Tuesday, 12 March 2013

Science Tuesday: MSIS Atmosphere Model – The Geekiest App?

This surely must be the geekiest app for any atmospheric scientists to have on a phone or tablet. You can now download the widely used "Mass Spectrometer Incoherent Scatter" (MSIS) Atmosphere Model from the iTunes App Store!

The MSIS model, is a widely used tool in atmospheric modelling, which provides neutral atmospheric composition and temperature from ground to near-Earth space.

Today, the model comes in three different incarnations, NRLMSIS-00, MSIS-E-90, and MSIS-86. While these represent a continuous development, they all have their applications in their own right. The text below is largely taken from the description pages of the model versions:

The main differences between NRLMSIS-00 and MSIS-E-90 "involve (1) the extensive use of drag and accelerometer data on total mass density, (2) the addition of a component to the total mass density that accounts for possibly significant contributions of O+ and hot oxygen at altitudes above 500 km, and (3) the inclusion of the SMM UV occultation data on [O2]."

The MSIS-E-90 Atmosphere Model "describes the neutral temperature and densities in Earth's atmosphere from ground to thermospheric heights. Below 72.5 km the model is primarily based on the MAP Handbook (Labitzke et al., 1985) tabulation of zonal average temperature and pressure by Barnett and Corney, which was also used for the CIRA-86. Below 20 km these data were supplemented with averages from the National Meteorological Center (NMC). In addition, pitot tube, falling sphere, and grenade sounder rocket measurements from 1947 to 1972 were taken into consideration. Above 72.5 km MSISE-90 is essentially a revised MSIS-86 model taking into account data derived from space shuttle flights and newer incoherent scatter results. For someone interested only in the thermosphere (above 120 km), the author recommends the MSIS-86 model. MSISE is also not the model of preference for specialized tropospheric work. It is rather for studies that reach across several atmospheric boundaries."

For download available are iOS versions for iPhone and iPad, and they are kindly provided free of charge by the MSIS main author, Alan Hedin.

Image credit: Atmospheric profile image is taken from the iTunes App Store's page for the iPhone version.

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