本文使用福爾摩沙衛星一號（FORMOSAT-1）所觀測之電漿密度不規則體，本文使用外逸長波輻射（OLR）代表間熱帶輻合區（ITCZ）中的大氣深層對流是否為電離層不規則體機制的種子。分成七個區域，非洲、印度、西太平洋、中太平洋、東太平洋、南美洲以及大西洋來研究不規則體與OLRs在月份分佈的相關性，結果表明，除了非洲以及南美洲外，其餘區域不規則體與OLRs並沒有存在相關性；即使是非洲，兩者的關聯性也僅在磁緯度正負15度以內。根據OLRs研究ITCZ中的大氣深層對流資料表示，大氣重力波無法成為電離層不規則體的種子。

This study uses data of plasma density irregularities observed by ROCSAT-1 (FORMOSAT-1) to correlate with the occurrences of deep atmospheric convection in the intertropical convergence zone (ITCZ) represented by the observation of outgoing longwave radiation (OLR) to search the seeds for the irregularity occurrences. Regions of study is divided into seven regions, Africa, Indian, West Pacific, Central Pacific, East Pacific, South America and Atlantic to search the correlation between the monthly occurrences of irregularities and OLRs. The results indicate that except South America and Africa sectors, there is practically no correlation existed between the occurrences of irregularities and OLRs. As for the Africa sector, the correlation between irregularities and OLRs only exists when the dip latitude is restricted within +- 15 degrees in latitude. The current study indicates that the inferred appearances of atmospheric gravity wave from the OLR observation in ITCZ cannot be used as the proxy for the seed in the subsequent occurrences of ionospheric irregularities.

1. Dungey, J. W. (1956), Convective diffusion in equatorial F-region, J. Atmos. Terr. Phys., 9, 304-310.
2. Farley, D. T., Bonelli, E., Fejer, B. G., and Larsen, M. F. (1986), The prereversal enhancement of the zonal electric field in the equatorial ionosphere. J.Geophys.Res.91, 13,723.
3. Graham, N. E., and T. P. Barnett (1987), Sea surface temperature, surface wind divergence and convection over tropical oceans. Science, 238, 657–659.
4. Guojun Gu, Chidong Zhang (2002), Cloud components of the Intertropical Convergence Zone .J.Geophys.Res.107, D21, 4565, doi:10.1029/2002JD002089.
5. Kelley, M. C., Baker, K. D., and Ulwick, J. C. (1979). Late time barium cloud striations and their possible relationship to equatorial spread F. J.Geophys.Res.84, 1898.
6. Kelley, M. C., M. F. Larsen, C. La Hoz, and J. P. McClure (1981), Gravity wave initiation of equatorial spread F: A case study, J.Geophys.Res.86, 9087-9100.
7. McClure, J. P., S. Singh, D. K. Bamgboye, F. S. Johnson, and H. Kil (1998), Occurrence of equatorial F region irregularities: Evidence for tropospheric seeding, J.Geophys.Res.103, 29,119, doi:10.1029/98JA085A0200722
8. Sultan, P. J. (1996), Linear theory and modeling of the Rayleigth-Taylor instability leading to the occurrence of equatorial spread F, J. Geophys. Res., 101(A12), 26875-26891.
9. Su, S.-Y., C. H. Liu, H. H. Ho, and C. K. Chao (2006), Distribution characteristics of topside ionospheric density irregularities: Equatorial versus midlatitude regions , J.Geophys.Res.111,A06305,doi:10.1029/2005JA011330.
10. Tsunoda, R. T. (1985), Control of the seasonal and longitudinal occurrence of equatorial scintillations by the longitudinal gradient in integrated E region Pedersen conductivity, J.Geophys.Res.90, 447-456.
11. Tsunoda, R. T. (2010a), On seeding equatorial spread F during solstices, Geophys. Res. Lett., 37, L05102, doi:10.1029/2010GL042576
12. Waliser, Duane E., Nicholas E. Graham, Catherine Gautier, (1993), Comparison of the Highly Reflective Cloud and Outgoing Longwave Radiation Datasets for Use in Estimating Tropical Deep Convection. J. Climate, 6, 331–353.
13. Zalesak, S. T., and S. L. Ossakow (1980), Nonlinear equatorial spread F: Spatially large bubbles resulting from large horizontal scale initial perturbations, J. Geophys. Res., 85, 2131-2142.
14. [http://www.esrl.noaa.gov/psd/data/gridded/data.interp_OLR.html/]
15. [http://www.esrl.noaa.gov/psd/data/gridded/data.noaa.hrc.html/]
16. [http://csrsddc.csrsr.ncu.edu.tw/]
17. [http://www.nspo.narl.org.tw/2011/tw/projects/FORMOSAT-1/program-description.html]