The structure of the local interstellar medium. I. High-resolution observations of Fe II Mg II and Ca II toward stars within 100 parsecs

High-resolution absorption measurements (lambda/Deltalambda greater than or similar to 100, 000) of the resonance lines of Fe II Mg II and Ca II are presented for all available observed targets within 100 pc. The Fe II and Mg II spectra were obtained with the Goddard High Resolution Spectrograph (GHRS) and the Space Telescope Imaging Spectrograph (STIS) instruments aboard the Hubble Space Telescope (HST). Of the 63 observations of targets within 100 pc, we present new measurements for 24 lines of sight. We also compiled all published absorption measurements based on Ca II spectra obtained by various ground-based instruments. For each observation we provide measurements of the central velocity, Doppler parameter, and column density for each absorption component. These three ions provide the best opportunity to measure the component velocity structure. Because these are the heaviest ions observed in absorption through the warm local interstellar medium (LISM), the narrow line widths minimize significant blending of components and allow for accurate measurements of the central velocity. We present a statistical analysis of the LISM absorption measurements, which provides an overview of some physical characteristics of warm clouds in the LISM, such as, temperature, turbulent velocity, ionization degree, and depletion. The complete collection and reduction of all LISM absorption measurements provides an important database for studying the structure of nearby warm clouds. Subsequent papers will present models for the morphology and physical properties of individual structures ( clouds) in the LISM.