Global Lightning and Sprite Measurements from International Space Station - GLIMS mission - T. Ushio, M. Sato, M. Suzuki, T. Morimoto, Y. Hobara, Y. Takahashi, M. Kikuchi, R. Ishida, A. Yamazaki, T. Abe, Y. Sakamoto, K. Yoshida, U. Inan, I. Linscott, Z-I. Kawasaki, S. Watanabe,
GLIMS とは? Global Lightning and sprite measurements の略 国際宇宙ステーションから雷放電と高高度発光現象 ( 代表的なものはスプライトと呼ばれる ) を全球規模で観測する計画
Outline Science background Sensor concept and design Current status of the mission Initial results
1. 背景 Lightning An electrical discharge which neutralizes the amount of charge inside cloud Electrical aspects of thunderstorm activities Responses to the convective activities
雷雲の電荷構造
雷放電について 雷放電 電荷分離によって蓄えられた雲内の電荷が放電によって中和される現象をいう. 落雷と雲放電 雲 大地間の放電を落雷 雷雲内の放電を雲放電という. 正極性落雷と負極性落雷 放電が開始する極性によって異なる.
負極性落雷のモデル 1. Initiation 雲から放電が開始する 2. Stepped Leader 大地に向けて間欠的に進展する 3. Return Stroke 放電路を短時間に雲に向けて進展し 雲内の電荷を中和する 4. Dart Leader 雲内に十分な負電荷が残ると 再度放電路に沿って進展する 5. Subsequent Return Stroke 再度放電路を短時間に雲に向けて進展し 雲内の電荷を中和する
Luminous events at high altitude Associated with lightning, high altitude luminous events were reported in 1990 s. Sprites are believed to be associated with giant lightning which have large currents.
What is the producing mechanism of sprites? QE model Generally accepted explanation is the Runaway breakdown model that the breakdown is caused by the quasi-static electric field associated with lightning Problems (a) Sprites can be caused by the lightning which has the charge moment less than a few hundred ckm (b) Sprites are not always coincident with the cloud to ground lightning. The spatial difference reported so far is maximum 50 km. (c) Sprites take place from several ms to hundreds ms just after the occurence of cloud to ground lightning. (d) The QE model cannot explain the horizontal structure of sprites such as column or carrot type, and also multiple column type sprites.
Electromagnetic pulses from lightning Figs. Correlation between number of columns and peak current [Adachi et al., 2004] Cloud discharge captured from VHF impulse observation Recently there are some reports that the lightning electromagnetic impulses are correlated with the horizontal structure of the sprites. It is difficult to simultaneously measure the horizontal structure of sprite and lightning impulse from ground observation. It is essential to observe the sprites and lightning at nadir direction from space.
Background Gamma emission observed by the CGRO/BATSE, RHESSI satellites TGF and Lightning High occurrence (1 event/2 day) Are these from lightning? Runaway electrons Smith et al. [2005] 制動輻射 Which lightning process produce gamma emission? Is there any connections to TLE? Needs for the simultaneous observation with lightning
Mission Overview JEM-GLIMS Mission Global Lightning and sprite MeasurermentS on JEM-EF Nadir observation of lightning and TLEs = Optical observation of lightning and TLE emissions = Electromagnetic observation of electromagnetic waves excited by lightning and TLEs Science Requirement 1 SR1 Science Requirement 2 SR2 Science Requirement 3 SR3 Criteria Capture temporal and spatial distribution of lightning and its associated phenomena Characterize the relationship between horizontal structure of sprite and lightning Characterize the relationship between the lightning/sprites and gamma emission MCE (Multi-mission Consolidated Equipment) GLIMS Instruments VLF anten VHF antennas
Success criteria Minimum Success Full Success Extra Success Global Distribution Continuously observe TLEs and lightning for more than 1 year with CMOS camera or VHF interferometer. Obtain data on the seasonal variation of the TLEs and lightning. Observe TLEs and lightning within the 80% of the area from -50 to 50 in latitude with 1 km and 200 us resolution for more than 2 years. Obtain data for estimating the effects on atmospheric composition due to the occurrence of TLEs and for assimilating the lightning data into meteorological models. Discover a new type of TLE. Spatial Structure Obtain at least one set of TLE data by using LSI or VITF. Determine the spatial and temporal difference between the horizontal progression of lightning and TLEs. Detect the TLEs with 1 km and 10 us resolution and lightning with 10 km and 10 us resolution. Clarify the mechanism by which TLEs are generated. Clarify the generation mechanism of the new type of the TLEs due to the EMP from horizontal progression of lightning Spectrum Observation - Detect at least one TLE by using the photometer at near-ultraviolet. Determine the electron temperature and existence or non-existence of the N 2 ion. Obtain the spectrum data for all the TLEs observed, and understand the mechanism of the electron acceleration Gamma ray observation - - VLF - - Detect lightning which is correlated with a gamma ray emission with 1 km and 10 us resolution. Specify the lightning process producing gamma rays. Understand the sources of the gamma ray emission from statistical data sets Detect at least one VLF signal from lightning
GLIMS 観測機器構成 名称 ID 仕様 目的 利点 CMOS カメラ フォトメタ VLF レシーバ VHF 干渉計 理学機器制御ユニット LSI PH VLFR VITF SHU CMOS センサを用いた 2 台のカメラ 雷とスプライトの撮像観測 雷発光とスプライト発光を空間的に分離できる! CCD で必要となる冷却装置が必要無い ( 省電力 ) 6 台のフォトメタ 雷とスプライトの発光強度を 50μ s の時間分解能で測定 雷発光とスプライト発光を時間的に分離できる! 1 式の VLF 帯電波受信アンテナ 雷から放射される VLF 帯電波 ( ホイッスラー波 ) を観測 スプライトの親雷放電の電流特性がわかる! 2 式の VHF 帯電波受信アンテナ 雷から放射される VHF 帯電波を観測 スプライトの親雷放電の時間的 空間的進展がわかる! 搭載コンピュータ LSI, PH, VLFR, VITF を制御する心臓部 コマンドによって観測器を自由に制御できる!
GLIMS 観測機器構成 m I S S S y s t e E B O X +28V GPS MDP DC / DC GPS time 1pps RS422 +5V +12V -12V SHU CPU (SH7145) S-RAM (8MB) Flash ROM (128MB) EEPROM B-unit digital (CMD, PW, sig) FPGA (Xilinx Vertex II) S-RAM (8MB) S-RAM (8MB) VITF GLIMS digital PW Analog Amp. PW HV PW RS422 PW A-unit digital (CMD, PW, sig) antenna antenna LSI (CMOS camera) PH (Photometer) VLFR (VLF receiver) antenna
雷 スプライトカメラ (LSI) 2 台の CMOS カメラ LSI-1: 広帯域フィルタ : 雷 LSI-2: 狭帯域フィルタ : スプライト Item Wavelength Table Summary of LSI specification. Value 740-830 nm (LSI-1) 762+/-5 nm (LSI-2) FOV 28.3 28.3 Optics F=1.4, f=25mm Detector CMOS (STAR-250) Pixel Number 512 512 Sensitivity 6.9E-6 W/m 2 Resolution Spatial Resolution Time Resolution 10 bit 0.55 km/pix @ nadir ground surface 34.5ms, 8.6ms, 2.1ms (29fps, 116fps, 464fps) selectable Size 185 87 75 mm 3 Mass Power 0.7 kg 0.8 W
雷 スプライトカメラ (LSI) 高度 [km] 400 ISS 高度 762nm 100 762nm 10 O 2
フォトメタ (PH) 6 台のフォトメタ N 2 1P, 2P, N 2 + 1N の発光強度測定 Item Wavelength Table Summary of PH specification. Value 150-280 nm 337+/-5 nm 762+/-5 nm 600-900 nm 316+/-5 nm 392+/-5 nm PH1 PH2 PH3 PH4 PH5 PH6 N 2 LBH N 2 2P (0,0) N 2 1P (3,1) N 2 2P (0,0) N 2 2P (1,0) N 2 + 1N (0,0) FOV 42.7 86.8 Optics F1.5 F1.72 Detector PMT (R7400) PDD (S1227) for PH1~3,5,6 for PH4 for PH1~3,5,6 for PH4 for PH1~3,5,6 for PH4 Sensitivity @SNR=10 0.1E-6 W/m 2 for PH1~3,5,6 10E-6 W/m 2 for PH4 HV Range 0-1000 V Resolution Sampling Freq. Size 12 bit 20 khz 209 136 130 mm 3 / UNIT Mass Power 2.3 kg 2.0 kg 5.4 W for Unit #1 for Unit #2
雷 スプライトカメラ (LSI) 高度 [km] 400 ISS 高度 150-280nm 100 150-280nm O 3 10
VLF 波動レシーバ (VLFR) VLF レシーバ (VLF Receiver) 雷放電励起の Whistler 波の検出 Table Summary of VLFR specification. Item Value Freq. Range 1-30 khz Resolution 14 bit Sampling Freq. 100 khz Antenna monopole antenna (15cm) Size (electronics) 126 83 20 mm 3 Size (antenna) φ212 mm 66 mm Mass 0.5 kg Power 0.8 W
VHF 電波受信器 (VITF) VHF 干渉計 (VHF InTerFerometer) 雷励起の VHF パルスの計測 Item Table Summary of VITF specification. Value Freq. Range Resolution Sampling Freq. Antenna 70-100 MHz 8 bit 200 MHz patch-type antenna Size (electronics) 208 180 57 mm 3 Size (antenna) 192 192 105 mm 3 Mass Power 9.25 kg 9.8 W
VITF Antennas MCE VITF antenna structure and location of these antennas at the bottom plate of MCE are shows in Figure 3.5-2. Nadir Patch-type antenna pattern Mounting structure Fig. 3.5-2 Picture of the VITF antennas. Teflon block
Electromagnetic wave emitted from lightning
An example of the electric field waveform from ground flash Initial breakdown Leader Return stroke E-Field Continuing curren UHF Radiation[dBm] -40-50 -60-70 -80-90 -100-110 247 248 249 250 251 Time[ms]
Methodology for the determination of incidence angle Radiation Source λθ 2π N 1 R m r n 1 1 n 0 N 1 R m r n 2 2 n 0 j2 mn exp N j2 mn exp N Anten na2 r 2 t φ D(=10 m) Anten na1 r 1 t * GRe m jgim m G m exp j m G m R m R m 12 1 2 12 cosθ= = λθ 2πD cθ 2πf D 干渉計原理 tan cos 1 1 G G Im Re m m c m 2 f md Phase difference Incident angle
対地放電 26
理学機器制御装置 (SHU) SHU (Science instruments Handling Unit) 全観測機器の制御 (power, A/D) イベントトリガ, データ取得 GPS との同期 データ圧縮 : HIREW (lossless compression) テレメトリ, コマンド Item Main Function FPGA Table Summary of SHU specification. Value Power control Data acquisition Event trigger Data compression (HIREW encoding) GPS time synchronization Command, Telemetry I/F (RS422 I/F) Xilinx Vertex II CPU S-RAM Mass Memory SH2 8MB x 2 for FPGA (temporal data buffering) 8MB for CPU 128MB (FIFO memory for TLM) Size (electronics) 208 180 57 mm 3 Mass Power 1.7 kg 10.3 W
GLIMS 観測器 VLFR antenna PH-U1 PH-U2 LSI-1 LSI-2 SMA connectors for VITF antennas Fig. Picture of GLIMS flight model.
GLIMS 機器と MCE SIMPLE REX-J IMAP/VISI HDTV IMAP/EUVI GLIMS/VITF-ANT GLIMS/VLFR-ANT GLIMS/LSI GLIMS/PH Nadir GLIMS/VITF-ANT
GLIMS 機器と MCE VITF Antenna B-Unit MCE VITF Antenna A-Unit LSI JAXA GLIMS Main Instruments Fig. Picture of MCE flight model. This picture was taken just before the MCE was installed into HTV3 / H-IIB. PH-U1 PH-U2 VLFR Antenna JAXA Fig. Picture of MCE base plane which would look nadir direction. LSI, PH, VLFR antenna, and VITF antennas were installed at this plane.
射場 NFI 取外し 2012 年 2 月 29 日 @ 種子島宇宙センター
HTV への組み込み
GLIMS 打上げ H-IIB / HTV3 Launch July 21, 2012 02:06:28 UT JAXA
GLIMS デリバリー HTV3 Approach & Docking July 27, 2012 NASA, JAXA
MCE 曝露部へ取付け MCE Installation August 9, 2012 NASA, JAXA
MCE 曝露部へ取付け MCE Installation August 9, 2012 NASA, JAXA
観測シーケンス 日陰での観測 観測終了 I SS JEM - GLIM S 観測時間帯 ISS の飛翔方向 太陽方向 地球日照 - 日陰 - ISS の飛翔方向 ISS 観測開始
観測モード 観測モード TLE モード : 雷放電,TLEs 観測 (ISS 日陰軌道 ) ITF モード : 雷放電観測 (ISS 日照 日陰軌道 ) TLE Mode ITF Mode LSI (CMOS カメラ ) PH ( フォトメタ ) ー VLFR (VLF 帯電波受信器 ) ー VITF (VHF 干渉計 ) : 電源 ON, トリガ機器 : 電源 ON ー : 電源 OFF
トリガシーケンス TLE モード PH トリガ : トリガ信号発行 : 取得データ長 LSI フレーム番号 : (n-1) n (n+1) (n+2) PH ( トリガ機器 ) トリガ閾値 VLFR ~2ms VITF 1 2 50 51 130 t = -100 t = 0 ( トリガ時刻 ) t = +400 (ms)
GLIMS 取得データ例 (1) 2012/12/15 00:56:28.198 UT スプライト発生イベントの可能性 ISS の位置 : アフリカ東部赤道域
GLIMS 取得データ例 (1) 2012/12/15 00:56:28.198 UT スプライト発生イベントの可能性 LSI-1 (740-830nm) LSI-2 (762±5nm) 雷が発光開始 T = -33ms T = -33ms
GLIMS 取得データ例 (1) 2012/12/15 00:56:28.198 UT 762nm に強い発光雷より高高度で発生を示唆 雷発光強度が最大化 拡大 T = 0ms T = 0ms
GLIMS 取得データ例 (1) 2012/12/15 00:56:28.198 UT 雷雲の微細構造 内部に明るいスポット 微弱な発光が残る 雷雲の散乱光 一部強発光が残る T = +33ms T = +33ms
GLIMS 取得データ例 (1) 2012/12/15 00:56:28.198 UT 雷雲の微弱な発光 微弱な発光が残る T = +66ms T = +66ms
GLIMS 取得データ例 (1) PH1 (150-280nm) TLEs( スプライト ) 発生の可能性 PH2 (337nm) PH3 (762nm) PH4 (600-900nm) PH5 (316nm) PH6 (392nm) 時刻 [ms] 0 100 200 300 400 500
GLIMS 取得データ例 (1) 2012/12/15 00:56:28.198 UT VITF 波形データ A-Unit B-Unit A-Unit B-Unit
INTERNATIONAL COLLABORATIONS
ASIM (The Atmosphere-Space Interactions Monitor) ESA module MMIA (Modular Multispectral Imaging Array) 4 cameras and 4 fotometers look forward towards the limb 2 cameras and 2 fotometers look dornwards towards the nadir MXGS (Modular X- and Gamma Ray Sensor) 1 detector looking downwards towards the nadir @ ISS Columbus module
LIS on TRMM
Complimentarities with other sensors Our mission (Japan) CMOS Camera, Photometers VHF interferometer Spectrometer Simultaneous observation Lightning Sprites from various sensors. Only ISS can do this! ASIM(ESA) TLEs, TGFs LIS(US) Lightning Imaging Sensor
Summary GLIMS mission was introduced. Science objectives and sensor concept were presented. Current status of the mission was briefly reported. Through the collaborations with other sensors on ESA and US modules, fruitful scientific results are expected.