Overview of HASDM and JB2008 W. Kent Tobiska http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 1
Basis for HASDM http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 2
High Accuracy Satellite Drag Model (HASDM) HASDM is a system run at USAF Space Command CSpOC (VAFB) HASDM V1 – 2001 to 2011 used J71 with F10 and Ap for -48 hours to +72 hours HASDM V2 – 2012 to present uses version of JB2008 with S10, M10, Y10, F10, Ap, and Dst (SET provided) for -48 hours to +144 hours 3 conceptual modules in HASDM JB2008 core (called JBH09) providing current epoch and forecasts to 72 hours ◗ Space Surveillance Network (SSN) observations of ~90 calibration satellites ◗ Dynamic Calibration of the Atmosphere (DCA) code acting as a data ◗ assimilation Kalman filtering method to incorporate derived densities from observations into modeled background HASDM provides thermospheric densities used for creating NORAD TLE catalog and for assessing debris/active satellite conjunctions Credit: Tobiska http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 3
Pedigree of models JB2008 CIRA08 W. Kent Tobiska <ktobiska@spacenvironment.net> Credit: Tobiska http://SpaceWx.com 4
Jacchia 1971 (CIRA 1972) Basis for MET v2, HASDM, JB2006, JB2008 All 4 have been modified from the original Jacchia version Provides modeled densities Between 25-75 km Between 75-120 km Above 120 km Mean reference atmosphere Computer source code available Credit: Tobiska http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 5
Jacchia 1971 (CIRA 1972) Main elements of Jacchia model Thermospheric and exospheric temperatures are ∞ - T 0 )e − σ (z − z 0 ) T(z) = T ∞ - (T (4-29) T ∞ = 379 + 3.24F 10.7 + 1.3(F 10.7 − F 10.7 ) (4-31) Diffusive equilibrium composition (N 2 , O, O 2 , Ar, He) Variations (solar cycle, diurnal, geomagnetic, semi- annual, seasonal latitudinal in lower thermosphere, seasonal latitudinal with He, gravity waves) Credit: Tobiska http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 6
Jacchia 1971 (CIRA 1972) Credit: Jacchia http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 7
Jacchia 1971 (CIRA 1972) Credit: Jacchia http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 8
Historical Density Model Errors at 350 km (1- s ) JB2006 JB2006 JB2008 Credit: F. Marcos http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 9
J71 1999 Unmodeled r Error 00011 Vanguard 2 Sphere - DB/Bave Values - 560 km 125 700 100 600 75 50 500 DRho = DB 22.4 % STD 25 DB/BAve % Solar Flux 0 400 -25 300 -50 -75 200 F 10.7 -100 -125 100 99.0 99.2 99.4 99.6 99.8 100.0 Year Credit: B. Bowman http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 10
Jacchia-Bowman 2008 thermospheric density model Motivation: significantly reduce 1- s error § Improvements § 1) uses the CIRA72 (Jacchia 71) model diffusion equations 2) new solar indices in the extreme and far ultraviolet wavelengths 3) new exospheric temperature and semiannual density equations 4) temperature correction equations for diurnal and latitudinal effects 5) density correction factors at high altitude (1500- 4000 km) 6) Dst index used for high latitude heating modeling Bowman et al. , AIAA-2008-6438_JB2008_Model.pdf (see § JB2008 link http://sol.spacenvironment.net/~JB2008/) Credit: Tobiska http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 11
Jacchia-Bowman 2008 § JB2008 is validated through comparisons of accurate daily density drag data that are previously computed for numerous satellites § For the 400 km altitude, the Jacchia 1971 18% standard deviation is reduced to 12% during periods of low geomagnetic storm activity Credit: Tobiska http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 12
Solar and geomagnetic drivers to the atmosphere http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 13
Solar EUV heating is specific to l and z S10 – 74% of the energy is here http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 14
Motivation for solar indices … capture photoabsorption, including SRC in FUV, for observation-based indices Altitude of unit optical depth for photoabsorption S10 M10 Xb10 Y10 Lya MgII Credit: M.H. Rees http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 15
JB2008 Thermosphere Overview – Ops Daily operational indices selected • JB2008 additionally uses 81-day center smoothed indices Credit: ISO 14222 http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 16
X b10 is an index to the daily background • X-ray background X-ray flux, based on the minimum hourly value for that day (which is calculated (X b10 ) and flare from the lower decile of the 1-minute X- Ray flux in that hour) (X hf ) indices X hf is the median flux within an hour • above X b10 X b10 is used along with Lyman- a in • creating the Y10 index while X hf is used in the Anemomilos Dst algorithm to create the derived velocity of solar ejecta X b10 and X hf shown for October-November 2003. http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 17
JB2008 Solar Indices/Proxies example Daily operational indices selection criteria http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 18
Solar models and data IS 21348:2007 Title: Process for determining solar irradiances Heritage: developed by ISO TC20/SC14/WG4 Provides process to determining solar irradiances Product type definition - measurements, reference spectra, empirical models, physics-based models, proxies Solar spectral categories - TSI and gamma rays through radio wavelengths Compliance criteria - reporting, documenting, publishing, archiving, certification Models (e.g. SIP) and data provided separately Credit: Tobiska http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 19
Solar EUV models & data Solar measurements rockets, AE-E, SOHO, TIMED*, SDO* Solar models SERF1 (EUV81), Nusinov, SERF2, EUV91, EUV97, NRLEUV, HEUVAC, SRPM, SIP*(SOLAR2000/SOLARFLARE/VUV2002) Solar proxies F10.7*, E10.7*, S10.7*, M10.7*, Y10.7*, Rz *IS 21348:2007 compliant Credit: Tobiska http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 20
Geomagnetic proxies Ap / Kp K A NOAA G Kp is the planetary index for 0 0 geomagnetic activity 1 3 Calculated as a weighted average 2 7 of K-indices from a network of 3 15 geomagnetic observatories Observatories do not report their 4 27 data in real-time, necessary for 5 48 G1 an operations center to make the 6 80 G2 best estimate of this index based on available data 7 140 G3 Ap invented to create daily 8 240 G4 average values from eight 3- 9 400 G5 hourly ranges http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> Credit: NOAA 21
Geomagnetic proxies Credit: SET http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 22
Real-time Dst used by SET Credit: SET http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 23
JB2008 Thermosphere – Geomagnetic Storm Drivers /Rice Operational goal achieved: redundant Dst, ± 6-days with 1-hour granularity and 1-hour latency Credit: SET http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 24
Geomagnetic storms during solar cycle decline ◆ Sep 10, 2017 large CME misses Earth http://sol.spacenvironment.net/~sam_ops/index.html? http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 25
Anemomilos Forecast Dst Anemomilos geomagnetic ring current index for satellite drag • The Greek word for thermosphere densities “ windmill ” • 6-day forecast of hourly Dst with 1-hour latency • It is a data-driven deterministic algorithm using solar observables to identify geoeffective events Credit: Tobiska http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 26
JB2008 Indices Credit: Tobiska http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 27
JB2008 and HASDM results http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 28
HASDM-Model density ratio HASDM / MODEL Density Ratio vs F10B (81-day average) during 2001-2007 (400 km) 1.2 1.1 1.0 Density Ratio 0.9 NRLMSIS J70MOD 0.8 JB2006 JB2008 MSISLSQ JB06LSQ 0.7 JB08LSQ J70LSQ ZERO 0.6 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 F10B (Ave) Credit: B. Bowman http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 29
Standard deviation comparison Density STD vs F10B During 2001-2007 ( 400 km ) 50 NRLMSIS 45 J70MOD JB2006 40 JB2008 35 Percentage Error 30 25 20 15 10 5 0 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 Credit: B. Bowman F10B (Ave) http://SpaceWx.com W. Kent Tobiska <ktobiska@spacenvironment.net> 30
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