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Publication numberCN101915771 A
Publication typeApplication
Application numberCN 201010272467
Publication date15 Dec 2010
Filing date3 Sep 2010
Priority date3 Sep 2010
Also published asCN101915771B
Publication number201010272467.3, CN 101915771 A, CN 101915771A, CN 201010272467, CN-A-101915771, CN101915771 A, CN101915771A, CN201010272467, CN201010272467.3
Inventors信秀丽, 张佳宝, 朱安宁
Applicant中国科学院南京土壤研究所
Export CitationBiBTeX, EndNote, RefMan
External Links: SIPO, Espacenet
Method for determining sandy soil moisture content based on low-frequency ground penetrating radar ground method
CN 101915771 A
Abstract
The invention relates to a method for determining the sandy soil moisture content based on a low-frequency ground penetrating radar ground method, which comprises the determining steps of: collecting ground penetrating radar data by utilizing a together-midpoint method to ensure the travel time of airwaves and ground waves; collecting the radar wave information of a soil section by utilizing a constant spacing method; calculating the dielectric constant of soil; substituting parameters to a formula to obtain the dielectric constant of soil; calculating the water content of soil; substituting the obtained soil dielectric constant epsilon to the formula theta=-5. 3*102+2.92*10-2epsilon-5.5*10-4epsilon2+4.3*10-6epsilon3 to obtain the soil water content. The method for determining the sandy soil moisture content based on a low-frequency ground penetrating radar ground method is suitable to the measurement of the soil water content in farmlands and small river basins, has the advantages of convenience, quick operation, high accuracy and no destruction and is especially suitable to the water content determination of sandy soil.
Claims(2)  translated from Chinese
  1. 基于低频探地雷达地波法的测定砂质土壤含水量的方法,其特征在于测定步骤为:a.通过共中点法采集探地雷达数据,以确定空气波和地波走时:发射天线和接收天线按固定步长沿着测线向相反方向对称地移动,保持一个共中心点,其雷达记录为天线间距与雷达波的走时关系,获取能清晰分离出空气波和地波的不同天线间距x对应的空气波走时tAW和地波走时tGW,回归获取tAW~x和tGW~x关系式;b.以固定间距法采集土壤剖面的雷达波信息:保持探地雷达发射天线和接收天线的间距不变,按固定步长沿着测线方向同时移动的获取雷达图像的测定方法,其雷达图像记录为测线与雷达波走时关系,根据tAW~x和tGW~x关系式计算出固定间距最佳天线间距时的tAW和tGW;c.土壤介电常数的计算:将参数代入公式得土壤的介电常数其中地波速率v、地波走时tGW、空气波走时tAW、天线间距x、c为电磁波在真空中的速度0.3mns‑1;d.土壤含水量的计算:将计算得到的土壤介电常数ε代入θ=‑5.310‑2+2.9210‑2ε‑5.510‑4ε2+4.310‑6ε3,得土壤含水量。 Method for the determination of low-sandy soil moisture GPR ground wave method based on measurement step is characterized by: a co midpoint through GPR data were collected to determine the air waves and the ground wave away: transmitting antenna and receiving antenna fixed step size symmetrically move in opposite directions along the survey line to maintain a common central point, which is recorded as the relationship between the travel radar antenna and radar pitch, access can be clearly separated from the different waves of air and ground wave antenna spacing When x corresponding air waves go tAW and ground-wave travel time tGW, return to get tAW ~ x and tGW ~ x relationship; b fixed pitch were collected soil profile of radar information: Keep GPR transmit and receive antennas spacing unchanged, while obtaining a fixed step size along the survey line direction measurement method radar images, radar images recorded when their survey line and take the relationship radar, according to tAW ~ x and tGW ~ x relationship calculate the fixed pitch tAW and tGW good antenna spacing of; c soil dielectric constant is calculated: the parameters into the formula to get the soil in which the dielectric constant wave velocity v, when to wave away tGW, when the air waves go tAW, antenna spacing x, c for electromagnetic wave velocity in a vacuum 0.3m ns-1; d soil moisture content is calculated: the calculated soil permittivity ε substitution θ = -5.3 10-2 + 2.92 10-2ε-5.5 10- 4ε2 + 4.3 10-6ε3, get the soil moisture content. FSA00000256878500011.tif FSA00000256878500011.tif
  2. 2.根据权利要求1所述的基于低频探地雷达地波法的测定砂质土壤含水量的方法,其特征在于共中点法确定空气波和地波走时的具体步骤为:测线长选择15m至20m,发射和接收天线的起始位置在测线中点南北各IOcm处,起始间距20cm,采集步长20cm,让两个天线每次各沿测线向外移动10cm。 2. Determination of claim sandy soil low frequency GPR ground wave method based on moisture content, wherein one of the co-midpoint method to determine the specific steps the air waves and ground-wave travel time is: survey line length selection 15m to 20m, the starting position of transmit and receive antennas in the survey line at the midpoint of the north and south IOcm, initial spacing 20cm, acquisition step 20cm, so that each of the two antennas each move outward along the survey line 10cm.
Description  translated from Chinese

基于低频探地雷达地波法的测定砂质土壤含水量的方法 Based on sandy soils low frequency measurement GPR ground wave method moisture method

一、技术领域 I. Technical Field

[0001] 本发明涉及一种砂质土壤剖面含水量测定方法,特别涉及一种基于低频探地雷达地波法的测定砂质土壤含水量的方法。 [0001] The present invention relates to a method for the determination of sandy soil moisture profile, particularly involving sandy soil was measured based on the low-frequency GPR ground wave method moisture content approach.

二、背景技术 II BACKGROUND ART

[0002] 长期以来,小尺度的土壤含水量的测定方法主要是烘干法、中子法、传感器法以及时域反射仪法,这些方法能较准确地测定土壤含水量,但都存在着耗时费力并对土壤具有一定的破坏性等问题。 [0002] For a long time, determination of soil moisture is mainly small-scale drying method, neutron, sensor method and time domain reflectometry method, these methods can more accurately measure soil moisture, but there is a consumption time-consuming and disruptive soil has some other issues. 上世纪90年代中期,遥感技术开始应用于区域尺度上的土壤水分测定,该方法能快速测定区域乃至全球的土壤表层含水量,信息量大,但是,遥感法的空间分辨率较低,而且通过遥感数据只能估计表层0. 05m深度的土壤含水量,受植被覆盖的影响也较大。 In the mid-1990s, remote sensing technology began to be used on a regional scale soil moisture, the method can be quickly determined regional and global surface soil moisture content, the amount of information, however, lower resolution remote sensing from space law, but also through Remote sensing data can only estimate the depth 0. 05m surface soil moisture, vegetation cover affected as well. 由此可见,在确定土壤含水量的时域反射仪方法和遥感方法之间,存在一个空间尺度上的技术空白,即在农田和小流域等中小尺度上,上述方法已经远远不能满足日益发展的土壤科学研究和现代化精准农业对大量、快速、准确的农田土壤水分动态信息的需求。 Thus, in determining soil moisture between the time domain reflectometer methods and remote sensing methods, there is a technical one blank space scales, that is, in the small-scale farms and small watersheds, the above method has been far from satisfying the growing soil science and modern precision large, rapid, and accurate information on the dynamic needs of agriculture on soil moisture farmland. 因而,发展科学依据充分的适用于农田和小流域的方便、快捷、准确、无破坏性的土壤含水量测定技术是一个需要重视和亟待加强的问题。 Thus, the development of scientific evidence sufficient farmland suitable for convenience and small watersheds, fast, accurate, non-destructive measurement of soil water content and technology is an urgent need to focus on strengthening the problem.

[0003] 探地雷达技术通过获取雷达波在土壤中的运行信息来估计土壤的介电常数,进而利用土壤介电常数和土壤含水量的经验公式或半理论关系式来计算土壤的含水量。 [0003] GPR technology through the acquisition radar operating information in the soil to estimate the dielectric constant of the soil, the soil moisture content and then to calculate the empirical formula of soil moisture content and soil dielectric constant or semi-theoretical relationship. 现有的探地雷达探测土壤含水量的方法按电磁波传播的类型分类主要有4种:反射波法、地波法, 反射系数法以及钻孔雷达法。 Existing ground penetrating radar to detect soil moisture by electromagnetic wave propagation method There are four main types of classification: wave reflection method, ground wave, the reflection coefficient method and borehole radar method. 其中地波法根据发射和接收天线距离以及探地雷达测定的地波运行时间来确定浅层土壤含水量,是目前认为具有潜力的土壤含水量测定方法。 Law according to which the ground wave transmitting and receiving antenna distance and measured GPR ground wave run-time to determine the shallow soil water content, is currently considered potential soil moisture content determination.

[0004] 目前,国际上应用地波法探测土壤含水量时采用的电磁波频率主要范围为225MHz〜900MHz。 [0004] Currently, the main application of electromagnetic wave frequency wave method to detect soil moisture when the international community adopted for 225MHz~900MHz. 而由于低频电磁波的分辨率低,受土壤质地、含水量等影响,雷达图像中不易识别出空气波和地波,目前国内外关于低频探地雷达地波法的研究还较少。 And because of the low-frequency electromagnetic waves low resolution, by soil texture, moisture and other factors, the radar image is not easy to identify the air waves and the ground wave, the current domestic and international research on low-frequency GPR ground wave method is also less. 但低频电磁波较之高频电磁波具有穿透能力增加,探测深度大等特点,研究层次较深和湿度高的土壤剖面的含水量具有优势。 However, compared to the low-frequency electromagnetic frequency electromagnetic waves have the ability to increase penetration, probing depth and other characteristics, research and high humidity levels deep soil moisture profile has advantages. 低频探地雷达地波法尤其适用于农田土壤含水量测定。 Low-frequency GPR ground Bofa You it applies to farmland soil moisture measurement.

[0005] 而地波法探测土壤含水量的模式主要有共中点法和固定间距法。 [0005] The ground wave method to detect soil moisture patterns are mainly co midpoint method and fixed spacing method. 共中点法作为一种变天线间距方法,测定结果精确性高,但需耗费大量的时间和人力,不适合在较大范围内(IOm-IOOOm)应用。 Total midpoint method as a method of varying antenna spacing, high accuracy measurement results, but need to spend a lot of time and effort, not suitable in a wide range (IOm-IOOOm) applications. 固定间距法具有快速、实时监测的优点,适合于较大尺度的土壤水分时空分布监测,但必须在已知反射界面深度的条件下进行的。 Fixed spacing method is rapid, real-time monitoring of the advantages of soil moisture suitable for large-scale spatial and temporal distribution of monitoring, but must be in a condition known depth of reflection interface. 将共中点法与固定间距法相结合来测定土壤含水量,则省时省力的多。 The total of the midpoint method to determine soil moisture Combination with fixed spacing, saving time and effort as many. 先通过共中点法获取不同天线间距的地波走时,然后选择一个能分离出空气波和地波的最佳天线间距,再利用固定间距法探测含水量。 First obtain different antenna spacing of ground wave away, and then select the best one can isolate the air waves and the ground wave antenna spacing, and then use a fixed pitch method to detect water content by co-midpoint method. 该方法的最大局限性在于,共中点法与固定间距法的最佳天线间距不统一。 The most significant limitation of this method is that total fixed midpoint method with optimal antenna spacing is not uniform spacing methods. 共中点法测定雷达图像中,天线间距越小,图像中的空气波和地波越接近,界面不清晰,难以拾取准确的空气波和地波;而固定间距测定雷达图像中,天线间距越大,雷达波信号越弱,异常信号增多,误差越大。 Determination of total midpoint radar images, the antenna spacing smaller image of air wave and ground wave closer, the interface is not clear, it is difficult to accurately pick up the air waves and ground waves; fixed distance measurement radar images, the antenna spacing more large, radar signal weaker increase abnormal signal, the greater the error. 因此,如何找到兼顾共中点法和固定间距法的最佳天线间距尤为关键。 Therefore, how to find the best balance between co-antenna spacing midpoint method and fixed spacing method is particularly critical.

[0006] 因此,本方法通过低频探地雷达利用共中点法和固定间距法相结合测定灌水前后的不同土壤含水量,为今后低频探地雷达在土壤学中的进一步应用提供依据。 [0006] Thus, the method by low-frequency ground penetrating radar altogether midpoint method and fixed-pitch Combination of different soil moisture was measured before and after irrigation, provide the basis for future low-frequency GPR further application in soil science in use.

三、发明内容 III SUMMARY OF THE INVENTION

[0007] 发明目的:本发明针对上述现有土壤含水率测定方法中存在的不足,提供一种适用于农田和小流域的方便、快捷、准确、无破坏性的土壤含水量测定方法,该方法尤其适用于砂质土壤的含水率测定。 [0007] The purpose of the invention: The present invention is directed to less than the above existing soil moisture content determination method exists to provide a suitable farmland and small watershed convenient, fast, accurate, non-destructive soil moisture measurement method especially for sandy soil moisture content determination.

[0008] 技术方案:基于低频探地雷达地波法的测定砂质土壤含水量的方法,测定步骤为: 通过共中点法采集探地雷达数据,以确定空气波和地波走时:发射天线和接收天线按固定步长沿着测线向相反方向对称地移动,保持一个共中心点,其雷达记录为天线间距与雷达波的走时关系,获取能清晰分离出空气波和地波的不同天线间距X对应的空气波走时tAW和地波走时tew,回归获取tAW〜χ和tew〜χ关系式;以固定间距法采集土壤剖面的雷达波信息:保持探地雷达发射天线和接收天线的间距不变,按固定步长沿着测线方向同时移动的获取雷达图像的测定方法,其雷达图像记录为测线与雷达波走时关系,根据tAW〜χ和tew〜 X关系式计算出固定间距最佳天线间距时的tAW和tew ;土壤介电常数的计算:将参数代入公 [0008] Technical Solution: Determination of sandy soils low-frequency GPR ground wave method based on moisture content, measured steps: by co midpoint GPR data were collected to determine the air waves and ground-wave travel: the transmitting antenna and receiving antenna fixed step size symmetrically move in the opposite direction along the survey line, keeping a common central point, which is recorded as radar antenna walking distance relationship with radar, can get a clear separation of the air waves and waves of different antennas to When walking distance air wave and ground wave tAW go tew X corresponding regression get tAW~χ and tew~χ relationship; a fixed spacing were collected soil profile radar information: Keep GPR transmit and receive antennas are spaced not change, at the same time get a fixed step size along the survey line determination of the direction of movement of radar images, radar images which are recorded as measured at the line and take the relationship radar, according to tAW~χ and tew~ X fixed relationship to calculate the optimal spacing tAW and tew antenna spacing; the soil dielectric constant is calculated: the parameters into the public

(c\2 (c(t -t UxY (C \ 2 (c (t -t UxY

式得土壤的介电常数 Soil type was permittivity

其中地波速率V、地波走时tew、空气 Which when ground wave velocity V, to wave away tew, air

、vj Iv X J, , Vj Iv X J,

波走时tAW、天线间距X、C为电磁波在真空中的速度0. 3m .ns-1 ;土壤含水量的计算:将计算得到的土壤介电常数ε 代入θ = -5. 3Χ 1(Γ2+2 92Χ 1(Γ2 ε -5. 5Χ 1(Γ4 ε 2+4. 3Χ 1(Γ6 ε 3,得 Wave travel time tAW, antenna spacing X, C is the speed of electromagnetic waves in a vacuum 0. 3m .ns-1; soil moisture content is calculated: the calculated soil permittivity ε substitution θ = -5 3Χ 1 (Γ2 +. 2 92Χ 1 (Γ2 ε -5. 5Χ 1 (Γ4 ε 2 + 4. 3Χ 1 (Γ6 ε 3, too

土壤含水量。 Soil moisture.

[0009] 共中点法确定空气波和地波走时的具体步骤为:测线长选择15m至20m,发射和接收天线的起始位置在测线中点南北各IOcm处,起始间距20cm,采集步长20cm,即两个天线每次各沿测线向外移动10cm。 [0009] A total midpoint method to determine the specific steps the air waves and ground-wave travel time is: select measuring 15m long line to 20m, transmitting and receiving antennas in the starting position of the survey line at the midpoint of the north and south IOcm starting spacing 20cm, acquisition step 20cm, ie every two antennas along each survey line moves outward 10cm.

[0010] 有益效果:方法中采用相对低频电磁波较之高频电磁波具有穿透能力增加,探测深度大等特点,研究层次较深和湿度高的土壤剖面的含水量具有优势。 [0010] beneficial effect: the use of a relatively low frequency electromagnetic method than with increased penetration of high-frequency electromagnetic waves, probing depth and other characteristics, research and high humidity levels deep soil moisture profile has advantages. 该方法将共中点法与固定间距法相结合来测定土壤含水量,省时省力;适用于农田和小流域的方便、快捷、准确、无破坏性的土壤含水量测定,并通过多条测线测定可以获得土壤剖面连续的含水量变化情况,即土壤含水量的三维分布情况,是对定点测定仪器的补充和扩展。 The method to determine total soil moisture midpoint method with a fixed pitch Combination, saving time and effort; apply to farmland and small watershed convenient, fast, accurate, non-destructive measurement of soil moisture, and by a number of survey lines Determination of the soil profile can be obtained continuous moisture content changes, namely the three-dimensional distribution of soil moisture content, and is a designated measurement instrument complement and extend. 另外,通过实验证明,在不同的含水量水平下,该方法都可以得到较为准确的测定结果。 In addition, experiments show that, at different levels of moisture content, which can get a more accurate measurement result.

四、附图说明 IV BRIEF DESCRIPTION

[0011] 图1天线间距-电磁波走时图; [0011] Figure 1 antenna spacing - electromagnetic waves travel time map;

[0012] 图2为砂质土壤初始㈧和灌水处理⑶的固定间距法测定图像(X = Im);其中图2-A为试验初始(未灌水)状态的土壤含水量基本一致,其探地雷达图像为水平直线;图2-B为灌水后,从测线5m处起,灌水区域由于含水量增大导致介电常数增大,从而导致地波的走时tew增大,探地雷达图像渐渐下凹。 Determination of fixed-pitch image [0012] FIG. 2 is a sandy soil and irrigation treatments initial viii ⑶ of (X = Im); Fig. 2-A which is basically the same initial test (not irrigation) soil moisture condition, its ground-penetrating Radar images horizontal line; Fig. 2-B after irrigation, starting at 5m from the survey line, irrigation area due to increased water content leads to the dielectric constant increases, leading to wave away when tew increases gradually GPR image concave.

五、具体实施方式 V. DETAILED DESCRIPTION

[0013] 实施例1 :[0014] 1、试验仪器 [0013] Example Example 1: [0014] 1, the test apparatus

[0015] 经过试验,50MHz的天线由于频率太低,不能检测到雷达地波信号,所以本方法采用天线频率为100MHz。 [0015] After testing, the antenna due to low frequency of 50MHz, the radar can not detect the ground-wave signal, the method in which the antenna frequency of 100MHz. 试验采用瑞典Mala GeoScience公司生产的RAMAC/GPR CUII通用主机系统采集数据,主要部件包括:两对频率分别为IOOMHz的非屏蔽接收和发射天线(通过光缆连接到主机)、IOOMHz的屏蔽天线、主机、电脑、光缆和其他配件。 Swedish Mala GeoScience test produced the RAMAC / GPR CUII generic host system to collect data, the main components include: two pairs of frequencies were IOOMHz unshielded receiving and transmitting antenna (connected to a host computer via cable), IOOMHz shielding antenna, the host, computers, cables and other accessories. 采集软件为RAMACGroundvision,图像滤波处理采用REFLEXW软件。 Acquisition software for RAMACGroundvision, image filtering using REFLEXW software.

[0016] 2、试验步骤 [0016] 2, Test Procedure

[0017] (1)通过共中点法采集探地雷达数据,以确定空气波和地波走时。 [0017] (1) ground-penetrating radar data collected by the co midpoint method to determine the air waves and the ground wave away. 即发射天线和接收天线按固定步长沿着测线向相反方向对称地移动,保持一个共中心点,其雷达记录为天线间距与雷达波的走时关系。 That transmit and receive antennas at a fixed step size along the survey line symmetrically move in the opposite direction, maintaining a common center point, its relationship to go for the record radar antenna spacing and radar. 测线长选择15m至20m,发射和接收天线的起始位置在测线中点南北各IOcm处,起始间距20cm,采集步长20cm,即两个天线每次各沿测线向外移动10cm。 15m to the survey line length selection 20m, transmitting and receiving antennas in the starting position of the survey line at the midpoint of the north and south IOcm, initial spacing 20cm, acquisition step 20cm, i.e. two per each antenna to move outwardly along the survey line 10cm .

[0018] (2)以固定间距法采集土壤剖面的雷达波信息。 [0018] (2) a fixed spacing were collected soil profile radar information. 固定间距法即保持探地雷达发射天线和接收天线的间距不变,按固定步长沿着测线方向同时移动的获取雷达图像的测定方法,其雷达图像记录为测线与雷达波走时关系。 Fixed spacing method which maintains the spacing of GPR transmit and receive antennas of the same, according to the fixed-step method for simultaneous determination to obtain radar images along the survey line direction, the radar image is recorded as measured at the line and take the relationship radar. 此处我们可以采用MALA公司的屏蔽天线(发射天线和接收天线间距为Im),可以方便地获取测线处的雷达信息。 Here we can use MALA's shielded antenna (transmit and receive antennas spacing Im), you can easily get information about the survey line at the radar. 采用固定间距法以20cm步长探测整条测线。 Fixed spacing 20cm step detection method to measure the entire line.

[0019] (3)探地雷达图像处理与解译。 [0019] (3) ground penetrating radar image processing and interpretation.

[0020] 原始的雷达图像需经过处理才能进行图像的判读、解译及目标体识别,从而获得更精确的目标信息。 [0020] The original image need to be treated before the radar image interpretation, interpretation and recognition target body, thereby obtaining a more precise target information. 采用ReflexW4.0软件进行预处理,基本步骤为:①去直流漂移;②静校正;③增益;④抽取平均道;⑤巴特沃斯带通滤波;⑥滑动平均。 ReflexW4.0 pretreatment using software, the basic steps are: ① to DC drift; ② statics; ③ gain; ④ average extraction Road; ⑤ Butterworth band-pass filter; ⑥ moving average.

[0021] (4) 土壤含水量的计算 [0021] (4) The calculation of soil moisture

[0022] 雷达波在土壤中的传播速度主要由土壤的相对磁导率和介电常数决定,由于在大多数土壤(低盐)的相对磁导率近似为1,地波速率主要受土壤的介电常数控制,通过空气波和地波的走时差可以计算出地波的速度V,从而得到土壤的介电常数: [0022] The radar wave propagation velocity in the soil primarily determined by the dielectric constant and the relative permeability of the soil, due to the relative magnetic permeability in most soils (salt) is approximately 1, the main ground-wave velocity of the soil by dielectric constant control, through the air waves and ground-wave residuals can be calculated to wave velocity V, resulting in the dielectric constant of the soil:

[0023] [0023]

[0024] 公式(1)中,c为电磁波在真空中的速度(0. 3m ns-1)。 [0024] Equation (1), c is the speed of electromagnetic waves in a vacuum (0. 3m ns-1). 地波走时tew、空气波走时tAW、天线间距χ可通过REFLEXW4. 0软件读取。 When the ground wave go tew, when the air waves go tAW, antenna spacing χ by REFLEXW4. 0 software to read.

[0025] 本研究中首先采用共中点法获得探地雷达图像,获取能清晰分离出空气波和地波的不同天线间距(X)对应的空气波走时(tAW)和地波走时(tffl),回归获取tAW〜χ和〜 χ关系式。 [0025] In this study, first by co midpoint get GPR images, access can be clearly separated from the different antennas spaced air waves and ground-wave (X) when the corresponding air wave travel time (tAW) and ground wave away (tffl) return to get tAW~χ and ~ χ relationship. 再根据tAW〜χ和tew〜χ关系式计算出屏蔽天线最佳间距时的tAW和tew,然后, 反推得出土壤的介电常数。 Then calculated based on the relationship tAW~χ and tew~χ tAW and tew shielded antenna optimum spacing, and then come to the soil dielectric constant thrust reversers. 土壤的介电常数和含水量紧密相关,证实可以通过测定土壤介电常数,再利用θ〜ε关系式精确地计算土壤体积含水量。 Soil moisture is closely related to the dielectric constant and confirmed by measuring the dielectric constant of the soil, and then use θ~ε relationship accurately calculate soil volumetric water content. 并提出了如下的经验关系式: And proposed the following empirical relationship:

[0026] θ = -5. 3 X 1(Γ2+2 92 X 1(Γ2 ε -5. 5 X 1(Γ4 ε 2+4. 3 X 1(Γ6 ε 3 (2) [0026] θ = -5. 3 X 1 (Γ2 + 2 92 X 1 (Γ2 ε -5. 5 X 1 (Γ4 ε 2 + 4. 3 X 1 (Γ6 ε 3 (2)

[0027] 由公式(1)、(2),可得土壤含水量。 [0027] by the formula (1), (2), available soil moisture.

[0028] 3、该方法测定土壤含水量精度 [0028] 3, the method for determining the accuracy of soil moisture

[0029] 为验证探地雷达对土壤含水量的预测结果,在黄淮海平原豫北封丘地区进行验 [0029] In order to verify the results of ground-penetrating radar to predict soil moisture in the North China Plain region North of Fengqiu test

5证,该地区土壤多为在黄河沉积物上发育的潮土。 5 cards, the soil in the area, mostly in the Yellow River Sediments Chao soil. 试砂质土壤层厚1. 5m以上,粘粒含量4. 59%,粉粒含量1. 69%,砂粒含量93. 72%,地表无植被覆盖。 1. 5m thick sandy soil test above 4.59% clay content, silt content of 1.69%, 93.72% sand content, surface without vegetation cover. 砂壤土层厚Im以上,粘粒含量12. 96%,粉粒含量10. 17%,砂粒含量75. 75%,地表l_2cm处有少量植被覆盖。 Im thick sandy loam over clay content of 12.96%, 10.17% silt, sand content of 75.75%, a small amount of surface vegetation cover l_2cm place. 试验中在测线一侧Im处开挖长1. 5m、深1. 5m的剖面,在剖面上选择距地表10cm、40cm、70cm、 100cm和130cm5个深度,在每个深度上随机选取5个点用TDR100便携式土壤水分测定仪测定土壤含水量。 Test Im in the survey line at the long side of the excavation 1. 5m, 1. 5m deep cross section in profile selection Jude Biao 10cm, 40cm, 70cm, 100cm and 130cm5 depths, each depth in the randomly selected five point with TDR100 portable soil moisture analyzer measurement of soil water content.

[0030] 共中点法_固定间距法测定砂质土壤含水量 [0030] Determination of sandy soil moisture midpoint _ Total fixed spacing method

[0031] 首先采用共中点法获得探地雷达图像,获取几个能清晰分离出空气波和地波的不同天线间距对应的地波和空气波走时,如图3所示。 [0031] First, using the midpoint method to obtain a total of GPR images, access can be clearly separated from several different antenna spacing air waves and ground wave corresponding to the wave and air wave travel time, shown in Figure 3. 共中点法测定雷达图像中地波和空气波均为天线间距χ和走时t的线性关系,回归获取tAW〜χ和〜χ关系式。 Determination of total midpoint ground wave radar images and air wave antennas are walking distance χ and t linear relationship, regression to obtain tAW~χ and ~χ relationship.

[0032] tAW = 3. 71*χ+0 60,R2 = 0. 997 (3) [0032] tAW = 3. 71 * χ + 0 60, R2 = 0. 997 (3)

[0033] tGW = 6. 97*χ+1 70,R2 = 0. 996 (4) [0033] tGW = 6. 97 * χ + 1 70, R2 = 0. 996 (4)

[0034] 根据(3)式,当天线间距χ = Im时,空气波走时tAW = 4. 31ns。 [0034] According to (3), when the antenna spacing χ = Im, the air waves go tAW = 4. 31ns.

[0035] 在测线5_9m处布置灌水区域后,采用固定间距法探测整条测线,天线间距设置为Im0试验初始(未灌水)状态的土壤含水量基本一致,其探地雷达图像为水平直线,探地雷达图像如图4(左)所示。 [0035] In the post-test line 5_9m irrigation area of the layout, with fixed pitch method to probe the entire survey lines, antenna spacing is set to Im0 initial test (not irrigation) consistent soil moisture status, its GPR image for horizontal line GPR image shown in Figure 4 (left). 灌水后,从测线5m处起,灌水区域由于含水量增大导致介电常数增大,从而导致地波走时tew增大,探地雷达图像渐渐下凹,如图4(右),随着发射天线和接收天线都进入灌水区域,双程走时逐渐稳定。 After irrigation, starting at 5m from the survey line, the irrigation area due to increased water content leads to the dielectric constant increases, resulting in increased time to wave away tew, ground penetrating radar image gradually concave, as shown in Figure 4 (right), along with transmit and receive antennas are entering the irrigation area, gradually stabilized TWT. 由于空气波走时tAW不受土壤含水量变化的影响而保持不变,因此根据固定的天线间距χ与空气波走时tAW,并采用REFLEXW软件读取灌水区域相应的地波走时tew,由公式(1)、(2)计算出土壤含水量。 Because tAW unaffected by changes in soil moisture and air waves go unchanged, therefore, according to fixed antenna spacing χ air waves go tAW, and the use of irrigation area REFLEXW software reads the appropriate time to wave away tew, by equation (1 ), (2) to calculate soil moisture.

[0036] 表1共中点-固定间距法测定灌水前后砂质土壤含水量 [0036] Table 1 Total midpoint - Fixed spacing determination sandy soil moisture before watering

[0037] [0037]

[0038] 表1为共中点法_固定间距法测定的灌水前后砂质土壤含水量。 [0038] Table 1 shows the total distance between the midpoint method _ fixed determination of sandy soil moisture before watering. 由表1可以看出,未灌水条件下,共中点法_固定间距法测得砂质土壤剖面平均含水量在天线间距Im时为6. 5%,TDR测得0-50cm深度处砂质土壤剖面平均含水量为6. 3%。 As can be seen from Table 1, no irrigation conditions, the total distance between the midpoint method _ fixed sandy soil profiles measured by the average water content in the antenna spacing Im was 6. 5%, TDR measured at a depth of 0-50cm sandy The average moisture content of the soil profile was 6.3%. 因此在未灌水条件下,共中点法-固定间距法的测值与TDR测值相比,绝对误差分别为0. 2%。 Therefore, under irrigation conditions are not total midpoint method - measuring the value of a fixed pitch method compared with the TDR measurement values, the absolute error of 0.2 percent. 灌水条件下, 共中点法-固定间距法测得砂质土壤剖面平均含水量在天线间距Im时为20. 2%,TDR测得0-50cm深度处的砂质土壤剖面平均含水量为19.7%。 Under irrigation conditions were midpoint method - Fixed spacing method was measured sandy average moisture content in the soil profile when Im antenna spacing of 20.2%, sandy soil profile TDR measured at a depth of 0-50cm average moisture content of 19.7 %. 因此在灌水条件下,共中点法-固定间距法的测值与TDR测值相比,绝对误差分别为0. 5%。 Therefore, under irrigation conditions were midpoint method - measuring the value of a fixed pitch method compared with the TDR measurement values, the absolute error of 0.5 percent.

[0039] 结果表明,在不同的含水量条件下,共中点法-固定间距法测得含水量结果都较为精确,可以用于砂质土壤的含水量监测。 [0039] The results show that under different moisture conditions were the midpoint method - Fixed spacing measured by water content results are more accurate and can be used to monitor the sandy soil moisture.

[0040] 通过获取共中点法图像中能清晰分离出空气波和地波的不同天线间距对应的tAW 和tew,回归获取tAW〜X和tew〜X关系式,再计算出屏蔽天线间距Im时的tAW和,兼顾了固定间距法和共中点法法的最佳天线间距,与直接由共中点法最佳天线间距3m进行的固定间距法测量相比,结果更精确。 By the midpoint method to obtain a total image can be clearly separated when different antenna spacing air waves and ground waves corresponding tAW and tew, return to get tAW~X and tew~X relationship, and then calculate the shielding antenna spacing Im [0040] The tAW and, taking into account the best antenna fixed spacing method and co midpoint spacing method, compared with the direct distance from the midpoint of the law altogether make the best antenna 3m fixed spacing measurement, results are more accurate. 值得一提的是,目前对于探地雷达探测深度的精确确定仍然是一个难题,还需要展开大量的基础性研究工作。 It is worth mentioning that the current ground-penetrating radar to accurately determine the depth is still a problem, you need to start a lot of basic research.

[0041] 4、该方法的应用 [0041] 4. The application of the method

[0042] 1、本方法适于测定砂质土壤含水量,而对于其他质地土壤由于雷达波衰减严重, 测定结果尚需改进; [0042] 1, this method is suitable for the determination of sandy soil moisture, soil texture and other severe attenuation due to the radar measurement results still need to improve;

[0043] 2、适于质地较均一的土壤; [0043] 2, suitable for homogeneous soil texture;

[0044] 3、可以用于土壤剖面的土壤含水量监测; [0044] 3, can be used to monitor soil moisture content in soil profile;

[0045] 4、可以用于研究土壤含水量的空间变异情况。 [0045] 4, can be used to study the spatial variability of soil moisture conditions.

[0046] 实施例2 : [0046] Example 2:

[0047] 基于低频探地雷达地波法的测定砂质土壤含水量的方法,测定步骤为:通过共中点法采集探地雷达数据,以确定空气波和地波走时:发射天线和接收天线按固定步长沿着测线向相反方向对称地移动,保持一个共中心点,其雷达记录为天线间距与雷达波的走时关系,获取能清晰分离出空气波和地波的不同天线间距X对应的空气波走时tAW和地波走时tGff,回归获取tAW〜χ和〜χ关系式;以固定间距法采集土壤剖面的雷达波信息:保持探地雷达发射天线和接收天线的间距不变,按固定步长沿着测线方向同时移动的获取雷达图像的测定方法,其雷达图像记录为测线与雷达波走时关系,根据tAW〜X和〜X关系式计算出固定间距最佳天线间距时的tAW和; 土壤介电常数的计算:将参数代入公式得土 [0047] Determination of sandy soils low-frequency GPR ground wave method based on moisture content, measured steps: by co midpoint GPR data were collected to determine the air waves and ground-wave travel: transmitting and receiving antennas fixed step size symmetrically along the survey line moving in the opposite direction, keeping a common central point, which is recorded as the relationship between the travel radar antenna and radar pitch, access can be clearly separated from the different waves of air and ground wave antenna spacing corresponding X When the air waves and ground waves go away tAW tGff, return to get tAW~χ and ~χ relationship; a fixed spacing were collected soil profile radar information: Keep spacing GPR transmit and receive antennas of the same, according to fixed At the same time obtaining step along the survey line direction measurement method radar images, radar images which are recorded as measured at the line and take the relationship radar calculates optimum spacing tAW fixed antenna spacing according tAW~X and ~X relationship and; soil dielectric constant is calculated: the parameters into the formula Tetouan

壤的介电常数 Dielectric constant of the soil's

其中地波速率V、地波走时tew、空气波走时 Which when ground wave velocity V, to wave away tew, air-wave travel time

tAW、天线间距X、C为电磁波在真空中的速度0. 3m ns-1 ;土壤含水量的计算:将计算得到的土壤介电常数ε 代入θ = -5. 3Χ 1(Γ2+2 92Χ 1(Γ2 ε -5. 5Χ 1(Γ4 ε 2+4. 3Χ 1(Γ6 ε 3,得土壤含水量。其中,上述共中点法确定空气波和地波走时的具体步骤为:测线长选择15m至20m, 发射和接收天线的起始位置在测线中点南北各IOcm处,起始间距20cm,采集步长20cm,即两个天线每次各沿测线向外移动10cm。 tAW, antenna spacing X, C is the speed of electromagnetic wave in vacuum 0. 3m ns-1; soil water content calculation: The calculated dielectric constant ε soil substituting θ = -5 3Χ 1 (Γ2 + 2 .. 92Χ 1 (Γ2 ε -5 5Χ 1 (Γ4 ε 2 + 4 3Χ 1 (Γ6 ε 3, where soil moisture was above the midpoint method to determine the specific steps total air waves and ground-wave travel time is: measuring line length selection 15m to 20m, the transmitting and receiving antennas in the starting position of the survey line at the midpoint of the north and south IOcm, initial spacing 20cm, acquisition step 20cm, i.e. two per each antenna moves outward along the survey line 10cm.

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