Despite difficult ice conditions and curious polar bears, a German research icebreaker with 100 scientists and crew members is comfortably adrift in the frozen Central Arctic, two months into a yearlong expedition to study the region’s changing climate.

“Mosaic is in full swing,” Jessie Creamean, a researcher from Colorado State University, wrote in an email, using the informal name for the expedition, the Multidisciplinary Drifting Observatory for the Study of Arctic Climate. The ship, the Polarstern, has been frozen into the ice since early October; Dr. Creamean and other researchers will be on board until next month, when a first relief team of scientists arrives on another icebreaker.

Dr. Creamean has been setting up portable equipment, nicknamed C-3PO, on the ice to sample particles and droplets in the air as part of her studies of how Arctic clouds form. She is also an “ice boss” on a 12-person crew that goes out every Monday and takes 60 ice cores — each about 20 to 40 inches long — for studies by various scientific teams.