Feasibility of irrigation monitoring with cosmic-ray neutron sensors

IF 1.8 4区地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY

Geoscientific Instrumentation Methods and Data Systems Pub Date : 2022-12-14 DOI:10.5194/gi-11-451-2022

C. Brogi, H. Bogena, M. Köhli, J. Huisman, H. Hendricks Franssen, Olga Dombrowski

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引用次数: 2

Abstract

Abstract. Accurate soil moisture (SM) monitoring is key in irrigation as it can greatly improve water use efficiency. Recently, cosmic-ray neutron sensors (CRNSs) have been recognized as a promising tool in SM monitoring due to their large footprint of several hectares. CRNSs also have great potential for irrigation applications, but few studies have investigated whether irrigation monitoring with CRNSs is feasible, especially for irrigated fields with a size smaller than the CRNS footprint. Therefore, the aim of this study is to use Monte Carlo simulations to investigate the feasibility of monitoring irrigation with CRNSs. This was achieved by simulating irrigation scenarios with different field dimensions (from 0.5 to 8 ha) and SM variations between 0.05 and 0.50 cm3 cm−3. Moreover, the energy-dependent response functions of eight moderators with different high-density polyethylene (HDPE) thickness or additional gadolinium thermal shielding were investigated. It was found that a considerable part of the neutrons that contribute to the CRNS footprint can originate outside an irrigated field, which is a challenge for irrigation monitoring with CRNSs. The use of thin HDPE moderators (e.g. 5 mm) generally resulted in a smaller footprint and thus stronger contributions from the irrigated area. However, a thicker 25 mm HDPE moderator with gadolinium shielding improved SM monitoring in irrigated fields due to a higher sensitivity of neutron counts with changing SM. This moderator and shielding set-up provided the highest chance of detecting irrigation events, especially when the initial SM was relatively low. However, variations in SM outside a 0.5 or 1 ha irrigated field (e.g. due to irrigation of neighbouring fields) can affect the count rate more than SM variations due to irrigation. This suggests the importance of retrieving SM data from the surrounding of a target field to obtain more meaningful information for supporting irrigation management, especially for small irrigated fields.

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宇宙射线中子传感器监测灌溉的可行性

摘要精确的土壤水分监测是灌溉的关键，因为它可以极大地提高水分利用效率。最近，宇宙线中子传感器（CRNSs）由于其占地面积大，已被认为是SM监测中一种很有前途的工具。CRNS在灌溉应用方面也有很大的潜力，但很少有研究调查使用CRNS进行灌溉监测是否可行，特别是对于面积小于CRNS足迹的灌溉田。因此，本研究的目的是使用蒙特卡罗模拟来研究使用CRNS监测灌溉的可行性。这是通过模拟不同田地尺寸（从0.5到8 ha）和SM在0.05和0.50之间的变化 cm3 cm−3。此外，研究了不同高密度聚乙烯（HDPE）厚度或添加钆热屏蔽的八种调节剂的能量依赖性响应函数。研究发现，造成CRNS足迹的中子中有相当一部分起源于灌溉田外，这对CRNS的灌溉监测是一个挑战。使用薄HDPE调节剂（例如5 mm）通常导致较小的占地面积，因此灌溉面积的贡献更大。然而，较厚的25 具有钆屏蔽的mm HDPE慢化剂改善了灌溉田地中的SM监测，因为随着SM的变化，中子计数具有较高的敏感性。这种慢化剂和屏蔽设置提供了检测灌溉事件的最高机会，尤其是当初始SM相对较低时。然而，SM的变化超出0.5或1 公顷灌溉田（例如，由于邻近农田的灌溉）对计数率的影响大于灌溉引起的SM变化。这表明了从目标农田周围检索SM数据的重要性，以获得更有意义的信息来支持灌溉管理，特别是对于小型灌溉农田。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Geoscientific Instrumentation Methods and Data Systems GEOSCIENCES, MULTIDISCIPLINARYMETEOROLOGY-METEOROLOGY & ATMOSPHERIC SCIENCES

CiteScore

3.70

自引率

0.00%

发文量

审稿时长

37 weeks

期刊介绍： Geoscientific Instrumentation, Methods and Data Systems (GI) is an open-access interdisciplinary electronic journal for swift publication of original articles and short communications in the area of geoscientific instruments. It covers three main areas: (i) atmospheric and geospace sciences, (ii) earth science, and (iii) ocean science. A unique feature of the journal is the emphasis on synergy between science and technology that facilitates advances in GI. These advances include but are not limited to the following: concepts, design, and description of instrumentation and data systems; retrieval techniques of scientific products from measurements; calibration and data quality assessment; uncertainty in measurements; newly developed and planned research platforms and community instrumentation capabilities; major national and international field campaigns and observational research programs; new observational strategies to address societal needs in areas such as monitoring climate change and preventing natural disasters; networking of instruments for enhancing high temporal and spatial resolution of observations. GI has an innovative two-stage publication process involving the scientific discussion forum Geoscientific Instrumentation, Methods and Data Systems Discussions (GID), which has been designed to do the following: foster scientific discussion; maximize the effectiveness and transparency of scientific quality assurance; enable rapid publication; make scientific publications freely accessible.