scholarly journals Impact of Radio Occultation Data on the Prediction of Typhoon Haishen (2020) with WRFDA Hybrid Assimilation

Atmosphere ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1397
Author(s):  
Shu-Ya Chen ◽  
Thi-Chinh Nguyen ◽  
Ching-Yuang Huang
Keyword(s):  
Radio Occultation ◽  
High Accuracy ◽  
Vertical Resolution ◽  
Physical Processes ◽  
Remarkable Improvement ◽  
Typhoon Track ◽  
Improve Model ◽  
Occultation Data ◽  
Data Sensitivity ◽  
Radio Occultation Data

FORMOSAT-7/COSMIC-2 (FS7/C2) satellite was successfully launched in June 2019. The satellite provides about 5000 radio occultation (RO) soundings daily over the tropical and partial subtropical regions. Such plentiful RO soundings with high accuracy and vertical resolution could be used to improve model initial analysis for typhoon prediction. In this study, assimilation experiments with and without the RO data were conducted with the WRFDA hybrid system for the prediction of Typhoon Haishen (2020). The experimental results show a remarkable improvement in typhoon track prediction with RO data assimilation, especially when using a nonlocal refractivity operator. Results in cycling DA and forecast are analyzed and verified for the RO data impact. Diagnostics of potential vorticity (PV) tendency budget helps explain the typhoon translation induced by different physical processes in the budget. The typhoon translation is essentially dominated by horizontal PV advection, but the track deviation can increase due to the vertical PV advection with opposite effects in the absence of RO data. Sensitivity experiments for different model initial times, physics schemes, and RO observation amounts show positive RO data impacts on typhoon prediction, mainly contributed from FS7. Complementary, an improved forecast of Typhoon Hagupit (2020) is also illustrated for the RO data impact.

scholarly journals Spherical Spline Application to Radio Occultation Data

2011 ◽  
Vol 1 (4) ◽  
pp. 379-395 ◽  
Author(s):  
Ch. Blick ◽  
W. Freeden
Keyword(s):  
Radio Occultation ◽  
Spline Approximation ◽  
High Accuracy ◽  
Bending Energy ◽  
The Earth ◽  
Spherical Spline ◽  
Smoothing Parameters ◽  
Occultation Data ◽  
The Given ◽  
Radio Occultation Data

Spherical Spline Application to Radio Occultation DataIn recent years, the importance of the Radio Occultation Method (ROM), an observation procedure of atmospheric quantities such as temperature, density, pressure, and water vapor, increased in value. Based on the global distribution and the high accuracy of the measurements between the Earth's surface up to 35km altitude, ROM offers new perspectives for climate monitoring. In order to compare the measurements, the data have to be visualized. This paper gives the basic definitions and theorems of spline approximation on the sphere. Via its adjustable smoothing parameters, ROM can be suitably adapted to approximate the given data. Further on, it demonstrates, splines as approximation structures realizing a minimal bending energy of their graphs provide a good approximation of the data at hand. Our results demonstrate that spherical spline approximation is an appropriate method to visualize the change over time of a given layer and to illustrate the vertical composition of the Earth's atmosphere. Moreover, ROM enables us to compare the layers of the atmosphere at different points in time as well as the approximation of parameters between the measurements on arbitrary points on the Earth.

scholarly journals The tropopause height analysis in equatorial region through the GPS-RO

2019 ◽  
Vol 76 ◽  
pp. 04002
Author(s):  
Rohaniza Mohd Zali ◽  
J S Mandeep
Keyword(s):  
Spatial Resolution ◽  
Equatorial Plane ◽  
Radio Occultation ◽  
High Spatial Resolution ◽  
Equatorial Region ◽  
Tropopause Height ◽  
Vertical Resolution ◽  
Well Performance ◽  
Occultation Data ◽  
Radio Occultation Data

This study was performed to analyze the variation level of tropopause height in vertical resolution using radio occultation (RO) data from GRACE database due to the high spatial resolution of radio occultation data. The analysis was conducted for data collected in the year of 2016 and latitudinal variation of study in a range of 30° S to 30° N for an equatorial region with an interval of 5°. The CPT and LRT technique is used in this analysis to identify the tropopause height due to well performance in the previous study. The analysis shows that the tropopause height location varies in the latitude of an equatorial region with the highest level reach up to 19.1 km and the lowest is 16.4km over the year of 2016. Therefore, from the analysis that shows the correlation of highest tropopause layer at near of equatorial plane for northern hemisphere while lower tropopause layer at southern hemisphere.

A global 3-D electron density reconstruction model based on radio occultation data and neural networks

2021 ◽  
pp. 105702
Author(s):  
John Bosco Habarulema ◽  
Daniel Okoh ◽  
Dalia Burešová ◽  
Babatunde Rabiu ◽  
Mpho Tshisaphungo ◽  
...  
Keyword(s):  
Neural Networks ◽  
Electron Density ◽  
Radio Occultation ◽  
Model Based ◽  
Occultation Data ◽  
Reconstruction Model ◽  
Radio Occultation Data

Analysis of selected Solar events with Mars Express radio occultation data 

2021 ◽  
Author(s):  
Özgür Karatekin ◽  
Ananya Krishnan ◽  
Nayeem Ebrahimkutty ◽  
Greg Henry ◽  
Ahmed El Fadhel ◽  
...  
Keyword(s):  
Radio Occultation ◽  
Mars Express ◽  
Solar Events ◽  
Occultation Data ◽  
Radio Occultation Data

Analyzing the Diurnal Cycle by Bayesian Interpolation on a Sphere for Mapping GNSS Radio Occultation Data

2021 ◽  
Vol 38 (5) ◽  
pp. 951-961
Author(s):  
Stephen S. Leroy ◽  
Chi O. Ao ◽  
Olga P. Verkhoglyadova ◽  
Mayra I. Oyola
Keyword(s):  
Diurnal Cycle ◽  
Radio Occultation ◽  
Basis Functions ◽  
Atmospheric Tides ◽  
Spherical Harmonic Degree ◽  
Construct Maps ◽  
Bayesian Interpolation ◽  
Occultation Data ◽  
High Degree ◽  
Radio Occultation Data

AbstractBayesian interpolation has previously been proposed as a strategy to construct maps of radio occultation (RO) data, but that proposition did not consider the diurnal dimension of RO data. In this work, the basis functions of Bayesian interpolation are extended into the domain of the diurnal cycle, thus enabling monthly mapping of radio occultation data in synoptic time and analysis of the atmospheric tides. The basis functions are spherical harmonics multiplied by sinusoids in the diurnal cycle up to arbitrary spherical harmonic degree and diurnal cycle harmonic. Bayesian interpolation requires a regularizer to impose smoothness on the fits it produces, thereby preventing the overfitting of data. In this work, a formulation for the regularizer is proposed and the most probable values of the parameters of the regularizer determined. Special care is required when obvious gaps in the sampling of the diurnal cycle are known to occur in order to prevent the false detection of statistically significant high-degree harmonics of the diurnal cycle in the atmosphere. Finally, this work probes the ability of Bayesian interpolation to generate a valid uncertainty analysis of the fit. The postfit residuals of Bayesian interpolation are dominated not by measurement noise but by unresolved variability in the atmosphere, which is statistically nonuniform across the globe, thus violating the central assumption of Bayesian interpolation. The problem is ameliorated by constructing maps of RO data using Bayesian interpolation that partially resolve the temporal variability of the atmosphere, constructing maps for approximately every 3 days of RO data.

scholarly journals Improvement of Rainfall Forecast by Assimilations of Ground-Based GPS Data and Radio Occultation Data

SOLA ◽  
2010 ◽  
Vol 6 ◽  
pp. 81-84 ◽  
Author(s):  
Hiromu Seko ◽  
Masaru Kunii ◽  
Yoshinori Shoji ◽  
Kazuo Saito
Keyword(s):  
Radio Occultation ◽  
Gps Data ◽  
Rainfall Forecast ◽  
Occultation Data ◽  
Radio Occultation Data
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