SA23A-01 INVITED
The Low-latitude Ionospheric Sensor Network (LISN) Distributed Observatory - The Implementation Phase
The first distributed observatory dedicated to study the low-latitude ionosphere and upper atmosphere has being
designed and is now being implemented in South America. Description of its three basic sensors (GPS
receivers, magnetometers and dynasondes) will be provided. These 3 instruments complement each other and
jointly provide a multi-dimensional view of the low-latitude space weather in South America. The initial LISN
project will connect 70+ GPS receivers, 5 sounders and several magnetometers, all placed in South America
west of the 55° W meridian. We also present a picture of the assimilation code that will be used to ingest
the instrumental observables and define atmospheric and ionospheric state parameters. It is expected that the
distributed observatory will provide new, time continuous, and spatially extended observations of the background
ionosphere, its motion, and the embedded structures. It is expected that several science efforts, such as studies
of the low-latitude electrodynamics, space weather-related onset of equatorial spread F, and transit of
atmospheric gravity waves throughout the LISN field of view will be invigorated by the availability of a new data set
that will contain a unique spatial resolution and unprecedented coverage.
http:jro.igp.gob.pe/lisn
SA23A-02
New topside measurements at Jicamarca
A new series of topside ionospheric measurements at Jicamarca
incorporating full-profile analysis of long-pulse data are presently
emerging. Full-profile analysis utilizes statistical inverse theory to
estimate ionospheric parameters (plasma number density, temperature,
and composition) simultaneously at all altitudes. Traditional
range-gated analysis of long-pulse data is impractical at Jicamarca,
where the long correlation time of the incoherent scatter invalidates
important assumptions regarding homogeneity. Coded longpulse methods
are often used at Jicamarca, but their sensitivity is limited by radar
clutter, rendering them marginal during solar minimum conditions. Full
profile analysis may be regarded as optimal, fully accounting for the
effects of the radar instrument function, the complete error
covariance matrix, and other experimental effects and biases in
principle. The poor conditioning and mixed determined nature of the
problem must be mitigated by regularization, however. Our technique is
incorporates Faraday rotation data for absolute calibration. Validation
necessitates spacecraft observations, including in situ (DMSP) and
path-integrated (COSMIC, C/NOFS) measurements.
http:landau.geo.cornell.edu
SA23A-03
FORMOSAT-3/COSMIC Radio Occultation Constellation Mission and the Future Plan for Global Climate Monitoring
The Radio Occultation (RO) has been drawn great attention in the global atmospheric field since the successful
"proof of the RO concept" program, GPSMET, in 1995. Shortly after the successful launch of the NSPO's
FORMOSAT-3 (or COSMIC in the States by NSPO's partner UCAR) in April 2006, the enormous RO data in 6-
satellites constellation distribution globally have been successfully retrieved and used in the assimilation system
widely. The FORMOSAT-3/COSMIC spacecraft constellation is the first operational GPS radio occultation
constellation mission. The COSMIC mission stands for Constellation Observing System for Meteorology,
Ionosphere, and Climate and carries three onboard instruments including GPS Occultation Receiver (GOX), Tri-
Band Beacon (TBB), and Tiny Ionospheric Photometer (TIP). All the six FORMOSAT-3/COSMIC satellites are
maintained in the good state of health and are on their way toward the final constellation of six separate orbit
planes with 30-degree separations as planned. Three out of six satellites have reached their final mission orbit of
800 km by the early February of 2007. The FORMOSAT-3/COSMIC has processed over 1800 good atmospheric
sounding profiles (~900 mostly above the land mass) per day that has over the number of worldwide
radiosondes launched per day. It's expected to reach 2500 good atmospheric sounding profiles per day in the
near future. The atmospheric radio soundings data are assimilated into the Numerical Weather Prediction (NWP)
models for real-time weather prediction and typhoon/hurricane forecast. This paper will emphasize the
performance of the FORMOSAT-3 that affect the RO data retrievals and the projection of the follow-on program(s)
to continue the RO constellation in the future. The ultimate success of a real-time operation of the FORMOSAT-
3/COSMIC mission in the final constellation formation can be anticipated.
http:www.nspo.org.tw
SA23A-04
Validating the Communication/Navigation Outage Forecasting System (C/NOFS) Algorithms Using Data from the COSMIC Campaigns
Models have been developed at AFRL that will ingest Communication/Navigation Forecasting System (C/NOFS) data in order to forecast the ionospheric density and the presence of irregularities. (The C/NOFS satellite is scheduled for launch in June 2008 into a low inclination (13°), elliptical (~ 375 x 710 km) orbit.) We present a validation exercise of the C/NOFS models using ground and satellite instrument data obtained as part of the 2006 COSMIC campaigns. The C/NOFS forecast models can be initialized using one of the assimilative GAIM models, or alternatively, using a physics-based model driven by the electric fields and winds, as will be measured by C/NOFS. In this talk we will compare the several forecast methods, using metrics to show their strengths and limitations. The electric field measured by the incoherent radar at Jicamarca, Peru is used as input for some of the model runs. Close to Jicamarca, the density profile derived from the model usually shows satisfactory agreement with ground truth data. Modeling the variation of ionospheric density as a function of latitude, however, has proven to be more difficult, due to the lack of knowledge of the neutral winds. The electron density profiles inverted from COSMIC measurements of GPS radio occultations are compared with the electron density profiles specified by the models and to the incoherent scatter observations at both Jicamarca and Arecibo. The validation studies clearly demonstrate the need for improved measurements of ionospheric and thermospheric parameters in the equatorial and off-equatorial regions. Particularly problematic is the determination of off-equatorial E region conductivity. C/NOFS, COSMIC and other collaborative ground and satellite observations will hopefully provide these measurements and greatly enhance our ability to predict ionospheric electron densities and the formation of scintillation-producing irregularities.
SA23A-05
GPS Occultation Measurements of Post-Sunset E-Region Conductivity
The GPS occultation method of ionospheric remote sensing provide a means to obtain information about the low- density nighttime E-region, particularly under conditions when sharp sporadic-E layers are present. E-region conductivity is an important factor in the development of low-latitude dynamo electric fields and the associated uplift of the equatorial ionosphere known as the pre-reversal enhancement. GPS occultation measurements made by the Ionospheric Occultation Experiment (IOX) under solar maximum conditions and by the recently launched six-satellite COSMIC constellation under solar minimum conditions can be used to develop a climatology of the post-sunset E-region. Initial results of a study involving these data sets will be presented.
SA23A-06
Observations of the ionosphere from COSMIC Tiny Ionospheric Photometers during recent multi-instrument campaigns
The Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) uses the Tiny Ionospheric Photometer (TIP) to characterize the nighttime ionosphere. The TIP is a compact, narrow-band, ultraviolet photometer operating at the 135.6 nm wavelength. This emission is produced by recombination of O+ ions and electrons, which is the natural decay process for the ionosphere. The strength of the emission is proportional to the square of the peak electron density. We present a review of the scientific observations made with TIP during recent multi-instrument campaigns. All six satellites were deployed into a single high inclination, low-earth orbit. A single TIP pass reveals the latitudinal morphology of the ionosphere with unprecedented detail. TIP data from multiple spacecraft reveal the longitudinal variability of the nighttime ionosphere and provide regional context for observations from ground-based radars, imagers and scintillation monitors. With the migration into six longitudinally distributed orbits, TIP is also beginning to reveal the temporal variability, allowing for detailed investigation of individual structures in the broader context of the global, nighttime ionosphere. Additionally, the combination of TIP sensors with COSMIC GPS occultation receivers and radio beacons, provides the opportunity to conduct multi-sensor investigations and high resolution imaging of low and midlatitude ionospheric structures.
SA23A-07
Determination of the Range of Irregularities Using Scintillation Spectra Derived From the GPS Occultation Sensor on COSMIC
Ground-based VHF and L-band scintillations, GPS TEC and 630.0 nm All-Sky Imaging Photometer (ASIP) observations at Kwajalein Island were coordinated with measurements by the Tiny Ionospheric Photometer (TIP) and the GPS occultation sensor (GOX) on COSMIC satellites during the September 2006 campaign. On 17 and 18 September 2006, all the ground based sensors and TIP showed the presence of plasma structures in the ionosphere. The GOX occultations, which had F-region intercepts within the field of view of ASIP images containing depletions of plasma density, detected scintillations. Spectral studies of these observed scintillations were used for ranging the irregularities from the COSMIC satellites. The presence of the ASIP images containing depletions, thus provides an additional constraint for the determination of the range of irregularities. We conclude that the spectral analysis of GOX scintillations provides reliable estimates of the range of irregularities in the disturbed equatorial F-region of the ionosphere.
SA23A-08
Extreme Equatorial and Low-Latitude Electric Fields and Thermospheric Winds During a Superstorm
Incoherent scatter radar data were obtained at all of the incoherent scatter radar stations in the NSF/Peruvian chain during part of the November 2004 Superstorm. In addition the storm caught the attention of many modeling groups. The electric field pattern at Millstone Hill (L=3.2) was typical for observations in the auroral oval on November 10. At lower latitudes, extreme penetrating electric fields (PPE) and disturbance dynamo (DD) effects were observed. Both of these field types yielded vertical plasma drifts at the magnetic equator that were higher than 100 m/s, the largest ever recorded for this drift component. The PPE event tracked the interplanetary electric field (IEFy) component for 10 hours from dawn to dusk with a factor of 10% for a positive IEFy and about 3% for the opposite sign. The equatorial field then departed from the IEF and reversed sign, indicating a huge disturbance dynamo. Three bursts of high winds with downward-phase progression were observed over Arecibo in agreement with dynamo action. The prereversal enhancement was suppressed during a period of northward interplanetary magnetic field (negative IEFy) but when the latter changed sign, the equatorial F layer rose to heights near 1000 km and a convective ionospheric storm (aka ESF) began. When the disturbance dynamo developed, the CIS was quenched. These results will be compared to TIMEGCM and to assimilative models at AFRL as well as to other sources of ionospheric data.