The Arctic and North Atlantic oceans have seen an increasing number of days when precipitation falls as rain, not snow.The Arctic is understood for its cold temperature levels, which enable rainfall to fall as snow. These changes can affect sea ice in the Arctic and weather condition patterns throughout the Northern Hemisphere.NASA scientists analyzed rainfall patterns over the Arctic and North Atlantic oceans from 1980 to 2016 and discovered a boost in the frequency of rainy days. The outcomes were published in the Journal of Climate.Increasing Rainfall Trends and Arctic WarmingThe most significant modifications took place in the North Atlantic, where it rained on average five more days per years at the end of the 36-year research study duration than at the start.”One thing to note is that there really is no dark brown anywhere, so in no way are we seeing any substantial reductions in the number of rains days,” said Chelsea Parker, a weather condition and climate researcher at NASAs Goddard Space Flight Center and co-author of the study.When temperature levels are above freezing, clouds are more likely to consist of liquid that drops as rain than ice that falls as snow, stated Linette Boisvert, a cryospheric scientist at NASA Goddard and lead author of the study.Impacts of Rainfall on Arctic Ice and Global WeatherWhen rains hits the snow-covered sea ice, it darkens the surface area and can magnify melting that in turn leads to more warming– a process understood as the ice-albedo feedback loop.
The Arctic and North Atlantic oceans have seen an increasing number of days when precipitation falls as rain, not snow.The Arctic is known for its cold temperatures, which enable precipitation to fall as snow. As temperatures warm, that snow is being changed by rain. These modifications can affect sea ice in the Arctic and weather patterns throughout the Northern Hemisphere.NASA researchers taken a look at rainfall patterns over the Arctic and North Atlantic oceans from 1980 to 2016 and found a boost in the frequency of rainy days. They likewise found that the length of the yearly rainy season grew longer. The outcomes were published in the Journal of Climate.Increasing Rainfall Trends and Arctic WarmingThe most dramatic changes happened in the North Atlantic, where it moistened typical 5 more days per decade at the end of the 36-year research study duration than at the beginning. The rest of the research study region– the main Arctic Ocean and its peripheral seas– saw approximately 2 extra rainy days per years. This comes as temperature levels in the Arctic are warming 4 times faster than the rest of the planet.The map above shows the change in number of rainy days annually, which has added to this decadal trend toward a rainier Arctic. It is based upon the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2), an international reanalysis item established by NASAs Global Modeling and Assimilation Office. The item takes in-situ and satellite observations, consisting of from NASAs Atmospheric Infrared Sounder (AIRS) on the Aqua satellite, and uses them to reproduce conditions that have actually taken place across the globe.Here, much of the North Atlantic is displayed in deep blue, which shows a larger boost in the number of rainy days per year (in between 1980 and 2016) compared to light blue areas. The Barents Sea north of Norway and the Kara Sea north of Siberia are also revealed in deep blue.”One thing to note is that there really is no dark brown anywhere, so in no chance are we seeing any substantial declines in the number of rains days,” said Chelsea Parker, a weather and environment researcher at NASAs Goddard Space Flight Center and co-author of the study.When temperatures are above freezing, clouds are most likely to contain liquid that drops as rain than ice that falls as snow, said Linette Boisvert, a cryospheric scientist at NASA Goddard and lead author of the study.Impacts of Rainfall on Arctic Ice and Global WeatherWhen rains hits the snow-covered sea ice, it darkens the surface area and can amplify melting that in turn results in more warming– a process referred to as the ice-albedo feedback loop. Snow on top of sea ice serves as insulation, showing solar radiation back to space and keeping the surface area cool. Rain gnaws at this snowy buffer.”If it rains during the sunlit months, the surface area is going to be a lot darker because the snow is damp compared to a fresh, dry, and thick snowpack. This damp snow surface is going to start taking in more of that inbound solar radiation,” Boisvert stated. When the snow melts, it forms ponds on the ice, producing a darker surface area and soaking up more solar radiation. This triggers a loop of ongoing warming and melting.Meanwhile, water vapor drives its own feedback loop. The environment can hold more water vapor as temperatures rise. As a heat-trapping greenhouse gas, this water vapor warms the Earths surface area and adds to melting the snow and ice. This melting exposes open ocean, allowing evaporation to occur, which launches more water vapor into the atmosphere.Feedback loops in the Arctic impact other parts of the world, too. Changes to the amount of heat in the Arctic can affect weather condition patterns further south. For instance, Parker pointed to severe temperature swings in the U.S. and polar air masses that form over the North Pole and move south over North America.”All of that,” Parker said, “is dependent on the degree to which the Arctic is experiencing climate change.”Reference: “Rainy Days in the Arctic” by Linette N. Boisvert, Melinda A. Webster, Chelsea L. Parker and Richard M. Forbes, 8 September 2023, Journal of Climate.DOI: 10.1175/ JCLI-D-22-0428.1 NASA Earth Observatory image by Wanmei Liang, utilizing information from Boisvert, L., et al. (2023 ).