- 著者
- Loren Joy De Vera Estrebillo Mitsuteru Sato Yukihiro Takahashi Hisayuki Kubota Kozo Yamashita Junichi Hamada Joel Marciano
- 雑誌
- 日本地球惑星科学連合2019年大会
- 巻号頁・発行日
- 2019-03-14
The Philippines is one of the most disaster-hit countries in the world. Its location in the western North Pacific (WNP) subjects it to numerous tropical cyclones (TC) each year that pose risk to lives, properties and infrastructures. There has been a significant development in the accuracy of TC track forecast that cross and/or make landfall within the Philippine Area of Responsibility (PAR) over the years with the use of ground-based synoptic observations, weather radars, and meteorological satellites. However, prediction of TC intensity remains a significant challenge. Lightning activity is an indicator of the dynamics and microphysics in thunderstorms, as well as severe weather phenomena, such as TCs and torrential rainfall among others. Recent studies suggest that lightning activity in tropical cyclones can give predictive information about its intensity development. Thus, a ground-based lightning observation system (V-POTEKA) has been developed, and it has been installed at three stations in the Philippines, Guam, and Palau to continuously monitor lightning activity in the WNP region since September 2017. The V-POTEKA system uses an event-trigger method that detects radio wave pulses from lightning discharges in the very low frequency (VLF) range of 1-50 kHz. It also consists of an automatic weather station (AWS), VLF sensors, and an automatic data-processing unit. The V-POTEKA system analyzes lightning data, extracts pertinent information, i.e., peak amplitude and time of the triggered waveform, and transmits data to a server through 3G communication. A geolocation software using the time-of-arrival method is being developed using the 3 sites along the WNP region. Further analysis will be conducted by incorporating data from other stations (Sapporo, Japan and Los Banos, Philippines), and an improved geolocation software will be used to investigate the relationship between the lightning activity and typhoon intensification during the dropsonde observation campaign conducted in September 2018.
- 著者
- Mitsuteru Sato Yukihiro Takahashi Makoto Suzuki Atsushi Yamazaki Tomoo Ushio
- 出版者
- 一般社団法人 電気学会
- 雑誌
- 電気学会論文誌A(基礎・材料・共通部門誌) (ISSN:03854205)
- 巻号頁・発行日
- vol.131, no.12, pp.1000-1005, 2011-12-01 (Released:2011-12-01)
- 参考文献数
- 15
- 被引用文献数
- 6 10
Six-channel spectrophotometers (PH) are the science instruments of JEM-GLIMS to measure absolute intensity of the emission originated from lightning discharges and upper atmospheric transient luminous events (TLEs). PH unit-1 (PH-U1) consists of four spectrophotometer channels named from PH1 to PH4, while PH unit-2 (PH-U2) two spectrophotometer channels named PH5 and PH6. Optical filters of these spectrophotometers are selected to detect TLE emission lines of N2 1PG, N2 2PG, N2+ 1NG, and N2 LBH. Since the bandwidth of the optical filter of PH2, 3, 5, and 6 is 10 nm and since PH1 measures NUV emission, photomultiplier tubes with high-voltage converters are used as a photon detector. To the contrary, PH4 uses a photodiode as a photon detector because the pass-band of the optical filter is enough wide to detect transient optical emission. Though PH does not equip spatial resolution, it can acquire light curve data with a high time resolution of 50 μs with a 12-bit resolution. Thus, the combinational analysis of PH data and Lightning and Sprite Imager (LSI) data, it is possible to clarify the relationship between TLEs and their parent lightning discharges, the occurrence condition of TLEs, and the energy of the electrons which excite TLE emission.