总被引：7，自引：0，他引：7  

王建源  陈艳春 《气象》1999,25(11):34-36

干旱造面山东省作物大面积减产和严重的经济损失,其原因主要有三个：一是降水时空分布不均,二是客水量减小,三是温度偏高,蒸散量增加,因此,必须建立健全干旱监测预警服务系统,加快水利建设的步伐,推广旱作节水农业技术。  相似文献