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Project Loon based augmentation for global ionospheric modeling over Southern Hemisphere

View Article: PubMed Central - PubMed

ABSTRACT

Global ionospheric products of vertical total electron content (VTEC) derived from GNSS measurements may have low accuracy over oceans and southern latitudes where there are not rich observations. Project Loon provides a great opportunity to enhance the measurements over those areas. In this contribution, a simulation of Project Loon based augmentation for global ionospheric modeling is performed by using the international reference ionosphere (IRI) which could simulate VTEC measurements for the balloons. The performance of the enhanced method based on simulation of Project Loon is investigated by comparing with VTEC maps from Ionosphere Associate Analysis Centers (IAACs) as well as IGS final GIMs. The comparison indicates that there is a better consistency between the VTEC maps by the enhanced method and IGS final GIMs. Also, obvious improvements of RMS maps in GIMs for the middle latitudes and southern latitudes are enabled by the augmentation of Project Loon. Additionally, JASON data are used to validate the specific improvement of the VTEC maps. The results show that the performance of VTEC maps is improved slightly, especially in southern latitudes. It is possible that the VTEC maps could be improved significantly by using real GPS measurements from balloons of Project Loon in the near future.

No MeSH data available.


RMS values of the differences between GIMs from IAACs and J2TEC for DOY 152–181 in 2015.
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f13: RMS values of the differences between GIMs from IAACs and J2TEC for DOY 152–181 in 2015.

Mentions: Additional validation of VTEC maps from IAACs as well as IGS final GIMs is performed with respect to JASON data. Figure 12 and 13 show the bias and RMS values of the differences between GIMs and J2TEC, respectively. The bias shows a similar trend as presented in Fig. 12. According to the bias, most VTEC values of GIMs from CODE, ESA, UPC, WHU and IGS are smaller than J2TEC, especially in middle and high latitudes in contrast to larger than J2TEC in low latitudes. While, VTEC values from JPL mostly are larger than J2TEC in northern latitudes and low southern latitudes. The absolute values of bias in southern latitudes are larger than those in northern latitudes, especially in mid-high latitudes. It indicates once more that the accuracy of VTEC maps in southern latitudes is lower. The RMS values presented in Fig. 13 also could depict this point. Because the RMS values are apparently larger in southern latitudes, especially in high latitudes. Also, the dispersion of RMS values in southern latitudes are in a relatively larger area. Since there are not rich GNSS measurements in southern latitudes, IAACs provide their quite different accuracy of VTEC values over Southern Hemisphere. These comparative results also indicate that WHU products have the same level of performance as the VTEC maps provided by IAACs. Overall, the IGS final combined GIMs is more stable and more accurate than GIMs provided by each center.


Project Loon based augmentation for global ionospheric modeling over Southern Hemisphere
RMS values of the differences between GIMs from IAACs and J2TEC for DOY 152–181 in 2015.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5382668&req=5

f13: RMS values of the differences between GIMs from IAACs and J2TEC for DOY 152–181 in 2015.
Mentions: Additional validation of VTEC maps from IAACs as well as IGS final GIMs is performed with respect to JASON data. Figure 12 and 13 show the bias and RMS values of the differences between GIMs and J2TEC, respectively. The bias shows a similar trend as presented in Fig. 12. According to the bias, most VTEC values of GIMs from CODE, ESA, UPC, WHU and IGS are smaller than J2TEC, especially in middle and high latitudes in contrast to larger than J2TEC in low latitudes. While, VTEC values from JPL mostly are larger than J2TEC in northern latitudes and low southern latitudes. The absolute values of bias in southern latitudes are larger than those in northern latitudes, especially in mid-high latitudes. It indicates once more that the accuracy of VTEC maps in southern latitudes is lower. The RMS values presented in Fig. 13 also could depict this point. Because the RMS values are apparently larger in southern latitudes, especially in high latitudes. Also, the dispersion of RMS values in southern latitudes are in a relatively larger area. Since there are not rich GNSS measurements in southern latitudes, IAACs provide their quite different accuracy of VTEC values over Southern Hemisphere. These comparative results also indicate that WHU products have the same level of performance as the VTEC maps provided by IAACs. Overall, the IGS final combined GIMs is more stable and more accurate than GIMs provided by each center.

View Article: PubMed Central - PubMed

ABSTRACT

Global ionospheric products of vertical total electron content (VTEC) derived from GNSS measurements may have low accuracy over oceans and southern latitudes where there are not rich observations. Project Loon provides a great opportunity to enhance the measurements over those areas. In this contribution, a simulation of Project Loon based augmentation for global ionospheric modeling is performed by using the international reference ionosphere (IRI) which could simulate VTEC measurements for the balloons. The performance of the enhanced method based on simulation of Project Loon is investigated by comparing with VTEC maps from Ionosphere Associate Analysis Centers (IAACs) as well as IGS final GIMs. The comparison indicates that there is a better consistency between the VTEC maps by the enhanced method and IGS final GIMs. Also, obvious improvements of RMS maps in GIMs for the middle latitudes and southern latitudes are enabled by the augmentation of Project Loon. Additionally, JASON data are used to validate the specific improvement of the VTEC maps. The results show that the performance of VTEC maps is improved slightly, especially in southern latitudes. It is possible that the VTEC maps could be improved significantly by using real GPS measurements from balloons of Project Loon in the near future.

No MeSH data available.