...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of hydrometeorology >Intercomparison of Evapotranspiration Estimates at the Different Ecological Zones in Jordan
【24h】

Intercomparison of Evapotranspiration Estimates at the Different Ecological Zones in Jordan

机译：约旦不同生态区蒸散量估算的比对

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

An estimate of evapotranspiration (ET) is needed for many applications in diverse disciplines such as agriculture, hydrology, and meteorology. The objective of this study was to compare two methods for estimating daily actual ET (ETa) from six sites located in four different ecological zones within Jordan. The first method used the analytical land-atmosphere radiometer model (ALARM) and the dimensionless temperature procedure, whereas the second method used ETa calculated from the FAO-56 reference evapotranspiration. ALARM converts general remotely sensed surface temperatures to aerodynamic temperature. Standard meteorological data from weather stations were used with both methods, and the Moderate Resolution Imaging Spectroradiometer (MODIS)-based leaf area index, surface temperature, and albedo were obtained to estimate ETa, using the former method. A validation study was conducted on an alfalfa field in Jordan Valley using ALARM and the American Society of Civil Engineers' (ASCE) method, which is very similar to FAO-56 except it uses alfalfa as a reference crop. Because this alfalfa field was irrigated and because of warm air advection, ET rates based on measurements of soil moisture change ranged from about 6 to 10 mm day(-1). For this range, the root-mean-square error (RMSE) for ALARM was 0.87 mm day(-1) and the coefficient of determination r(2) was 0.36, whereas the RMSE for ASCE was 1.25 mm day(-1) and r(2) = 0.06. There was good agreement between minimum, maximum, and average ETa for the two methods at all sites except for Irbid, for which the minimum and, consequently, the average were different. Much of the site-to-site and temporal variability was found to be statistically significant. Reasons for this variability include soil types, vegetation cover, irrigation, and warm advection.
机译：在农业，水文学和气象学等不同学科的许多应用中，都需要对蒸散量（ET）进行估算。这项研究的目的是比较两种方法来估算约旦境内四个不同生态区中六个地点的每日实际ET（ETa）。第一种方法使用分析性陆-大气辐射计模型（ALARM）和无量纲温度程序，而第二种方法使用从FAO-56参考蒸散量计算得出的ETa。警报将一般的遥感表面温度转换为空气动力学温度。两种方法均使用了来自气象站的标准气象数据，并使用前一种方法获得了基于中分辨率成像光谱仪（MODIS）的叶面积指数，表面温度和反照率来估算ETa。使用ALARM和美国土木工程师学会（ASCE）方法在约旦河谷的紫花苜蓿田进行了一项验证研究，该方法与FAO-56非常相似，只是它使用紫花苜蓿作为参考作物。由于该苜蓿田被灌溉并且由于热空气平流，基于土壤湿度变化的测量得出的ET速率约为6至10毫米天（-1）。在此范围内，ALARM的均方根误差（RMSE）为0.87 mm·天（-1），测定系数r（2）为0.36，而ASCE的RMSE为1.25 mm·天（-1）， r（2）= 0.06。除厄尔比德（Irbid）外，这两种方法的最小，最大和平均ETa值在所有站点之间都具有良好的一致性，因为最低和因此平均值不同。发现许多地点间和时间上的差异具有统计学意义。这种变化的原因包括土壤类型，植被覆盖，灌溉和热对流。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号