A Frequency‐Agile Distributed Sensor System to address space weather effects upon ionospherically dependent systems

Rice, D.; Eccles, J. V.; Sojka, J. J.; Raitt, J. W.; Brady, Jesse; Hunsucker, R. D.

doi:10.1029/2008rs004083

Cited by 2 publications

(2 citation statements)

References 14 publications

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“…The DDDR model is the D and E region model within the HF absorption model currently deployed at the Community Coordinated Modeling Center called Absorption by the D and E region of HF signals with normal incidence, which calculates nonderivative absorption of HF signals occurring during propagation through the D region [ Webb et al ., ]. The unknown parameters in the DDDR model EUV and X‐ray spectrum have been adjusted to provide good comparisons with HF absorption measurements and VLF propagation characteristics, observed in the HF Investigation of D‐Region Ionospheric Variation Experiment HIDIVE and frequency AGILE experiments [ Eccles et al ., ; Rice et al ., , ].…”

Section: Instrumentation and Modelsmentioning

confidence: 99%

Ionospheric model‐observation comparisons: E layer at Arecibo Incorporation of SDO‐EVE solar irradiances

et al. 2014

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This study evaluates how the new irradiance observations from the NASA Solar Dynamics Observatory (SDO) Extreme Ultraviolet Variability Experiment (EVE) can, with its high spectral resolution and 10 s cadence, improve the modeling of the E region. To demonstrate this a campaign combining EVE observations with that of the NSF Arecibo incoherent scatter radar (ISR) was conducted. The ISR provides E region electron density observations with high-altitude resolution, 300 m, and absolute densities using the plasma line technique. Two independent ionospheric models were used, the Utah State University Time-Dependent Ionospheric Model (TDIM) and Space Environment Corporation's Data-Driven D Region (DDDR) model. Each used the same EVE irradiance spectrum binned at 1 nm resolution from 0.1 to 106 nm. At the E region peak the modeled TDIM density is 20% lower and that of the DDDR is 6% higher than observed. These differences could correspond to a 36% lower (TDIM) and 12% higher (DDDR) production rate if the differences were entirely attributed to the solar irradiance source. The detailed profile shapes that included the E region altitude and that of the valley region were only qualitatively similar to observations. Differences on the order of a neutral-scale height were present. Neither model captured a distinct dawn to dusk tilt in the E region peak altitude. A model sensitivity study demonstrated how future improved spectral resolution of the 0.1 to 7 nm irradiance could account for some of these model shortcomings although other relevant processes are also poorly modeled.

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Section: Instrumentation and Modelsmentioning

confidence: 99%

Ionospheric model‐observation comparisons: E layer at Arecibo Incorporation of SDO‐EVE solar irradiances

et al. 2014

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“…Space Environment Corporation (SEC) has deployed a network of Space Weather‐Aware Receiver Elements (SWAREs) to monitor radio signals from VLF through HF [ Rice et al , 2009] following earlier HF monitoring efforts [ Eccles et al , 2005]. The SWAREs produce their own three‐dimensional ionospheric models based on International Reference Ionosphere (IRI) F region [ Bilitza , 2001], combined with the DDDR (Data Driven D ‐Region) [ Eccles et al , 2005] model for the E and D region.…”

Section: Sporadic E Propagationmentioning

confidence: 99%

First results of mapping sporadic E with a passive observing network

et al. 2011

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1] Sporadic E (E s ) can have dramatic effects on communications in the HF and low VHF range, producing over-the-horizon propagation for signals normally restricted to line-of-sight, and sometimes blocking F region propagation of signals in the lower HF range. Measuring the E region winds believed to produce E s is difficult, and no practical means of predicting E s occurrence currently exists other than statistical models. We describe a low-cost observing network based on software-controlled receivers that continuously watches for E s in near-real time using oblique HF propagation from existing transmitters. Results from an 11-day pilot campaign in July 2008 demonstrated that even a limited number of receivers in the network can readily determine the presence and extent of E s patches. These observations indicate that E s often develops quickly over regions of several hundred kilometers rather than gradually drifting across an area. These widespread E s "blooms" have been observed near winter solstice and occasionally at other times of the year; their lifetime depends on the season but can be several hours during the summer. The current network allows the extent of E s in portions of North America to be evaluated: the geographical distribution of E s and bounds on the density of the layer are inferred from its effects on the ionospheric maximum usable frequency (MUF). This study demonstrates quantitatively that E s mapping can provide information about E s layer geographical growth and decay. The observed sudden widespread E s blooms are space weather events that can have significant impact on HF/lower VHF communications and propagation model predictions.

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A Frequency‐Agile Distributed Sensor System to address space weather effects upon ionospherically dependent systems

Cited by 2 publications

References 14 publications

Ionospheric model‐observation comparisons: E layer at Arecibo Incorporation of SDO‐EVE solar irradiances

Ionospheric model‐observation comparisons: E layer at Arecibo Incorporation of SDO‐EVE solar irradiances

First results of mapping sporadic E with a passive observing network

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