Ionospheric Assimilation Model for Space Weather Monitoring and Forecasting I. T. Lee 1 W. H. Chen 2, T. Matsuo 3,4, C. H. Chang 2, C. H. Lin 2, J. Y. Liu 6, W. Wang 7, A. D. Richmond 7 [1] Meteorological R&D Center, Central Weather Bureau, Taipei, Taiwan. [2] Department of Earth Science, National Cheng Kung University, Tainan, Taiwan. [3] University of Colorado Boulder, Boulder, Colorado, USA. [4] National Oceanic and Atmospheric Administration, Boulder, Colorado, USA. [5] National Space Organization, Hsinchu, Taiwan. [6] Institute of Space Science, National Central University, Jhongli City, Taiwan. [7] High Altitude Observatory, National Center for Atmospheric Research, Boulder, Colorado, USA

Content System overview Assimilation Results Validations Forecasting Summary

Assimilation System EnKF Hourly Observations RO NE Profile GPS-TEC Initial Condition Ne, O +, O & O 2 ratio, TN, UN, VN Initial Condition Ne, O +, O & O 2 ratio, TN, UN, VN Advanced Condition Forecast Products TEC, foF 2, NmF 2, NE slices Neutral Density, etc.

Background Model 4 A self-consistent and non-linear system. Solving the three-dimensional momentum, energy and continuity equations for thermosphere and ionosphere. The standard low-resolution grid: Latitude: -87.5° to 87.5° Longitude: -180° to 180° Lower boundary: ~97 km Upper boundary: ~500 to ~700 km Resolution: 5°×5°×0.5lev (75,168 grids) Thermosphere Ionosphere Electrodynamic General Circulation Model (TIE-GCM)

Profiles from 160 to 450 km Vertical resolution: 10 km Assimilation window: 60 min. Quality control applied FORMOSAT-3/COSMIC

Data Assimilation Research Testbed (DART) Observation Operator H(x) TIE-GCM Model States (NE,TN, U, V…) Electron Density Profiles Matsuo and Araujo-Pradere [2011], Lee et al. [2012], and Matsuo et al. [2013] Geomagnetic Quiet Time Period Period: :00 UT – :00 UT Assimilation System: NCAR TIE-CGM + DART Observation range: from 160 to 450 km, 10 km resolution Observation error: 10% instrument error + Abel inversion error Localization function: Gaspari-Cohn function – Horizontal distance: 20°x 20°; Vertical distance: 200 km Assimilation window: 60 minutes Ensemble members: 90 members – Gaussian perturbation: Solar flux (F10.7), Hemispheric power, Cross-tail potential 6

24 Hours RMSE Percentage 7

Global NmF2 map Lat-Alt slices at -75E 8

Mid-latitude enhancement Hemispheric asymmetric Evening enhancement 9 Lee et. al. [2011]

Geomagnetic Disturbed Condition Period: :00 – :00 UT Observation range: from 160 to 450 km with 10 km step Observation error: 10% instrument error and Abel inversion error Assimilation window: 60 minutes Ensemble members: 90 members – Gaussian perturbation: Solar flux (F10.7) [5], Hemispheric power[8], Cross-tail potential[10] Localization function: Gaspari-Cohn function – Horizontal distance: 20°x 20°; Vertical distance: 200 km 10

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WELL IT GOOD FOR OPERATION? From research to operation,

Validation with Ionosonde (NmF2) Evening enhancement Hemispheric asymmetric 13

Receivers Observations Collocated grids Validation with JPL GIM-TEC 14

Validation for Neutral Density Image reprinted from Matsuo et al. [2012] 15

IONOSPHERIC WEATHER FORECASTING Future Task

Possible for Ionospheric Forecasting Forecasting PeriodAssimilatied Period

Not yet! Need more work!

Summary Successful to assimilate the F3/C GOX observations with TIE-GCM to assimilate global 3D electron density structures by using DART. The validations of the assimilation well agree with independent measurements of ionosonde and JPL GIM as well as neutral density obtained CHAMP data. Although the RMSE revels possible ability for ionospheric weather forecasting, the validation shows the forecasted results still far away from independent observations.

Thanks for your attention~ Wait for FORMOSAT-7 Next Year.