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Abstract NRLMSIS® 2.0 is an empirical atmospheric model that extends from the ground to the exobase and describes the average observed behavior of temperature, eight species densities, and mass density via a parametric analytic formulation. The model inputs are location, day of year, time of day, solar activity, and geomagnetic activity. NRLMSIS 2.0 is a major, reformulated upgrade of the previous version, NRLMSISE‐00. The model now couples thermospheric species densities to the entire column, via an effective mass profile that transitions each species from the fully mixed region below ~70 km altitude to the diffusively separated region above ~200 km. Other changes include the extension of atomic oxygen down to 50 km and the use of geopotential height as the internal vertical coordinate. We assimilated extensive new lower and middle atmosphere temperature, O, and H data, along with global average thermospheric mass density derived from satellite orbits, and we validated the model against independent samples of these data. In the mesosphere and below, residual biases and standard deviations are considerably lower than NRLMSISE‐00. The new model is warmer in the upper troposphere and cooler in the stratosphere and mesosphere. In the thermosphere, N2and O densities are lower in NRLMSIS 2.0; otherwise, the NRLMSISE‐00 thermosphere is largely retained. Future advances in thermospheric specification will likely require new in situ mass spectrometer measurements, new techniques for species density measurement between 100 and 200 km, and the reconciliation of systematic biases among thermospheric temperature and composition data sets, including biases attributable to long‐term changes.
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This content will become publicly available on January 28, 2026
The Thermosphere Was Poorly Predictable Not Only During but Also Before and After the Starlink Storm on 3–4 February 2022
Abstract Observation‐based simulations of the ionosphere were performed with the NRLMSISE‐00 model for six locations around the globe during 1–9 February 2022, which includes the so‐called Starlink Storm. Unlike other studies, we focused on the magnetically quiet days around the storm. Unexpectedly, the observed values of the F2‐layer peak density were ∼50% larger than the simulated values. We show that this implies that the daytime O density in the thermosphere was systematically ∼30% larger than the NRLMSISE‐00 predicts. Further investigation shows that this discrepancy is not an exclusive feature of the period around the Starlink Storm and a similar problem happens for some periods for different years. It is unclear if the reason is an actual increase of the O density or its underestimation by the model. Resolving this problem is critical for providing accurate predictions of the atmosphere to avoid the degradation of normal operation or even loss of space assets.
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- PAR ID:
- 10575088
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Geophysical Research Letters
- Volume:
- 52
- Issue:
- 2
- ISSN:
- 0094-8276
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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