Text: Elin Vinje Jenssen / Norwegian Polar Institute. Translated by: Stephen Hudson / Norwegian Polar Institute
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Polar clouds can tell us things we don’t know—but should know—about the climate of the future.

CLOUDS ON  THE HORIZON Fewer and fewer Antarctic petrels are finding their way from the coast up into the mountains around the Norwegian research station Troll in Dronning Maud Land. Over the last twenty years, the petrel population in this area has declined sharply; this decrease is linked to warming oceans, extreme weather and failing food supplies. Photo: Stein Tronstad / Norwegian Polar Institute

 

Sunshine and clear skies are many people’s idea of summer perfection—but did you know that the gray clouds that roll in from time to time play a critically important role in keeping our planet habitable?

About 5 Degrees Warmer Without Clouds

Globally, clouds have a strong cooling effect on the climate. Without them, Earth would be roughly five degrees warmer on average, explains researcher Stephen Hudson of the Norwegian Polar Institute.
– Clouds reflect sunlight before it reaches the ground, reducing temperature both locally and globally. They also act like blankets that trap heat, raising surface temperature. Locally, it’s the balance of these two effects that shapes weather and climate.

CLOUD OBSERVATORY AT TROLL For the first time, clouds can be studied from Troll. The integrated cloud observatory was completed earlier this year thanks to dedicated efforts by staff from the Polar Institute and partner institutions. Photo: Stephen Hudson / Norwegian Polar Institute

Amplify or Dampen?

Hudson is part of an international research project (TONe) investigating what happens to clouds as the climate changes. The scientists aim to determine whether the cooling effect of clouds will change as the atmosphere warms—and if so, whether clouds will amplify or dampen global warming.

See the first balloon launch from the Troll cloud observatory

Since 1950, the Earth’s average temperature has risen by 1.1 °C—and it keeps climbing, according to the UN Intergovernmental Panel on Climate Change. Warming leads to many consequences, including increased precipitation, accelerated ice melt and rising sea levels. People, animals and plants around the world are affected by a warmer climate.
–We know clouds respond to climate change, but the question is how—and by how much, says Hudson.

DAILY BALLON LAUNCH The cloud observatory launches one weather balloon per day, all year round. Each balloon carries a radiosonde that measures temperature, humidity and wind up to 30 km in the atmosphere. Very little such data exist from this region, but we desperately need it—researchers already see signs of climate change here in Dronning Maud Land. Photo: Norwegian Polar Institute

Uncharted Territory

One of the major challenges for today’s climate models is that they lack data on how a warmer climate affects clouds. Climate models estimate average temperatures decades into the future, but modelling clouds is a complex task. Clouds form and evaporate within minutes.

LEADING THE CLOUD RESEARCH –The goal is for the weather balloons and other instruments to give us more knowledge about the atmosphere over and around Troll, and especially about the role clouds play in the climate puzzle in Dronning Maud Land, says researcher Stephen Hudson of the Norwegian Polar Institute. Photo: Natalie Snyder

 
Fellow scientists worldwide are continuously improving their models, but despite these efforts much remains unknown. The greatest uncertainty concerns how polar clouds will respond to warming. In the Arctic there are some studies of cloud behaviour, but in Antarctica there is very little current knowledge of cloud properties or their responses to warming.
 
– The remote location and harsh conditions make it more challenging to collect data from Antarctica than from almost anywhere else on Earth, says Hudson.

Mixed-Phase Clouds May Hold Answers

In Antarctica the most common clouds are so-called mixed-phase clouds, composed of both ice crystals and liquid water droplets.
As temperatures rise, the balance between water droplets and ice crystals in these clouds shifts: there is more liquid water and less ice. Thick clouds rich in liquid water droplets reflect more sunlight, whereas thin, ice-dominated clouds let more sunlight through.

FIRST BALLON FLIGT Stephen Hudson prepares for the first balloon launch from Troll. Photo: Erland Loso / Norwegian Polar Institute

When clouds contain more water droplets and fewer ice crystals, they reflect more sunlight and emit more infrared radiation toward the surface.

– This could mean that the cooling effect clouds once provided may vanish, and instead warming could accelerate—especially at high latitudes where the bright surface already reflects much sunlight and where the sun doesn’t shine for months at a time, as in Antarctica, explains Hudson.
 
Changes in cloud properties in a warming climate further complicate the picture. It is urgent to gain deeper insight into how clouds react to a warmer climate, and what that means for the ice sheet in East Antarctica.
 
– Multiple studies already show increased sea-ice melt and loss of land ice in Antarctica, but the role of clouds remains a major uncertainty.

TEAM AT THE OBSERVATORY The team that helped set up the cloud observatory: from left, Senior Engineer Marius Bratrein and Researcher Stephen Hudson (both from the Polar Institute), with scientists Ryan Neely III (University of Leeds) and Mike Town (Earth & Space Research). Photo: Hans Fredrik Aaby

Rising to the Skies in Search of Knowledge

Stephen Hudson leads the new Norwegian cloud studies, which starting this year will be expanded in Antarctica—specifically at the new cloud observatory at Troll Reserch Station in Dronning Maud Land. Only a few other sites on the continent have conducted similar cloud measurements; the United States, Switzerland and Germany have all performed cloud observations from their stations.
 
The Troll cloud observatory was installed earlier this year by researchers and logistics personnel from the Polar Institute, the University of Leeds, Earth and Space Research and Washington State University. It consists of three containers on a platform set into a mountainside near the station. They contain instruments and sensors that collect data on clouds, aerosols and radiation, as well as a system for daily weather-balloon launches.

OBSERVATORY NETWORK  The cloud observatory with Troll Research Station in the background. The observatory is part of the Troll Observing Network (TONe), which includes eight observatories collecting long-term time series on the entire Earth system — all established at and around Troll Research Station. Photo: Erland Loso / Norwegian Polar Institute

 
Weather balloons transmit information back to Troll station via radio frequencies. The data collected primarily cover temperature, pressure, humidity, wind speed and wind direction.
 
– The atmospheric data from the balloon flights will be critical to understanding cloud formation, winds and precipitation, as well as contributing to global weather forecasts, explains Hudson.

VALUABLE DATA –The cloud observatory will become a polar flagship activity for Norway in Antarctica. – Much of the other research, monitoring and mapping we conduct in the south takes place not at Troll but out in the field. With the cloud observatory, we now have a presence at Troll as well, says TONe project leader Christina Alsvik Pedersen. Photo: Norwegian Polar Institute

Into Climate Models

Troll’s physical location—on the slope between the coast and the high interior plateau of Antarctica—makes its observations especially valuable, says TONe project leader Christina Alsvik Pedersen at the Polar Institute.
 
– Data on clouds and the atmosphere collected at the observatory will provide new and crucial insight into the energy and mass balance of this region. A better understanding of cloud properties gives researchers a stronger foundation for improving how clouds are represented in weather and climate models. Modelling clouds today is a major challenge, which makes this research particularly important.
 
The cloud observatory is part of TONe, which includes eight observatories collecting long time series on the entire Earth system—all installed at and around Troll research station.
 
– In short, observations are needed to understand the Earth system, and observations are in short supply in Antarctica. The cloud observatory is a step in the right direction to help us find answers to whether and how global warming affects clouds in Antarctica—and which feedbacks are most important, says Stephen Hudson.

INTERIOR OF ANTARCTICA Troll station and the cloud observatory (in front) lie about 235 km from the coast, at Jutulsessen in Dronning Maud Land, and operate year-round. In winter, Troll is run by its six winterover crew; in summer, many more people staff the station and its surrounding areas. Photo: Stephen Hudson / Norwegian Polar Institute

 

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