13 January 2014

More on the UW King Air

Sorry for the long delay between posts. It has been somewhat of a busy week for me and I've had a number of other "chores" to work on. Much has happened with OWLeS since I last posted. We had 5 research flights in 4 days into lake-effect storms last week alone, as many as we had all of December! There were even 2 flights in one day, during one of which I got the privilege of flying in the 2nd seat. That meant that I got to tell the pilot where and how high to fly. So needless to say, myself and everyone else here have been tired and exhausted - getting up at 4 AM several times during the week was not on my original list of "things to do" before I came to NY, but we make the best of it.

Today (Monday) was a down day, meaning we were not collecting any data...which makes sense given that there are no lake-effect storms going on at the moment in our area. For me, down days like this are usually spent getting other stuff done. This past week, I've been working on editing a paper that we are trying to get published in one of the atmospheric science journals. I've also been plotting data from each of our flights and putting them online so other people associated with OWLeS can see them. I'm also in one class this spring, which started today, so eventually I will have homework and readings to do for that. On top of all this, I still have my own master's degree research to finish up - I haven't been able to work on any of that since November!

But instead of doing lots of work today, I helped give King Air tours to the undergraduate students from some of the other colleges involved in OWLeS - Millersville University, SUNY-Oswego, and Hobart and William Smith. These tours were more in-depth than the open house that we had back in December. I decided it was a good time to snap a number of photos of the airplane that I've been meaning to get - ones showing more of the instruments so that I can tell you a little bit about what each instrument does.

Instruments of the left wing of the King Air
A - FSSP precipitation probe
Measures certain sizes of precipitation particles that pass through a laser

B - Turbulence probe
By measuring fluctuations in wind speed (and thus air pressure) at a hole on the front of the tube, we can figure out the air turbulence

C - Rosemount temperature probe
Air flows into an opening at the front and is constricted at the back. This constriction forces some of the air up into a chamber where a temperature sensor is located. Ideally, water droplets will be too heavy to be drawn up into this chamber. If water were to collect on the temperature sensor, it would cause errors in the measurements when it evaporates 

D - 2DP precipitation probe
Another instrument which measures sizes of precipitation particles by examining the shadow that particles make when they pass through a laser

Instruments on the front of the King Air
E - Gust probe (wind instrument)
Measures the air pressure at four small holes on the front of the instrument tube. Two holes are oriented horizontally and two vertically. Differences in air pressure between the two horizontal holes gives us the horizontal (east-west-north-south) wind while differences between the two vertical holes gives us the vertical (up-down) wind

F - CDP cloud particle probe
Yet another instrument that measures the sizes of precipitation and cloud particles, once again using a laser

G - Liquid water probe
Instrument which uses a laser to estimate the amount of liquid water in a cloud. It can also measure the sizes of water droplets

CDP probe

Liquid water probe

Right wing of the King Air
H - CIP particle imaging probe
One final instrument which measures the sizes of cloud particles passing through a laser

I  - LWC100 liquid water probe
An instrument which directly determines the amount of liquid water in clouds by measuring how much water hits a metal rod and evaporates. This rod is heated to a constant temperature, but as water hits the rod and evaporates (cooling the rod), more electricity has to be given to the rod to keep it at that temperature. By knowing exactly how much electricity is needed, we can figure out how much liquid water is hitting the rod in the first place

J - Reverse flow temperature probe
This instrument has four metal tubes that extend outward and are cut at 45° angle at their ends. These tubes are connected to a larger central chamber which houses a temperature sensor and has an opening at the back. As air flows past the tubes, these angled ends create an area of negative pressure right behind the tubes. Because air flows from high to low pressure, the negative (low) pressures suck the air out from inside the chamber through the tubes, which causes air to flow into the larger chamber from the opening in the back (i.e. reverse flow). This is the air that is measured by the temperature sensor. Meanwhile, any water droplets are (hopefully) too heavy to get sucked in the back and eventually get blown off the probe

There are a few other instruments on the airplane, including two that measure air pressure and dewpoint temperature, that I don't have photos for. But below are a couple pictures of our radar, lidar, and the windows that they pass through when the airplane is in the air.

View of the radar and lidar from right outside airplane door

Radar and lidar windows as viewed from the backside of the airplane
Now you all know a lot more about the King Air than I knew just 6 months ago!

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