Using Double-Frequency Ground Penetrating Radar To Measure Ice Accumulation

In cold regions, ice accumulation often affects navigation, flood control, water supply, power generation, and other human activities. Under extreme conditions, it can also result in an ice flood. Examples of ice breakup and ice sheet in Heilongjiang River are shown in Figures 1 and 2.

Therefore, in situ measurements of the ice conditions of rivers, lakes, canals, and reservoirs are important to mitigate and prevent ice disasters.

Figure 1: Beiji village, Heilongjiang River, China, where an ice breakup occurred. Credit: Hui Fu

Ice thickness and water depth are important parameters of such observations, and their measurement methods can be generally divided into two types: contact and non-contact measurements. Contact measurements include traditional drilling and the use of resistance heating line and pressure sensors. The non-contact measurement methods include sonar; remote sensing by satellite, airborne and ground-based radar; and ground penetrating radar (GPR).

There has been continuous improvement of the GPR measurement method in recent years, with the technology offering the advantages of compactness, low cost, and high efficiency. The GPR can also be dragged over long distances for ice condition measurements, so the GPR method is very suitable for ice measurement.

The principle of GPR is that high-frequency short-pulse electromagnetic waves are transmitted into the ice from the transmitting antenna of the radar system placed on the ground; the waves encounter underground formations or targets of differing electrical properties and are reflected back to the ground surface where they are received by the receiving antenna of the radar system (Figure 3). The dielectric constant of air is 1, that of water is about 80, that of ice is 3ā€“4, and that of sandstone (silt) is 5ā€“30. The differences among the dielectric properties of air, ice, water, and sandstone enable detection of layers between two materials with different dielectric permittivities using a GPR.

Figure 3: Basic principle of the use of a GPR to measure ice thickness and water depth. Credit: Xinlei Guo

In addition to ice thickness, the corresponding water depth of the measuring site is also needed because ice thickness is only one of the causes of ice jams or ice dams. For example, if the water depth is high enough, the ice can be transported easily in the river, so thicker ice does not always cause an ice jam or dam.

Although GPR systems are widely used for the measurement of ice thickness and water depth, the current single-frequency GPR is incapable of accurate simultaneous measurement of ice thickness and water depth. Of course, the water depth can be measured in the summer, but when you measure the ice thickness in the winter with a single-frequency GPR, it is hard to follow the same measurement route. In view of the shortcomings of the use of single-frequency ground penetrating radar (GPR) for simultaneous measurement of ice thickness and water depth, a double-frequency GPR with 100 and 1500 MHz antennas was developed (Figure 4).

Figure 4: In situ measurement of double-frequency GPR in Mohe County section of the Heilongjiang River. Credit: Xinlei Guo

The advantage of double-frequency GPR is the simultaneous collection of ice thickness and water depth data. It also improves the efficiency of the observation process and can be seamlessly integrated with a GIS system for enhanced prediction and response to ice disasters. Through a time-sharing process, the system uses frequencies of 100 and 1500 MHz to measure water depth and ice thickness, respectively. The example of a measurement result is shown in Figure 5.

Figure 5: Measured ice thickness and water depth in the Longdao Wharf section of the Heilongjiang River, April 2016. The air temperature was about -10 Ā°C, most reaches had snow on top. Credit: Hui Fu

Analysis of the data collected by the developed double-frequency GPR revealed that some factors that affected its ice thickness and water depth measurement accuracies were as follows. 1) The complex process of ice jamming produces ice jams with differing multilayered structures containing randomly distributed porosities. This alters the materialā€™s dielectric constant, which is the basis of the measurement principle of the radar system. 2) Ice in a sandy river contains varying masses of sediment, with additional sediment transported by the water at the bottom of the river. This is one of the factors that influence the dielectric constants of the water and ice, and, hence, the measurement accuracy of GPR.

These findings are described in the article entitled Double-frequency ground penetrating radar for measurement of ice thickness and water depth in rivers and canals: Development, verification and application, recently published in the journal Cold Regions Science and Technology. This work was conducted by Hui Fu, Zhiping Liu, Xinlei Guo from the China Institute of Water Resources and Hydropower Research, and Haitao Cui from Dalian Zhongrui Science and Technology Development Company.

About The Author

Hui Fu

Hui is a research scientist with the China Institute of Water Research.

Speak Your Mind!


A Qualitative Study Of Electricity And Decarbonisation Challenges In The Nordic RegionĀ 

The Nordic countries ā€” Denmark, Finland, Iceland, Norway, and Sweden ā€” have aggressive climate and energy policies in place and have already emerged as leaders in renewable energy and energy efficiency. Although renewable sources of energy already comprise a substantial role in the regionā€™s electricity portfolio, their utilization is expected to grow rapidly between 2016 […]

Chemistry Throughout History: Fragmented And Funny Facts

The history of chemistry originated in the accidental discovery of gold. Throughout history, queens and kings desired gold and sought after it. This gave rise to alchemy in the middle ages; the sole dream of the alchemists was to transform ordinary metals into gold. There was a belief that the ā€˜Philosopherā€™s stoneā€™ could turn any […]

Unanswered Questions Surrounding Nitrogen Oxide

About four billion and several million years ago, the earth was born from the infinitesimal particles floating in a rotating cloud of hydrogen and helium. From the beginning of its life, the earth could not maintain the atmosphere around its volume because it lacked its current polarity. The appearance of charged metals in the lithosphere […]

Positive Vs. Negative Feedback Mechanisms

Positive and negative feedback mechanisms refer to any process that regulates the value of one variable in the face of another variable, thus increasing or decreasing the change in the value of the initial variable. In biology, feedback mechanisms are related to an organism maintainingĀ homeostasis. Homeostasis refers to the tendency of an organism to regulate […]

When Rock Meets Life

It all started in 2005 during a trip to the United States, where I went to a famous conference in geochemistry (Goldschmidt Conference, Moscow, Idaho). The following weeks I crossed the Rocky Mountains and visited many national parks, including Yellowstone Park. Of the many geological, geothermal, and volcanic curiosities in Yellowstone National Park, and outside […]

Post-weaning Diet In Archaeological Human Populations

There are two unique evolutionary characteristics in human childhood. First, human children take a longer time to acquire the physical and reproductive capacity of adults, compared with closely related primate species like the chimpanzee. Second, food provisioning from older individuals after the end of weaning is essential for the survival and health of human children. […]

Improvement Of Fatigue Prediction For Better Material Design

Fatigue represents the loss of a material’s performance (mainly mechanical properties) under constant cyclic, or periodic, loading. In general, researchers only investigate the number of cycles until a failure under constant conditions, which are frequency and applied load amplitude (stress or strain). Over the years, researchers have proposed several models to predict the number of […]