Antarctica Project Overview
Now that the flurry of getting all of the equipment packed and shipped has passed, I have some time to post an update. It seems most appropriate to begin by giving a few more details on the project and what we hope to accomplish. First off, this project is being funded by the National Science Foundation and is a collaborative effort between the National Center for Atmospheric Research (NCAR) and the University of Colorado (CU). I am managing the project on the NCAR side and Mark Seefeldt is managing the project on the CU side. The overall purpose of the project is to show that we have the ability to measure snowfall in the Antarctic environment. The "snowfall" I'm referring to is not necessarily snow depth though. What we are interested in is how much Liquid Water Equivalent (LWE) snowfall is falling. LWE sounds complicated but it is simply the amount of liquid water you would get if you melted all the snow. You can also achieve this by weighing the amount of snow that has fallen without having to melt it. So why measure LWE instead of snow depth? For those of you who have had to shovel snow, you know that six inches of fluffy snow is much easier to shovel than six inches of wet, slushy snow. The difference between the two is that the wet, slushy snow has a much higher LWE amount than the fluffy snow. Applying that principal to Antarctica, we ultimately want to know how much frozen water is falling across the continent to compare against what is being lost to melting and sublimation (the process of water changing directly from ice to vapor without first melting).
Several people have asked "Aren't we already doing this, though?" Surprisingly no. Measuring LWE snowfall is still a challenge and is an active area of ongoing research around the world. A question I commonly get asked is "can't you just put a bucket out and let it snow in the bucket and then weigh it after the storm?" While this would seemingly be the simple solution to the problem, the answer is "only if there is no wind and only if the snow falls in the bucket and doesn't build up on the rim of the bucket, which can actually cap over a gauge if that process continues long enough, causing the gauge to look like a giant ice cream cone". Snow falls at a rate of roughly three feet per second and because it is much less dense than rain, even light winds of 10 mph can significantly decrease the amount of snow falling in the bucket. This is because most of it would simply blow over and past the bucket instead of into the bucket due to the inherent sideways motion the wind imparts on the snow. It is actually quite rare for there to be no wind during snowfall events, particularly in Antarctica where wind speeds of 70 mph are not uncommon. In fact, there is still no established worldwide standard for measuring LWE snowfall (though the World Meteorological Organization will soon be releasing that standard based on research from another project I was involved in).
Alright, so we don't have a world standard for measuring LWE snowfall because it's really hard to do, but my colleagues and I are going to Antarctica to do just that. So just how do we plan to accomplish that? We will be deploying a suite of different sensors including temperature sensors, acoustic snow depth sensors (that measure snow depth by bouncing sound waves off the snow and measuring the amount of time it takes the sound wave to go from the sensor to the snow and back again), wind speed sensors, particle counting sensors (that will measure the number of snow particles every minute), particle size and fall speed sensors (that will measure the size of the particles and the speed they are falling), solar radiation sensors (to help determine when cloud cover is present), and a snow gauge. The snow gauge is a fancy version of the bucket I discussed above. It is essentially an outer protective casing with a bucket inside that sits on a mass balance. The mass balance automatically measures the weight of the bucket every 6 seconds and stores the data. We will also be installing a shield around the gauge that is designed to slow the wind down so that the snow falls more vertically into the gauge. We will be testing the efficiency of this shielding as part of this research.
I don't have any pictures of things to share (yet) but will be posting pictures of our sites as we set them up with more discussion on this once we are in Antarctica. I am tentatively scheduled to depart Oct 23 to head to New Zealand. I will probably post another update as that date gets closer, and then update my blog more frequently once I am on the ice.
One month to go!
Several people have asked "Aren't we already doing this, though?" Surprisingly no. Measuring LWE snowfall is still a challenge and is an active area of ongoing research around the world. A question I commonly get asked is "can't you just put a bucket out and let it snow in the bucket and then weigh it after the storm?" While this would seemingly be the simple solution to the problem, the answer is "only if there is no wind and only if the snow falls in the bucket and doesn't build up on the rim of the bucket, which can actually cap over a gauge if that process continues long enough, causing the gauge to look like a giant ice cream cone". Snow falls at a rate of roughly three feet per second and because it is much less dense than rain, even light winds of 10 mph can significantly decrease the amount of snow falling in the bucket. This is because most of it would simply blow over and past the bucket instead of into the bucket due to the inherent sideways motion the wind imparts on the snow. It is actually quite rare for there to be no wind during snowfall events, particularly in Antarctica where wind speeds of 70 mph are not uncommon. In fact, there is still no established worldwide standard for measuring LWE snowfall (though the World Meteorological Organization will soon be releasing that standard based on research from another project I was involved in).
Alright, so we don't have a world standard for measuring LWE snowfall because it's really hard to do, but my colleagues and I are going to Antarctica to do just that. So just how do we plan to accomplish that? We will be deploying a suite of different sensors including temperature sensors, acoustic snow depth sensors (that measure snow depth by bouncing sound waves off the snow and measuring the amount of time it takes the sound wave to go from the sensor to the snow and back again), wind speed sensors, particle counting sensors (that will measure the number of snow particles every minute), particle size and fall speed sensors (that will measure the size of the particles and the speed they are falling), solar radiation sensors (to help determine when cloud cover is present), and a snow gauge. The snow gauge is a fancy version of the bucket I discussed above. It is essentially an outer protective casing with a bucket inside that sits on a mass balance. The mass balance automatically measures the weight of the bucket every 6 seconds and stores the data. We will also be installing a shield around the gauge that is designed to slow the wind down so that the snow falls more vertically into the gauge. We will be testing the efficiency of this shielding as part of this research.
I don't have any pictures of things to share (yet) but will be posting pictures of our sites as we set them up with more discussion on this once we are in Antarctica. I am tentatively scheduled to depart Oct 23 to head to New Zealand. I will probably post another update as that date gets closer, and then update my blog more frequently once I am on the ice.
One month to go!
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