skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • Home
  • Search Results
  • Page 1 of 1

Search for: All records

Creators/Authors contains: "Tran, Tham"

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. ; ; (, Solar Physics)
    Mandrini, Cristina H (Ed.)
    Abstract The Mt. Wilson Observatory archive of observations of solar disk magnetic fields, Doppler velocities, and spectral line intensities is a resource for studying the Sun’s state from 1967 to 2013. Instrument changes/upgrades during this time must be considered when interpreting this record. Portions of this record have been previously released. This publication documents the data record in order to allow its independent interpretation. The archive is available through two directory trees which can be accessed athttp://sha.stanford.edu/mwo/msm.html. The calibration of the observations is impacted by the solar surface convective flows, which produce offsets for both differential rotation and meridional circulation functions. The effects of these offsets have been reduced in this and other publications by temporal averaging. 
    more » « less
    Full Text Available 
  2. ; ; (, Solar Physics)
    Abstract The methods for reducing the observations from the 150-foot tower telescope on Mt. Wilson are reviewed, and a new method for determining the poleward and rotational velocity deviations is described and applied. The flows we study are smaller than global and change with the solar cycle, so we describe them as poleward and rotational deviations rather than meridional circulation when we discuss solar surface flows. Due to a calibration problem with the data prior to 1983, only observations between 1983 and 2013 are presented at this time. After subtraction of latitude-dependent averages over the 30-year period of observation, the residual deviations in both the poleward and the rotational velocity are well synchronized and correspond to what is widely recognized as torsional oscillations. Both flow components need to be included in any model that replicates the torsional oscillations. 
    more » « less
  3. ; ; (, Research Notes of the AAS)
    Abstract We summarize the analysis methods used to derive differential rotation leading to the Torsional Oscillations (TO) and a new method for determining Meridional Circulation (MC). The new MC results show a reversal of the flow direction at near-polar latitudes with the time of reversal corresponding closely to the time of sunspot Minima. 
    more » « less
    Full Text Available