## JB2008

Welcome to the JB2008 empirical thermospheric density model website. A new empirical thermospheric density model, Jacchia-Bowman 2008, is developed as an improved revision to the Jacchia-Bowman 2006 model which is based on Jacchia’s diffusion equations. Driving solar indices are computed from on-orbit sensor data, which are used for the solar irradiances in the extreme through far ultraviolet, including x-ray and Lyman-α wavelengths. New exospheric temperature equations are developed to represent the thermospheric EUV and FUV heating. New semiannual density equations based on multiple 81-day average solar indices are used to represent the variations in the semiannual density cycle that result from EUV heating. Geomagnetic storm effects are modeled using the Dst index as the driver of global density changes. The model is validated through comparisons with accurate daily density drag data previously computed for numerous satellites in the altitude range of 175 to 1000 km. Model comparisons are computed for the JB2008, JB2006, Jacchia 1970, and NRLMSIS 2000 models. Accelerometer measurements from the CHAMP and GRACE satellites are also used to validate the new geomagnetic storm equations.

### Indices

**Instructions**

To run the JB2008 model you will need the solar (SOLFSMY.TXT) and geomagnetic storm indices (SOLRESAP.TXT and DSTFILE.TXT) from the downloadable files in the Current Indices table above: the geomagnetic storm indices are generated from hourly Dst values during moderate to high geomagnetic activity, and from 3-hour ap values during low to no storm activity. Also, note that there is 45-day lag between the current Day-Of-Year and the last data DOY in the indices files.

If you desire to compute the storm indices yourself then you need to download the code file (DTCMAKEDR.for.txt, version 5.3), and edit directory/file paths. You then need to use the updated Dst values (DSTFILE.TXT) and ap values (SOLRESAP.TXT), which are updated here daily. The DTCMAKEDR.for program will then generate a new DTCFILE.TXT file. This file is the one above currently being automatically generated on this web sit

### Code

**JB2008 Code files**

(after downloading remove the .txt entension)

**Matlab users: **

- JB08DRVY2K.for.txt
- JB2008.for.txt
- DTCMAKEDR.for.txt
- DTCMAKEDR Code.zip contains source code, compile instructions, and help pages

- Download JB2008 Command Line Matlab.zip

to download code and view help pages

### Publications

**A description of indices used in the JB2008 Thermospheric Model.**- COSPAR CIRA Draft, chapter 4, 2008
- Tobiska, et. al.
- JB2008_solar_geomag_indices-2.pdf

**The solar and geomagnetic inputs into the JB2008 thermospheric density model for use by CIRA08 and ISO 14222**- CIRA08 and ISO 14222, JB2008 Proxy indices
- Tobiska
- C01-0003-10.ppt.pdf

**A New Empirical Thermospheric Density Model**

JB2008 Using New Solar and Geomagnetic Indices- JB2008 model using new indices
- Bowman et al.
- AIAA_2008-6438_JB2008_Model.pdf

**The thermospheric semiannual density response**

to solar EUV heating- Thermospheric semiannual variations
- Bowman et al.
- JASTP_Semi_Dens_Resp_2008.pdf

**The development of new solar indices for use in thermospheric density modeling**- JB2006 indices
- Tobiska et. al.
- JB2006_JASTP_2008_803.pdf

**The JB2006 empirical thermospheric density model**- JB2006 model
- Bowman et. al.
- JASTP_Bowman_JB2006_2008.pdf

**Accuracy of Earth’s Thermospheric Neutral Density Models**- 2006 6167 Model Comparisons
- Marcos et. al.
- JB2006_AIAA_2006-6167.pdf

**The development of new solar indices for use in thermospheric density modeling**- 2006_6165_Development of New Solar Indices for thermospheric modeling
- Tobiska et. al.
- SET_AIAA_2006_revD.pdf

**COSPAR 2006 Session C4.1 Paper COSPAR2006-A-01661**- New solar indices for improved thermospheric densities
- Kent Tobiska
- COSPAR2006-A-01661.pdf

**New Satellite Drag Modeling Capabilities**- 2006_470_Satellite_Drag _Modeling Capabilities
- Marcos
- JB2006_AIAA_2006_470.pdf

**Improvements in Modeling Thermospheric Densities Using New EUV and FUV Solar Indices**- 2006_237_Density_Improvements
- Bowman, Tobiska
- JB2006_AAS_2006_237.pdf

**Solar and Geomagnetic Space Environment Specification for Operations**- 2006_471_Solar_Geomagnetic _Specification_for_Ops
- Tobiska, Fry
- JB2006_AIAA_2006_471.pdf

**Advances in Solar Inputs for Precision Orbit Determination**- 2005_252_Solar_Inputs
- Tobiska
- JB2006_AAS_2005_252.pdf

**The Semiannual Thermospheric Density Variation at Altitudes of 160-300 km**- 2005_254_Semiannual_Density
- Bowman
- JB2006_AAS_2005_254.pdf

**Drag Coefficient Variability at 175-500 km from the Orbit Decay Analyses of Spheres**- 2005_257_Drag_Coef_Variability
- Bowman, Moe
- JB2006_AAS_2005_257.pdf

**The Effects of Surface Composition and Treatment on Drag Coefficients of Spherical Satellites**- 2005_258_Surface_Effects_on _CD_of_Spheres
- Moe, Bowman
- JB2006_AAS_2005_258.pdf

**The Semiannual Thermospheric Density Variation From 1970 to 2002 Between 200-1100 km**- 2004_174_Semiannual_Density _Between_200_1100_km
- Bowman
- JB2006_AAS_2004_174.pdf

**A Method For Computing Accurate Daily Atmospheric Density Values From Satellite Drag Data**- 2004_173_AAS_EDR_Method
- Bowman et. al.
- JB2006_AAS_2004_173.pdf

**High Accuracy Satellite Drag Model (HASDM) Review**- 2003_625_HASDM_Review
- Bowman, Strorz
- JB2006_AAS_2003_625.pdf

**High Accuracy Satellite Drag Model (HASDM)**- 2002_4886_HASDM
- Storz et. al.
- JB2006_AIAA_2002_4886.pdf

**HASDM Validation Tool Using Energy Dissipation Rates**- 2002_4889_HASDM_Tool_Using _Energy Dissipation_Rates
- Storz
- JB2006_AIAA_2002_4889.pdf

**True Satellite Ballistic Coefficient Determination for HASDM**- 2002_4887_True_B
- Bowman
- JB2006_AIAA_2002_4887.pdf

**Atmospheric Density Variations at 1500-4000 km Height Determined from Long Term Orbit Perturbation Analysis**- 2001_132 Den_Var _1500-4000km
- Bowman
- JB2006_AAS_2001_132.pdf

**Orbit Perturbation Analysis of West Ford Needles Clusters**- 2000_4236_Needles_Perts
- Bowman
- JB2006_AIAA_2000_4236.pdf

### License

**SOFTWARE LICENSE AND WARRANTY AGREEMENT
JB2006 and JB2008 empirical thermospheric density models**

Space Environment Technologies License and Warranty Agreement for software source code and for software and/or data products (collectively referred to herein as “software”).

This is a legal agreement between you and Space Environment Technologies (referred to herein as “SET”) covering your use of the software. Be sure to read the following agreement before using the software. By installing or using the software, you indicate your unconditional acceptance of the terms of this agreement. IF YOU DO NOT ACCEPT THE TERMS OF THIS AGREEMENT, DO NOT USE THE SOFTWARE AND DESTROY ALL COPIES OF IT.

This software is publicly distributed for use without charge as a courtesy to aerospace users. You may also use this software according to the terms of separately negotiated contracts with Space Environment Technologies. This software is distributed without charge and without restrictions by SET. Commercial distribution of the software is permitted through this license with the restriction that an acknowledgement be made to the distributor Space Environment Technologies and that this website is provided to users for access of additional information. You may not modify, adapt, translate, reverse engineer, decompile, or disassemble the software or the data products that drive this software.

The software and related documentation are provided “AS IS” and without warranty of any kind. SET EXPRESSLY DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. ANY WRITTEN OR ORAL INFORMATION OR ADVICE GIVEN BY SET, ITS AGENTS, DISTRIBUTORS, OR EMPLOYEES, SHALL NOT IN ANY WAY BE CONSTRUED AS GRANTING OR CREATING A WARRANTY. UNDER NO CIRCUMSTANCES SHALL SET BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, DAMAGES FOR LOSS OF PROFITS, INFORMATION, OR GOODWILL) THAT RESULT FROM THE USE OR INABILITY TO USE THE SOFTWARE OR RELATED DOCUMENTATION, EVEN IF SET HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

This Agreement shall be governed by the laws of the State of California. If for any reason a court of competent jurisdiction finds any provision of this Agreement, or portion thereof, to be unenforceable, that provision of the Agreement shall be enforced to the maximum extent permissible so as to effect the intent of the parties, and the remainder of this Agreement shall continue in full force and effect. The distributor of the software is Space Environment Technologies. The manufacturer of the solar indices used by both JB2006 and JB2008 is Space Environment Technologies. All rights of Space Environment Technologies will be exercised or enforced.

### Figures

Figure 1. HASDM-to-Model density ratios at 400km altitude as a function of F10B

Figure 2. Density percentage errors (1 standard deviation) from model density values at 400 km altitude compared to HASDM density values.

Figure 3. The amplitude function F(z) for three different years (1990, 1993, 2002), with semiannual amplitudes plotted for each satellite for each year. The constant F(z) function from Jacchia is also plotted.

Figure 4. A multiple storm during 2004, showing the different storm events.

Figure 5. Major 2004 storms with Dst, ap (left scale) , and density (Rho) ratios displayed. The density ratios are based on orbit averaged model density values / GRACE 2004 density average.

Figure 6. Major 2003 storms with Dst, ap (left scale), and density (Rho) ratios displayed. The density ratios are based on orbit averaged model density values / CHAMP 2003 density average.

Figure 7. Model density 1-standard deviation errors as a function of ap ranges representing storm magnitudes. Values are based on orbit averaged percent density differences between the calibrated accelerometer data, from both CHAMP and GRACE, and the different model values. JB2006 uses the same geomagnetic storm modeling as J70.