Ice Extent in Lake Superior
Ice provides an essential part of the ecology of Lake Superior. The lake is the largest of the five Great Lakes of North America and is in the north of the United States and Canada. This large body of water is home to a diverse group of species, including fish and aquatic plants, and the ice on the lake helps regulate the environment.
The average thickness of ice on the lake is around 10cm, but can vary by season. In the fall and winter months, it can reach up to 30cm thick. The lake often freezes over completely, with less open water in winter than in summer. The National Ice Center publishes ice charts once weekly to show the extent of ice cover. As of February 2021, around 44 percent of Lake Superior was covered by ice.
Winter temperatures the previous year (2020) were much colder than average, resulting in a higher-than-average ice cover in Lake Superior. In the spring and summer (April to August 2020), the amount of ice on the lake continued to increase, reaching an average of around 75% in August.
The lake ice is an important factor for shipping. Pilotage has to be employed in areas with high ice coverage, and low-lying areas often have to be closed when the lake is frozen. The ice also affects fishing, as the lake provides a significant source of food for the local community. The ice prevents many species from spawning, which can lead to reduced hauls for some fishermen.
Many factors influence the amount of ice on the lake, including wind, water temperature, and the amount of sunlight. In winter, ice forms quickly when temperatures drop quickly, and when the sun is not bright enough to break up the ice forming. Wind can also play a role in how quickly the ice covers, as it can move the ice around and either push it further out or move it back closer to the shore.
The ice can often form thick ice shelves, which can remain until late Spring or early Summer. These thick ice sheets can provide valuable information for scientists trying to study climate change, as it can provide a better understanding of the lake’s dynamics and how it responds to changing weather patterns.
Ice Extent in Lake Superior from September to February
The extent of the lake’s ice cover gradually decreases from September to February. This can be seen on the National Ice Center’s ice charts, which show a gradual decrease in coverage. In September, around 75% of the lake is covered in ice, but by February, it is down to around 44%. This gradual decrease is due to both the warmer temperatures and increased exposure to direct sunlight in the winter, which can both contribute to a decrease in ice coverage.
This decrease in ice coverage is also related to the winter storm activity. During the winter months, the lake can experience strong winds and heavy rainfall, which can both contribute to a decrease in ice coverage. This can be particularly pronounced when temperatures drop over a short period of time, as winter storms can rapidly increase the size of the ice shelf.
Despite the decrease in coverage, the lake still experiences periods of high ice coverage during the winter. This can be seen on the ice charts, which show that in some months, the lake can reach 100% coverage.
The decrease in ice coverage is usually accompanied by an increase in open water. In winter, the open water areas are much larger than in the summer months, due to both the reduced ice coverage and the increased exposure to direct sunlight. This increased open water area can result in more evaporative cooling, which can sometimes lead to colder temperatures.
Effect of Climate Change on Ice Extent in Lake Superior
Climate change has been known to have an impact on the amount of ice in Lake Superior. There are several aspects of climate change that can affect the lake’s ice cover. One of the most well-known is increased temperatures. Higher temperatures can cause more sunlight to be absorbed by the lake’s surface, resulting in faster ice melting. Higher temperatures can also lead to increased evaporation, which can further decrease the lake’s ice coverage.
Another aspect of climate change that can affect the lake’s ice coverage is increased precipitation. Increased precipitation can often lead to increased levels of runoff entering the lake, resulting in a decrease in ice coverage. It can also cause the lake’s water to be more turbulent, resulting in more fragmented ice shelves.
A third factor that can affect the lake’s ice coverage is changes in wind direction and speed. Wind can have a significant effect on the lake’s ice coverage, as it can push the ice away from the shore or towards it. Stronger winds are also capable of breaking apart ice shelves, resulting in increased fragmentation.
Finally, changes in air pressure can also affect the lake’s ice coverage. Low air pressure can push the ice away from the land and cause it to drift out onto the open water. High pressure, on the other hand, can cause the ice to break up and form smaller ice sheets.
Ice Extent in Lake Superior over Time
Ice coverage has been decreasing in Lake Superior over the last few decades. This is largely due to climate change, but other factors, such as a reduction in air pressure and increased winter storm activity, are also playing a role. In recent years, the lake’s ice coverage has decreased by an average of around 10 percent each year, and the decrease is expected to accelerate in the years to come.
The decrease in ice coverage has had a number of impacts on the local ecology. In the short-term, it can lead to more open water for aquatic species, allowing them greater access to the food and shelter that can be found in the lake’s waters. In the long-term, however, the decreased ice coverage can have a detrimental effect on the lake’s environment, as it makes it more difficult for the lake’s ice to form in the winter months.
The decrease in ice coverage is expected to continue in the future. This is likely to have an even greater impact on the lake’s ecology in the coming years, with effects that could reach far beyond the lake’s shores.
Impact of Ice Extent on Shipping in Lake Superior
The ice coverage in Lake Superior has a direct impact on shipping. Areas where the ice is thicker or more widespread will require pilots to navigate them. This can be a time-consuming and hazardous task, due to the risk of the ice shifting and blocking the ship’s path. The ice can also cause vessels to become trapped, as the water can freeze for extended periods of time in the colder months.
A decrease in ice coverage has the potential to improve safety in navigating the lake. As the open water areas become larger, it becomes easier for a pilot to plot a course around the ice without having to worry about it shifting or blocking their path. However, a decreased ice coverage can also make it harder to predict where the ice will form in the future, as it can be difficult to predict when and where the lake will freeze.
The decrease in ice coverage can also impact the lake’s fisheries. Fish migrate according to the lake’s ice coverage, and a decrease in ice coverage can result in reduced catches for local fishermen. In addition, the decrease in ice coverage can lead to increased pollution and the spread of aquatic diseases, as the colder waters can act to slow the spread of pollutants and pathogens.
How Climate Change Action can Help Maintain Lake Superior’s Ice Extent
The ice coverage in Lake Superior is likely to continue to decrease in the future, as climate change continues to take its toll. However, there are a number of actions that can be taken to help mitigate the effects of climate change on the lake’s ice coverage. For instance, reducing emissions of greenhouse gases can help slow down the rate at which the lake’s ice is melting.
The introduction of alternative energy sources, such as solar and wind power, can also help reduce the amount of emissions entering the atmosphere, and thus slow down the rate of climate change. Reducing emissions of pollutants into the lake can also help reduce the impact of climate change on the lake’s ice coverage, as these pollutants can contribute to ice melt.
Finally, increasing conservation efforts can also help mitigate the effects of climate change on the lake’s ice coverage. By protecting and preserving the lake’s ecosystems, we can help ensure that the lake’s ice coverage remains stable, even as temperatures continue to rise.
Conclusion
The ice coverage in Lake Superior is an important factor for both shipping and the local ecology. As temperatures rise and climate change advances, the lake’s ice coverage is likely to continue to decrease. Nevertheless, there are a number of actions that can be taken to help reduce the impact of climate change on the lake’s ice coverage, such as reducing emissions and increasing conservation efforts.
