| Title | Data-based optimization of a simple shortwave fadeout absorption model |
| |
| Author | Fiori, R A D ;
Chakraborty, S; Nikitina, L |
| Source | Journal of Atmospheric and Solar-Terrestrial Physics vol. 230, 105843, 2022 p. 1-11, https://doi.org/10.1016/j.jastp.2022.105843  Open Access |
| Image |  |
| Year | 2022 |
| Alt Series | Natural Resources Canada, Contribution Series 20210218 |
| Publisher | European Geophysical Union |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf; html |
| Province | Canada; British Columbia; Alberta; Saskatchewan; Manitoba; Ontario; Quebec; New Brunswick; Nova Scotia; Prince Edward Island; Newfoundland and Labrador; Northwest Territories; Yukon; Nunavut |
| NTS | 1; 2; 3; 10; 11; 12; 13; 14; 15; 16; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 52; 53; 54; 55; 56; 57; 58; 59; 62; 63; 64; 65;
66; 67; 68; 69; 72; 73; 74; 75; 76; 77; 78; 79; 82; 83; 84; 85; 86; 87; 88; 89; 92; 93; 94; 95; 96; 97; 98; 99; 102; 103; 104; 105; 106; 107; 114O; 114P; 115; 116; 117; 120; 340; 560 |
| Subjects | geophysics; Science and Technology; Nature and Environment; modelling; models; ionosphere; solar variations; absorption; statistical analyses; D-RAP Model; Natural hazards; Methodology;
Communications |
| Illustrations | location maps; tables; time series; plots; rose diagrams; bar graphs |
| Program | Public Safety Geoscience Assessing space weather hazards |
| Released | 2022 03 03 |
| Abstract | Electron density enhancement caused by electromagnetic radiation emitted during a solar X-ray flare has the potential to increase high frequency (HF; 3-30 MHz) absorption in the dayside D-region
ionosphere, impacting shortwave radio signals by reducing the signal strength, a phenomenon commonly referred to as shortwave fadeout. Data-based optimization of a simple absorption model is performed incorporating solar X-ray flux data and 30 MHz
riometer data from stations distributed across Canada. In a single event study the data-based optimization model is shown to overestimate absorption by 1% for the duration of an X2.1 solar X-ray flare. This corrects an underestimation by the NOAA
D-region Absorption Prediction (D-RAP) model. In a statistical study, based on 87 events, data-based optimization performed on an event-by-event basis showed excellent overall agreement between measured and modelled data: the Pearson correlation
coefficient was R=0.88, and the slope of the best-fit line to the data was m=0.91. A generalized model was developed using data from all 87 events collectively. Although good agreement was found between the measured and modelled data sets,
correlation and slope were slightly reduced to R=0.75 and m=0.80. Model accuracy is characterized by prediction efficiency (PE) which peaked at PE=0.78 for the event-by-event evaluation and PE=0.48 for the collective data set. The results of this
study highlight the advantages of data-based optimization in modelling absorption due to shortwave fadeout. |
| Summary | (Plain Language Summary, not published)
Space weather refers to the dynamic conditions on the Sun and in the space environment, in particular, in the near-Earth environment, that can affect
critical infrastructure. NRCan operates the Canadian Space Weather Forecast Centre and conducts research into space weather effects on power systems, pipelines, radio communications and GNSS positioning to help Canadian industry understand and
mitigate the effects of space weather. This paper presents a simple model, developed from a Canadian network of riometer instruments, of the absorption of radio signals caused by a solar flare. |
| GEOSCAN ID | 328728 |
|
|