Growing season evapotranspiration from Tamarix ramosissima stands under extreme arid conditions in northwest China   总被引：1，自引：0，他引：1  

J. H. Si  Q. Feng  X. Y. Zhang  W. Liu  Y. H. Su  Y. W. Zhang 《Environmental Geology》2005,48(7):861-870

Given the increasing threat of water shortages in the extremely arid regions (rainfall<50 mm year⁻¹) of northwestern China, growing season evapotranspiration (ET) associated with native species such as Tamarix ramosissima is of particular interest. Consequently, this study sought to evaluate the accuracy of daily ET estimates using Bowen ratio data, as well as measuring seasonal ET and development of an energy balance for a stand of T. ramosissima. Bowen ratio apparatus measurements of ET were carried out on a stand of T. ramosissima in a 2.04 km² field, which are all covered with T. ramosissima near Erdaoqiao, Ejina Province, Inner Mongolia Autonomous Region, China. Soil moisture content and green area index were also monitored. Daily ET could be accurately estimated from Bowen ratio data on a continuous basis over the 153-day growing season. The mean daily T. ramosissima ET over this period was 1.62 mm day⁻¹, for a seasonal total of 248.20 mm. In this extremely arid locale, the great majority of available energy dissipated over the growing season was a result of sensible rather than latent heat fluxes. While the heat storage term was the main source of energy at night and a considerable sink of energy during the daytime, the magnitude of the daily mean soil heat flux was small. Such a determination of temporal and ecosystem-specific ET patterns allows an improved prediction of ET in the desert riparian zone.  相似文献   

Vertical distribution of stable isotopic composition in atmospheric water vapor and subsurface water in grassland and forest sites, eastern Mongolia     

Maki Tsujimura  Lisa Sasaki  Atsuko Sugimoto  Dai Matsushima  Mijiddorj Saandar 《Journal of Hydrology》2007,333(1):35-46

  相似文献   

科尔沁沙地典型区生长季蒸散发估算及其变化特征          下载免费PDF全文

张圣微  张鹏  张睿  刘廷玺 《水科学进展》2018,29(6):768-778

为揭示科尔沁沙地典型区地表参数和蒸散发的时空分布以及变化特征,采用Landsat-7和气象数据,并结合METRIC(Mapping Evapotranspiration at high Resolution with Internalized Calibration)模型,分析了研究区净辐射(Rn)和蒸散发(ET)的时空变化、不同土地覆被类型ET特征及其影响因素。结果表明:(1)研究区典型土地覆被沙丘和草甸的Rn和ET估算值与涡度相关实测值拟合结果均良好,说明METRIC模型可以为研究区提供合理的ET估算;(2)研究区下垫面Rn和ET的时空分布情况为:各年Rn和ET在年内变化趋势相同,空间上不同土地覆被类型中水体的Rn和ET最大,农田和草甸次之,沙丘最小;(3)沙丘的CV值大于农田与草甸,表明年际间沙丘的ET波动较大,农田和草甸相对稳定,ET年际变化主要受气象因素的影响。  相似文献   

Application of HYDRUS-1D in understanding soil water movement at two typical sites in the North China Plain          下载免费PDF全文

WANG Shi-qin  SONG Xian-fang  WEI Shou-cai  SHAO Jing-li 《地下水科学与工程》2016,4(1):1-11

Recharge and discharge, such as rainfall infiltration and evapotranspiration in vertical direction, are major processes of water cycle in the shallow groundwater area of the North China Plain. During these processes, soil water movement in the unsaturated zone plays an important role in the transformation from rainfall infiltration to groundwater. The soil water movement models were developed by using HYDRUS-1D software at two typical experimental sites in Cangzhou (CZ) and Hengshui (HS) with different soil, vegetation and similar climate conditions. As shown in the results, the comparison in precipitation infiltration features between the two sites is distinct. The soil water experiences strong evaporation after precipitation infiltration, which accounts for 63% of the total infiltration at the HS site where the soil is homogenous. It is this strong evaporation effect that leads to slight increase of soil water storage. At the CZ site, where the soil is heterogeneous, the evaporation effect exists from July to October of the simulation period. The total evaporation accounts for 33% of the total infiltration, and the evaporation rate is slow. At the end of the simulation period, the soil water storage increases and the water table decreases, indicating a strong storage capacity at this site.  相似文献   

基于实测资料对日蒸散发估算模型的比较   总被引：1，自引：0，他引：1  

刘波  翟建青  高超  姜彤  王艳君 《地球科学进展》2010,25(9):974-980

利用设置于江西省南昌县的新型高精度自动蒸渗仪,于2007年9月1日至2008年8月31日的实测陆面实际蒸散发过程,检验了面蒸散发互补关系模型CRAE (Complementary Relationship Areal Evapotranspiration)、GG模型 (Granger-Gray)、平流-干旱模型AA (Advection-Aridity)3个逐日路面实际蒸散发模型在不同时间尺度上的计算精度,并对计算误差的影响因素进行了讨论.结果表明:该地区实测年蒸散发量为746.1 mm,采用各模型的推荐经验参数对该地区蒸散发的估算结果误差较大,普遍干旱条件下蒸散发的计算值比观测值偏小,而湿润条件下的计算值偏大.通过对各模型的经验参数进行调整,各模型对年蒸散发量的计算精度大为提高,但逐日蒸散发过程的计算精度改进效果有限,在7日的时间尺度上,计算结果显著优于逐日的计算结果,在此时间尺度下,AA模型仍存在一定的系统误差,CRAE模型的估算精度相对较差,GG模型的总体计算效果相对最好.根据与蒸渗仪观测结果的对比分析,根据区域特征进行参数调整后的模型,需要在7日及更长时间尺度上,蒸散发模型的估算结果较为可靠.上述研究对全面认识陆面实际蒸散发特征、理解各蒸散发模型在不同时间尺度上的模拟能力、正确认识气候变化条件下的水循环特征具有重要意义.  相似文献   

陆面过程模式SIB2与包气带入渗模型的耦合及其应用   总被引：1，自引：0，他引：1  

周剑  李新  王根绪  潘小多 《地球科学进展》2008,23(6):570-579

土壤含水量对陆—气相互作用过程中的能—水平衡计算以及降雨、农业灌溉对地下水补给的研究起着关键的作用。但现阶段大多数陆面过程模式对土壤含水量的计算采用一维水桶模式,忽略了流域尺度上的侧向补给、地下水位的变化、包气带土壤的非线性渗透特性对土壤含水量的影响。针对这一问题,在国内外研究较为成熟的饱和—非饱和理论的基础上,编程实现了包气带土壤水分传输方程的求解,并与陆面过程模式（SIB2）相耦合,建立起研究分层包气带土壤水分运移、非稳态的地下水位、和地表蒸散发之间定量关系的模型。最后,利用建立的耦合模型,以河西走廊黑河流域中游临泽农业综合观测场的灌溉试验为例,模拟干旱内陆平原区小麦生长期间定额灌水条件下土壤含水量的变化。计算结果表明：模型能够准确计算瞬时土壤含水量、非稳态的地下水位,并对小麦生长过程中的耗水量进行估算,进而为农业合理灌溉提供了科学的理论基础。  相似文献