SPA Snow Characteristics Analysis System

system function

The Snow Pack Analyzing System (SPA) developed by Sommer Corporation is a unique snow water featuremonitorThe system can continuously monitor snow water equivalent, snow density, snow depth, and ice and water content in snow.The SPA system consists of SPA sensors (also known as SWS, Snow Water Sensor), impedance analysis boxes, and snow depth sensors.

Working principle

Snow Depth

The principle of measuring sensors,correctCalculate the snow depth between the sensor and the snow surface based on the transmission time of ultrasonic waves. The impact of temperature on measurement is addressed through automatic temperature compensation.

SPA is suitable for long-term in-situ observation and has strict requirements for installation sites. The shape of the sensor is flat and linear. By measuring the dielectric constants of ice, water, and air in the snow layer, the snow water equivalent, average snow density, and liquid water content can be obtained. The theoretical basis is that the dielectric constants of snow, water, and air are different at high frequencies (10KHz or higher).

permittivity measurement

The composition of snow consists of three parts, including ice、Water and air. differentcomponentIt will produce different measurement effects, and these different substances have different dielectric constants. Using a flat strip sensor（SPA sensor) and use at least two frequency bands to eliminate the effects caused by individual substances.

Liquid water content、Ice content、Snow density and snow water equivalent

In snow, the specific volume is equivalent to the content of liquid water and ice. Based on this information, we can calculate the density of snow. Based on the comprehensive snow density and snow depth, we can define the snow water equivalent.

system configuration

singleSPA sensor measurement

This plan only includes a single oneSPA sensor. The main pole is used to fix the chassis（data collector）Deep snowImpedance analysis box of SPA system, and then sensor stretchingpoleInstalled around the main pole. The length of the sensor is5 meters, snow depth fixed on the cross arm of the main pole，giveSPA sensor combined with observation. This system can measure

lSnow Depth

lsnow water equivalent

lAverage snowfall density

lAverage liquid water content

fourSPA sensor measurement

This plan adds three more sensors on the basis of the single sensor version mentioned aboveSPA sensor. The two horizontally installed sensors are used to measure snow density and snow water equivalent at different depths, which can also obtain the density profile of snow; The two sensors installed in a slope can measure a larger area, making the observation more representative. So this version of the system can measure the following elements:

1. Snow Depth

2. Average snowfall density

3. Snow density profile

4. snow water equivalent

5. Average liquid water content

6. Liquid water content profile

SPA can continuously monitor the liquid water content in the snow layer, which is a unique feature. During the snowmelt (ice) period, such as spring, when liquid water overflows or is about to overflow from the snow, SPA can monitor this state and provide a warning of this critical state, thereby providing good forecasting basis for disasters such as avalanches, ice melting, and floods. In addition, in some hydropower companies and government flood control departments, it is necessary to closely monitor water resources, collect water, and estimate the amount of snowmelt.Through these measurement feedbacks, floods can be prevented. In the fields of agriculture and mining, the impact of water infiltration into soil or underground caused by snowmelt can be eliminated.

The liquid water content in snow, as well as the melting water content and saturation, can all be determinedestimateCome out. Now, we canThe SPA system measures these parameters. Therefore, the system can provide very important updated information for hydrological design. In addition, this information is also very important for snow melting models, compared to some remote telemetry data. SPA can be controlled on the ground to complete calibration. Snow density and liquid water content in snow are important for assessing the risk of avalanches caused by wet snow，These are all very important parameters,SPA can help improve the data quality and density of measurement units, therefore, the system can increase the safety of people living in mountainous areas and scattered areas.

No ice layer impact

In snow, snow pillows usually have some problems due to the ice layer. This phenomenon is caused by the melting of snow and the repeated freezing of ice layers in the area, which will have a certain impact on the measurement results. The SPA system will not have such an impact due to ice layers.

The SPA system can install up to four SPA sensors, and the specific number of installations depends on the user's needs. Sensors can have a certain inclination or be kept level with the snow field. These different possible installation methods can optimize the requirement information, includingbelowThree installation methods:

1: Integrated installation method

This installation method consists of a tilted SPA sensor and a horizontal SPA sensor. The density of snow, snow water equivalent, and the content of ice and liquid water constitute the complete material content in snow, which can be measured by tilted sensors, and horizontal sensors can provide additional measurement information, such as the tightness of snow to the ground.

2: Sectional installation method

The SPA sensor is installed in a horizontal position, which can increase the measurement of snow profile density and liquid water content. By using this method, possible moving snowmelt conditions can be measured and a snow density profile can be generated.

3: Area installation method

Multiple SPA sensors can be installed in a star shape, and the measured values of the sensors can be averaged to provide a three-dimensional range condition, and remote telemetry data can also be calibrated.

system composition

Technical Parameter

data display

references

1. Zhang Wei, Shen Yongping, He Jianqiao, He Bin, Nurlan Hazezi, Xue Jiao, Wang Guoya 'Observation and analysis of snow characteristics in different underlying areas during snowmelt period in Mount Taishan Glacier and Frozen Soil, Issue 03, 2014

2. Zhang Bo; Liu Zhihui; Wang Hui; Fang Shifeng;; Analysis of snowmelt water infiltration and simulation of infiltration rate during snowmelt period [J]; Anhui Agricultural Science; Issue 24, 2013

3. Tian Hua; Yang Xiaodan; Zhang Guoping; Zhao Lina;;Analysis of Meteorological Causes of Snowmelt Floods in Xinjiang in Mid March 2009[A]; Proceedings of the 2010 Academic Annual Meeting of the Chinese Water Conservancy Society (Volume 1) [C]; 2010

4. Choi G, Robinson D, Kang S.Changing northern hemisphere snow seasons[J]. Journal of Climate, 2010, 23(19): 5 305-5 310.

5. [Wang Jian, Li Shuo. The impact of climate change on snowmelt runoff in mountainous areas of inland arid regions in China [J]. Chinese Science: Volume D, 2005, 35 (7): 664-670.]