[ howling wind ]
Walt: We just returned from the GPM Cold Season
Precipitation Experiment held in Ontario, Canada.
And it was a very successful experiment. We collected the bulk of the
data that we went up there to get, and I think that everybody is very happy with the dataset.
I would say that it did not snow across the norther tier of the United
States and Southern Canada as much as we had hoped it would this year, but surprisingly
enough, even given the relative lack of snow that we had,
we got all the events that we basically wanted.
One of the objectives for this field campaign was to
test the range of snowfall intensities
that occur. And the idea being there that we would be able to
sort of find where it is in that spectrum of events that we would actually be able to
detect falling snow from space with the GPM
Core satellite.
[ jet engine ]
Through the duration of the campaign we went the full
six weeks using all the aircraft hours that were available to us on the DC-8.
We flew about 14 missions, for a total about 75 flight hours
I sort of assumed we would show up and basically burn out our flight
hours in a very short time up there in frequent heavy snowfall
events, and what actually transpired is that we ended up using the entire
duration of the field campaign to get our datasets because the snow events
were sort of spaced fairly regularly and
were not that heavy and we kept wanting to get the heavier event, and it took a while
to get that. Steve: As you can see it's snowing pretty good
this morning at the CARE site. Pretty nice large aggregates.
It's exactly what we're looking for and it just keeps coming down.
Walt: So we've completed the GCPEx experiment in terms of being
on the ground and collecting the data. Now a phenomenal effort actually goes
into quality controlling all of the data we collected. That is, to make sure that
all of those datasets that we collected are usable,
there's no bad data in the datasets, and that has to be done for
a huge number of ground instruments that were deployed, both radars
direct measurements of snowfall using gauges, particle
imaging systems, all of those data on the ground. And then you have to move to the aircraft
data, which is also very complex because you've got several different probe types
that were flying in the clouds, looking at different aspects of the precipitation
and all of that data has to be quality controlled. And finally you have the
satellite simulator, or the DC-8, that carried the radiometer, the
COSMIR radiometer and the APR-2 radar.
All of those data have to be--and we're talking gigabytes and terabytes--
of data that has to be quality controlled. That will take on the order of six months to
a year to accomplish. And that connection in between what I
measured during this field campaign to what I think I'm going to see in space
essentially encompasses the development process of
making an algorithm to retrieve the snowfall from space.
[ rain ]
[ rain dripping ]