You are here

Next-Generation Forecasting Model of Global Equatorial Scintillation

Description:

TECHNOLOGY AREA(S): Space Platforms 

OBJECTIVE: Develop next-generation scintillation model to provide specification and forecasting of scintillation in the global equatorial ionosphere and to quantify the effects of scintillation on GPS, navigation, and communication systems. 

DESCRIPTION: Typical ionospheric scintillation models ingest scintillation data in near real-time from ground-based sensors for nowcasting of ionospheric impacts on radio frequency links. For forecasting, these models may rely largely on a climatological model which can, in general, reproduce the global morphology of scintillation. A next-generation scintillation model is needed to be able to more accurately forecast the onset time, spatial coverage, strength, zonal drift, decay, duration, and day-to-day variability of scintillation in the global equatorial ionosphere, as well as to provide specification of ionospheric scintillation. The work of this task includes three parts. (1) Create a new forecasting model. In order to achieve the forecasting capability, the new model should identify and specify the drivers and their roles for the generation of scintillation. The primary drivers for equatorial scintillation are electric fields/plasma drifts, solar flux, solar wind effects (such as penetration electric fields), neutral winds, atmospheric gravity waves, and geomagnetic activity. Other important parameters for the growth of plasma instabilities that result in scintillation are the F-peak altitude and vertical gradient in the bottomside F-region plasma density. The new model must have high spatio-temporal resolution to capture the patchy and moving structures of ionospheric irregularities and scintillation, besides variations with solar activity, longitude, season, and latitude (especially equatorial anomaly). The new model can be first-principles model or data assimilative model, or a combination. (2) Use real-time data to drive and calibrate the model. The new model should be able to integrate real-time measurements, including plasma density profile from a sparsely populated global digisonde network, GPS radio occultation TEC and scintillation data, ion drifts from ground radars, in-situ density and drift data and trans-ionospheric radio beacon relative TEC and/or scintillation data, to drive the model and to use real-time measurements of GPS and/or VHF/UHF scintillation to calibrate the model’s output. (3) Determine scintillation impacts on radio frequency links. The new model is expected to provide specification and quantitative prediction of ionospheric phase screen parameters that can be used to specify and forecast scintillation effects on GPS, navigation, and satellite communication (narrowband and wideband) systems, including amplitude fading, phase spectrum, and spectral strength of trans-ionospheric radio signals at different frequencies and arbitrary incidence angles. These impacts are relevant to commercial, civil and military users. 

PHASE I: Develop the concept and framework of the scintillation forecasting model. Identify data sources that will be used to develop, drive, and calibrate the model. Perform proof-of-concept analysis that demonstrates the forecasting capability of the model. Develop methodologies for integrating the scintillation model into Air Force operational model systems. Define key metrics of model specification and forecasting performance. 

PHASE II: Complete the development of the first version of the forecasting model. Demonstrate the model’s capabilities of specifying global equatorial scintillation. Specify different driving parameters to test the model’s forecasting capabilities of scintillation occurrence and day-to-day variability. Compare the model output with observations. Develop methodologies for integrating real-time data into the model for driving and calibrating the model. 

PHASE III: Use real-time data to drive and calibrate the model. Validate and refine the model’s global specification and forecasting capabilities against operationally relevant scintillation metrics and observations. Integrate the model into the Air Force model system for operational use. 

REFERENCES: 

1: Secan, J. A., R. M. Bussey, E. J. Fremouw, and S. Basu, An improved model of equatorial scintillation, Radio Sci., 30(3), 607–617, doi:10.1029/94RS03172, 1995.

2:  Retterer J. M., Forecasting low-latitude radio scintillation with 3-D ionospheric plume models: 2. Scintillation calculation, J. Geophys. Res., 115, A03307, doi:10.1029/2008JA013840, 2010.

3:  Béniguel Y., Global Ionospheric Scintillation Model, Technical Manual, IEEA, 2011.

4: Priyadarshi, S., A Review of Ionospheric Scintillation Models, Surv. Geophys., 36, 295–324, DOI 10.1007/s10712-015-9319-1, 2015.

KEYWORDS: Scintillation, Specification, Forecast, Equatorial Ionosphere, Model, Impact 

CONTACT(S): 

Chaosong Huang (AFRL/RVBXC) 

(505) 846-6775 

chaosong.huang.1@us.af.mil 

US Flag An Official Website of the United States Government