Portable observation systems that can be set up and operated unattended at field sites to measure, for example, temperature, winds, humidity, surface pressure, solar and infrared radiation, rainfall, and sometimes more specialized variables such as sensible and latent heat fluxes, momentum flux, surface radiation temperature, net radiation, soil moisture, and soil heat flux. They are often self-contained, powered by solar cells and batteries, and able to transmit data to a base station from remote locations. Typically they are deployed in a network from a few kilometers to tens of kilometers apart to provide baseline data for mesoscale multifaceted observational studies.