What We See Over Open Ocean

Narration: Reem Hannun

Transcript:

1

00:00:00,020 --> 00:00:04,100

Part of what makes ATom fun is just flying over the open ocean,

2

00:00:04,100 --> 00:00:08,170

and it's interesting just to see how

3

00:00:08,170 --> 00:00:12,230

you know, we're trying to sample chemistry in remote

4

00:00:12,230 --> 00:00:16,430

regions, but when you go on these flights, you really see that there

5

00:00:16,430 --> 00:00:20,600

aren't many places that humans have not yet impacted.

6

00:00:20,600 --> 00:00:24,670

We live and breathe in the atmosphere and

7

00:00:24,670 --> 00:00:28,740

even though it seems quite inert, it's a really dynamic medium

8

00:00:28,740 --> 00:00:32,840

and there's a lot of chemistry going on, so it's just something I've

9

00:00:32,840 --> 00:00:36,970

always been interested in; I've always been interested in spectroscopy,

10

00:00:36,970 --> 00:00:41,180

and how you can use lasers to make these really incredibly specific

11

00:00:41,180 --> 00:00:45,250

and sensitive measurements. I'm working on the in situ airborne

12

00:00:45,250 --> 00:00:49,290

formaldehyde instrument, which is an instrument that measures formaldehyde

13

00:00:49,290 --> 00:00:53,460

in the atmosphere. Our instrument on the plane is literally a

14

00:00:53,460 --> 00:00:57,640

black box, with a couple of switches.

15

00:00:57,640 --> 00:01:01,830

I don't know, it's not that exciting to look at, but

16

00:01:01,830 --> 00:01:05,850

on the inside, it's pretty fun.

17

00:01:05,850 --> 00:01:09,910

We have an inlet on the window of the airplane, and our instrument pulls in air through

18

00:01:09,910 --> 00:01:13,990

this inlet in a series of tubes, into our detection cell, where the laser

19

00:01:13,990 --> 00:01:18,170

passes through and then the formaldehyde in that

20

00:01:18,170 --> 00:01:22,220

sample will absorb and re-emit photons and the

21

00:01:22,220 --> 00:01:26,290

re-emitted photons are what we measure and detect as formaldehyde.

22

00:01:26,290 --> 00:01:30,380

So we actually count the number of photons and so on our screen, we can

23

00:01:30,380 --> 00:01:34,490

read the number of counts per second or per unit time

24

00:01:34,490 --> 00:01:38,540

and if we see the counts go up, it means we have a lot of formaldehyde and

25

00:01:38,540 --> 00:01:42,880

and if we see the counts go down, it means we have less. So when we're flying,

26

00:01:42,880 --> 00:01:47,100

on ATom, formaldehyde can be pretty low, because we're flying over

27

00:01:47,100 --> 00:01:51,320

kind of remote open ocean, but when we fly into

28

00:01:51,320 --> 00:01:55,560

air parcels that are continental outflow,

29

00:01:55,560 --> 00:01:59,800

we'll see elevated formaldehyde, and this

30

00:01:59,800 --> 00:02:04,030

can be from biomass burning or from

31

00:02:04,030 --> 00:02:08,280

any like human-caused activity, so

32

00:02:08,280 --> 00:02:12,340

formaldehyde is an indication of oxidation chemistry, and we care about

33

00:02:12,340 --> 00:02:16,420

oxidation because it will tell us, let's say the

34

00:02:16,420 --> 00:02:20,530

rate at which methane gets oxidized, and methane is a

35

00:02:20,530 --> 00:02:24,710

very potent greenhouse gas, and we'd like to be able to better understand

36

00:02:24,710 --> 00:02:40,750

methane's lifetime as the climate changes.