In this thesis chromospheric features called Penumbral Microjets (PMJs) are investigated in a sunspot. Observations of high resolution in space, time and wavelength from the Swedish 1-meter Solar Telescope (SST) are used to probe the Ca II 8542 Å-line. The goal is to obtain detailed spectral signatures of PMJs in the Ca II 8542 Å -line, as well as basic statistical measures such as lifetime and sizes. This is achieved by the implementation of an automated detection scheme employing dimensionality reduction methods and a simple learning algorithm which together reduce and classify the observations from the SST. The advantages of employing an automated numerical detection scheme are exploited to assemble a large sample of objects and extract statistically significant results from it. The obtained statistical values and spectra are then discussed and put in a wider context.