Modeling and ground observations of the ionosphere related to the COSMIC Project

Ground observations have been used to study the ionosphere by providing ele ctron density profiles and TEC distribution, In this paper, the existing gr ound and space facilities related to constructing the Constellation Observi ng System for Meteorology, ionosphere, and Climate (COSMIC) Project are rev iewed. We show that these observations can be employed to validate results derived from COSMIC satellites. In addition, the NCAR TIEGCM model is intro duced to simulate ionosphere TEC during year of the solar minimum. The obse rvations and simulations present a clear signature of the equatorial anomal y, in which the TEC shows a minimum on the magnetic equator and a maximum o n each side. Meanwhile, it is interesting to see that the value of TEC in J une (Day 170) becomes weaker with the crests moving toward the geomagnetic equator.