HAO Science

...from the Sun's interior to the Earth's atmosphere

The High Altitude Observatory, through its collaboration with scientists and scientific organizations around the world is recognized as one of the premier authorities of Sun and Sun-Earth studies.

Tightly integrated activities between HAO's scientific staff and its Instrumentation Group (engineering team) strengthen its core program, and in turn yield a variety of exciting results in the scientific exploration of the Sun and the influences it exerts on the terrestrial atmosphere and climate.

The scientific program of HAO is solar-terrestrial physics, broadly interpreted. Included is solar physics, physics of the heliosphere, the study of geospace and space weather, and the physics of the Earth's magnetosphere and upper atmosphere.

Research Highlights

Global Modeling of Thermospheric Airglow in the Far-Ultraviolet

 Synthetic ultraviolet global images
Thursday, April 27, 2017

The Global Airglow (GLOW) model has been updated and extended to calculate ultraviolet light emitted by the upper atmosphere, including during the day, the night, and in the aurora.

The NASA Ionospheric Connection Explorer (ICON) Mission

Variation of NmF2 log 10 [1/cm3] for different seasons
Wednesday, April 26, 2017

The NASA Ionospheric Connection explorer (ICON) will study the coupling between the thermosphere and ionosphere at low- and mid-latitudes by measuring the key parameters.

Solar Cycle Variability Induced by Title Angle Scatter in a Babcockl-Leighton Solar Dynamo Model

Variability in sunspot number (SSN) in STABLE dynamo simulations of the solar cycle using the observed random scatter in sunspot pair tilt angle of 15 degrees. (a) 19 magnetic cycles are highlighted with red and blue representing the northern and southern hemispheres respectively. Red shaded areas indicate periods when the SSN in the north exceeds that in the south and blue shaded areas indicate the opposite. (b) Long-term SSN variability in the same simulation, exhibiting extended periods of low and high a
Saturday, April 15, 2017

We present results from a three-dimensional Babcock–Leighton dynamo model that is sustained by the explicit emergence and dispersal of bipolar magnetic regions (BMRs). On average, each BMR has a systematic tilt given by Joy’s law.

Rossby Waves On The Sun

Rossby waves on the Sun
Friday, April 14, 2017

Space weather forecasting capability is six decades behind terrestrial weather forecasting," you will often hear at gatherings of scientists determined to understand the connections between our star and our home on Earth. It is an accurate statement in terms of capability.

A Study of Large Wind Shears Near the Mesopause and the Tropopause

Vertical profiles of maximum wind shear
Thursday, April 13, 2017

The NCAR Whole Atmosphere Community Climate Model (WACCM), with a quasi-uniform horizontal resolution of $\sim$25km and a vertical resolution of 0.1 scale height, produces large horizontal winds and vertical shears maximizing in the mesosphere and lower thermosphere (MLT), similar to those found

Variability and predictability of the space environment as related to lower atmosphere forcing

Monthly mean, globally integrated total gravity wave flux of energy
Tuesday, April 4, 2017

Most of the large events affecting the thermosphere and ionosphere part of the space environment come from the Sun, the solar wind, and Earth’s magnetosphere, but even in “quiet time” periods lacking those sources of variability, conditions in the thermosphere and ionosphere continue to fluctuate

Gravity wave variation from the troposphere to the lower thermosphere during a stratospheric sudden warming event: A case study

Vertical energy flux
Monday, April 3, 2017

High resolution Whole Atmosphere Community Climate Model (WACCM) simulations are used to study how gravity waves vary during a stratospheric sudden warming (SSW) event from the source region to the lower thermosphere.

A study of large wind shears near the mesopause and the tropopause

Vertical profiles of maximum wind shear
Friday, March 31, 2017

The NCAR Whole Atmosphere Community Climate Model (WACCM), with a quasi-uniform horizontal resolution of $\sim$25km and a vertical resolution of 0.1 scale height, produces large horizontal winds and vertical shears maximizing in the mesosphere and lower thermosphere (MLT), similar to those found

Meridional Circulation Dynamics in a Cyclic Convective Dynamo

Meridional flow variations induced by magnetic cycles.
Friday, March 24, 2017

Surface observations indicate that the speed of the solar meridional circulation in the photosphere varies in anti-phase with the solar cycle.

Driving Solar Giant Cells Through the Self-Organization of Near-Surface Plumes

Global 3D simulations of solar giant-cell convection.
Friday, March 24, 2017

Global 3D simulations of solar giant-cell convection have provided significant insight into the processes which yield the Sun’s observed differential rotation and cyclic dynamo action.

Areas of Focus

A TIEGCM Simulation of the Anomalous Electron Heating Effect on the E-region Ionosphere

In the ionospheric E-region, the electrons are magnetized because their frequency of rotation around the magnetic field is much greater than their frequency of collisions with the neutrals. Thus, the electrons drift mostly perpendicular to the electric fields.

Assimilative Mapping of Ionospheric Electrodynamics (AMIE)

The AMIE procedure is an optimally constrained, weighted least-squares fit of electric potential distribution to diverse types of atmospheric observations. Knowledge of these distributions is important in many areas of magnetospheric, ionospheric, and thermospheric physics.

Center for Integrated Space Weather Modeling (CISM)

CISM is a National Science Foundation (NSF)/Science and Technology Center (STC) program to develop a complete Sun-Earth model.

Challenges in Observing Short-term Tidal Variability

Modeling the upper levels of the Earth’s atmosphere, is one of the strengths of the Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIME-GCM) supported as a community model by scientists at the High Altitude Observatory.


CISM_DX is a community-developed suite of integrated data, models, and data and model explorers, for research and education. The data and model explorers are based on code written for OpenDX and Octave.

Coupled Magnetosphere Ionosphere Thermosphere Model (CMIT)

The Coupled Magnetosphere Ionosphere Thermosphere (CMIT) model consists of the Lyon-Fedder-Mobarry (LFM) model of the magnetosphere coupled to the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM).

Coupling, Energetics and Dynamics of Atmospheric Regions (CEDAR)

CEDAR is the dominant national and international research program in terrestrial aeronomy. Scientifically, CEDAR is devoted to the characterization and understanding of the atmosphere above ~60 km, with emphasis on the energetic and dynamic processes that determine the basic composition and structure of the atmosphere.

Data-Optimized Coronal Field Model (DOCFM)

DOCFM is an NCAR/CfA collaboration that is funded by AFOSR to model the global coronal magnetic field using magnetometric and other observations, with the goal of improving space weather forecasts of magnetic orientation within coronal mass ejections.


The FORWARD model is a suite of IDL and fortran codes that calculates simulated coronal polarization signals from numerical and analytical models of the corona.

Global Scale Wave Model (GSWM)

The GSWM solves the linearized and extended Navier-Stokes equations for steady-state global temperature and wind perturbations. GSWM may be used to calculate an "unforced" planetary wave response for a specified period and zonal wavenumber, or the thermally-driven response for either a diurnal or semidiurnal atmospheric tide.


The LFM Code is an integrated simulation model for the global magnetosphere-ionosphere system. The heart of the model is a time-dependent, ideal MHD calculation of the state of the magnetosphere.

Support of The Center for Integrated Space Weather Modeling (CISM)

The Center for Integrated Space Weather Modeling (CISM) is a National Science Foundation Science and Technology Center initiated in 2002. The consortium is led by Principal Investigator Professor W. Jeffrey Hughes at Boston University.

Thermosphere Ionosphere Electrodynamic General Circulation Models (TGCMs)

The NCAR TGCM's are three-dimensional, time-dependent models of the EARTH's neutral upper atmosphere.


The Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension (WACCM-X) is a comprehensive numerical model, spanning the range of altitude from the Earth’s surface to the upper thermosphere.

Whole Atmosphere Community Climate Model (WACCM)

WACCM is a comprehensive numerical model, spanning the range of altitude from the Earth's surface to the thermosphere.

Fabry Perot Interferometer at Resolute Bay, Canada

Resolute, Canada (75N) is the site chosen for the deployment of the National Science Foundation Advance Modular Incoherent Scatter Radar (AMISR). AMISR is a state of the art phase array radar, which allows fast electronic steering of the radar beam to track fast moving auroral features.

Fabry-Perot Interferometer at Boulder, Colorado

On March 16, 2012, a Fabry-Perot Interferometer (FPI) was installed at the NCAR Marshall field site, just to the south-east of Boulder, to observe thermospheric and mesospheric winds.

Fabry-Perot Interferometer at Palmer, Antarctica

The Palmer station Fabry-Perot interferometer project is funded by the National Science Foundation Office of Polar Programs. The goal is to study the upper atmosphere and ionosphere over the Antarctica Peninsula. Palmer station is an year-around US Antarctica Research station located on the Anvers Island near the Antarctica Peninsula.


HiWind was the first balloon borne Fabry-Perot interferometer designed to measure summer time polar cap thermospheric neutral winds. Thermospheric wind measurements are critically needed for space weather research. HiWind was launched June 14, 2011 from Kiruna, Sweden.

Mauna Loa Solar Observatory

The Mauna Loa Solar Observatory (MLSO) has been operating since the mid-1960s, providing a nearly-continuous record of solar data to the community. MLSO data includes white light corona, emission corona, H-alpha (disk and limb), He-I, and photometric.

The Community Spectro-polarimetric Analysis Center (CSAC)

CSAC provides a suite of community resource tools for analysis of the precision polarization data for remote sensing of magnetic fields in the outer solar atmosphere.

Collaborating with Fudan University

HAO Senior Scientist Philip Judge spent three weeks at China's Fudan University in October 2015. As an official Visiting Researcher, Philip worked with his host Roger Hutton, and recent graduate Wenxian Li, on magnetically sensitive emission lines formed in the solar corona.

Preparing for the 2017 total Eclipse

On 21 August 2017 a total solar eclipse will pass across the continental United States, from Oregon on the west coast to South Carolina on the east. The eclipse will be a phenomenal experience for the millions of people who see it, but it also offers a unique opportunity to conduct scientific research of the solar atmosphere.

Support of Coupling, Energetics and Dynamics of Atmospheric Regions (CEDAR)

HAO maintains a web page for the National Science Foundation (NSF) Coupling, Energetics and Dynamics of Atmospheric Regions (CEDAR) community that includes links to the CEDAR Science Steering Committee, contact information for CEDAR participants, Announcements of Opportunity, th

Support of The Center for Integrated Space Weather Modeling (CISM)

The Center for Integrated Space Weather Modeling (CISM) is a National Science Foundation Science and Technology Center initiated in 2002. The consortium is led by Principal Investigator Professor W. Jeffrey Hughes at Boston University.

CME Initiation, Evolution, and Interplanetary Consequences

HAO scientists have carried out 3D isothermal MHD simulations of the evolution of the large scale coronal magnetic field as a twisted magnetic flux tube is driven (slowly) through the lower boundary into a pre-existing coronal arcade field.

Coronal and Heliospheric Evolution

The magnetic field in the Sun's atmosphere continuously evolves through processes of emergence, diffusion, and reconnection, resulting in ongoing reorganizations of the global coronal/helio- spheric magnetic morphology, as well as in the slow buildup of magnetic energy in twisted or sheared magnetic fields.

Impact of Energetic Particles on the upper Atmosphere

Energetic particles, namely electrons and protons, released from the magnetosphere cover a wide range of energies from a few electron volts (eV) to hundreds of milli-electron volts (MeV).

Long-Term Solar Variability

HAO scientists pursue an interdisciplinary, system-wide view on the origins and impacts of solar and stellar cycle variation, with a particular focus on magnetic minima as times of low activity and relatively simple heliospheric structure.

Magnetic Flux Emergence

Understanding the process of magnetic flux emergence through the solar convection zone is crucial for understanding the link between the observed magnetic activities at the surface and the dynamo-generated magnetic fields in the interior.

Modeling high-speed flows in the Earth’s Magnetotail

The magnetosphere is created by the interaction between the solar wind and the Earth’s magnetic field. On the dayside of the Earth pressure from the solar wind compresses the Earth’s dipole magnetic field and on the night side this interaction stretches it out forming a region of space commonly referred to as the magnetotail.

Satellite Drag Physical Modeling for Transition to Operations

The ionosphere and upper atmosphere play a major role in space operations, including communications, navigation, and satellite drag. Satellite drag, the drag force exerted by the tenuous upper atmosphere on orbiting bodies, is the leading cause of error in predicting the locations of objects in low-Earth orbit.

Solar Convecton and Mean Flows

Any inquiry into the ultimate origins of solar magnetic activity must soon confront turbulent thermal convection. Convection is a means by which the Sun shines. Energy liberated by nuclear fusion deep in the core of the Sun filters outward by the diffusion of photons.

Studying Atmosphere Coupling Using Mesoscale-resolving WACCM

An important pathway for the terrestrial weather to affect the space weather is through atmosphere waves, such as atmospheric tides, planetary waves and gravity waves. The impacts of the planetary-scale waves have been extensively studied observationally and numerically.

Sunspots and Photospheric Dynamics

Sunspots are the most prominent manifestations of magnetic field in the visible layers of the solar atmosphere. Their origin is a dynamo process operating in the solar convection zone.

The Sun as a Dynamo

The ultimate origins of solar variability lie below the visible surface, where turbulent convection, differential rotation, and meridional flows work together to produce magnetic fields through the operation of a stellar dynamo, giving rise to the 22-year solar magnetic cycle.