Reaching for the clouds

Clouds are key components in the Earth’s weather and climate system, and about 60 percent of the Earth is covered by clouds. They transport heat and moisture from the warm tropical regions into the cold polar regions, and where warm air from the tropics meets cold air from the poles, you can both observe and feel the impact of clouds.

Despite this, the processes that lead to the formation of clouds are not yet fully understood. By doing more research and understanding more about clouds, we can get even more accurate weather and climate forecasts.

– Clouds are one of the largest sources of uncertainty in current climate models. We are therefore trying to better understand the development of mixed-phase clouds, how they evolve, and how that affects the weather and climate, says Tim Carlsen, researcher at the Department of Geosciences at the University of Oslo.

He and his colleagues have conducted the Mixed-phase Clouds and Climate (MC²) campaign at Andøya Space, a five-week-long scientific measurement campaign that combined measurements from a research aircraft with ground-based observations.

The focus of the MC² campaign are mixed-phase clouds, which consist of both liquid water and ice, and their role for the Earth’s climate. Their importance is undisputed, but their exact properties are still very uncertain.

– We are looking into how much of the mixed-phase clouds are water droplets and how much are ice crystals. This is important for how the clouds develop and evolve, and other factors, such as how much sunlight they reflect, says Robert Oscar David, another of the researchers from the University of Oslo in the MC² campaign.

Andøya – a natural laboratory for climate science

During the research flights, the researchers investigated the distribution of liquid water and ice crystals in low- to mid-level clouds. These types of clouds are common in the Arctic.

– Andøya is a really unique location because it’s at a crossroads where air from the Arctic meets air from farther south, says Carlsen.

– The type of clouds we are investigating are frequently found here at this time of year. That makes Andøya a natural laboratory for us, adds David.

Andøya Space has a long history of offering research infrastructure to universities and research institutions from all over the world.

– Our main task is to provide the infrastructure and services that makes such campaigns possible, says Laura Scholtz, project manager for the MC² campaign at Andøya Space. – This includes facilities for performing ground-based measurements and delivering data from our own instruments at the Alomar Observatory.

This is the third year the researchers in the MC² project are at Andøya.

– This time we utilize a research aircraft from the National Institute for Aerospace Research “Elie Carafoli” (INCAS) in Romania. It is a key component in the campaign that we haven’t had earlier, says Carlsen.

The aircraft will help to put the ground-based observations into a larger perspective. It carries instruments that measure the number and size of ice crystals and liquid droplets in the clouds. The pilots and operators from INCAS are part of the campaign team at Andøya, planning and coordinating the flights with the scientists.

– Two of them operate the instruments during the flight. The plane also has room for one mission scientist, says Laura-Kristin Scholtz.

– To have a mission scientist onboard is a great advantage because it allows us to record exactly what kind of clouds we’re flying through and enables us to make in-flight decisions to easier find what we are after, says David.

In addition to INCAS in Romania, researchers from the Universities of Bergen, Gothenburg and Leipzig are part of the MC² campaign. The team from the University of Oslo is led by Professor Trude Storelvmo.

– We also have two postdoctoral researchers, three PhD students and three master’s students who are actively involved in the measurements. They are critical for the project, and will use the data in their own research, says David.

– With MC² we hope to solve one important piece of the puzzle of the role clouds play in the Earth’s climate, says Carlsen.