NOAA/SEC

Today's SOLAR2000 E10.7 Index

SET/SpaceWx

An Overview of the Solar EUV Irradiance Index E10.7 from the SOLAR2000 Model

SOLAR2000 is an empirical solar irradiance specification tool for characterizing solar irradiance variability across the solar spectrum. The implementation of the SOLAR2000 includes a new EUV proxy, E10.7, which has the same units as the commonly-used F10.7 radio index. E10.7 can be used in existing solar-terrestrial models where F10.7 is traditionally used, but it offers significant improvement as an index of the solar EUV energy input to the thermosphere and ionosphere. Applications of SOLAR2000 irradiances and E10.7 include satellite operations, HF radio propagation, and GPS applications. The E10.7 daily index was developed by the Space Environment Technologies (SET) SpaceWx Division and is provided to NOAA/SEC through a Cooperative Research and Development Agreement (CRADA).

Today's (and prior 54 days) solar EUV index E10.7

• The top 'Past 54-days and Todays E10.7' plot panel shows the past 54 days of E10.7 variations; the right-most value is today's value, also called a 'nowcast' for the current 24-hour period. The E10.7 value is also shown numerically on the top panel title. The date and UT time of the update are displayed on the plot's x-axis label.
• The bottom 'Validation of Todays vs Historical E10.7' plot panel is used to demonstrate the uncertainty of the current E10.7 calculations compared to solar cycle 23 historical values. The scatter plot shows the fit between the historical nowcast value (y-axis) and the historical actual calculated value (x-axis) i.e., the ability of the SOLAR2000 nowcast algorithm to create today's value.
  • Today's nowcast values are superimposed upon the historical comparison, and appear as black crosses marking the one-standard deviation limits.
  • The nowcast is for the current 24-hour period, and the value changes as input proxy measurements (e.g., F10.7, Mg II) become available during the day.
• The color coding is a visual aid that highlights the amplitude variations with respect to the solar cycle (blue is near solar minimum, green is moderate solar activity, and red near solar maximum); see the Solar Cycle 23 Historical figure.

Last update 12 Apr 2002, Disclaimer, Privacy Policy, Contact SEC