Modelling water,nutrients, and organic carbon in forested catchments: a HYPE application          下载免费PDF全文

Charlotta Pers  Johan Temnerud  Göran Lindström 《水文研究》2016,30(18):3252-3273

Both monitoring and model simulation are useful for understanding and detecting changes in the environment. To understand and simulate leaching in small forested catchments, it is important to have knowledge of soil processes. Here, we describe recent development of the Hydrological Predictions for the Environment (HYPE) model for forested catchments. HYPE includes an organic carbon (OC) variable in addition to previously published nitrogen (N), phosphorus (P), and water flow models. The aspects addressed in the current study included P concentrations under low‐flow conditions and high concentrations of inorganic N. HYPE was further developed based on nine small forested catchments (0.5–200 ha) in Sweden, which were calibrated separately using local data. The model (excluding the OC variable) was tested on a larger set of forest catchments from the operational HYPE model of Sweden (S‐HYPE). We observed the following: (1) dissolved organic P could make a significant contribution to the total P concentration in a stream during low‐flow periods, (2) the inorganic N concentration simulated in a stream improved when part of the atmospheric N was retained in the soil, (3) the soil flow path formulation was critical for simulating concentration dynamics, and (4) evaluating an additional variable (OC) further elucidated the soil runoff processes in the model. Copyright © 2016 Swedish Meteorological and Hydrological Institute. Hydrological Processes published by John Wiley & Sons, Ltd.  相似文献   

Bedload transport measurements with impact plate geophones: comparison of sensor calibration in different gravel‐bed streams          下载免费PDF全文

Dieter Rickenmann  Jens M. Turowski  Bruno Fritschi  Carlos Wyss  Jonathan Laronne  Ronel Barzilai  Ian Reid  Andrea Kreisler  Johann Aigner  Hugo Seitz  Helmut Habersack 《地球表面变化过程与地形》2014,39(7):928-942

Indirect bedload transport measurements have been made with the Swiss plate geophone system in five gravel‐bed mountain streams. These geophone sensors record the motion of bedload particles transported over a steel plate mounted flush with the channel bed. To calibrate the geophone system, direct bedload transport measurements were undertaken simultaneously. At the Erlenbach in Switzerland, a moving‐basket sampler was used. At the Fischbach and Ruetz streams in Austria, a Helley–Smith type bedload sampler provided the calibration measurements. A Bunte‐type bedload trap was used at the Rofenache stream in Austria. At the Nahal Eshtemoa in Israel, Reid‐type slot bedload samplers were used. To characterize the response of the geophone signal to bedload particles impacting on the plate, geophone summary values were calculated from the raw signal and stored at one second intervals. The number of impulses, i.e. the number of peaks above a pre‐defined threshold value of the geophone output signal, correlated well with field measured gravel transport loads and was found to be a robust parameter. The relations of impulses to gravel transport loads were generally near‐linear, but the steepness of the calibration relations differed from site to site. By comparing the calibration measurements from the different field sites and utilizing insights gained during preliminary flume experiments, it has been possible to identify the main factors that are responsible for site specific differences in the calibration coefficient. The analysis of these calibration measurements indicates that the geophone signal also contains some information about the grain size distribution of bedload. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

基于CompactRIO的多通道强震动数据采集器FPGA的实现     

吴华灯  叶春明 《华南地震》2014,(3):33-39

提出以Compact RIO作为硬件平台,用Lab VIEW FPGA技术实现48通道强震动数据采集器底层数据采集功能。详细阐述了设计要点及从技术上实现了时钟同步、数据采集、标定信号输出、量程设置、状态显示、外触发信号接入等功能。结果表明,数据采集器的噪声、动态范围、幅频响应等主要技术指标满足国内地震行业标准DB/T 10-2001的要求,数据采集器的线性度误差满足DB/T 22-2007的要求。实现的阶段成果能为人们利用NI产品进行强震动数据采集器开发提供重要参考。  相似文献   

SWY-Ⅱ型水位传感器的校准方法研究     

石岩  何案华  贾鸿飞  雷晨  李秀丽 《华北地震科学》2014,(1):5-11

提出一种水位传感器准确度的实验室校准方法,并结合地震台站的实际观测情况,对实验室校准方法进行改进,提出一种地震台站现场水位传感器的校准方法。通过地震台站现场校准方法的提出,从原理上基本解决了由于现场环境因素、压敏元件的非线性因素给水位观测带来的系统误差。  相似文献   

加速度谐波失真度对速度型地震计振动台标定的影响          下载免费PDF全文

马洁美  滕云田  左爱斌  范晓勇  张炼 《地震学报》2014,36(6):1124-1130

本文对加速度和速度谐波失真度进行了理论计算, 并基于美国国家仪器公司研发的实验室虚拟仪器工程平台(Labview), 设计出低频振动信号数字化测量系统, 实现了振动台面对加速度波形、 速度波形及其失真度的测量. 基于该系统的实验数据与中国计量科学研究院设定的参考值偏差较小. 对地震计的测试结果表明, 加速度波形及其失真度对振动波形的精度描述更为严格, 能有效提高地震计振动测试的准确程度.   相似文献   

时频联合分析地震计正弦标定数据     

刘明辉  ;林湛  ;周银兴  ;马士振  ;崔仁胜  ;吴卫远 《地震地磁观测与研究》2014,(1):231-235

介绍短时傅里叶变换,分析地震计正弦标定信号的特点,提出基于时间域和频率域联合分析正弦标定波形组起始点的方法,可以准确找出每组正弦标定信号的频率和振幅,计算地震计的速度响应灵敏度。  相似文献   

CPF变化对Landsat TM/ETM+辐射校正结果的影响     

黄绍霖  徐涵秋  王琳 《吉林大学学报(地球科学版)》2014,44(4):1382

随着时间的推移,卫星传感器的老化会使得原有的辐射定标参数文件(CPF)失效。最典型的当属Landsat-5卫星,该卫星自1984年发射以来,已经进行了多次CPF修正;而Landsat-7卫星的CPF也经过了数次修改,以保证辐射校正结果的准确性。以Landsat TM/ETM+遥感影像为例,分别以2003、2009年的CPF对它们进行辐射校正,并对结果进行对比。结果表明,除ETM+的绿光波段外,TM、ETM+影像基于2009年CPF计算的各波段均值都要小于2003年。而这一变化也使得由此计算的指数产生差异：归一化植被指数(NDVI)间的差异可达0.48%,建筑用地指数(IBI)间的差异可达5.94%。  相似文献   

青藏高原探空大气水汽偏差及订正方法研究   总被引：4，自引：1，他引：3  

梁宏  张人禾  刘晶淼  孙治安  李世奎 《大气科学》2012,36(4):795-810

水汽是大气的主要成分和降水的主要物质来源.青藏高原大气水汽分布对区域天气和气候有很大影响,为了探讨探空观测的大气水汽总量（R）资料的可靠性,本文以地基GPS遥感的大气水汽总量（G）为参照标准,对拉萨（1999~2010年）和那曲（2003年）的R进行对比分析和偏差（R-G）订正.结果表明:近10多年拉萨站R比G明显偏小,偏小程度随使用不同的探空仪而异.GZZ-2型机械探空仪和GTS-1型电子探空仪多年平均的PW偏差分别为-8.8%和-3.9%,随机误差分别为17.6%和13.6%.近10多年PW偏差变化呈减少趋势,这与探空仪性能改进有关.分析发现,青藏高原PW偏差具有明显季节变化和日变化特征,夏季比冬季明显,1200 UTC比0000 UTC明显.拉萨站GZZ-2型和GTS-1型探空仪在1200 UTC多年平均的PW偏差分别为-15.8%和-7.3%,在0000 UTC分别为-1.6%和-0.4%.那曲站GZZ-2型探空仪在1200 UTC和0000 UTC的PW偏差分别为-12.4%和-0.3%.分析还表明,太阳辐射加热与气温的日变化和季节变化是造成高原PW偏差日变化和季节变化的重要原因.据此,提出了高原PW偏差的订正方法,并以拉萨和那曲站为例进行PW偏差订正,订正后的PW系统偏差显著减少,随机误差也相应得到了改善.  相似文献   

基于线结构光的3维目标测量与多分辨率建模   总被引：2，自引：0，他引：2  

李清泉  王植  李宇光 《测绘学报》2006,35(4):371-378

随着数字化技术的发展,对高精度的3维模型的需求也日益增长。介绍一个利用线结构光扫描获取目标3维信息的测量系统.详细介绍整个系统的硬件组成和目标表面3维轮廓的获取过程。还提出一种适用于线结构光测量系统的标定方法。为了根据需要调整3维模型的分辨率和数据量,使用改进的边折叠三角网简化算法实现多分辨率3维建模。实验中对3维目标进行测量并给出可视化结果。  相似文献   

无重力数据情况下阜新似大地水准面的确定     

李吉之  孙艳崇 《测绘工程》2006,15(4):31-32,36

将地球位模型计算的阜新似大地水准面拟合于GPS水准实测的似大地水准面。其方法是对每一个GPS水准点,以选定的地球位模型计算其高程异常值,并与其GPS水准实测高程异常值进行比较,得到高程异常的改正值,以此改正附近2.5′×2.5′格网点上用地球位模型计算的高程异常。  相似文献