Space Weather

Space weather generally refers to the changing environment between the Sun and Earth that arises due to changes in the sun's activity. A dramatic example is the generation of intense solar flares which greatly enhance the amount of X-ray radiation impinging on the Earth’s upper atmosphere. Most space weather effects of concern, however, arise from changes in the sun’s interplanetary magnetic field and the solar wind (mostly electrons and protons) embedded in this field. Such changes, at times, lead to a highly perturbed magnetosphere (to its particles and fields) and in turn to disturbances in lower regions. Energetic electrons and ions of magnetospheric origin can damage sensitive electronics on high orbiting spacecraft, harm astronauts, and through particle precipitation, produce color auroras and ionospheric disturbances including ionospheric currents. Ground induced currents arise from such currents in the upper atmosphere and can be a hazard to power grids. Ionospheric disturbances which include scintillations may alter or block signals leading to communication problems on aircraft flying polar routes, to disruption of Global Positioning System (GPS) services, and in general to systems relying on trans-ionospheric signal propagation. In general, solar storms leading to these effects typically reach Earth a day or two after the event and there is a need to better understand and predict their impacts.

CPI is an active member of the American Commercial Space Weather Association (ACSWA) and has decades of experience in developing first principles physics models relevant to the ionosphere, thermosphere, and auroral zone. This includes significant experience in working with solar data, energetic particle data, and remote sensing data. We have performed algorithm development for a variety of space weather satellite instruments (e.g., DMSP/SSUSI, TIMED/GUVI, and GOES-13/EUVS), sensor modeling, operational software engineering, as well as have calibration/validation (Cal/Val) experience (e.g., EUVS, DMSP, NPP) that is applicable to current and future solar EUV and particle sensors. These capabilities fall into four major areas.

Geostationary Operational Environmental Satellite (GOES) Extreme Ultraviolet Sensor (EUVS)

CPI and NRL physicists provided the first validation of the important new GOES EUV sensor, which provides energy fluxes in
five bands. A contract was awarded by NOAA's Space Weather Prediction Center (SWPC) to NRL in October, 2006 followed by a 12-month effort to develop a calibration algorithm for the EUV Sensor (named EUVS) and conduct a validation of early on-orbit data. (Read More)

Ionospheric Scintillation

CPI has extensive experience in ionosphere specification from dual frequency (L1 and L2) Global Positioning System (GPS) measurements (Reilly and Singh, Radio Sci., 39, 1671, 2004). We have devised a technique to combine both range and phase measurements to remove instrument-related variations, which are more prevalent in range measurements. Our standard methodology for ionosphere specification has been to solve for the effective sunspot number (SSNe) and simultaneously solve for biases using discrete inverse theory. (Read More)

The Joint Polar Satellite System (JPSS)

JPSS is the civilian component of the former joint civilian and military National Polar Orbiting Operational Environmental Satellite System (NPOESS) program. After the separation of NPOESS into its civilian and military portions, the National Oceanic and Atmospheric Administration (NOAA) was given responsibility for the early afternoon orbit as JPSS. The Department of Defense, as the Defense Weather Satellite System (DWSS), was given responsibility for the early morning orbit. The separate JPSS and DWSS programs continue to share the Common Ground System for satellite operation and data product processing. (Read More)

Special Sensor Ultraviolet Spectrographic Imager (SSUSI)

The Special Sensor Ultraviolet Spectrographic Imager (SSUSI) is a space-based remote sensing instrument with a spectrograph and imaging mode that was developed to measure emissions in the ultraviolet (UV).  In imaging mode, SSUSI measures emission across the disk within five bands: Ly α [119 -124 nm], 130.4 [128-132 nm], 135.6 [134-137 nm], N2 Lyman Birge Hopfield LBHS [140-152 nm], and LBHL [165-180 nm]. (Read More)