Observation experiment device and method for measuring evaporation process of earth surface deadwood falling object layer after rainfall

Abstract

The invention relates to an observation experiment device and method for measuring the evaporation process of an earth surface deadwood falling object layer after rainfall, the device comprises a litter layer bearing observation part, a water leakage measuring device, a mounting bracket and a data collector, the litter layer bearing observation part is used for measuring the water absorption interception amount of litters filled in an original state; the water leakage measuring device is used for measuring the water seepage amount of the litter layer, and the data acquisition device is used for respectively acquiring an interception amount signal and a water seepage amount signal. According to the method, the evapotranspiration amount of the surface litter layer in a certain time period and the rainfall interception amount of the surface litter layer can be obtained through measurement of the weight change of the litter layer and calculation of a balance formula, and the device provides powerful support for accurate calculation of forest land rainfall distribution and water balance analysis.

Description

Technical Field

[0001] The present invention relates to the field of forest land rainfall distribution and water balance analysis, and particularly to a method for measuring the evapotranspiration of the surface litter layer in forest land rainfall distribution and water balance analysis. Background Art

[0002] Forest litter interception means that when rainfall reaches the ground after being intercepted by the forest canopy and its underlying vegetation, a part of the rainwater is intercepted and absorbed by the litter layer and then enters the atmosphere through the evaporation process. The amount of intercepted water is called the litter layer interception amount. Surface litter interception is an important link in many physical processes such as runoff generation, sediment production, and chemical substance migration and transformation in the basin. Studying the interception effect of the surface litter layer and its evaporation process is of great significance for studying the impact of land use / cover type changes on the basin hydrological process.

[0003] Currently, the common observations of the litter layer interception amount include the following two types. First, it is the method of directly observing the rainfall interception amount of the litter. That is, a circular iron ring screen is stacked on the rain gauge arranged in the forest, and the original dead branches and leaves with the same thickness as that of the forest land are covered on the screen. The difference between the observed value of the rain gauge without dead branches and leaves and that with dead branches and leaves is the rainfall interception amount of the litter. However, this method completely separates the litter layer from the water connection with the soil layer, so the measured litter interception amount is difficult to reflect the real situation. Second, it is the water holding capacity measurement method. This type of method mainly measures the water holding capacity of the litter layer. The usual practice is to first collect the litter samples in the wild, air-dry (or bake) and weigh the samples in the laboratory, then soak them in water and weigh them again. The mass difference before and after soaking is the water holding capacity. This test can reflect the role of the litter in conserving water sources, but it cannot effectively explain the interception effect of the litter during the precipitation process, especially it cannot reflect its dynamic characteristics.

[0004] The rainfall interception amount of the surface litter usually includes the water adsorption amount of the surface litter and the evaporation amount on the litter surface. The above observation methods can only clarify the water interception capacity of the surface litter layer, but cannot express the change of its water flux, that is, there is no effective observation means for the evaporation process of the surface litter layer. Usually, it can only be generally summarized by the difference in the weight of the litter before and after water absorption, which has an impact on the accurate analysis of its water balance process. Summary of the Invention

[0005] In view of the above deficiencies in the background art and to accurately measure the evaporation amount of the surface litter layer, the present invention proposes a device and method for continuously observing the evapotranspiration of the surface litter layer. By continuously measuring the intercepted water amount and the leakage water amount of the litter layer, the evapotranspiration of the litter layer is calculated according to the water balance principle.

[0006] The technical solution adopted by the present invention to solve its technical problems is:

[0007] An observation experiment device for measuring the evaporation process of the surface litter layer after rainfall, comprising a litter layer bearing observation part, a seepage water measurer, a mounting bracket, and a data collector;

[0008] The mounting bracket is inserted into the observation pit, a weighing sensor is provided at the top of the mounting bracket, and the litter layer bearing observation part is suspended below the weighing sensor through a suspension wire;

[0009] The litter layer bearing observation part includes a stacked sleeve barrel at the upper part and a water collecting funnel at the lower part. The lower edge of the stacked sleeve barrel is connected to the upper edge of the water collecting funnel, and the radius of the lower edge of the stacked sleeve barrel is equal to the opening radius of the upper edge of the water collecting funnel; a filter screen is provided between the stacked sleeve barrel and the water collecting funnel; the stacked sleeve barrel is used for placing experimental litter, and the water collecting funnel is used for collecting seepage water that infiltrates during rainfall;

[0010] The seepage water measurer is arranged below the water collecting funnel; and is used for collecting the seepage water flowing out of the water collecting funnel;

[0011] The data collector is respectively connected to the seepage water measurer and the weighing sensor; and collects signals.

[0012] The mounting bracket includes at least three support rods, and the lower ends of the three support rods are inserted into the soil in the observation pit, and the upper ends are connected to a vertex.

[0013] The support rod is in an "inverted L" shape.

[0014] The height of the stacked sleeve barrel is adjustable, and it is formed by concentrically sleeving a plurality of annular enclosing plates, and the lower edge of each annular enclosing plate is clamped with the upper edge of its lower-layer annular enclosing plate.

[0015] At least three hoisting wire mooring rings are evenly arranged on the outer side of the upper edge of the water collecting funnel, for enabling one end of the suspension wire to pass through and be tightened.

[0016] A suspension hook is provided below the weighing sensor, for hanging the suspension wire.

[0017] The stacked sleeve barrel, the filter screen and the water collecting funnel are made of metal.

[0018] The seepage water measurer is a self-recording rain gauge.

[0019] An observation experiment method for measuring the evaporation process of the surface litter layer after rainfall, comprising:

[0020] Step 1: Assemble the experimental device for measuring the evaporation amount of the surface litter layer, dig out the observation pit and place the experimental device, and fill the experimental litter into the stacked sleeve barrel of the experimental device in its original state;

[0021] Step 2: Use a data collector to regularly collect the weight change of the stacked buckets of the experimental device after rainfall and the amount of infiltrated and leaked water collected in the water collection funnel. At the same time, observe the rainfall in the experimental site and calculate the surface evaporation E int (t) of the litter layer in the experimental site.

[0022] When placing the experimental device, make the upper edge of the stacked bucket at least 1 cm higher than the surface of the litter on the ground, and the lower edge flush with the surface of the litter on the ground. Adjust the suspension line to make the filter layer flush with the ground.

[0023] The present invention has the following beneficial effects and advantages:

[0024] 1. This invention will propose an observation experiment method for measuring the evaporation process of the surface litter layer after rainfall, which can achieve continuous observation during the subsequent evaporation process of the intercepted rainfall in the surface litter layer, clarify the dynamic changes of each observed quantity (such as the weight change of the litter layer and the infiltration water volume of the litter layer) during the evapotranspiration process of the surface litter layer at different time periods, and can more accurately observe the influence of the surface litter layer on rainfall interception. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic diagram of the principle for measuring the evapotranspiration amount of the surface litter layer of the present invention;

[0026] Figure 2 is a schematic diagram of the observation device for measuring the evaporation amount of surface dead branches and leaves of the present invention;

[0027] Figure 3 is a schematic diagram of the litter layer bearing observation part of the present invention;

[0028] Figure 4 is a schematic diagram of the support of the present invention;

[0029] In the figure, 1 is the litter layer bearing observation part, 2 is the infiltrated and leaked water detector, 3 is the installation support, 4 is the data collector, 5 is the ground surface, 6 is the observation pit, 11 is the stacked bucket, 12 is the hoisting wire mooring ring, 13 is the filter layer, 14 is the water collection funnel, 15 is the water outlet, 31 is the support rod, 32 is the weighing sensor, 33 is the suspension hook, 34 is the suspension wire, d1 is the diameter of the circular enclosing plate d1 = 50 cm; h1 is the height of the circular enclosing plate, h1 = 5 cm; h2 is the height of the water collection funnel, h2 = 20 cm. d2 is the width of the installation support d2 = 53 cm; h1' is the height of the upper arc of the support h1' = 20 cm; h2' is the height of the vertical part of the support h2' = 100 cm. DETAILED DESCRIPTION OF THE INVENTION

[0030] To make the above objects, features, and advantages of the present invention more apparent and understandable, the following further details the specific implementation methods of the present invention in conjunction with the accompanying drawings. Many specific details are set forth in the following description to facilitate a full understanding of the present invention, but the present invention can be implemented in many other ways different from those described herein. Those skilled in the art can make similar improvements without departing from the connotation of the invention. Therefore, the present invention is not limited by the specific implementations disclosed below.

[0031] First, obtain the rainfall amount (simulated or natural rainfall) entering the device. Then, by measuring the dynamic change in the weight of the litter layer in the device during rainfall and the change in the amount of water leaking through the litter layer to the lower layer during rainfall, and combining the above formula, calculate the evaporation amount of the litter layer during this time period.

[0032] The device of the present invention includes the following several parts, namely: the litter layer bearing and observing part 1, the seepage water detector 2, the data collector 4, and the installation bracket 3.

[0033] The main body of the litter layer bearing and observing part 1 includes a stacked sleeve barrel 11 in the upper part and a water collecting funnel 14 in the lower part. The stacked sleeve barrel 11 is composed of multiple layers of decomposable / combinable ring structures (ring-shaped enclosing plates 111). The ring-shaped enclosing plates 111 are made of thin iron sheets (thickness 1 mm), with a ring diameter of 50 cm and a ring height of 5 cm. Each ring-shaped enclosing plate 111 can be combined and connected or decomposed through the inner diameter change structure of the upper and lower edges (that is, the outer diameter of the upper edge expands slightly outward, and the inner diameter of the lower edge contracts slightly inward). During use, the original litter layer on the ground surface is moved into this stacked sleeve barrel 11, and the stacking layers of the stacked sleeve barrel 11 are adjusted according to the thickness of the litter layer to ensure that the overall depth inside the stacked sleeve barrel 11 is greater than the thickness of the litter layer. A filter screen 13 is installed at the bottom of the lowermost ring-shaped enclosing plate 111. The mesh material is metal wire, and the mesh grid specification is 1 mm, achieving the purpose that the litter does not leak while water can seep. A conical water collecting funnel 14 is installed under the lowermost ring-shaped enclosing plate 111. The funnel height is 20 cm, and the upper mouth diameter is 50 cm. The water leaking from the stacked sleeve barrel 11 can be collected by this water collecting funnel 14 and flow out through the lower end water outlet 15. The manufacturing material is thin iron sheet (thickness 1 mm), and the upper end is riveted and connected to the lowermost ring-shaped enclosing plate 111. The lower end of the device is the water outlet 15.

[0034] At least 3 hoisting wire mooring rings 12 are installed on the outer edge of the upper part of the main body of the litter layer bearing and observing part 1 for the tight installation of the suspension wire 34. During installation, the above-mentioned litter layer bearing and observing part 1 is connected to the suspension ring of the bracket through the suspension wire 34, and by adjusting the length of the suspension wire, the filter screen layer 13 of the lowermost ring-shaped enclosing plate of the device is made horizontal with the ground surface 5 of the observation pit 6 to ensure that the bottom of the litter layer is flush with the ground surface, so that the litter surface layer in the experimental device is horizontal and at the same height as the surrounding litter.

[0035] The seepage water detector 2 is a self-recording rain gauge. The upper end of the instrument corresponds to the water outlet 15 of the water collecting funnel 14 of the litter layer bearing observation part 1, collects the seepage water of the litter layer, and can regularly measure the collected water volume signal through the data collector 4. The acquisition time interval can be adjusted according to the experimental requirements.

[0036] The installation bracket 3 is welded by a support rod 31 with a diameter of 10 mm (the material is iron). The support rod 31 is in an "inverted L" shape. When there are two support iron rods 31, the appearance presents an inverted "U" shape. It is also possible to use three support rods 31 evenly arranged and welded at the top. The overall horizontal width of the installation bracket 3 is 53 cm and the length is 100 cm. When observing, first dig an observation pit 6 in the test site. The diameter of the pit is 55 cm and the depth is 80 cm. The support rod 31 of the installation bracket 3 is inserted closely into the pit wall and into the bottom soil of the pit. The arc-shaped upper part of the installation bracket 3 is above the ground surface. A suspension line is installed at the top of the installation bracket 3, and a weighing sensor 32 is connected to the suspension line.

[0037] Installation and Observation Methods

[0038] Excavation of the observation pit: Select a horizontal ground with a surface litter layer, and dig a test pit 6 according to the external dimensions of this device. The surface of the test pit 6 is cylindrical, and the depth is the height of the water collecting funnel 14 + the height of the self-recording rain gauge (the height of the water collecting funnel is 20 cm, and the height of the self-recording rain gauge is 40 cm), that is, the depth of the test pit is 60 cm and the diameter is 55 cm.

[0039] Combination of the bearing device: Set the combined number of the stacked barrels 11 according to the thickness of the surface litter layer of the test site, and load the surface litter layer into the stacked barrels 11 in its original state to ensure that the upper end of the stacked barrels 11 is 1 cm higher than the surface of the litter layer.

[0040] Installation of the bracket: Connect the bearing device to the weighing sensor 32 at the upper end of the installation bracket 3 through a suspension line, and then insert the installation bracket 3 closely into the bottom of the observation pit along the observation pit wall. The insertion depth of the bracket 3 is such that the lowermost end of the suspended stacked barrels 11 is level with the soil surface around the observation pit.

[0041] Installation of the seepage water volume measuring device: Place the self-recording rain gauge at the bottom of the observation pit 6, and align the upper water inlet with the water outlet 15 of the water collecting funnel 14 of the stacked barrels 11.

[0042] Installation of the data collector: Install the data collector 4 outside the observation pit 6, and connect the data lines of the weighing sensor 32 and the self-recording rain gauge to the data collector 4.

[0043] Observation method: After installing the experimental device, set the data acquisition time interval according to the experimental requirements, regularly collect the weight change of the experimental stacked buckets 11 after rainfall and the quantity of seepage water collected, and simultaneously observe the rainfall in the experimental area. The surface evaporation quantity of the litter layer can be obtained through the following formula:

[0044]

[0045] Where: E int (t) is the evaporation quantity of the litter layer per unit time;

[0046] P net (t) is the rainfall (simulated or natural rainfall);

[0047] S u is the water interception quantity of the litter layer per unit time (obtained from the weight difference of the stacked buckets 11 per unit time); S l is the seepage water quantity of the litter layer per unit time (obtained from the seepage water quantity collected per unit time).

[0048] Finally, it should be noted that the above is the preferred implementation mode of the present invention. It should be pointed out that for those of ordinary skill in the art of this technology, without departing from the principle described in the present invention, several improvements and refinements can still be made, and these improvements and refinements should be regarded as the protection scope of the present invention.

Claims

1. An observation and experimental device for measuring the evaporation process of the surface litter layer after rainfall, characterized in that, It includes a litter layer load observation unit (1), a seepage water measurer (2), a mounting bracket (3), and a data collector (4); The mounting bracket (3) is inserted into an observation pit (6). A weighing sensor (32) is provided at the top of the mounting bracket (3). The litter layer load observation unit (1) is suspended below the weighing sensor (32) through a suspension wire (34); The litter layer load observation unit (1) includes a stacked sleeve (11) in the upper part and a water collecting funnel (14) in the lower part. The lower edge of the stacked sleeve (11) is connected to the upper edge of the water collecting funnel (14), and the radius of the lower edge of the stacked sleeve (11) is equal to the opening radius of the upper edge of the water collecting funnel (14); A filter screen (13) is provided between the stacked sleeve (11) and the water collecting funnel (14); The stacked sleeve (11) is used to place experimental litter, and the water collecting funnel (14) is used to collect the seepage water that infiltrates during rainfall; The seepage water measurer (2) is arranged below the water collecting funnel (14); It is used to collect the seepage water flowing out of the water collecting funnel (14); The data collector (4) is respectively connected to the seepage water measurer (2) and the weighing sensor (32); It collects signals.

2. The observation and experimental device for measuring the evaporation process of the surface litter layer after rainfall according to claim 1, characterized in that, The mounting bracket (3) includes at least three support rods (31), and the lower ends of the three support rods (31) are inserted into the soil in the observation pit, and the upper ends are connected to a vertex.

3. The observation and experiment device for measuring the evaporation process of the surface litter layer after rainfall according to claim 1, characterized in that, The support rod (31) is in an "inverted L" shape.

4. The observation and experimental device for measuring the evaporation process of the surface litter layer after rainfall according to claim 1, characterized in that, The height of the stacked sleeve (11) is adjustable. It is formed by concentrically sleeving a plurality of annular baffles (111). The lower edge of each annular baffle (111) is clamped with the upper edge of its lower-layer annular baffle (111).

5. The observation and experimental device for measuring the evaporation process of the surface litter layer after rainfall according to claim 3, wherein, At least three hoisting wire mooring rings (12) are evenly arranged on the outer side of the upper edge of the water collecting funnel (14) for one end of the suspension wire (34) to pass through and be tightened.

6. The observation and experiment device for measuring the evaporation process of the surface litter layer after rainfall according to claim 1, wherein A suspension hook (33) is provided below the weighing sensor (32) for hanging the suspension wire (34).

7. The observation and experiment device for measuring the evaporation process of the surface litter layer after rainfall according to claim 1, characterized in that, The stacked sleeve (11), the filter screen (13), and the water collecting funnel (14) are made of metal.

8. The observation and experimental device for measuring the evaporation process of the surface litter layer after rainfall according to claim 1, characterized in that, The seepage water measurer (2) is a self-recording rain gauge.

9. An observation experiment method for measuring the evaporation process of the surface litter layer after rainfall, characterized in that, It includes: Step 1: Assemble the experimental device for measuring the evaporation amount of the surface dead litter layer, dig out the observation pit (6) and place the experimental device, and fill the dead litter into the stacked sleeve (11) of the experimental device in its original state; Step 2: Use the data collector (4) to regularly collect the weight change of the stacked sleeve (11) of the experimental device and the amount of seepage water collected in the water collecting funnel (14) after rainfall, and at the same time observe the rainfall amount in the experimental area, and calculate the surface evaporation amount Eint(t) of the dead litter layer in the experimental area.

10. The observation experiment method for measuring the evaporation process of the surface litter layer after rainfall according to claim 9, characterized in that, When placing the experimental device, make the upper edge of the stacked sleeve (11) at least 1 cm higher than the surface of the dead litter on the ground, the lower edge flush with the surface of the dead litter on the ground, and adjust the suspension wire (34) to make the filter screen layer (13) flush with the ground.

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