CN104459052A - Vegetation evapotranspiration monitoring device and method suitable for complex surface - Google Patents

Abstract

The invention discloses a vegetation evapotranspiration monitoring device suitable for a complex surface. According to the vegetation evapotranspiration monitoring device disclosed by the invention, by regulating air flows at the inlet and the outlet and combining a stirring fan, the air humidity condition in a hood box of the vegetation evapotranspiration monitoring device is regulated, and water vapor is prevented from condensing; a base of the vegetation evapotranspiration monitoring device is provided with telescopic seat legs and a soft transparent sealing material and does not have a need of ensuring strict sealing when being mounted, so that the mounting difficulty is greatly weakened, and the vegetation evapotranspiration monitoring device is suitable for being mounted and used under the complex surface condition; as being mounted on the ground surface, the vegetation evapotranspiration monitoring device has small influence on the underground hydrology process including groundwater replenishment and soil moisture movement. The invention also discloses a vegetation evapotranspiration monitoring method suitable for the complex surface. According to the vegetation evapotranspiration monitoring method disclosed by the invention, the evapotranspiration rate of vegetation is determined by determining variations of temperature and humidity of air in the sealed box body caused by vegetation evapotranspiration and a humidity difference of exchanged air; the accuracy is high, and dynamic variation of vegetation evapotranspiration can be captured. The vegetation evapotranspiration monitoring device has a simple and clear structure, is flexible in size, convenient and simple in mounting and low in cost and can be widely applied to the fields including the ecological field, the meteorological field, the hydrological field and the agriculture and forest field.

Description

A kind of vegetation being applicable to complicated earth surface is evapotranspired monitoring device and method

Technical field

The invention belongs to plant physiology, ecological monitoring and meteorological model measurement technology field, be specifically related to a kind of vegetation being applicable to complicated earth surface and evapotranspire the method for monitoring, also relate to a kind of vegetation being applicable to complicated earth surface simultaneously and to evapotranspire monitoring device.This invention can be widely used in the fields such as agricultural, ecology, meteorological model.

Background technology

Along with the development of demographic and economic, global water resources shortage problem day is aobvious serious, especially in the area such as Arid&semi-arid area, karst, and the controlling key element of moisture ecologic environment especially.It is the important step of ecosystem material recycle that vegetation is evapotranspired, and be also the important parameter of agricultural irrigation, hydrologic research and forecast and water resources management, be the research emphasis of the subjects such as pedology, geography, hydrology and ecology always.At present, measure the method for evapotranspiring both at home and abroad and mainly comprise lysimeter, TDP method (Thermal dissipation probe), Chamber technique, porometer method and soil water balance estimation algorithm etc.Wherein, TDP method and porometer method are mainly used in the transpiration of vegetation, can not take into account surface evaporation; Vortex correlation is mainly used in the water balance monitoring of Large-scale areas.Lysimeter and Soil water balance equation can be used for small scale and evapotranspire and measure or estimation, and wherein lysimeter is traditional classical method, measures accurately, but its install complicated, involve great expense, and to affect to underground hydrologic condition; And Soil water balance equation needs a large amount of sample collections and mensuration.In addition, lysimeter and Soil water balance equation are in edaphic condition complex area (as native stone hybridization, the unequal area of clay distribution), and applicability has larger shortcoming.Such as in karst, due to the geologic background that it is special, SOIL DISTRIBUTION is discontinuous, very totally different with the edaphic condition of other the regional ecosystem, and soil moisture (storehouse) change estimation difficulty, Soil water balance equation is difficult to use.And for lysimeter, on the one hand native stone mixes and improves its installation difficulty, also can change rock-soil structure to a certain extent on the other hand, make lysimeter environment lose karst feature, affect reliability and the representativeness of result.At present, occur more evapotranspiring the improvement of equipment and research and development for vegetation, as CN1657931, CN2152214 etc., but it is all comparatively short of in the applicability in complicated earth surface region.Therefore, design and be a kind ofly adapted to complicated landform, easy for installation, the cheap equipment of evapotranspiring is very necessary, all significant to agricultural production, ecology and hydrology field.

Summary of the invention

The vegetation that the present invention is directed to the complicated earth surface areas such as karst is evapotranspired and measures the problem of difficulty, be there are provided a kind of vegetation being applicable to complicated earth surface evapotranspire monitoring method, easy to implement the method, easy and simple to handle, measurement result precision is high, can measure complicated earth surface area vegetation evapotranspiration exactly.

Another object of the present invention there are provided a kind of vegetation being applicable to complicated earth surface to evapotranspire monitoring device, apparatus structure is simple and clear, size is flexible, simple to operate, with low cost, applicability is wide, efficiently solve region with a varied topography (as karst) vegetation evapotranspire measure difficulty problem, for instructing agricultural and forestry production, promoting ecosystem Water Cycle research etc., all significant.

In order to realize above-mentioned object, the present invention adopts following technical measures:

A kind of vegetation being applicable to complicated earth surface evapotranspire monitoring device, comprise the base of shaped as frame, also comprise the Telescopic base leg being arranged on base bottom, base is covered with translucent cover case, the top of translucent cover case is provided with agitation fan, translucent cover case side is provided with admission line and outlet pipe, outlet pipe is communicated with adjustable wind speed aspiration pump, draft tube Temperature Humidity Sensor is installed in admission line, be provided with escape pipe Temperature Humidity Sensor, barometer and gas meter in outlet pipe, the surrounding of base is provided with soft transparent encapsulants.

The top of base as above is provided with seal groove, and the bottom opening of translucent cover case is embedded into seal groove and is sealed by soft rubber O-ring seal.

Soft transparent encapsulants as above is soft glass or soft transparent plastic.

Admission line one end as above is communicated with the air intake opening being arranged on translucent cover lower box part, and the admission line other end extends to above air intake opening, and outlet pipe is communicated with the gas outlet of translucent cover upper box part.

The vegetation being applicable to complicated earth surface is evapotranspired the device of monitoring, also comprises the data acquisition unit be connected with draft tube Temperature Humidity Sensor, escape pipe Temperature Humidity Sensor, barometer and gas meter.

Translucent cover case as above comprises stainless steel insert and is arranged on the optics force-bearing plate on stainless steel insert.

The vegetation of complicated earth surface is evapotranspired the method for monitoring, comprises the following steps:

Steps A, by floor installation in earth's surface, target sample ground, the Telescopic base leg length bottom adjusting base, makes base maintenance level, firm; If mounting seat place is soil layer, then digs a soil box at soil layer, soft transparent plastic is imbedded, if mounting seat place is rock, then first with soil, rock surface hollow place is filled and led up, then with little sand hill or earth, soft transparent plastic is pushed down, translucent cover case is arranged on base;

The air utilizing adjustable wind speed aspiration pump to cause humidity to raise by evapotranspiring due to vegetation in translucent cover box body when step B, mensuration is extracted out and makes to be formed in cover case negative pressure, sucking outside air by admission line replenishes in translucent cover case, and adopt agitation fan to stir air in translucent cover case, make air humidity in translucent cover case even, turn-on data collector switch, regulate acquisition interval, air mass flow, temperature, humidity and outlet air pressure in real-time automatic monitoring the humiture recorded in admission line and outlet pipe;

Step C, monitored after by adjustable wind speed aspiration pump, agitation fan and data acquisition unit power-off, moved away from by translucent cover case, base stays put, and measures the evapotranspiration of tested vegetation in measurement period according to following formula:

$W_{\mathrm{in}\left(t\right)}=\frac{18\·{\mathrm{Rhum}}_{\mathrm{in}\left(t\right)}\·610.78e^{\frac{17.269T_{\mathrm{in}\left(t\right)}}{273.16+T_{\mathrm{in}\left(t\right)}-35.86}}}{R\·(273.16+T_{\mathrm{in}\left(t\right)})}\·V\·\frac{P}{P_0}$

$W_{\mathrm{out}\left(t\right)}=\frac{18\·{\mathrm{Rhum}}_{\mathrm{out}\left(t\right)}\·610.78e^{\frac{17.269T_{\mathrm{out}\left(t\right)}}{273.16+T_{\mathrm{out}\left(t\right)}-35.86}}}{R\·(273.16+T_{\mathrm{out}\left(t\right)})}\·V\·\frac{P}{P_0}$

$\mathrm{Wb}=(W_{\mathrm{out}\left(\mathrm{te}\right)}-W_{\mathrm{out}\left(t0\right)})\·\mathrm{Vb}\·\frac{P}{P_0}$

$\mathrm{ET}=\frac{\underset{t=0}{\overset{\mathrm{te}}{\mathrm{\Σ}}}((W_{\mathrm{out}\left(t\right)}-W_{\mathrm{in}\left(t\right)})\·\mathrm{\Δt})+\mathrm{Wb}}{1000\·A}$

In formula, W _{in (t)}and W _{out (t)}measure air moisture transfer rate in moment turnover feed channel respectively, Rhum _{in (t)}and Rhum _{out (t)}be respectively relative air humidity in turnover feed channel, T _{in (t)}and T _{out (t)}for air themperature in turnover feed channel, V is the air mass flow that outlet pipe is measured, and P is outlet air pressure, P ₀for standard atmospheric pressure, R is calibrating gas constant, W _{out (t0)}and W _{out (te)}be respectively beginning period and end of term gas outlet air humidity (g/m ³), t0 schedules to last the just time, and te is the time in the end of term, and Vb is the cumulative volume of translucent cover case and base (11), and Wb is steam variable quantity in case, ET be certain period interplantation by evapotranspiration, Δ t is data sampling interval, and A is base area.

The present invention has following advantage and effect compared with the prior art:

1, cardinal principle monitors vegetation evapotranspiration (ET) according to the change of aerial temperature and humidity and the psychrometric difference of containment housing and environment (external world) institute exchange of air in mensuration containment housing;

2, the present invention adopts translucent cover case and base, and light transmission is good, and when ensureing to measure, in case, the cooperation of vegetation normal light is used;

3, device pedestal is provided with telescopic seat leg and soft transparent material, is applicable to the region (as karst) of (as hillside fields) with a varied topography, native stone hybridization;

4, in cover case, form certain negative pressure by aspiration pump, whole device does not require strict sealing, greatly reduces device installation difficulty, improves its applicability in complicated earth surface region, simplicity;

5, device imports and exports air quantity (wind speed) by regulating, and is extracted out outside casing by steam that vegetation is evapotranspired in case, and in conjunction with air stirring fan in case, effectively can prevent steam condensation in case, improve measurement device precision; In addition, owing to keeping ventilating, when device long-time running, in casing, temperature rises very little, reduces the impact on the growth of device implants as much as possible;

6, device of the present invention is installed on earth's surface, as less in the recharge of ground water, soil water movement impact on groundwater hydrological process;

7, device of the present invention has the features such as structure is simple and clear, size is flexible, simple to operate, with low cost, applicability is wide, efficiently solve region with a varied topography (as karst) vegetation evapotranspire measure difficulty problem.

Accompanying drawing explanation

Fig. 1 a is device overall schematic of the present invention, Fig. 1 b device pedestal schematic diagram of the present invention.

Wherein: 1-translucent cover case, 2-agitation fan (without concrete model requirement, market is all purchased), 3-optics force-bearing plate, 4-outlet pipe, 5-admission line, 6-gas meter (without concrete model requirement, market is all purchased), 701-draft tube Temperature Humidity Sensor; 702-escape pipe Temperature Humidity Sensor (without concrete model requirement, market is all purchased), 8-barometer is (without concrete model requirement, market is all purchased), 9-is adjustable wind speed aspiration pump (without concrete model requirement, market is all purchased), 10-data acquisition unit is (without concrete model requirement, market is all purchased), 11-base, 12-Telescopic base leg, the soft transparent plastic of 13-, 14-seal groove, 15-soft rubber O-ring seal.

Fig. 2 a is soft sealing rubber ring structural representation, and Fig. 2 b is seal groove structure schematic diagram, and Fig. 2 c is air feeder structure schematic diagram, and Fig. 2 d is outlet duct structures schematic diagram, and Fig. 2 e is scalability base seat leg structural representation.

Fig. 3 a contrasts histogram for the present invention and weight method institute measured value, and Fig. 3 b is the present invention and weight method measured value Regression Analysis Result.

Result shows, institute contrive equipment monitoring evapotranspiration and weight method is kissed and very good.In addition, regretional analysis shows, regression coefficient is 0.998, and the coefficient of determination is 0.95.More than illustrate, device of the present invention has higher precision.

Fig. 4 a is the temperature inside the box of measuring in the wild of the present invention and box outside temperature dynamic change correlation curve schematic diagram, (b) Fig. 4 b be the present invention measure in the wild into and out of stomatodeum air humidity dynamic changing curve schematic diagram.

Result shows that less (a), the temperature inside the box raises also not obvious Fig. 4 for the import of device and outlet temperature difference.Meanwhile, import and export air humidity curve (about between 7:30 to 18:30) difference comparatively large (Fig. 4 b) by day; And night, import and export air humidity curve overlapped substantially, this is consistent with vegetation physiological habit.Illustrate that evaporation device of the present invention can catch vegetation exactly and to evapotranspire dynamic change.

Embodiment

The present invention is further described below in conjunction with accompanying drawing and instantiation.

Embodiment 1:

The vegetation being applicable to complicated earth surface is evapotranspired the method for monitoring, and its ultimate principle to be evapotranspired due to vegetation and the air humidity difference that causes the change of air humidity in confined space and confined space and environment (external world) to exchange measures vegetation evapotranspiration (ET) according to measuring.The steps include:

Steps A, by target plant sample block (as 1m ²corn crop) cover with an airtight translucent cover case 1, detailed process is: base (11) is installed on earth's surface, target sample ground, adjusting base four scalable case leg (12) length, makes base maintenance level, firm; Below base, there is native part to dig a shallow soil box, soft for base transparent material (13) is imbedded, if installation place has rock exposed, be difficult to excavation, then first with soil, rock surface hollow place is filled and led up substantially, with little sand hill or earth, soft for base transparent material (13) is pushed down again, ensure that rock contacts well with soft transparent material, reach basic sealing (not needing to ensure strict sealing); Translucent cover case (1) being carefully placed in (along putting into seal groove (14) under cover case) above base, in put procedure, carefully not injuring vegetation; Whole box height should higher than the height of institute's measuring plants;

Outlet pipe 4 installed by step B, translucent cover case 1, admission line 5, outlet pipe 4 connects adjustable wind speed aspiration pump 9, and sky put by admission line 4; The air that the humidity utilizing adjustable wind speed aspiration pump 9 to cause evapotranspiring due to vegetation in translucent cover case 1 casing during mensuration is higher is extracted out and form certain negative pressure in cover case (1), sucking the lower outside air of humidity by admission line 5 supplements in cartonning, and adopt air in agitation fan 2 agitation box, make air humidity in translucent cover case 1 even.Turn-on data collector switch, regulate acquisition interval (as 10s etc.), open aspiration pump, agitation fan switch, air mass flow, temperature, humidity and outlet air pressure in real-time automatic monitoring the humiture recorded in (time interval can be set as 10s, 1min etc.) admission line 5 and outlet pipe 4.Due to adjustable wind speed aspiration pump 9 work time, certain negative pressure (a little less than ambient pressure) is caused in outlet conduit 4 He in whole case, therefore, in translucent cover case 1, air only can discharge casing from outlet pipe 4 by adjustable wind speed aspiration pump 9, outside air then (is difficult to sealing place by other gaps on admission line 5 and device, as base and earth's surface joining place) enter casing, reach air exchange object, therefore, whole casing only need ensure substantially to seal, and the rate of air sucked in required of aspiration pump is the air exchange amount with the external world in case;

Step C, monitored after by aspiration pump, agitation fan and data acquisition unit power-off, moved away from by cover case, cover case base stays put, to monitor next time.According to device measuring principle, the evapotranspiration of tested vegetation in measurement period is " in case atmospheric vapour content " and deducts " inlet air moisture content " with " outlet air moisture content " sum, adopts following formulae discovery:

$W_{\mathrm{in}\left(t\right)}=\frac{18\·{\mathrm{Rhum}}_{\mathrm{in}\left(t\right)}\·610.78e^{\frac{17.269T_{\mathrm{in}\left(t\right)}}{273.16+T_{\mathrm{in}\left(t\right)}-35.86}}}{R\·(273.16+T_{\mathrm{in}\left(t\right)})}\·V\·\frac{P}{P_0}$

$W_{\mathrm{out}\left(t\right)}=\frac{18\·{\mathrm{Rhum}}_{\mathrm{out}\left(t\right)}\·610.78e^{\frac{17.269T_{\mathrm{out}\left(t\right)}}{273.16+T_{\mathrm{out}\left(t\right)}-35.86}}}{R\·(273.16+T_{\mathrm{out}\left(t\right)})}\·V\·\frac{P}{P_0}$

$\mathrm{Wb}=(W_{\mathrm{out}\left(\mathrm{te}\right)}-W_{\mathrm{out}\left(t0\right)})\·\mathrm{Vb}\·\frac{P}{P_0}$

$\mathrm{ET}=\frac{\underset{t=0}{\overset{\mathrm{te}}{\mathrm{\Σ}}}((W_{\mathrm{out}\left(t\right)}-W_{\mathrm{in}\left(t\right)})\·\mathrm{\Δt})+\mathrm{Wb}}{1000\·A}$

Formula (1)

In formula (1), W _{in (t)}and W _{out (t)}measure air moisture transfer rate (g/s) in moment turnover feed channel respectively, Rhum _{in (t)}and Rhum _{out (t)}be respectively relative air humidity (%) in turnover feed channel, T _{in (t)}and T _{out (t)}for air themperature (DEG C) in turnover feed channel, V is the air mass flow (m measured in outlet pipe ³/ s), P is outlet air pressure (Pa), P ₀for standard atmospheric pressure (101325Pa), R is calibrating gas constant (8.314J/ (mol K ⁾), W _{out (t0)}and W _{out (te)}be respectively beginning period and end of term gas outlet air humidity (t0 schedules to last the just time, and te is the time in the end of term) (g/m ³), Vb is device box (cover case and base) cumulative volume (m ³), Wb is steam variable quantity (g) in case, ET be certain period interplantation by evapotranspiration (mm), Δ t is data sampling interval (s), and A is device pedestal area (m ²).

Embodiment 2: the potted plant evapotranspiration determination test of corn, measures accuracy mainly for detection of device.Detailed process is: base 11 is installed on dry cement plate (floor) upper (it is 0 that dry cement plate evapotranspires by (A), therefore measure to evapotranspire be potted plant contribution), scalable case leg 12 length of adjusting base four, makes base maintenance level substantially, firm; (B) with little sand hill, the soft transparent material 13 on base 11 is pushed down, ensure that floor contacts well with soft transparent material (not needing to ensure strict sealing); (C) by after potted plant for corn weighing, being placed in base, translucent cover case 1 being carefully placed in (along putting into seal groove 14 under cover case) above base; (D) on translucent cover case, be installed into feed channel 5 and outlet pipe 4, escape pipe is connected with aspiration pump 9; E, on admission line install a draft tube Temperature Humidity Sensor 701, outlet pipe is installed escape pipe Temperature Humidity Sensor 702, gas meter (or wind gage) 6 and barometer 8, four sensors is connected with data acquisition unit 10; (F) open agitation fan switch, simultaneously turn-on data collector switch, adjustments acquisition interval is 10s, unlatching aspiration pump power supply, starts to monitor import and export epidemic disaster and wind speed, air pressure dynamic change; (G) by aspiration pump, agitation fan and data acquisition unit power-off after having monitored, cover case has been moved away from, taken out of potted plant weighing; (H) repeat above step 9 time (repeating for 9 times), calculate period potted plant weight change of at every turn weighing, and utilization calculates evapotranspiration with period in-built monitoring gained humiture, air pressure and the data on flows of putting according to formula (1).Acquired results is as shown in Figure 3 a and Figure 3 b shows, visible, and it is very good that institute's contrive equipment monitoring evapotranspiration and weight method are coincide.In addition, regretional analysis shows, regression coefficient is 0.998, and the coefficient of determination is 0.95.More than illustrate, device of the present invention has higher accuracy and precision.

Embodiment 3: field monitoring is tested, mainly for investigating device of the present invention operation stability and reliability in the wild.Testing site is positioned at testing site, somewhere, karst ecological Studies station, Chinese Academy of Sciences's ring river.Locality belongs to typical lime lithotype karst peak cluster depression, and SOIL DISTRIBUTION is discontinuous, and topographical features is complicated, and assorted stone is grown thickly.This device is installed in the grassplot of testing site, test period be first day noon to second day noon, weather is fine.Detailed process is: (1) basis surface condition practically, and seat leg 12 length of adjusting base 11, makes base 11 level be installed on earth's surface; (2) there being native part to dig a shallow soil box, soft for base transparent material 13 is imbedded; And in rock exposed section, then first with soil, rock surface hollow place is filled and led up, then with little sand hill, soft for base transparent material 13 is pushed down, ensure that rock contacts well (not needing to ensure strict sealing) with the soft transparent material of base; (3) annexation described in the embodiments 4 such as translucent cover case 1, outlet pipe 4, admission line 5, Temperature Humidity Sensor (701,702), barometer 8, flowmeter 6, agitation fan 2, aspiration pump 9 is connected, turn-on data collector switch, setting data acquisition interval is set as 10s, open aspiration pump and agitation fan switch, monitoring import and export epidemic disaster and wind speed, air pressure dynamic change; (4) formula (1) is adopted to calculate vegetation evapotranspiration.Result as shown in figures 4 a and 4b, can be seen, less (Fig. 4 a), test average diurnal difference of temperature on the same day is less than 0.68 DEG C, illustrates that the temperature inside the box rising is not obvious for import and outlet temperature difference.Meanwhile, in-built monitoring gained humiture, air pressure and the data on flows of putting of same period is utilized to calculate evapotranspiration (Fig. 4 b).Can see, (about between 7:30 to 18:30) period differs larger by day to import and export air humidity; And at night, import and exhaust air humidity overlap substantially, this is consistent with the physiological habit of vegetation.This illustrates that evaporation device of the present invention can catch vegetation exactly and to evapotranspire dynamic change.

Embodiment 4:

As shown in Fig. 1 (b) He Fig. 2 (a-e), a kind of vegetation being applicable to complicated earth surface evapotranspire monitoring device, comprise translucent cover case 1, agitation fan 2, optics force-bearing plate 3, outlet pipe 4, admission line 5, gas meter 6, draft tube Temperature Humidity Sensor 701; Escape pipe Temperature Humidity Sensor 702, barometer 8, adjustable wind speed aspiration pump 9, data acquisition unit 10, base 11, scalable base leg 12, soft transparent material 13, seal groove 14, soft rubber O-ring seal 15.Its annexation is: the skeleton of translucent cover case 1 is stainless steel insert, and optics force-bearing plate 3 close installation is in the surrounding of the translucent cover case 1 of rectangular parallelepiped and top (5 faces), and ensure box sealing, agitation fan is installed on one jiao, translucent cover case 1 top; Be provided with admission line 5 and outlet pipe 4 in translucent cover case 1 side, wherein outlet pipe 4 is connected with aspiration pump 9, and admission line 5 opens wide (putting sky), as the air exchanging apparatus of device of the present invention; The skeleton of base 11 is stainless steel insert, the scalable base leg 12 of base 11 4 welded corner joint four, base 11 surrounding is provided with soft transparent material 13, base 11 top surrounding is welded with seal groove 14, insert soft rubber O-ring seal 15 in seal groove 14, when ensureing that translucent cover case 1 is put on base, translucent cover case 1 and base 11 joining place seal substantially; Draft tube Temperature Humidity Sensor 701 is installed in admission line; Escape pipe Temperature Humidity Sensor 702, barometer 8, gas meter (or wind gage) 6 are installed in outlet pipe, above-mentioned four sensors are connected with data acquisition unit, for monitoring and recording import and export pipeline humiture, air pressure and air mass flow.

Described translucent cover case 1 is sealed transparent cover case, and the skeleton of translucent cover case 1 is stainless steel, and all install optics force-bearing plate 3 for 5 of translucent cover case 1, it has higher intensity, weather resistance, resistance to feature of being exposed to the sun, and box sizes determines size as required; Be provided with air stirring fan 2 in translucent cover case 1, air stirring fan 2 is without model requirement, and market all can be bought, for mixing air in case;

The skeleton of described base 11 is made up of stainless steel, and the corner of base 11 is provided with 4 scalable seat legs 12, and surrounding transparent material is soft transparent organic material (soft glass), and base is applicable to being installed on MODEL OVER COMPLEX TOPOGRAPHY thus; Seal groove 14 is arranged at base top, can adopt wide 6cm, the seal groove 14 of degree of depth 8cm, and seal groove 14 can place the soft rubber O-ring seal that thickness is 2.0cm, width is 6cm, is closely connected with translucent cover case 1 for base 11;

The outlet pipe 4 of described device and the caliber of admission line 5 can adopt 100mm, one end of admission line 5 is communicated with the air intake opening on translucent cover case 1 (air intake opening can arrange and be positioned at the 20cm place that is above the ground level), the other end of admission line 5 extends to (position of the 2m that is above the ground level) above air intake opening, realize with bend pipe, (actual outlet is aspiration pump gas outlet in the gas outlet on outlet pipe 4 one end and translucent cover case 1 translucent cover case 1 (can be arranged on be above the ground level 1.8m place), realize with bend pipe), in translucent cover case 1, air-flow flows from lower to upper; Outlet pipe 4 is connected with adjustable wind speed aspiration pump 9, and sky put by admission line 5, reaches the inside and outside air exchange object of translucent cover case 1, in order to regulate translucent cover case 1 humidity, prevents condensation in case; The maximum rate of air sucked in required of adjustable wind speed aspiration pump 9 should be able to reach 6-8m ³/ min, without concrete model requirement, market is all purchased;

Described data acquisition unit 10 and four sensors (two Temperature Humidity Sensors 7, barometer 8 and flowmeters 6) form the monitoring system of device of the present invention, wherein admission line Temperature Humidity Sensor is installed in admission line 5, and its excess-three sensor is all installed in outlet pipe 4; Wherein said humiture probe is high sensitivity humiture coupling probe, and the moisture probe response time is less than 60s, and without concrete model requirement, market is all purchased; Described gas flow (wind speed) counts 6, barometer 8 all without concrete model requirement, market is all purchased; Described data acquisition system (DAS) 10 has adjustment acquisition time interval function, and can gather more than 6 groups data, without concrete model requirement, market is all purchased simultaneously.

Translucent cover case in described contrive equipment and base are formed " confined space " of device of the present invention, in order to cover target sample ground vegetation (as 1m ²corn), in confined space, air humidity will rise gradually due to the evapotranspiration of vegetation; Base is provided with telescopic seat leg and soft transparent material, makes it be applicable to complicated earth surface area.Agitation fan, adjustable wind speed aspiration pump, inlet pipeline and outlet conduit structure cost apparatus air exchange system in device, agitation fan, for mixing air in cover case, reduces error at measurment; One of object of air exchange is extracted out outside case by the air that in translucent cover case, humidity raises because vegetation is evapotranspired, and supplement the lower air of ambient humidity, prevents condensation vapor in cover case; Two of the object of air exchange utilizes aspiration pump in cover case, form certain negative pressure (a little less than ambient pressure), therefore in case, air is only extracted out by aspiration pump by outlet pipe, inlet pipeline and other cracks being difficult to seal are then as the import of outside air, thus, device only needs to ensure substantially to seal to get final product (not needing to ensure strict sealing), reduces the installation difficulty of device; Three of the object of air exchange forms air circulation in case, the flowing of simulation outside air, in addition because this device is translucent cover case, has certain " greenhouse " effect, ensure that air circulation can effectively prevent the temperature inside the box from raising, reduce device to the impact of surveyed vegetation growth.2 Temperature Humidity Sensors, 1 barometer, 1 air flowmeter (or wind gage) and data acquisition unit structure cost apparatus automatic monitoring system in device, monitoring inlet pipeline temperature and humidity and outlet conduit humiture, air pressure and air velocity (or flow), according to mass balance principle, inlet air amount equals outlet air amount, therefore, only air pressure and flow is measured at outlet conduit.In observation process, first open agitation fan switch, make it run about 1min, turn-on data collector switch, regulates data collection interval (will not need this step after setting), opens aspiration pump switch more afterwards simultaneously, starts Monitoring Data.

Specific embodiment described herein is only to the explanation for example of the present invention's spirit.Those skilled in the art can make various amendment or supplement or adopt similar mode to substitute to described specific embodiment, but can't depart from spirit of the present invention or surmount the scope that appended claims defines.

Claims (7)

1. the vegetation being applicable to complicated earth surface is evapotranspired the device of monitoring, comprise the base (11) of shaped as frame, it is characterized in that, also comprise the Telescopic base leg (12) being arranged on base (11) bottom, base (11) is covered with translucent cover case (1), the top of translucent cover case (1) is provided with agitation fan (2), translucent cover case (1) side is provided with admission line (5) and outlet pipe (4), outlet pipe (4) is communicated with adjustable wind speed aspiration pump (9), draft tube Temperature Humidity Sensor (701) is installed in admission line (5), escape pipe Temperature Humidity Sensor (702) is installed in outlet pipe (4), barometer (8) and gas meter (6), the surrounding of base (11) is provided with soft transparent encapsulants.

2. a kind of vegetation being applicable to complicated earth surface according to claim 1 evapotranspire monitoring device, it is characterized in that, the top of described base (11) is provided with seal groove (14), and the bottom opening of translucent cover case (1) is embedded into seal groove (14) and is sealed by soft rubber O-ring seal (15).

3. a kind of vegetation being applicable to complicated earth surface according to claim 2 evapotranspire monitoring device, it is characterized in that, described soft transparent encapsulants is soft glass or soft transparent plastic.

4. a kind of vegetation being applicable to complicated earth surface according to claim 3 evapotranspire monitoring device, it is characterized in that, described admission line (5) one end is communicated with the air intake opening being arranged on translucent cover case (1) bottom, admission line (5) other end extends to above air intake opening, and outlet pipe (4) is communicated with the gas outlet on translucent cover case (1) top.

5. a kind of vegetation being applicable to complicated earth surface according to claim 4 evapotranspire monitoring device, it is characterized in that, also comprise the data acquisition unit (10) be connected with draft tube Temperature Humidity Sensor (701), escape pipe Temperature Humidity Sensor (702), barometer (8) and gas meter (6).

6. a kind of vegetation being applicable to complicated earth surface according to claim 5 is evapotranspired the device of monitoring, and it is characterized in that, described translucent cover case (1) comprises stainless steel insert and is arranged on optics force-bearing plate (3) on stainless steel insert.

7. the vegetation utilizing device described in claim 6 to carry out complicated earth surface evapotranspire monitoring a method, it is characterized in that, comprise the following steps:

Steps A, base (11) is installed on earth's surface, target sample ground, Telescopic base leg (12) length of adjusting base (11) bottom, makes base (11) keep level, firm; If mounting seat (11) place is soil layer, then dig a soil box at soil layer, soft transparent plastic (13) is imbedded, if mounting seat (11) place is rock, then first with soil, rock surface hollow place is filled and led up, with little sand hill or earth, soft transparent plastic (13) is pushed down again, translucent cover case (1) is arranged on base (11);

Step B, the air utilizing adjustable wind speed aspiration pump (9) to cause humidity to raise by evapotranspiring due to vegetation in translucent cover case (1) casing during mensuration is extracted out and is made to form negative pressure in translucent cover case (1), sucking outside air by admission line (5) replenishes in translucent cover case (1), and adopt agitation fan (2) to stir translucent cover case (1) interior air, make translucent cover case (1) interior air humidity even, turn-on data collector (10) switch, regulate acquisition interval, real-time automatic monitoring the humiture recorded in admission line (5) and outlet pipe (4) interior air mass flow, temperature, humidity and outlet air pressure,

Step C, monitored after by adjustable wind speed aspiration pump (9), agitation fan (2) and data acquisition unit (10) power-off, translucent cover case (1) is moved away from, base (11) stays put, and measures the evapotranspiration of tested vegetation in measurement period according to following formula:

$W_{\mathrm{in}\left(t\right)}=\frac{18\·{\mathrm{Rhum}}_{\mathrm{in}\left(t\right)}\·610.78e^{\frac{17.269T_{\mathrm{in}\left(t\right)}}{273.16+T_{\mathrm{in}\left(t\right)}-35.86}}}{R\·(273.16+T_{\mathrm{in}\left(t\right)})}\·V\·\frac{P}{P_0}$

$W_{\mathrm{out}\left(t\right)}=\frac{18\·{\mathrm{Rhum}}_{\mathrm{out}\left(t\right)}\·610.78e^{\frac{17.269T_{\mathrm{out}\left(t\right)}}{273.16+T_{\mathrm{out}\left(t\right)}-35.86}}}{R\·(273.16+T_{\mathrm{out}\left(t\right)})}\·V\·\frac{P}{P_0}$

$\mathrm{Wb}(W_{\mathrm{out}\left(\mathrm{te}\right)}-W_{\mathrm{out}\left(t0\right)})\·\mathrm{Vb}\·\frac{P}{P_0}$

$\mathrm{ET}=\frac{\underset{t=0}{\overset{\mathrm{te}}{\mathrm{\Σ}}}((W_{\mathrm{out}\left(t\right)}-W_{\mathrm{in}\left(t\right)})\·\mathrm{\Δt})+\mathrm{Wb}}{1000\·A}$

In formula, W _{in (t}) and W _{out (t)}measure air moisture transfer rate in moment turnover feed channel respectively, Rhum _{in (t)}and Rhum _{out (t)}be respectively relative air humidity in turnover feed channel, T _{in (t)}and T _{out (t)}for air themperature in turnover feed channel, V is the air mass flow that outlet pipe is measured, and P is outlet air pressure, P ₀for standard atmospheric pressure, R is calibrating gas constant, W _{out (t0)}and W _{out (te)}be respectively beginning period and end of term gas outlet air humidity (g/m ³), t0 schedules to last the just time, and te is the time in the end of term, Vb is the cumulative volume of translucent cover case (1) and base (11), and Wb is steam variable quantity in case, and ET is that certain period interplantation is by evapotranspiration, Δ t is data sampling interval, and A is base (11) area.