this story, I thought Environment Canada's plan to use a high-speed camera to capture images of snowflakes as they fall was a bit flaky too. However, I've met several Environment Canada scientists over the years. I know they take their work seriously. So, rather than write this off as just some frivolous study, and I did some more digging into the story.Reading
In the winter of 2008/2009, scientists at the Centre for Atmospheric Research Experiments (CARE), near Egbert, Ontario, participated in a joint study with colleagues at the National Oceanic and Atmospheric Administration (NOAA), the National Center for Atmospheric Research (NCAR) and the Federal Aviation Administration (FAA). They set up several different types of snow gauges at the same location and observed the differences in the data they collected. This was all to examine the quality of the data that they were getting, and thus the quality of the information that they were releasing to the public. Adding up the total accumulation of snow and rain between December 2008 and April 2009 for each gauge, they found that some gauges were measuring up to three times the amount that others were reading. Some variation was expected, because the gauges all have different sensitivities and capacity, and the size of the opening the snow falls into varies by model as well.
The findings of this study were published in the June issue of the Bulletin of the American Meteorological Society (BAMS), and one of the key challenges identified in the summary and discussion was:
"Accounting for the reduction in snow catch due to distortion of snowflake trajectories by the airflow pattern around a gauge. A number of wind shields have been created to reduce this effect, but no shield has yet been invented that has high collection efficiency and is smaller than 4 m in diameter." (BAMS, June 2012, pg827)
A snow gauge is typically made with three parts. A funnel or opening that the snow falls down into, a see-saw-like set of catches that the falling snow collects on, and a reservoir to store the liquid. One snow catch is always in position to collect snow on it. When the weight of the snow gets too high, it tips the scale and that catch lowers to dump the snow into the reservoir, which brings the other catch up to collect snow. The problem that was being found in many cases is that the snow wasn't falling directly onto the snow catch of the gauge. Many of the flakes were being influenced too much by the winds around the gauge and therefore missing the catches and not being recorded.
This is where Environment Canada's new project comes in.
According to the National Post, Environment Canada's notice says that the camera will show "the movement of snowflakes and eliminate the motion blur making it possible to track air flow, velocity, acceleration as well as flake size and shape change in some instances."
By examining snowflakes with a high-speed camera and seeing the details of how they develop and change shape, they hope to better understand the exact motion of flakes as they fall, and perhaps how the snow catches can better collect the snow. Having a better understanding of that may help with the design of better snow gauges and wind shields, that can report snowfall amounts much more accurately.