The Tiny Ionospheric Photometer (TIP) on the Constellation Observing System for Meteorology, Ionosphere, and Climate (FORMOSAT-3/COSMIC) characterizes the nighttime ionosphere using 135.6-nm radiative recombination emission. TIP measures horizontal structure of the ionosphere with high precision and high spatial resolution. Latitudinal, longitudinal, and temporal distribution of the nighttime ionosphere is specified. We present a review of ionospheric observations made with TIP during the first five months of operation. Comparisons are made with other ionospheric sensors in order to validate the TIP observations and to demonstrate TIP resolution and sensitivity performance. Equatorial anomalies observed by TIP are compared with estimates of the E x B vertical drift during the post-sunset pre-reversal enhancement in the Peruvian sector. Low latitude irregularity structures observed by TIP are compared with measurements from ground-based sensors including: imaging photometers, ionosonde, and UHF scintillation receivers. Detailed measurements of low latitude density depletion depth and width are provided. Global ionospheric morphology observed by TIP is compared with similar observations by COSMIC radio occultation, and the GAIM model. The complexity of the underlying neutral winds is revealed by the TIP ionospheric morphology.
