HAO

NCAR High Altitude Observatory

The long-term trends of nocturnal mesopause temperature and altitude revealed by the Na lidar observations between 1990 and 2018 at mid-latitude

Graph showing WACCM-X (2.0) simulated summer temperature profiles of year 1974 and year 2003
Sunday, December 2, 2018

The nighttime mesopause, marking the boundary of mesosphere and thermosphere and having the coldest atmospheric temperature, is formed mainly by the combination of radiative cooling by CO2, and the adiabatic flow in the Mesosphere and Lower Thermosphere.

Pitch angle scattering of energetic electrons by bursty bulk flows (BBFs)

Pitch angle scattering of electrons in high resolution LFM fields
Tuesday, November 13, 2018

Mary Hudson and others have studied field line curvature scattering by the magnetic field structure associated with Bursty Bulk Flows (BBFs), using simulated output fields from the Lyon‐Fedder‐Mobarry (LFM) global magnetohydrodynamic (MHD) code for specified solar wind input.

The eruption of a prominence carrying coronal flux rope forward synthesis of the magnetic field strength measurement by COSMOS

(a) The inferred line-of-sight (LOS) magnetic field B_LOS obtained from the forward synthesis of the circular polarization signal from the MHD model data at a time during the quasi-static phase of the flux rope; (b) The same as (a) but only show the pixels of the measured B_LOS with sufficient signal to noise ratio; (c) The axial field strength in the mid cross-section of the flux rope; (d) The 3D field lines of the coronal magnetic field as view
Tuesday, November 13, 2018

From a magnetohydrodynamic (MHD) simulation of the eruption of a prominence hosting coronal flux rope, Yuhong Fan and others carry out forward synthesis of the circular polarization signal (Stokes V signal) of the FeXIII emission line at 1074.7 nm produced by the MHD model.

On the variability of the semidiurnal solar and lunar tides of the equatorial electrojet (EEJ)

Plot showing EEJ obtained from Huancayo and Fuquene observatories
Friday, November 9, 2018

The variabilities of the semidiurnal solar and lunar tides of the equatorial electrojet (EEJ) are investigated during the 2003, 2006, 2009 and 2013 major sudden stratospheric warming (SSW) events in this study.

Transport of Internetwork Magnetic Flux Elements in the Solar Photosphere

Graph of displacement probability distributions
Tuesday, October 23, 2018

The motions of small-scale magnetic flux elements in the solar photosphere can provide some measure of the Lagrangian properties of the convective flow.

MLSO Honors the Sun at AstroDay West

Radio dish

On October 6th, the MLSO staff participated in AstroDay 2018, an educational outreach event coordinated by the Mauna Kea Observatories. 3,000 people attended. This was the second occurrence of this event, located in Kailua-Kona, on the west side of Hawaii Island.

Characterization of Cameras for the COSMO K-Coronagraph

Digital image sensors
Thursday, October 11, 2018

Digital image sensors are ubiquitous in astronomical instrumentation and it is well known that they suffer from issues that must be corrected for data to be scientifically useful.

Rotational and Activity Evidence for a Subgiant with a Sun-Like Cycle

Sun-like activity cycle of HD 81809 binary system in calcium HK emission
Wednesday, October 10, 2018

HD 81809 has one of the highest-quality activity cycles from the sample of stars synoptically observed in the Mount Wilson Observatory HK Project.

A Numerical Investigation on the Thermospheric Sodium Layer

Time and altitude distribution
Tuesday, October 2, 2018

The extension of the neutral atomic Na layer into thermosphere (up to 170 km) was observed in low and high latitudes.

Retrieving Global Wilson Currents from Electrified Clouds using Satellite Passive Microwave Observations

Global total TRMM current
Wednesday, October 3, 2018

Peterson et al. (2015) developed an algorithm for estimating the electric field vector at any point above an electrified cloud from passive microwave observations. 

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