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L. C. Tsai

pictureDr. Tsai has extensive experience in three major aspects of the study of the ionosphere and upper atmosphere: theory, instrument (including dynasonde, digisonde, OTH radar, ISR, VHF radar, fixed frequency Doppler sounder, GPS/MET, GPS, SAR, and a few optical remote sensing instruments), and data analysis. Education: Ph.D. in Electrical Engineering, Utah State University, Logan, Utah, March 1995. M.S. in Electrical Engineering, Utah State University, Logan, Utah, June 1991. B.S. in Electronic Engineering, National Chiao Tung University, Hsinchu, Taiwan, June 1986.


Ph.D., Utah State University , USA

Research interests: Ionospheric Physics, Radar Signal Processing

Head of : Ionospheric Sounding Laboratory




         Since 2000, we have developed a compensatory Abel inversion technique to retrieve ionospheric electron densities (Ne) through the compensated total electron content (TEC) data from the GPS/MET and FS3/COSMIC (FormoSat -3/ Constellation Observing System for Meteorology, Ionosphere and Climate) programs. Averagely two thousands Ne  profiles per day have been successfully retrieved and used to produce numerical ionospheric maps and models representing the complex properties on a world-wide scale.
























TWIM TaiWan Ionospheric Model


The TaiWan Ionospheric Model (TWIM) developed in 2008 is a three-dimensional numerical and phenomenological model of ionospheric Ne. The TWIM consists of vertically-fitted α-Chapman-type layers, with distinct F2, F1, E, and D layers, for which the layer parameters such as peak density, peak density height, and scale height are represented by surface spherical harmonics. These results are useful for providing reliable radio propagation predictions and in investigation of near-Earth space and large-scale Ne distribution with diurnal and seasonal variations, along with geographic features such as the equatorial anomaly.



































New Low latitude Ionospheric Tomographic Network

Since 2006, the New LITN has been setup and used the ITS30 coherent receiving system developed by Northwest Research Engineering, LLC, to receive mutually coherent signals (at 150, 400, and 1066.7 MHz) from NIMS Operational, NIMS Maintenance, Geodetic, COSMIC, and Russian Navigation satellites. The expected results would have no world analogues in geophysical coverage and a complex of various tomographic approaches involved; these results would be of great interest for the near-Earth space physics and space weather research as well as for efficient ionospheric monitoring over a seismo-hazardous region.

































We have built up two Dynasondes, also referred as MF/HF radars, at Chung-Li and Hua-Lien, Taiwan, separately. The Dynasonde utilizes an interferometric array to receive ionospherically reflected signals and/or echoes and is a fully digital research ionosonde capable of providing high precision spatial and temporal ionospheric measurements. Further utilizing multi-pulsed sets transmitted at closely spaced frequencies, the measurements include time-of-flight and multiple complex amplitudes and can be used to determine signal/echo parameters. The Dynasonde data has been used for (1) remote sensing the ionosphere structure, and (2) MF/HF radio frequency environment surveillance.






















Stiles, G. S., F. T. Berkey, B. Whatcott, and L.-C. Tsai, The use of transputer for real-time data processing in an ionospheric radar, Applications of Transputers 3, IOS Press, Amsterdam, pp. 1-6, 1991.

Tsai, L.-C., F. T. Berkey, and G. S. Stiles, On the derivation of an improved parameter configuration for the Dynasonde, Radio Sci., 28 (5), 785-793, 1993.

Tsai, L.-C., F. T. Berkey, and G. S. Stiles, The true-height analysis of ionograms using simplified umerical procedures, Radio Sci., 30 (4), 949-959, 1995.

Tsai L.-C., F. T. Berkey, and G. S. Stiles, Derivation and error analysis of echo phase parameters for the dynasonde, Radio Sci., 32 (2), 557-566, 1997.

Tsai L.-C., J. Y. Liu, F. T. Berkey, and G. S. Stiles, The use of level singular value decomposition techniques for vector velocity determinations and its application to TID observations, Adv. Space Res., 20 (6), 1277-1280, 1997.

Tsai L.-C., and J. Y. Liu, Ionospheric observations of the solar eclipse on 24 Oct. 1995 at Chung-Li, Terrestial, Atmospheric and Oceanic Sciences, 8 (2), 221-232, 1997.

Liu, J.Y., C. C. Hsiao, L. C. Tsai, C. H. Liu, F. S. Kuo, H. Y. Lue, C. M. Huang, Vertical phase and group velocities of ionospheric gravity waves derived from ionograms, J. of Atmospheric and Solar-Terrestrial Physics, 60, 1679-1686, 1998.

鄭惇仁,蔡龍治,應用模糊集合理論於中壢電離層探測儀自動化電離圖判讀,物理雙月刊, 21(5), 592-599, 1999.

Liu, J. Y., H. F. Tsai, L.-C. Tsai, and M. Q. Chen, Ionospheric total electron content observed during the 24 October 1995 solar eclipse, Adv. Space Res., 24(11), 1495-1498, 1999.

Liu, J. Y., H. F. Tsai, C.-C. Wu, C. L. Tseng, L.-C. Tsai, W. H. Tsai, K. Liou, and J. K. Chao, The effect of geomagnetic storm on ionospheric total electron content at the equatorial anomaly region, Adv. Space Res., 24(11), 1491-1494, 1999.

Liu, J. Y., Y.-H. Chu, M.-Q. Chen, L.-C. Tsai, and C.-M. Huang, Modeling and ground observations of the ionosphere related to the COSMIC project, Terrestial, Atmospheric and Oceanic Sciences, 11 (1), 349-364, 2000.

Tsai, L-C, and F. T. Berkey, Ionogram analysis using fuzzy segmentation and connectedness techniques, Radio Sci., 35(5), 1173-1186, 2000.

Tsai, L.-C., F. T. Berkey, A. Y. Wong, and Jackie Pau, Dynasonde observations of ionospheric modification experiments with the HIPAS observatory, J. of Atmos. and Solar-Terr. Phys., 63, 107-116, 2001.

Tsai, L.-C., W. H. Tsai, W. S. Schreiner, F. T. Berkey, and J. Y. Liu, Comparisons of GPS/MET retrieved ionospheric electron density and ground based ionosonde data, Earth Planets Space, 53, 193-205, 2001.

Tsai, L.-C., C. H. Liu, W. H. Tsai, and C. T. Liu, Tomographic imaging of the ionosphere using the GPS/MET and NNSS data, J. of Atmos. and Solar-Terr. Phys., 64(18), 2003-2011, 2002.

Tsai, L.-C., W. H. Tsai, Improvement of GPS/MET ionospheric profiling and validation with Chung-Li ionosonde measurements and the IRI, Terrestial, Atmospheric and Oceanic Sciences, 15(4), 589-607, 2004.

Tsai, L.-C., W. H. Tsai, J. Y. Chou, and C.H. Liu, Ionospheric tomography of the reference GPS/MET experiment through the IRI model, TAO(SCI Journal), 17(1), 263-276, 2006.

蔡龍治、蕭棟元、陳政儀、蔡偉雄、朱延祥、劉兆漢,福衛三號於全球電離層氣象觀測與研究,物理雙月刊, ?28(6), 896-909, 2006.

Tsai, L.-C., C.H. Liu, and T. Y. Hsiao,Profiling of ionospheric electron density based on the FormoSat-3/COSMIC data: results from the intense observation period experiment, Terr. Atmos. Ocean. Sci. (SCI Journal), 20, 181-191, doi: 10.3319/TAO.2007.12.19.01(F3C).2009

Hsiao, T. Y., L.-C. Tsai, and F. T. Berkey, The initial results of the Chung-Li Dynasonde for the RF environment surveillance and ionospheric observations, Terrestial, Atmospheric and Oceanic Sciences (SCI Journal), 19 (5), 515-524.

Hsiao, T. Y., L.-C. Tsai, and C. H. Liu, The initial results of coherent beacon radio receiving systems of transit satellites for low-latitude scintillation near Taiwan, Terr. Atmos. Ocean. Sci. (SCI Journal), 20, 261-271, doi: 10.3319/TAO.2007.12.03.01(F3C).2009

Hsu, M.-L, P. K. Rajesh, J. Y. Liu, L.-C. Tsai, H.-F. Tsai, C.-H. Lin, K. F. Dymond, C. Coker, D. H. Chua, S. A.Budzien, and C.-Z. Cheng (2009), Ionospheric electron density concurrently derived by TIP and GOX of FORMOSAT-3/COSMIC, Terr. Atmos. Ocean. Sci. (SCI Journal), 20, 207-214, doi: 10.3319/TAO.2008.04.24.02(F3C)

Tsai, L.-C., C.H. Liu, T. Y. Hsiao, and C. C. Chang (2009), Maps of the ionospheric F2-layer characteristics derived from GPS radio occultation observations, Terrestial, Atmospheric and Oceanic Sciences (SCI Journal), doi:10.3319/TAO.2008.07.07.02(AA).

Tsai, L.-C., C. H. Liu, T. Y. Hsiao, and J. Y. Huang (2009), A near real-time phenomenological model of ionospheric electron density based on GPS radio occultation data, Radio Science (SCI Journal), 44, doi:10.1029/2009RS004154.

Kakinami, Y., J. Y. Liu, L.-C. Tsai and K.-I Oyama (2010), Ionospheric electron content anomalies detected by a FORMOSAT-3/COSMIC empirical model before and after the Wenchuan earthquake, International Journal of Remote Sensing (SCI Journal), Vol. 31, 13, 3571-3578.

Tsai, L.-C., C. H. Liu, and J. Y. Huang (2010),Three-dimensional and numerical ray tracing on a phenomenological ionospheric model, Radio Science (SCI Journal), 45, doi:10.1029/2010RS004359.

Dmitriev, A. V., P. T. Jayachandran, L.-C. Tsai (2010), Elliptical model of cutoff boundaries for the solar energetic particles measured by POES satellite in December 2006, J. Geophys. Res. (SCI Journal), doi:10.1029/2010JA015380.

Tsai, L.-C., K. Kevin Chang, and C. H. Liu (2011), GPS radio occultation measurements on ionospheric electron density from low Earth orbit, Journal of Geodesy (SCI Journal), doi:10.1007/s0019001104769.

Suvorova, A. V., L.-C. Tsai1, A. V. Dmitriev (2011), On relation between mid-latitude ionospheric ionization and quasi-trapped energetic electrons during 15 December 2006 magnetic storm, Planetary and Space Science, doi:10.1016/j.pss.2011.11.001.

Kakinami, Y., J. Y. Liu, and L.-C. Tsai (2012), A comparison of a model using the FORMOSAT-3/COSMIC data with the IRI model, Earth, Planets and Space, 64, 545-551.

Macalalad, E. P., L.-C. Tsai, J. Wu, C.H.Liu (2012), Application of the TaiWan Ionosphere Model to Single-Frequency Ionospheric Delay Corrections for GPS Positioning, GPS Solution, doi:10.1007/s10291-012-0282-8.

陳冠宏,吳究,蔡龍治,陳揚仁 (2012),改良式模稜函數法應用於台灣地區GNSS定位研究,地籍測量學會會刊, 第卅卷第3 期,第22-36 頁.

Contact us

Telephone:  +886-3-4227151 ext 57621 , 57647
Address: R3-413Center for Space and Remote Sensing Research No.300, Jhongda Rd., Jhongli City, Taoyuan County 32001, Taiwan (R.O.C.)