University of Colorado at Boulder University of Colorado CU Home Search A to Z Index Map
Laboratory for Atmospheric and Space Physics

The SNOE SXP Data

The SNOE SXP Data Website

An overview of the SNOE SXP calibration and data reduction is presented by:
Bailey, S. M, T. N. Woods, C. A. Barth, and S. C. Solomon, R. Korde, L. R. Canfield, Measurements of the Solar Soft X-ray Irradiance by the Student Nitric Oxide Explorer: First Analysis and Underflight Calibrations, J. Geophys. Res., 105, A12, 27179, 2000.

Some initial results using the SXP data as input to modeling studies is presented by:
Solomon, S. C., S. M. Bailey, and T. N. Woods, Effect of Solar Soft X-rays in the Lower Ionosphere, Geophys, Res., Lett., 28, 2149, 2001.

The Solar X-ray Photometer (SXP) on the SNOE spacecraft has the primary objective of determining the solar soft x-ray irradiance energy input to the upper atmosphere for studies of how that energy input controls nitric oxide abundances. The SXP has made daily measurements of the solar soft x-ray irradiance between 2 and 20 nm since March 11, 1998. The available data product is 935 days of SNOE SXP measurements of the integrated 2 to 7 nanometer irradiance. Other data are also available in the data set, and will be explained below. The image below is a plot of the available data.

sxp

The layout of the SNOE SXP data set is as follows.
There are 8 columns, 2 of which are SNOE data products.

TIME     TIME           SNOE 2-7nm   SNOE 2-7nm   F10.7       F10.7    Lyman              Ap
YYYYDDD  Year.Frac      Measured     1 A.U.                   ave      Alpha
                        mW/m^2       mW/m^2                            p/sec/cm^2

1998070  1998.190       0.447        0.453         99.4       103.7    3.89E+11           28 
1998071  1998.193       0.471        0.477        100.3       103.7    3.89E+11           14 
1998072  1998.196       0.455        0.460        103.7       103.8    3.88E+11           12 
1998073  1998.198       0.494        0.500        118.2       103.8    3.94E+11           10 
1998074  1998.201       0.543        0.549        131.6       103.9    3.98E+11           20 
1998075  1998.204       0.591        0.597        122.6       103.9    3.99E+11           12 
1998076  1998.207       0.591        0.597        124.3       104.0    3.95E+11            8 
1998077  1998.209       0.623        0.629        125.9       104.1    4.01E+11            4 
1998078  1998.212       0.633        0.638        123.5       104.3    4.05E+11            4 
1998079  1998.215       0.682        0.688        125.5       104.6    4.07E+11            8

Column 1: Time, in YYYYDDD format
Column 2: Time, in Year.Fraction_of_year format
Column 3: SNOE SXP 2 – 7 nm solar irradiance (mW / m^2)
Column 4: SNOE SXP 2 – 7 nm data, adjusted to 1 A.U.
Column 5: F10.7 daily data (Ottawa/Penticton radio flux)
Column 6: F10.7 81-day average data (Ottawa Penticton radio flux)
Column 7: UARS SOLSTICE Lyman Alpha (photons / sec / cm^2)
Column 8: Fredericksburg Ap geomagnetic activity index

NOTE to MSIS users

MSISE-90 is Hedin’s two-dimensional thermospheric model, which provides estimates of the temperature of the atmosphere and of the number density of seven prevalent species (H, He, N, O, N2, O2, and Ar). It uses the 10.7 cm radio flux (for the previous day, and a 81-day smooth centered on the requested day) and the Ap geomagnetic indices as input.

For full details on the MSISE-90 model see:

Hedin, A, MSIS-86 Thermosphere Model, J. Geophys. Res., 92, 4649-4662, 1987.

and

Hedin, A, Extension of the MSIS Thermosphere Model into the Middle and Lower Atmosphere J. Geophys. Res., 96, 1159-1172, 1991.