Modeling of Site Diversity Gain Using Rain Radar Data in Japan

Author(s):  
Peeramed Chodkaveekityada ◽  
Hajime Fukuchi
2021 ◽  
Author(s):  
Anastase Charantonis ◽  
Vincent Bouget ◽  
Dominique Béréziat ◽  
Julien Brajard ◽  
Arthur Filoche

<p>Short or mid-term rainfall forecasting is a major task with several environmental applications such as agricultural management or flood risks monitoring. Existing data-driven approaches, especially deep learning models, have shown significant skill at this task, using only rainfall radar images as inputs. In order to determine whether using other meteorological parameters such as wind would improve forecasts, we trained a deep learning model on a fusion of rainfall radar images and wind velocity produced by a weather forecast model. The network was compared to a similar architecture trained only on radar data, to a basic persistence model and to an approach based on optical flow. Our network outperforms by 8% the F1-score calculated for the optical flow on moderate and higher rain events for forecasts at a horizon time of 30 minutes. Furthermore, it outperforms by 7% the same architecture trained using only rainfall radar images. Merging rain and wind data has also proven to stabilize the training process and enabled significant improvement especially on the difficult-to-predict high precipitation rainfalls. These results can also be found in Bouget, V., Béréziat, D., Brajard, J., Charantonis, A., & Filoche, A. (2020). Fusion of rain radar images and wind forecasts in a deep learning model applied to rain nowcasting. arXiv preprint arXiv:2012.05015</p>


2014 ◽  
Vol 142 (5) ◽  
pp. 1738-1757 ◽  
Author(s):  
Jeffrey G. Cunningham ◽  
Sandra E. Yuter

Abstract The instability characteristics associated with different radar-derived mesoscale organization modes are examined using six cool seasons of operational scanning radar data near Portland, Oregon, and operational sounding data from Salem, Oregon. Additionally, several years of Microwave Rain Radar Ka-band vertically pointing radar data from Portland and Merwin, Washington, are used to characterize the nature and occurrence of generating cells and fall streaks. The combination of a new metric, convective-stratiform intermittency, with the classification of radar reflectivity maps into convective and stratiform precipitation types was applied to periods when the freezing level was >1.4-km altitude. This method distinguishes periods with embedded convective within stratiform mesoscale organization from those that were mostly convective or mostly stratiform. Mesoscale organization occurs in a continuum of states with predominantly stratiform structure occurring most frequently. Generating cells in the snow layer are common in cool-season storms and are primarily associated with potential instability aloft. For mostly stratiform and embedded convective within stratiform 3-h periods, the vertically pointing radar data showed nearly ubiquitous fall streaks in the snow layer originating above 3-km altitude. Stronger generating cells enhanced reflectivity in the rain layer consistent with a seeder mechanism. Stronger generating cells were more common during embedded convection within stratiform than in mostly stratiform periods. Nearly all embedded periods have active or latent (potential) instability. Hydrostatic instability more typically occurred at higher altitudes for embedded convective within stratiform periods compared to mostly convective periods. The occurrence of vertical wind shear instability was primary below 2-km altitude and was not typically associated with levels with generating cells.


Sign in / Sign up

Export Citation Format

Share Document