April 2013

NGDC begins a new era of POES processing, the following paragrphs are excerpts from External_Users_Manual_POES_MetOp_SEM-2_processing_V1.pdf

The product described here is the raw and processed data from the Space Environment Monitor-2 instrument suite on the NOAA POES and EUMETSAT MetOp polar orbiting sun synchronous satellites. Each satellite currently carries duplicate SEM-2 sensors that measure the space particle radiation that creates the aurora and forms the Earth’s radiation belts. The raw and processed data is derived from the SEM-2 level 1B sensor data. The processing transforms the data into environmental information needed for monitoring the space radiation impacts on such things as atmospheric chemistry and satellite systems. The processing changes the raw sensor bits to physical quantities with error bars and adds additional information such as the local magnetic field components that are needed for interpreting the spatial and temporal variation of the data. The processing works on the near real time level-1b data files retrieved from the NOAA Data Distribution System (DDS) and makes the level-2 data immediately available to outside users. The near real time data are telemetered to the ground approximately once per 100 minute satellite orbit.

A form of the POES/MetOp level-2 processing was originally developed and run by the NOAA Space Weather Prediction Center [Greer and Evans, 2000]. The new processing system and data products described here is intended to replace the legacy SWPC system due to a variety of reasons such as maintenance challenges and improved data accuracy.

December 2008

A New Product for Visualizing Energetic Particle Data from NOAA`s POES Satellites

This product was developed by Ethan Peck, 2008 Hollings Scholar from Cornell University,and his summer program mentor Daniel Wilkinson with the National Geophysical Data Center (NGDC).The product was first announced to the user community in a poster presented at the 2008 Fall Agu meeting in San Francisco, CA. Paper # U13A-0048 was included in the session titled " The Van Allen Radiation Belts and Their Impact on Modern Space Science"

View the poster here (5MB pdf version 8).

Click to view Sample movies

NOAA’s Polar Orbiting Environmental Satellites (POES) monitor the energetic particle environment along their orbit paths -- nominally 850 KM altitude, 98 degree inclination and a 100 minute period. Bi-directional detector telescopes provide energetic particle measurements along the zenith (0°) and the horizon (90°).  POES data are downloaded once per orbit and delivered to the Space Weather Prediction Center (SWPC) in Boulder, CO where the telemetry is converted into scientific data records and incorporated into space weather alerts and forecasts.  Archive files are prepared daily and submitted immediately to the National Geophysical Data Center (NGDC) where they have been archived since their inception in 1978. 

Our goal was to create flux maps of the POES energetic particle data that allow archive users to visually browse this archive.  We attempted to balance spatial and temporal resolution against the constraint that each map represents a complete global view.  We found that when accumulating the data into 2x2 degree bins that 210-260 orbits were needed to create a map of this sort.  A single satellite can generate such a map in around 15 days; however, by combining data from 5 satellites only four days were needed to generate a complete global map.   

We use a sliding average to increase the timeliness of the multi-day maps.   Electron fluxes are displayed at three energy integrals of > 30, > 100, and > 300 keV.  Proton fluxes are displayed at several discreet energy intervals between 30 keV and  6900 keV in addition to a > 6900 keV integral. The resultant maps reveal the flux distribution of energetic electrons and protons present in the South Atlantic Anomaly and the “horns” of the radiation belts.  Animated sequences of those maps illustrate the dynamic evolution of those populations during event intervals.  

Users should note that these maps are meant to provide a general overview of the POES energetic particle data.  Cross contamination between proton and electron detectors can occur and these plots have not been corrected for this.  For example, the > 6900 KeV proton (P6) plots in the bottom row can reflect significant contamination by relativistic electrons when they are present.  Neutral particles can also appear in these data as a band of enhanced flux along the magnetic equator as seen in the 80-240 keV protons (P4) below.  Also, no correction is made for the differences in sensitivity between SEM-2 instruments onboard the various satellites – data from each satellite is given equal weight in the averages.  In addition, orbital banding will occur during intervals when the particle environment changes rapidly as compared to the length of the interval.  

Routine map production will include one sliding average map for each day for which SEM-2 data from POES are available -- July 1998 to the present.  These static images will be used to produce movies for quickly browsing the entire archive and a sliding 54-day movie representing the most recent activity. 

Your comments and suggestions are invited.

Aurora probability products by Ethan Peck: Invariant latitude & Magnetic Local Time (png), geographic coordinates (png), geographic monthly 1998 - 2008 (mpg).