Copula, a new approach for optimum design of Voxel-based GNSS tropospheric tomography based on the atmospheric dynamics

Mousavian, Roya; Hossainali, Masoud Mashhadi; Lorenz, Christof; Kunstmann, Harald

doi:10.1007/s10291-022-01340-1

Cited by 3 publications

(2 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The CFD solving process generally consists of three main parts: pre-processing, solving and post-processing, of which the STAR-CCM+ solving process can be represented by the following flow chart [7][8]. As shown in figure 1.…”

Section: The Solution Process Of the Cfdmentioning

confidence: 99%

Design of an All-electric Bus Cooling System Incorporating Computational Fluid Dynamics

2022

KME

View full text Add to dashboard Cite

With the emphasis on renewable energy and environmental protection, new energy vehicles are gradually entering the social space and electric vehicles are once again moving to new heights. The aim of this paper is to investigate the design of a cooling system for a purely electric bus incorporating computational fluid dynamics. This paper follows the principle of "determine the heat source distribution of the prototype -calculate the temperature rise of the prototype -design an optimised cooling structure -analyse the cooling effect -propose the design of the prototype cooling structure". This paper studies the temperature rise and cooling of the prototype, focusing on the effect of different cooling structures on the temperature rise of the prototype. Based on the heat transfer, a finite element model of the engine is established and the losses and heat source distribution of the prototype are calculated by combining empirical equations and MAP diagrams of the engine losses. The heat transfer process of the engine is investigated, including the heat transfer process within and between the components of the prototype in contact with each other, and the convective heat transfer process between the prototype and the fluid contact surface. Based on the CFD (Computational Fluid Dynamics) method, the flow and temperature fields of the physical air-cooled prototype are calculated using the existing CFD mathematical model, and the influence of the flow field of the prototype heat exchanger ventilation duct on the engine temperature rise is analysed. A forced air cooling solution for the prototype was proposed to determine the structure of the vents, the location of the ventilation holes and the size of the cooling fan. The effect of forced air cooling on the temperature rise of the prototype is compared with the effect of natural air cooling. A parallel water jacket should be designed and its structure optimised in order to compare the effect of the water jacket on the temperature rise of the prototype before and after optimisation. Finally, all studies are combined to provide reference recommendations for the design of the prototype cooling structure.

show abstract

Section: The Solution Process Of the Cfdmentioning

confidence: 99%

Design of an All-electric Bus Cooling System Incorporating Computational Fluid Dynamics

2022

KME

View full text Add to dashboard Cite

show abstract

“…Hence, it has become one of the most promising techniques to reconstruct the four-dimensional distribution of atmospheric WV [6]. Plenty of Global Navigation Satellite System (GNSS) tropospheric WV tomography (GNSS tomography) studies and experiments have been carried out in different regions [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. A GNSS tomographic domain covering the ground-based GNSS receiver network is usually cuboid-shaped or box-shaped within the troposphere, and it is first needed to discretize into many tomographic voxels in the process of tomographic solving.…”

Section: Introductionmentioning

confidence: 99%

Development of a New Vertical Water Vapor Model for GNSS Water Vapor Tomography

Wan

Zhang

et al. 2022

Remote Sensing

View full text Add to dashboard Cite

One of the main challenges of Global Navigation Satellite System (GNSS) tomography is in solving ill-conditioned system equations. Vertical constraint models are typically used in the solution procedure and play an important role in the quality of the GNSS tomography, in addition to helping resolve ill-posed problems in system equations. In this study, based on a water vapor (WV) parameter, namely IRPWV, a new vertical constraint model with six sets of coefficients for six different WV states was developed and tested throughout 2019 in the Hong Kong region with four tomographic schemes, which were carried out with the model and the traditional vertical constraint model using three different types of water vapor scale height parameters. Experimental results were numerically compared against their corresponding radiosonde-derived WV values. Compared with the tests that used the traditional model, our results showed that, first, for the daily relative error of WV density (WVD) less than 30%, the new model can lead to at least 10% and 49% improvement on average at the lower layers (below 3 km, except for the ground surface) and the upper layers (about 5–10 km), respectively. Second, the skill score of the monthly root-mean-square error (RMSE) of layered WVD above 10 accounted for about 83%, 87%, and 64%. Third, for the annual biases of layered WVD, the new model significantly decreased by 1.1–1.5 g/m3 at layers 2–3 (about 1 km), where all schemes showed the maximal bias value. Finally, for the annual RMSE of layered WVD, the new model at the lower (about 0.6–3 km) and upper layers improved by 13–42% and 5–47%, respectively. Overall, the new model performed better on GNSS tomography and significantly improved the accuracy of GNSS tomographic results, compared to the traditional model.

show abstract

Optimized Approach for Near-Real-Time Three-Dimensional Water Vapor in the GNSS Based on the Informer Model

Yixin,

Pengfei,

Shirong

et al. 2024

Preprint

View full text Add to dashboard Cite

The integration of near-real-time three-dimensional (3D) water vapor data into numerical weather prediction is crucial for monitoring and forecasting extreme weather events but faces various challenges. We focus on reconstructing the 3D water vapor field using Global Navigation Satellite System (GNSS) water vapor tomography techniques, emphasizing two primary concerns: achieving high-precision initial 3D water vapor values and effectively partitioning the vertical tomography grid. We introduce a novel real-time, high-precision water vapor prediction model, namely, the Informer-WV model, based on the Informer framework, whose predictions serve as the initial values for tomography. Furthermore, we propose an innovative method for nonuniform vertical delineation of the tomography grid in which the upper boundary height of the 3D tomography grid is determined by the vertical prediction accuracy of the model. For practical application purposes, Hong Kong, China, was chosen as the study area. The Informer-WV model, utilizing ERA5 reanalysis data, successfully predicted the regional water vapor density for 2022. The model demonstrated a remarkable prediction accuracy, with an annual root mean square error (RMSE) better than 0.80 g/m³ compared to the actual ERA5 values. Building on this high-precision prediction, we adjusted the upper boundary altitude of the tomography grid to 5.2 km, specifically for Hong Kong. By benchmarking against radiosonde-derived water vapor density data, we analyzed the near-real-time tomography inversion results for the two weakest prediction periods of the model. The RMSE of the water vapor inversion values derived from our optimized method was reduced to 1.26 g/m³. This approach not only improved the accuracy by 19% relative to the initial predictions but also significantly outperformed the traditional tomography method.

show abstract

Copula, a new approach for optimum design of Voxel-based GNSS tropospheric tomography based on the atmospheric dynamics

Cited by 3 publications

References 32 publications

Design of an All-electric Bus Cooling System Incorporating Computational Fluid Dynamics

Design of an All-electric Bus Cooling System Incorporating Computational Fluid Dynamics

Development of a New Vertical Water Vapor Model for GNSS Water Vapor Tomography

Optimized Approach for Near-Real-Time Three-Dimensional Water Vapor in the GNSS Based on the Informer Model

Contact Info

Product

Resources

About