Cloud- and fog-measuring device and method

Abstract

The invention relates to a cloud- and fog-measuring device (1) having a first optical particle sensor (2) for a time-resolved measurement of at least one parameter of particles (3) in a first sample volume (4) of air from an environment (5) by means of a first volume flow measuring device (6) for determining the flow rate of the air flowing through the first sample volume (4), wherein a computing device (7) is provided, by means of which the presence of a cloud and / or fog in the air can be determined from the at least one parameter.

Description

[0001] Device and method for cloud and fog measurement

[0002] This application claims priority from German patent application No. 10 2024 105 298.8, the contents of which are incorporated herein by reference.

[0003] The invention relates to a device for measuring clouds and fog.

[0004] The invention further relates to a method for measuring clouds and fog.

[0005] To improve the general understanding of weather and climate phenomena, the measurement of fog and clouds is important in atmospheric research, especially the early detection of fog formation and the development of fog and clouds.

[0006] According to the current state of the art, cloud observations are only possible based on remote sensing.

[0007] State-of-the-art methods for measuring clouds and fog are carried out using satellites or ground-based instruments.

[0008] Remote sensing methods for measuring clouds and fog are known from the state of the art.

[0009] In particular, it is known from the general state of the art to use cloud spectrometers, cloud radar, LiDAR (Light Detecting and Ranging), ceilometers and sun photometers for cloud measurement.

[0010] The ceilometer, which can also be called a laser cloud altimeter or laser ceilograph, is a cloud altimeter that uses a laser beam to determine the cloud base.

[0011] The ceilometer measures the travel time of a laser light pulse emitted vertically upwards from the ground to the cloud and back. From the determined travel time and the speed of light, the height of the cloud base can be determined.

[0012] A disadvantage of the remote sensing methods known from the state of the art is the fact that they do not represent direct measurements.

[0013] The present invention is based on the object of creating a device for measuring clouds and fog which avoids the disadvantages of the prior art, in particular enabling reliable detection of cloud and fog formation and the development of clouds and fog. According to the invention, this object is achieved by a device having the features mentioned in claim 1.

[0014] The present invention is further based on the object of creating a method for measuring clouds and fog which avoids the disadvantages of the prior art, in particular enabling reliable detection of cloud and fog formation and the development of clouds and fog.

[0015] According to the invention, this object is achieved by a method having the features mentioned in claim 7.

[0016] The device according to the invention for measuring clouds and fog comprises a first optical particle sensor for the time-resolved measurement of at least one parameter of particles in a first sample volume of ambient air, with a first volume flow measuring device for determining a flow rate of the air through the first sample volume. Furthermore, a computing device is provided, by means of which the presence of a cloud and / or fog in the air can be determined from the at least one parameter.

[0017] The device according to the invention has the advantage that it is cheaper in its procurement costs than the solutions known from the prior art and offers the possibility of direct measurement instead of remote sensing.

[0018] The device according to the invention is used in particular for measuring clouds and fog in the atmosphere.

[0019] Furthermore, the use of the optical particle sensor can also be used to determine other physical properties of the fog or cloud under investigation. In particular, the properties of the fog droplets and the fog density can be determined.

[0020] In particular, the device according to the invention enables in situ measurement of clouds, very low clouds and fog layers, including fog density.

[0021] Thus, the device according to the invention is suitable for use in the field of atmospheric research, meteorology, humidity measurement and air quality measurement.

[0022] It can be provided that the optical particle sensor determines an effective diameter of the particles in the sample volume as a first parameter.

[0023] For this purpose, the optical particle sensor can measure the particles using light scattering. In this case, the particle size, but not the particle composition, is analyzed from a scattering cross-section. In particular, the optical particle sensor can comprise a chamber for the sample volume, in which a laser is arranged and through which the particles move. The particles can be, for example, dust particles and / or fine dust particles. Laser radiation is then reflected by the particles and / or, depending on their size, scattered by Mie scattering.

[0024] It can be provided that the optical particle sensor determines the number of particles in the sample volume as a second parameter.

[0025] In conjunction with the volume flow determined by the volume flow measuring device and assumptions about a mass density of the measured particles, a mass flow of particles through the sample volume can be determined.

[0026] It can be provided that the air flows continuously through the sample volume and the volume flow of the air is continuously measured.

[0027] In an advantageous development of the device according to the invention, a drying device can be provided for drying the air before it enters the first sample volume.

[0028] Fog droplets typically form from the condensation of water on aerosol particles. In high humidity conditions, the aerosol particles attract water vapor. When the water vapor condenses, a layer of water forms around the aerosol particle, which now forms the dry core of the fog droplet. The absorption of water vapor and the condensation of liquid water around the aerosol particle change the apparent size of the particle, causing it to be registered as a larger particle by an optical particle sensor.

[0029] If the water content of the particles formed as mist droplets is removed by the drying device before they enter the first sample volume, this apparent particle size is reduced again and the dry particle diameter is measured by the optical particle sensor.

[0030] Even in the case of using a drying device, the noise level of the mass flow can be used to infer the presence of a cloud and / or fog in the air being examined.

[0031] Stainless steel can be dispensed with.

[0032] In an advantageous development of the device according to the invention, the drying device can be provided with at least one desiccant, in particular a plurality of silica gel spheres. It is particularly advantageous if the drying device operates without additional energy consumption using a desiccant.

[0033] This allows the device to be used even with low energy resources.

[0034] Such a situation can be advantageous, for example, when used away from energy sources or on a mobile platform, particularly an unmanned aircraft system (UAS). This means that the energy required by the mobile platform is not needed to achieve successful drying.

[0035] The desiccant can preferably also comprise or consist of a zeolite. This has a low mass density and is therefore suitable for use on unmanned aircraft.

[0036] An advantageous development of the device according to the invention can provide a second optical particle sensor for the time-resolved measurement of at least one parameter of particles in a second sample volume of air from the same environment with a second volume flow measuring device for determining a flow rate of the air through the second sample volume, wherein the computing device is configured to determine the presence of the mist from a comparison, in particular a difference, of the measurement of the at least one parameter by the first optical particle sensor and the measurement of the at least one parameter by the second optical particle sensor.

[0037] By using the first and second optical particle sensors simultaneously, a differential signal from both sensors can be evaluated. Alternatively or additionally, a quotient signal can also be evaluated.

[0038] If the two optical particle sensors are arranged in close proximity to each other, preferably less than 20 cm, particularly preferably less than 5 cm, apart, it can also be ensured that the air is taken from the same environment for feeding into the respective sample volume.

[0039] It is particularly advantageous if the drying device is provided for drying the air supplied to the first optical particle sensor.

[0040] The difference signal preferably results from the measurement of the dried air with the first optical particle sensor and the measurement of the undried air with the second optical particle sensor. The difference in particle quantities results, in the procedure described above, from the drying of the air introduced into the first optical particle sensor. The difference thus provides information about the amount of water in the water layer surrounding the aerosol particles.

[0041] It is beneficial to measure the particle number concentration (PNC). This indicates how many particles of a given size are present in a volume of air. This can be expressed in units of # / L or, using additional information, in micrograms / L.

[0042] To improve the reliability of the differential measurement, it can be provided that the first optical particle sensor and the second optical particle sensor are of the same design.

[0043] Instead of optical particle sensors, other particle sensors can also be provided. In particular, the optical particle sensors can be designed as optical particle counters (OPC).

[0044] The device can be provided with two identical optical particle sensors or optical particle counters, of which the first optical particle sensor is designed with the drying device, in particular a diffusion drying system.

[0045] Due to the design and the technical arrangements described above, both sensors can detect an identical air sample or air from the same environment.

[0046] Due to the design, simultaneous measurement of dried and non-dried air is possible.

[0047] The difference between the two measurements, one with and one without drying the air, makes it possible to determine the moisture content and water vapor content of the air sample with high precision.

[0048] This allows properties of water droplets, such as size distribution, number of condensed particles and number of non-condensed particles, as well as hygroscopic growth, to be quantified.

[0049] An unmanned aircraft may be provided on which at least the first optical particle sensor is arranged.

[0050] In an advantageous development of the device according to the invention, an unmanned aircraft can be provided, wherein at least the first optical particle sensor, the drying device, and the second optical particle sensor are arranged on the unmanned aircraft. It is particularly advantageous if the drying device is designed in a lightweight construction. This allows the system comprising the first optical particle sensor, the second optical particle sensor, and the drying device to be miniaturized and lightweight.

[0051] This allows the system to be installed on an unmanned aircraft, especially a small unmanned aircraft (UAS).

[0052] By installing the system on the unmanned aircraft, the spatial, especially vertical, extent of the cloud or fog layer can be determined with high flexibility and spatial resolution.

[0053] Furthermore, a spatially resolved measurement of the properties of the fog droplets or cloud droplets and their particle number concentration can be carried out.

[0054] The device according to the invention is particularly advantageous for use in weather observation by meteorological services, in cloud observation, in fog measurement, in particular at airports, and in air quality measurement.

[0055] In an advantageous development of the device according to the invention, a protective device can be provided above an air inlet area into the sample volume.

[0056] If a protective device is provided above the air inlet area, the entry of unwanted particles, for example from the rotors of the unmanned aircraft, and thus a change in the size distribution of the particles due to the influence of the unmanned aircraft is avoided.

[0057] Especially when using multicopter drones, a vertical vortex field can develop. This can potentially wash unwanted particles into the air inlet of the optical particle sensors and / or the drying device.

[0058] Such entry is prevented by an appropriate protective device, which can in particular be designed as a mushroom-shaped cap.

[0059] This avoids outliers in particle measurements and improves data quality.

[0060] Furthermore, an insulation device can be provided, which is preferably made of Styrofoam to reduce weight and encloses the device with the exception of the air inlet area and the rotors of the unmanned aircraft. This can protect the device from moisture and rain. Furthermore, the symmetry of the unmanned aircraft can be increased. This makes the volume flow in the air inlet area less uneven. If only the first optical particle sensor is provided, the device can have two air inlet areas. A first air inlet area can lead to the drying device, while a second air inlet area without a drying device leads to the first sample volume.

[0061] A switching device may be provided to alternate the air supply to the first optical particle sensor between the two air inlet areas. This alternately supplies dried and undried air to the first optical particle sensor.

[0062] The difference between the two signals can then be used to determine the presence of clouds and / or fog.

[0063] A solution with two optical particle sensors is preferred, one with a drying device and one without.

[0064] The optical particle sensor without a drying device measures water droplets. The optical particle sensor with a drying device measures the dry matter content or dust.

[0065] The difference can be used to determine the presence of clouds and / or fog and the processes taking place in the cloud

[0066] The invention further relates to a method for measuring clouds and fog having the features mentioned in claim?

[0067] The method according to the invention for measuring clouds and fog comprises at least the following steps: a) taking air from an environment into a first sample volume b) time-resolved measurement of at least one parameter of particles in the first sample volume of the air by means of a first optical particle sensor c) determining a flow rate of the air through the first sample volume by means of a first volume flow measuring device d) determining a presence of a cloud and / or fog in the air from the at least one parameter.

[0068] The method according to the invention enables the measurement and / or detection of clouds and fog. Fog consists of particles or aerosol particles composed of solids and / or water suspended in air.

[0069] Using the method according to the invention, the boundaries and extents of fog layers can be determined, and furthermore, the concentrations of fog droplets and humid aerosol particles can be determined. In an advantageous development of the method according to the invention, it can be provided that in step a), the air is at least partially dried before being absorbed into the first sample volume.

[0070] At least partial drying of the air before inclusion in the first sample volume allows quantification of the water content in comparison to a dry core of the fog droplets.

[0071] It may be provided that the air is dried only at alternating time intervals before being supplied to the first sample volume.

[0072] This allows a difference measurement to be determined between dried and undried air samples. By ensuring that the environment remains constant between time intervals, reliable information can be obtained about the relative water content compared to the dry mass of the particles in one and the same air environment.

[0073] In order to exclude a change in the environment, the respective time interval can be chosen to be short compared to an air movement.

[0074] In an advantageous development of the method according to the invention, it can be provided that in step a) a second sample volume of air from the same environment is additionally taken; in step b) a time-resolved measurement of the at least one parameter of particles in the second sample volume of air is additionally carried out by means of a second optical particle sensor; in step c) a determination of a flow rate of the air through the second sample volume is carried out by means of a second volume flow measuring device; in step d) the presence of the mist is determined from a comparison, in particular a difference, between the measurement of the at least one parameter by the first optical particle sensor and the measurement of the at least one parameter by the second optical particle sensor.

[0075] The interval-based differential measurement described above can be replaced and / or supplemented in a particularly reliable manner by using two sensors. The use of the second optical particle sensor eliminates complex switching mechanisms and prevents measurement interruptions. This further increases measurement precision.

[0076] It is particularly advantageous if the first optical particle sensor and the second optical particle sensor are of the same design. In an advantageous development of the method according to the invention, the determination of a spatial fog distribution can be carried out in a step e) by repeating the cloud and fog measurements according to steps a) to d) at different locations, in particular using an unmanned aerial vehicle.

[0077] If the method according to the invention is carried out on an unmanned aircraft, it can be performed at various locations within the environment or atmosphere. This allows for a spatially resolved determination of the properties of the atmosphere, in particular of a cloud.

[0078] For this purpose, in particular a satellite-based positioning system can be used to determine the current location of the device.

[0079] Of particular advantage here is the determination of the vertical extent of a cloud or fog field as well as the physical properties of the cloud or fog field along the vertical extent.

[0080] Features described in connection with one of the subject matters of the invention, specifically the device and method according to the invention, can also be advantageously implemented for the other subject matters of the invention. Likewise, advantages mentioned in connection with one of the subject matters of the invention can also be understood to apply to the other subject matters of the invention.

[0081] It should also be noted that terms such as "comprising," "having," or "with" do not exclude other features or steps. Furthermore, terms such as "a" or "the," which indicate a singular number of steps or features, do not exclude a plurality of features or steps—and vice versa.

[0082] In a purist embodiment of the invention, however, it may also be provided that the features introduced in the invention with the terms "comprising," "having," or "with" are listed exhaustively. Accordingly, one or more lists of features may be considered complete within the scope of the invention, for example, for each claim. The invention may, for example, consist exclusively of the features mentioned in claim 1.

[0083] It should be noted that terms such as "first" or "second," etc., are used primarily to distinguish between respective device or method features and are not necessarily intended to imply that features are mutually dependent or related to one another. Exemplary embodiments of the invention are described in more detail below with reference to the drawings.

[0084] The figures each show preferred embodiments in which individual features of the present invention are illustrated in combination with one another. Features of one embodiment can also be implemented independently of the other features of the same embodiment and can therefore be readily combined by a person skilled in the art to form further useful combinations and subcombinations with features of other embodiments.

[0085] In the figures, functionally identical elements are provided with the same reference numerals.

[0086] They show:

[0087] Figure 1 is a schematic representation of a possible embodiment of a device according to the invention;

[0088] Figure 2 is a schematic representation of a possible embodiment of a drying device;

[0089] Figure 3 shows a block diagram of a possible embodiment of a method according to the invention;

[0090] Figure 4 shows an exemplary representation of measurement curves of a potential temperature recorded by means of the device according to the invention;

[0091] Figure 5 shows an exemplary representation of measurement curves of a relative humidity recorded by means of the device according to the invention; and

[0092] Figure 6 shows an exemplary representation of measurement curves of a particle occurrence recorded by means of the device according to the invention.

[0093] Figure 1 shows a schematic representation of a possible embodiment of a device 1 for measuring clouds and fog.

[0094] The device 1 for cloud and fog measurement comprises a first optical particle sensor 2 for the time-resolved measurement of at least one parameter of particles 3 in a first sample volume 4 of air from an environment 5, with a first volume flow measuring device 6 for determining a flow rate of the air through the first sample volume 4. Furthermore, a computing device 7 is provided, by means of which the presence of a cloud and / or fog in the air can be determined from the at least one parameter. In the exemplary embodiment shown in Figure 1, the first volume flow measuring device 6 is designed as part of the first optical particle sensor 2. The device 1 preferably comprises a power supply device 8, which can be designed in particular as an accumulator and / or battery.

[0095] The embodiment of the device 1 shown in Figure 1 preferably further comprises a drying device 9 for drying the air before it enters the first sample volume 4.

[0096] The drying device 9 will be described in more detail later in connection with Figure 2.

[0097] In the embodiment shown in Figure 1, the drying device 9 preferably has at least one desiccant, in particular a plurality of silica gel balls 10.

[0098] In the embodiment of the device 1 according to the exemplary embodiment shown in Figure 1, a second optical particle sensor 11 for detecting particles 3 in a second sample volume 12 of air from the same environment 5 with a second volume flow measuring device 13, which is designed as part of the second optical particle sensor 11, for determining a flow rate of the air through the second sample volume 12 is preferably also provided as part of the device 1.

[0099] In particular, in the embodiment of the device 1 shown in Figure 1, the computing device 7 is preferably configured to determine the presence of the fog from a comparison, in particular a difference, of the measurement of the at least one parameter by the first optical particle sensor 2 and the measurement of the at least one parameter by the second optical particle sensor 11.

[0100] The embodiment of the device 1 shown in Figure 1 is preferably designed such that the first optical particle sensor 2, the drying device 9, and the second optical particle sensor 11 are arranged on an unmanned aircraft 14. Furthermore, in the embodiment shown in Figure 1, the computing device 7 and the power supply device 8 are also arranged on the unmanned aircraft 14.

[0101] In the embodiment shown in Figure 1, the computing device 7 preferably also has a radio module (not shown) for real-time communication with a ground station (not shown).

[0102] Furthermore, in the embodiment shown in Figure 1, a protective device 15 is preferably arranged above an air inlet area 16. The air flows from the environment 5 toward the sample volumes 4, 12 via the air inlet area 16.

[0103] The protective device 15 and the air inlet area 16 are preferably designed such that the flow of air is homogenized and laminarized on its way to the sample volumes 4, 12.

[0104] It may be provided that the optical particle sensor 2.1 1 is of type N3, manufactured by Alphasens, UK.

[0105] It can be provided that the components of the device 1 are arranged on the unmanned aircraft 14 by means of a carbon fiber frame.

[0106] One or more additional meteorological sensors, such as a temperature sensor and / or a pressure sensor and / or a humidity sensor, can also be provided on the device 1.

[0107] The embodiment of the device 1 shown in Figure 1 is designed for an independent operation duration of 1 to 3 hours, preferably 2 hours.

[0108] A total mass of the device 1 shown in Figure 1 less the unmanned aircraft 14 is preferably 400 g to 500 g, particularly preferably 440 g.

[0109] Figure 2 shows a schematic representation of a possible embodiment of the drying device 9.

[0110] In the embodiment shown in Figure 2, the drying device 9, like the embodiment shown in Figure 1, is designed as a diffusion dryer. The drying device 9 preferably has a desiccant, in particular a plurality of silica gel spheres 10. Furthermore, the drying device 9 comprises an inner tube 17 and an outer tube 18 arranged coaxially with the inner tube 17, which has a larger diameter than the diameter of the inner tube 17.

[0111] In the embodiment shown in Figure 2, a desiccant receiving chamber 19 is formed in the space between the inner tube 17 and the outer tube 18, in which the desiccant, in this case the silica gel spheres 10, is accommodated. In the example shown in Figure 2, only a few silica gel spheres 10 are shown for illustrative purposes.

[0112] It can be provided that the silica gel spheres 10 each have a diameter between 2 mm and 5 mm. It can be provided that an average diameter of the silica gel spheres 10

[0113] 3.4 mm. Furthermore, in Figure 2, the air flow is symbolized by an arrow 20. The air flow according to arrow 20 is directed toward the first optical particle sensor 2.

[0114] It can be provided that the inner tube 17 and the outer tube 18 each have a length of 8 cm to 20 cm, in particular 12 cm. Preferably, the inner tube 17 and the outer tube 18 are of equal length.

[0115] It may be provided that the inner tube 17 is formed from a cured resin, has an inner diameter of 6 mm to 7 mm, preferably 6.2 mm, and a thickness of 0.5 mm to 1 mm, preferably 0.8 mm.

[0116] The inner tube 17 may be provided with perforations, the diameter of which is smaller than the minimum diameter of the silica gel spheres 10. The perforations allow air to come into contact with the desiccant, particularly through diffusive transport. The diameter of the perforations is preferably 1.4 mm to 1.6 mm. In particular, the average diameter of the perforations may be 1.5 mm.

[0117] It can be provided that the inner tube 17 is formed by means of a 3D printing process, in particular by means of a resin printer.

[0118] It can be provided that the inner tube 17 is provided on its outer side with a conductive coating, in particular a conductive paint, so that no particles are prevented by static charge from entering the desiccant receiving space 19.

[0119] It may be provided that the outer tube 18 is formed using a 3D printing process. Preferably, the outer tube 18 is formed from a polylactide using a 3D printing process.

[0120] It is particularly advantageous if the mass of the drying device 9 including the desiccant is at most 150 g, preferably at most 100 g, particularly preferably between 20 and 50 g.

[0121] As a result, the drying device 9 is particularly suitable for use on the unmanned aircraft 14 and is superior to known heating dryers due to its low energy consumption and low mass.

[0122] A working time limited by the drying effect of the desiccant is insignificant compared to the operational time of the unmanned aircraft 14. Figure 3 shows a block diagram of a possible embodiment of a method for cloud and fog measurement.

[0123] In a receiving block 30, air from the environment 5 is taken into the first sample volume 4. In a measuring block 31, a time-resolved measurement of at least one parameter of the particles 3 in the first sample volume 4 of the air is carried out by means of the first optical particle sensor 2.

[0124] In a flow rate block 32, the flow rate of the air through the first sample volume 4 is determined by means of the first volume flow measuring device 6.

[0125] In a determination block 33, the presence or absence of fog in the air is determined from at least one parameter.

[0126] Preferably, within the receiving block 30, the air is at least partially dried before being taken into the first sample volume 4.

[0127] Preferably, within the scope of the receiving block 30, air from the same environment 5 is additionally taken into the second sample volume 12.

[0128] Preferably, within the scope of the measuring block 31, a time-resolved measurement of the at least one parameter of the particles 3 in the second sample volume 12 of the air is additionally carried out by means of the second optical particle sensor 11.

[0129] Preferably, within the scope of the flow rate block 32, a determination of the flow rate of the air through the second sample volume 12 is carried out by means of the second volume flow measuring device 13.

[0130] Preferably, furthermore, within the scope of the determination block 33, the presence of the fog is determined from a comparison, in particular a difference measurement of the at least one parameter by the first optical particle sensor 2 and the measurement of the at least one parameter by the second optical particle sensor 11.

[0131] Preferably, furthermore, within the scope of a distribution block 34, a spatial fog distribution is determined by repeating the cloud and fog measurement in steps 30 to 33 at different locations, preferably by means of the unmanned aircraft 14.

[0132] This can be achieved with spatial resolution by using the unmanned aircraft 14, preferably in combination with a positioning system arranged on the unmanned aircraft 14. Figure 4 shows an exemplary representation of measurement curves of a potential temperature acquired by means of the device 1 according to the invention.

[0133] In Figure 4, the potential temperature in units of Kelvin (Pot. Temp. [K]) is plotted on a horizontal axis. The height of the device 1, which is mounted on the unmanned aerial vehicle 14, above the ground, i.e., the height above ground level (Höhe ü.B. [m] or Altitude above ground level), is plotted on a vertical axis in units of meters.

[0134] Three curves are shown because the device 1 was equipped with three temperature sensors to perform the measurement in this case. The measurement curves were acquired by ascending the device 1 vertically along the vertical profile with the aid of the unmanned aerial vehicle 14.

[0135] You can see slight deviations in the temperature curves depending on the respective sensor.

[0136] Figure 5 shows an exemplary representation of measurement curves of a relative air humidity recorded by means of the device 1 according to the invention.

[0137] Again, the height above the ground is plotted along the vertical axis. Relative humidity in percent (RH [%]) is plotted on the horizontal axis. Again, the device 1 for determining the measured values ​​shown in Figure 5 comprises three humidity sensors, which are represented by the three curves in Figure 5.

[0138] Figure 6 shows an exemplary representation of measurement curves of a particle occurrence recorded by the device 1. Again, the height above the ground is plotted along the vertical axis.

[0139] On the horizontal axis in Figure 6, the determined total mass of all particles 3 with a diameter of less than 10 pm, which can also be referred to as PM10, is plotted. The unit is pg / m 3 given (PM10 [pg / m 3 ]).

[0140] To determine this value, the volume of the particles 3 is determined from the scattering cross sections determined by the optical particle sensors 2, 11, and ultimately their mass is determined by estimating a density. Furthermore, the optical particle sensors 2, 11 determine the number of particles 3 within the sample volume 4, 12 within a unit of time, and the resulting volume flow through the sample volumes 4, 12 is determined by the volume flow measuring devices 6, 13.

[0141] From this, an average particle mass per m 3 in the air of the environment 5 from which the air samples were taken. If such a time-resolved measurement is performed and a current height of the device 1 above the ground is simultaneously documented, the particle occurrence can be projected onto the respective height of the respective environment 5. Figure 6 shows two curves: a moist air curve 40 and a dry air curve 41.

[0142] In the example shown in Figure 6, the humid air curve 40 thus represents the total particle mass per m 3 depending on the height, which was determined by the second optical particle sensor 11, which does not have a drying device 9.

[0143] The dry air curve 41, on the other hand, provides information about the dry mass of the particles 3 in the respective environment 5 of the respective height and was determined by means of the first optical particle sensor 2, in which the air was dried by means of the drying device 9.

[0144] By comparing curves 40 and 41, the water content in the total particle mass within the respective environment 5 can be estimated from their difference.

[0145] This allows the presence of fog or clouds to be measured or detected. Outside of a cloud, it is expected that particles 3 will have little or no water layer, which is why curves 40 and 41 are expected to coincide.

[0146] In the experiment shown in Figure 6, a cloud base, represented by the cloud baseline 42, was penetrated at a height of just under 80 m above the ground and the device 1 was located above the cloud baseline 42 within the cloud.

[0147] It is thus apparent from Figure 6 that a significant difference between the moist air curve 40 and the drying curve 41 is to be expected, in particular, when the device 1 is located within a cloud and / or a fog or a cloud and takes the air samples from the environment 5 arranged there.

[0148] Furthermore, the experiment shown in Figure 6 demonstrates the possibility of determining a spatial, in this case vertical, fog distribution by repeating the cloud and fog measurements according to blocks 30 to 33 shown in Figure 3 at different locations, in this case at different altitudes, in particular by means of the unmanned aerial vehicle 14.

[0149] The project leading to this application has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sktodowska-Curie grant agreement No 861291. Reference symbols

[0150] 1 device

[0151] 2 first optical particle sensor

[0152] 3 particles

[0153] 4 first sample volume

[0154] 5 Surroundings

[0155] 6 first volume flow measuring device

[0156] 7 Computing device

[0157] 8 Energy supply facility

[0158] 9 Drying device

[0159] 10 silica gel balls

[0160] 11 second optical particle sensor

[0161] 12 second sample volume

[0162] 13 second volume flow measuring device

[0163] 14 unmanned aerial vehicles

[0164] 15 Protective device

[0165] 16 Air intake area

[0166] 17 inner tube

[0167] 18 outer tube

[0168] 19 Desiccant storage room

[0169] 20 Arrow

[0170] 30 recording blocks

[0171] 31 measuring block

[0172] 32 Flow rate block

[0173] 33 Investigation Block

[0174] 34 Distribution block

[0175] 40 Humid air curve

[0176] 41 Dry air curve

[0177] 42 Cloud baseline

Claims

Patent claims 1. Device (1) for cloud and fog measurement, comprising a first optical particle sensor (2) for the time-resolved measurement of at least one parameter of particles (3) in a first sample volume (4) of air from an environment (5) with a first volume flow measuring device (6) for determining a flow rate of the air through the first sample volume (4), wherein a computing device (7) is provided, by means of which a presence of a cloud and / or fog in the air can be determined from the at least one parameter.

2. Device (1) according to claim 1, characterized in that a drying device (9) is provided for drying the air before it enters the first sample volume (4).

3. Device according to claim 2, characterized in that the drying device (9) has at least one drying agent, in particular a plurality of silica gel balls (10).

4. Device (1) according to one of claims 1 to 3, characterized by a second optical particle sensor (11) for the time-resolved measurement of at least one parameter of particles (3) in a second sample volume (12) of air from the same environment (5) with a second volume flow measuring device (13) for determining a flow rate of the air through the second sample volume (12), wherein the computing device (7) is designed to determine the presence of the mist from a comparison, in particular a difference, of the measurement of the at least one parameter by the first optical particle sensor (2) and the measurement of the at least one parameter by the second optical particle sensor (11).

5. Device (1) according to claim 4, characterized in that an unmanned aircraft (14) is provided, wherein at least the first optical particle sensor (2), the drying device (9) and the second optical particle sensor (11) are arranged on the unmanned aircraft (14).

6. Device according to one of claims 1 to 5, characterized by a protective device (15) above an air inlet area (16) into the sample volume (4, 12).

7. Method for measuring clouds and fog with at least the following steps: a) taking air from an environment (5) into a first sample volume (2) b) time-resolved measurement of at least one parameter of particles (3) in the first sample volume (2) of the air by means of a first optical particle sensor (2) c) determining a flow rate of the air through the first sample volume (4) by means of a first volume flow measuring device (6) d) determining a presence of a cloud and / or fog in the air from the at least one parameter.

8. The method according to claim 7, characterized in that in step a) the air is at least partially dried before being taken into the first sample volume (4).

9. The method according to claim 7 or 8, characterized in that in step a) a second sample volume (12) additionally takes air from the same environment (5); in step b) a time-resolved measurement of the at least one parameter of particles (3) in the second sample volume (12) of the air is additionally carried out by means of a second optical particle sensor (11); in step c) a flow rate of the air through the second sample volume (12) is determined by means of a second volume flow measuring device (13); in step d) the presence of the cloud and / or fog is determined from a comparison, in particular a difference, between the measurement of the at least one parameter by the first optical particle sensor (2) and the measurement of the at least one parameter by the second optical particle sensor (11).

10. Method according to one of claims 7 to 9, characterized by e) determining a spatial fog distribution by repeating the cloud and fog measurement according to steps a) to d) at different locations, in particular by means of an unmanned aircraft (14).

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