HAO

NCAR High Altitude Observatory

Removal of Spectro-Polarimetric Fringes by 2D PCA

Graph depicting the transformation of the PCA basis through a series of carefully chosen rotations
Monday, February 25, 2019

We investigate the application of 2-dimensional Principal Component Analysis (2D PCA) to the problem of removal of polarization fringes from spectro-polarimetric data sets.

Magnetic tsunami in the Sun triggers new space weather events in 2020

Image of global tachocline fluid top surface deformations

Most people have heard about tsunamis in the Earth’s oceans. Those occur when large masses of water get violently moved at the ocean floor, as a result of earthquakes or volcanic eruptions.

Space storms that go off-scale

Image of Hydrogen-α solar spectroheliogram

Terrestrial and space weather storm scales have a common shortcoming: The scales end at “5.” Nature of course doesn’t know this and sometimes produces a disturbance that is simply off the charts.

High cadence visible and infrared spectra of the Sun during eclipse

Graph of raw counts are plotted against wavelength in air for spectral lines
Friday, February 1, 2019

We study visible and infrared spectra, from 310 nm to 5 microns, obtained during the 21st August 2017 eclipse. The instruments were situated at Camp Wyoba (altitude 2402 m) on Casper Mountain, WY.

The Mid-latitude Thermospheric Dynamics from An Inter-hemispheric Prospective

Graph depicting Meridional and Zonal Winds
Monday, January 28, 2019

Using Fabry-Perot interferometers (FPI) at five mid-latitude stations (Boulder, Palmer, Millstone Hill, Mt. John, and Kelan) in both hemispheres, we examine the inter-hemispheric and seasonal variations of mid-latitude thermospheric dynamics.

First computer model to simulate a realistic solar flare

Image depicting a solar flare or cme

A team of scientists has, for the first time, used a single, cohesive computer model to simulate the entire life cycle of a solar flare.

Alfvénic Heating in the Cusp Ionosphere-Thermosphere

Graph showing volumetric Joule heating rates
Wednesday, December 19, 2018

The effect of electromagnetic variability on ionosphere-thermosphere heating in the low-altitude geomagnetic cusp is examined.

The Effect of Small-Scale Magnetic Structures on Inferred Solar Continuum Brightness

Average intensity of magnetic structures
Monday, December 3, 2018

Solar irradiance models indicate that irradiance variations are dominated by changes in disk-coverage of magnetic structures, whose brightness is thought to be determined by their size and average magnetic flux density.

The Extended Solar Cycle: Muddying the Waters of Solar/Stellar Dynamo Modeling Or Providing Crucial Observational

Graph depicting extended solar cycles
Monday, December 3, 2018

In 1844 Schwabe discovered that the number of sunspots increased and decreased over a period of about 11 years, that variation became known as the sunspot cycle.

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