Research on the Application of VR Technology in Meteorological Simulation

Abstract

Recent years, due to the direct or indirect damages caused by meteorological disasters more and more attention have been paid to natural disasters. At same time, diversified and multi-sensory interactive meteorological services is increasingly demanded. In this study, novel interactive meteorological service was compared with the traditional communication methods. Combining with case studies and systems creation, a virtual reality weather simulation framework was proposed, and a realistic virtual game environment providing real-time and historical weather information was created. The primary goal of this study is to build a weather display cabinet game system by using virtual reality technology, and promoting public's understanding of the principles of weather changes. With the interactive games in realistic scenarios, public's awareness for disasters prevention could be promoted. It is helping to change public's traditional understanding of meteorological theories, and will provide a more convenient way for the public to explore more effective weather forecasts. The simulation system is supported by VR technology. It was combined with Leap Motion interactive equipment to make popularization games for weather science. T-test data analysis showed that the application of VR technology in weather games has strong operability and interactivity.

1. INTRODUCTION

1.1 Research background

In recent years, meteorological disasters have caused direct or indirect damage to human lives and property, national economic construction, and national defense construction. Natural disasters can cause losses of millions to tens of billions of yuan, and countless casualties in the disaster zone. How to effectively popularize meteorological knowledge and raise public awareness of meteorological disaster prevention and mitigation is necessary . However, the traditional methods of meteorological science popularization often have certain limitations, and it isn't easy to stimulate the public's enthusiasm for active participation, learning, and exploration. Considering that, the expected goals of meteorological science popularization are challenging to achieve.

Fig. 1. Meteorological remote sensing icon.

Fig. 2. Weather Virtual Classroom.

With the rapid development of digital media technology and art forms, the traditional popularization of science and technology has been transformed into the stage of scientific communication; and the communication channels have gradually developed from one-way to two-way; and the popularization of science has undergone changes, from "installation" to diversification and modernization. Direction development, thus more emphasis on the interaction and interactivity of popular science [1]. Through the combination of theory and practice, this paper increases the application of virtual reality technology in the design of interactive user meteorological science education system, changes the one-way "infusion" teaching method, and uses the traditional meteorological science method to simulate the dynamic computer The form superimposes the three-dimensional dynamic virtual image into the actual scene in real-time through the virtual reality device and displays it, and the effect is remarkable. Popular science content combined with the display of virtual reality technology, through the player's perspective, with vivid virtual scene design to convey the phenomenon principle of natural disasters and to express the scientific knowledge of meteorology with solid interaction, immersion, and fun.

1.2 Research purposes

The purpose of this research is to use VR technology combined with the application of Leap Motion interactive equipment in meteorological science popularization games to add interactive animation, game-style animation, and other forms, change the traditional way of science popularization of meteorology, and strengthen the impact on science transmission. Besides, models that use virtual reality technology to highly simulate and restore various meteorological phenomena are created, and at the same time, three-dimensional virtual reality technology is adopted to simulate and restore the visual and sound effects of weather environments such as wind, rain, and snow, allowing players to interact in the virtual weather environment. In this case, players can have a real visual impact and operational experience, thus achieving the goal of meteorological science popularization. At the same time, through the application of virtual reality technology, it is also possible to highly restore and explain the changing meteorological principles, which is conducive to promoting disaster warning and disaster prevention knowledge publicity through meteorological games full of meteorological science [2].

1.3 Research method

For this topic, the literature analysis method and the case study method are mainly adopted, while through the T-test data analysis, the related information of virtual reality and meteorological science popularization games is summarized and sorted out, and in-depth structural research is conducted. Besides, the virtual science game method is used. Through the Leap Motion interactive device, the user's game interest in the science popularization is enhanced; virtual reality technology is applied to building; and a virtual computer simulation system is created. Other than that, the multi-source information of weather is integrated into the same system to show users the virtual simulation world of popular science games, and finally achieve the purpose of edutainment.

2. THEORETICAL ANALYSIS

2.1 Analysis of traditional meteorological popularization

The traditional way of popularizing meteorological science is to analyze and organize meteorological data , and introduce meteorological knowledge to people in the most simple and easy-to-understand style through the use of newspapers, television, radio, online video, and other media, thus enhancing the means of popularizing science concerning the awareness of meteorological disaster prevention and mitigation. As we all know, meteorological activities are closely related to people's daily life. Therefore, the scientific popularization of meteorological knowledge plays a vital role in the development of human society. The weather forecast allows people to predict the weather that will happen and enable people to prepare for the weather. However, the traditional methods of meteorological science popularization are unilateral indoctrination. The content is limited to the changes in temperature and rain in several cities in the next few days. Users will feel the acceptance process for audiences due to the lack of interactivity and immersion in popular science methods. Besides, as the science popularization process is monotonous, the target group will lose the original interest in popular science content[3].

Fig. 3. Meteorological data platform.

The ways of making weather forecasts contain synoptic forecasting methods, statistical forecasting methods, and dynamical forecasting methods. These three weather forecasting methods are too specialized, and the data display is dull. Simultaneously, meteorological science popularization resources include the business platform of the meteorological department, the meteorological science popularization education base, popular science venues, and different forms of graphic publicity materials, such as wall charts, brochures, books, and magazines. The single form of popular science products restricts people’s understanding of the limitations of meteorological knowledge. Existing TV, Internet, and weather APP make people passively accept meteorological science information, lacking interaction and interest.

Fig. 4. Weather APP.

2.2 Analysis of VR weather science game mode

On March 1, 2007, the International Disaster Reduction Strategy (UN/ISDR) announced a set of video games called "Prevent Disasters". In fact, this is an attempt by the International Disaster Reduction Strategy to popularize game science. In displaying meteorological science popularization, interactive devices such as Leap Motion, HTC VIVE, Oculus Rift and Gear VR can enrich the interactivity and interest of popular science and increase the sense of immersion through Arduino and other devices. In addition, in the weather forecast dissemination, the form of a virtual studio is used to convey meteorological science , and an independent digital high-definition and standard-definition weather forecast virtual studio all-in-one system, full Chinese high-definition real-time nonlinear editing software, weather forecast production system software, 3D weather virtual studio software, real-time multi-format (support mpg2) signal output and collection, and real-time mixed delivery of reliable weather information are adopted.

Fig. 5. Weather forecast virtual studio.

Virtual reality technology uses computer simulation to visualize the content of popular science , which is immersive. Interactive weather science games have strong characteristics, namely, novelty, and entertainment. For example, users will have a more pleasant experience in the science popularization of participating in the game, get a full range of audiovisual enjoyment and receive information more vividly. As a result, users can more easily understand and accept the knowledge of meteorological science and eventually reach the level of meteorological science-expected result [4]. Virtual reality technology dominates a positive role in the generalization of meteorological science. It can enrich users' understanding of meteorological knowledge and enhance users' awareness of disaster prevention and mitigation. In addition, its proposal can improve the interaction and interest of the current methods of meteorological science popularization and promote the development of meteorological science popularization.

Fig. 6. AR climate science show.

2.3 The feasibility of weather simulation

This research used computer graphic technologies to design the three-dimensional dynamic design of meteorological elements and weather constructed through modeling, where MAYA software and Particle systems in Unity3D were used. An accurate scale same with the real scene was created in the game to scientifically simulate the weather scene. The 3D model made MAYA was imported into Unity3D, and details in models such as mud, grass and tress was created with brush tools in different scene. Sky box is a tool for making sky in Unity. The rainwater model is made using the Particle System in Unity3D game engine. An interactive weather simulation exhibition scene was established. Combining with Leap motion control technology, a wide spatial field of view was created. The created multi-sensory weather simulation system make up for the unidirectional and space limitations of traditional weather forecast transmission.

2.4 Design of meteorological simulation controlled with Leap motion

The Leap motion controller is designed to track hand and finger movements in space, which can be used for humancomputer-interaction . The Leap motion controller is a small USB device that is meant to be placed on the desktop. For VR usage, the controller can be attached onto the HMD facing the users’ viewing direction. The Leap motion controller is an infrared light-based stereo-scopic camera [5]. By illuminating the close space near to the cameras with infrared light, it can capture a user’s hands and fingers . By utilizing some sort of tracking algorithm, it is able to estimate the position and orientation of the hand and its fingers. The controller’s action area is featured with the width of 150° multiplied by 120° and spans about 80 cm originating from the device. The basic functionality of the Leap motion is the ability to track a user’s hands. The position and orientation of the hand and its fingers are being tracked and can be directly mapped onto a virtual skeleton model . The SDK provides easy access to data of all fingers and its bones [6]. Weather simulation interaction uses Leap motion SDK to write code to recognize gesture modules and perform game data storage, data exchange, reading and writing, data recognition, and editing. The gesture control module includes query Leap motion SDK unit, weather model modeling unit, VR virtual reality technology unit and Arduino tactile trigger device unit. The design of weather simulation adds Leap motion controller, which can more effectively promote the feasibility and interactivity of the game as well as the immersion of game players.

Fig. 7. Leap motion controller.

Fig. 8. Gesture presentation diagram.

Fig. 9. Virtual skeleton model.

3. EMPIRICAL RESEARCH

3.1 Principle of design

In the current research, the virtual weather display cabinet system displays the three-dimensional weather picture formed by rain in the virtual cabinet to create a real-life animation. Through the HTC VIVE device, multi-touch interaction in the virtual scene, based on the principle of meteorological generation, by special processing of constructing a three-dimensional model through the actual shot of meteorological phenomena, and then superimposing the three-dimensional animation into the scene, a weather display scene created by rain is formed. In the virtual display cabinet, the generation principles of convective precipitation, frontal precipitation, and topographic precipitation will be displayed, respectively .Virtual technology is employed for meteorological science popularization and services to improve visual effects and promote interactive experiences conducive to meteorology—popularization of knowledge [7].

Fig. 10. Virtual weather schematic map.

3.2 Data Resources

Meteorological simulation VR uses weather maps and analyzes the changing trends, moving directions, and speeds of weather systems and weather areas based on synoptic principles. It employs numerous long-term meteorological observation data and establishes weather changes based on the principles of probability statistics from the model. These dynamic analyses, statistical analysis, and numerical analysis are applied in different meteorological levels of the meteorological simulation VR system. The detection and setting of temperature, wind speed, and precipitation are crucial factors in meteorological simulation. Satellite imagery and meteorological remote sensing monitoring are used when being combined with 3D model reconstruction of meteorological and landform morphology and mapping to the virtual reality environment[8]. GPS meteorological remote sensing technology provides geographic positioning and accurate data support for three-dimensional landform design and meteorological value change modulation used in virtual weather . In addition, the weather simulation data is integrated into the system design of the weather game to provide players with authenticity and immersion.

Fig. 11. Weather simulation VR game framework.

3.3 Game effectiveness

The weather simulation game includes three meteorological environments, respectively, topographical precipitation, prevalent precipitation, and frontal precipitation. Users can learn about the meteorological environment through the first-person perspective (FPS) or the third-person perspective (TFS). The game has also set up voice and text prompts, which can interactively adjust and control the UI interface in the game through the HTC VIVE gamepad. Voice input can promptly remind users to avoid the impact of natural disasters in the game, thereby enhancing users' understanding of the nature of meteorological disasters. Besides, the game has single and multiplayer options. If conditions permit, a virtual weather classroom can be established to realize multiplayer game activities, hence achieving the game's purpose. At the same time, real-time communication between users can be achieved through the voice system.

3.4 Implementation

The game program is implemented with a cross-platform and virtual reality game engine (Unity3D). Unity3D software can realize the application of the particle system in the game and the natural arrangement of rainfall and wind speed changes. Meteorological data is integrated with meteorological remote sensing. Barotropic vorticity equation fD+βv=0 and regression method T = a1x1 + a2x2 + a3x3 + a4x4 + a5x5 +.......(A)were used to obtain temperature and atmospheric motion values. It combined with 3D MAX to model the geomorphic environment, which was then imported into Unity3D as FBX file for particle system settings to generate scenes. UI was realized with UX tools and unreal schematics , and built-in components was used to design and build immersive and user-friendly interfaces. Integrate hand interaction with Leap Motion somatosensory device, natural and smooth virtual reality interaction could be experienced with the interactive objects. Weather simulation VR device is operable in Windows 10 system and is used together with HTC VIVE virtual reality equipment.

4. CHARACTERISTIC ANALYSIS OF METEOROLOGICAL SIMULATION

4.1 The multi-sensory nature of weather simulation

To explore a more effective weather forecasting method, the BBC Meteorological Department carried an experiment where operator could feel the weather with hand. In the experiment, Ultraleap's somatosensory feedback system, gesture tracking suite and the Looking Glass holographic display were used. Ultraleap's ultrasonic somatosensory feedback technology was used to simulate various weather situations, including raindrops on the hands (rainy), skin exposure to the sun (sunny), snow, etc. In this study, Leap Motion based cross-platform weather simulation system is integrated with data storage, data exchange, data reading and writing, data recognition, and engine platform editing, and it was used to write code to identify the action module in weather simulation. The development of meteorological simulation is a data module calculated and visualized based on meteorological remote sensing data such as wind, rain, thunder, and lightning with the barotropic vorticity equation and regression methods.

Fig. 12. Looking Glass holographic display.

The constructed model scene in the weather simulation properly restored the natural weather environment and the particle effect. and the Unity 3D engine particle plug was used to mimic the natural phenomena. For example, by adjusting the parameters in U3D, topographical precipitation could be mimicked. In the process of texture selection, the photos of rain with transparent channels are used as weather textures in order to achieve the most realistic effect. With the combination of the Leap Motion somatosensory device and Unity game engine , users are allowed to control the game through gestures [9]. Players could choose different weather systems and control different weather levels through different gestures. Interacting with the game in a multi-sensory and diversified manner could intuitively understand weather knowledge and realize meteorological science population.

Fig. 13. Leap Motion Somatosensory Device.

4.2 Setting of weather model characteristics

The meteorological science popularization system uses the U3D game engine to create virtual scenes, designs the meteorological model, writes codes according to the computer C# language, and uses the Particle System to make Rain_Light particles. Since meteorological science popularization should be scientific and authentic, when making particles, information about rain was fully collected to ensure that the natural rainfall and the sound of rain can be expressed. Subsequently, the two dark cloud models, namely Clouds Medium and Clouds Light were produced, and combined with the rain model, to create the effect of raining and provide users with an interactive and immersive meteorological science popularization system. Considering that, in the meteorological science popularization system, different modules were used to promote users to learn meteorological knowledge in virtual scenes, and explore the principle of meteorological generation through interaction [10].

The weather model is based on the attributes of weather (such as rainfall). In the virtual reality interactive part, Leap Motion equipment is used for production, and its SDK provides a complete set of documentation for the Unity3D development environment. In the current research, it is found that in the number gestures "1" to "5" that people make, the number of fingers stretched out corresponds to the number . In Leap Motion SDK, the code hand.Fingers. Extended() can determine whether the fingers are flexed or extended by identifying the pointing of the fingers and that of the palm. Using this code, the computer can recognize the number of straight fingers and then execute commands in various gesture situations by using “if” statements. Taking "Rain" as an example, the Particle System is used to make three Prefabs representing light rain, moderate rain, and heavy rain in the game in advance. These Prefabs simulate the rainfall of light rain, moderate rain, and heavy rain. After the player makes different gestures, the “if” statement determines their motions and finally invokes other Prefabs to create environments under different weather levels.

Fig. 14. Leap Motion gesture instruction diagram.

4.3 Gesture operation analysis of weather games

For example, when the player makes a gesture “number 3”, the conditional sentence hand. Fingers. Extended()==3 in the “if” statement is true at this time, while all the other conditional sentences hand. Fingers. Extended()==1 are false. At this point, Unity begins to execute the execution statement under the condition of the hand. Fingers. Extended ()==3. Thus, under the action of the “if” statement, Unity calls the heavy rain Prefab to simulate corresponding effect. In addition to the above functions, the gesture recognition device can also recognize gestures such as circle and click. Weather science games use these gestures to replace mouse operations, which enriches the gameplay.

The weather simulation scene in this design fully made use of the interactive environment built in the game. It determined the division of interactive somatosensory numbers in the game interface construction and formed a weather scene display with different effects. The following program code in Unity3D was used:

float touchDistance=pointable.TouchDistance;

Pointable.Zonezone=pointable.TouchZone;

Finger farLeft=frame.Fingers.Leftmost;

Finger mostForwardOnHand=frame.Hands[0].

Fingers.Frontmost;

Tool rightTool=frame.Tools.Rightmost;

Vector pointingToward=pointable.Direction;

FrameframeOfThisPointableObject=pointable.Frame;

HandattachedHand=pointable.Hand;

if(hand.Fingers.Extended().Count==1)

{

Rain_Light.SetActiveRecursively(true);

Rain_Medium.SetActiveRecursively(false);

Rain_Heavy.SetActiveRecursively(false);

CloudsMedium.SetActiveRecursively(false);

CloudsLight.SetActiveRecursively(false);

}

elseif(hand.Fingers.Extended().Count==2)

{

Rain_Light.SetActiveRecursively(false);

Rain_Medium.SetActiveRecursively(true);

Rain_Heavy.SetActiveRecursively(false);

CloudsMedium.SetActiveRecursively(false);

CloudsLight.SetActiveRecursively(false);

}

elseif(hand.Fingers.Extended().Count==3)

The above code is a programming design for the amount control of rainfall and the code control of gesture number. To construct a virtual scene in weather simulation, the player can use Leap motion to bring out the corresponding model information and control the amount of rainfall with geature.

5. TEST AND ANALYSIS OF METEOROLOGICAL SCIENCE POPULARIZATION SYSTEM

5.1 Questionnaire design

In this paper, users conduct case practice on multi-sensory meteorological somatosensory under the conditions of the meteorological simulation. In this study, the test results are included in average scores, and the final results can accurately reflect the actual situation. Differences in gender and age was ignored and data was sort according to the generally recognized results. Corresponding questionnaire questions (Table 1) were established, and T-text test method was used to analyze the data and fill in the questionnaire.

Table 1. Test object statistics table.

5.2 Descriptive analysis

This questionnaire survey adopts the form of an online survey. After users experience the weather simulation, they will publish the electronic version of the questionnaire through the professional questionnaire survey platform "Questionnaire Star." According to the questionnaire design, the entire score of the scoring standard is 10 points. Among them, 40 people ranging from 20 to 45 participated the test. The test is carried out in a laboratory, and the experience time is 5 minutes per person. The effect of weather simulation will be evaluated after finished, and the survey information will finally be collected for data analysis.

5.3 Result analysis

From the results of data analysis, it can be seen that there are significant differences in the different indicators of the two groups (P<0.05)(Table 2). The average simple operation of the gamepad in the experimental group is 8.20, and the average simple operation of the game pad in the control group is 7.53. It could be found that the operation of the experimental group is 7.53(Table 3). The simple average score was significantly more significant than the control group, and other indicators also obeyed this rule. The simple average value of the handle operation of the experimental group can fully explain the weather simulation game design that meets the user experience and verifies that the operation of the weather simulation game is more effective than the traditional weather communication method.

Table 2. T test single factor analysis.

Table 3. P value difference analysis.

6. CONCLUSION AND FUTURE RESEARCH

In combination with Leap Motion interactive equipment, meteorological science popularization will be more in line with users’ life needs and psychological needs, thereby improving the user's quality of life. Meanwhile, the meteorological interactive science popularization design will be more humane and diversified. By analyzing experimental data, the application of VR technology in weather games can create dynamic simulation science scenes and enable users to promote interaction between themselves and the weather scenes in meteorological science learning in order to achieve scientific and practical science popularization purposes. At the same time, users can also experience "freedom" in this natural interaction while obtaining information inadvertently. The integration of VR technology and the field of meteorology provides essential support for the breakthrough and improvement of various contents in the field of meteorology and accelerates the interactive development of the field of meteorological science.

Future research: 1) the diversification of system development modules should be strengthened, and the design of weather simulation somatosensory based on virtual reality technology should be further promoted and the coordination between game content and interface design should be further improved; 2) Promote the research and development of the integration of game visual thinking perception and somatosensory form, Strengthen the applicability of game content, penetrate PRT, and promote the generation of generalized skills.