What makes the sound warm up?

[lamont]

the sound goes from 45F in the winter, to 55F in the summertime.

what makes it warm up?

1. conductive heating from the air: unlikely, air is a pretty good insulator

2. conductive heading from the ground: thermal energy probably runs the other way

3. radiative heating by the sun: sunny days heat up the sound?

4. warm runoff: warm spring rains dumping into the sound?

i'm leaning towards #4 since all the water that runs into the sound can carry with it a lot of heat energy.

of course the sound is still 45F now, so it hasn't warmed up one bit yet...

[CaptnJack]

#5 there's also a shift in the Alaska current which is a nearshore southerly current bringing water down from the Queen Charlottes. And in the upwellings offshore, those are a bit outside my oceaographic understanding though. None of those are super big influences as evidenced by the general lack of warming in the Strait of Juan de Fuca.

Most of the warming in Puget Sound proper is actually due to radiant energy from the sun. And there's no nearly as much exchange in the Sound as you'd think. e.g. Ecology has a south Puget Sound circulation model (SPASM is the unofficial name) and about 90+% of the water in the Shelton area is actually just sloshing back and forth with the tides. The main body of Puget Sound is similar on a reduced scale.

There are major "sills" inhibiting water exchange at Admiralty Inlet, Tacoma Narrows, and the mouth of Hood Canal. The "new" water entering past Port Townsend is colder and saltier than the water in Puget Sound proper, so it sinks. The older, fresher, warmer water floats on top. And by the end of the summer that mass has absorbed quite a bit of heat. Obviously there's even less exchange in Hood Canal and south of the Narrows. While water has a high latent heat capacity, there's also a heck of a lot of wattage with 12+hr days and a fairly high angle of incidence (much higher than in higher latitudes). That's my general understanding from hanging out with the Oceanographic geeks at work

[lamont]

well, at a SWAG:

assuming the insolation here is about 150 W/m^2 and looking at a 10 m^3 vertical shaft of water, in order to bring that up 5.5 K ( 45F to 55 F) it takes:

4.1484 J / cm^3 / K * 5.5 K * 10,000,000 cm^3 = 228,162,000 J

so about 228 mega-joules to warm up the top 33 feet of a 1-meter square column.

228,162,000 J / 150 (J/s) = 1,521,080 sec = 17 days

i need to dig up a better number for solar insolation for puget sound in the summertime... i think that might be closer to our yearly average...

[Grateful Diver]

I think it's all the seasonal divers coming out in their wetsuits ...

... Bob (Grateful Diver)

[sheahanmcculla]

I think it's all the seasonal divers coming out in their wetsuits ...

... Bob (Grateful Diver)

Your right Bob, and there is only one way to warm yourself up in a wetsuit. I was waiting for someone to mention this!

[dsteding]

Radiative heat from the sun, and don't discount the thermal transfer from warmer air temperatures.

One of the prime drivers is warming in the shallows (think black-bottomed pool) followed by current driven mixing. Probably why Lake Washington develops such warm shallow water.

[CaptnJack]

well, at a SWAG:

assuming the insolation here is about 150 W/m^2 and looking at a 10 m^3 vertical shaft of water, in order to bring that up 5.5 K ( 45F to 55 F) it takes:

4.1484 J / cm^3 / K * 5.5 K * 10,000,000 cm^3 = 228,162,000 J

so about 228 mega-joules to warm up the top 33 feet of a 1-meter square column.

228,162,000 J / 150 (J/s) = 1,521,080 sec = 17 days

i need to dig up a better number for solar insolation for puget sound in the summertime... i think that might be closer to our yearly average...

Here's a chart of average Kw/m2 for Seattle during each month of the year
http://www.solarpanelsplus.com/solar-insolation-levels/
So you are in the ballpark. ~5.75 to 6Kw/hr = 21megaJ/hr. This doesn't count albedo (reflectivity), but as far as I can tell without doing too much trigonometry the albedo of water should be <10% during the June-July window (when the sun is highest). There's a lag of course and that's why max temps are achieved in August/September.

The key concept is that the sun doesn't need to warm up the whole water column. Its not mixing due to a combination of thermal and salinity differences overlaid on bathymetric constraints.

[Pez7378]

I like to listen to the scientists try to figure this stuff out. ](*,) Although I don't understand any of what you guys are talking about, and I do understand your desire and need for knowledge, I wonder why you can't just accept that it is, because it is.

[airsix]

Come on you guys. You should be embarrassed that a guy with business degree is here to remind you that you forgot about latent heat flux (evaporative cooling). You've got the incoming solar radiation part right, but it's offset partly by the energy consumed by the liquid gas phase change. That's a big part of the equation. You can't leave it out.

-Ben

[CaptnJack]

Come on you guys. You should be embarrassed that a guy with business degree is here to remind you that you forgot about latent heat flux (evaporative cooling). You've got the incoming solar radiation part right, but it's offset partly by the energy consumed by the liquid gas phase change. That's a big part of the equation. You can't leave it out.

-Ben

Actually its not that large a player and is totally overwhelmed by radiation. The "Cattleman's association" and Farm Bureau bring up "evaporative cooling" with every temperature related problem in streams. Eps. over on the Eastside. Trees block evaporative cooling, hence shade makes the water warmer! Nope. There is long wave re-radiation of heat at night (and during the day). That is important, but its not the reason Puget Sound gets warmer

[airsix]

I still think it needs to be factored into the equation. I thought I had read that the cooling effect was around 75w/m^2. That doesn't make it THE factor, but it definitely makes it one of the factors.

/me googles for some backup data....

The largest heat loss for the ocean is due to evaporation, which links heat exchange with hydrological cycle (Fig. 4). On global average the heat loss by evaporation is 78 watts per square meter.

I'm just saying if you want an accurate calculation you need to factor this in. 78w/m^2 isn't anything to sneeze at.

The "Cattleman's association" and Farm Bureau bring up "evaporative cooling" with every temperature related problem in streams. Eps. over on the Eastside.

That's not an 'East-side hillbillies don't understand science' jab is it? Don't forget my county has one of the highest per-capita concentration of engineers, mathematicians, and scientists in the nation. We can do high math and even speak proper English. :hello2: (friendly banter - not getting my hackles up)

Here is some good info:
http://eesc.columbia.edu/courses/ees/cl ... o_atm.html
http://eesc.columbia.edu/courses/ees/cl ... index.html

-Ben

[Pez7378]

Don't forget my county has one of the highest per-capita concentration of engineers, mathematicians, and scientists in the nation. We can do high math and even speak proper English. :hello2: (friendly banter - not getting my hackles up)

-Ben

And I bet some of them even know a thing or two about nuclear reactors. They've also got a cheatin' ass SWAT team. (yeah yeah, cheat to win I know) I'm not bitter.

[airsix]

And I bet some of them even know a thing or two about nuclear reactors. They've also got a cheatin' ass SWAT team. (yeah yeah, cheat to win I know) I'm not bitter.

Special tactics, PEZ. Special tactics.
Oh, we've got one of the world's most powerful supercomputers too. We use it to process complex genomic sequences, do bioremediation research, and play Unreal Tournament at 42,000 frames per second (with the unused clock cycles).

-Ben

[CaptnJack]

And I bet some of them even know a thing or two about nuclear reactors. They've also got a cheatin' ass SWAT team. (yeah yeah, cheat to win I know) I'm not bitter.

Special tactics, PEZ. Special tactics.
Oh, we've got one of the world's most powerful supercomputers too. We use it to process complex genomic sequences, do bioremediation research, and play Unreal Tournament at 42,000 frames per second (with the unused clock cycles).

-Ben

Yeah but you don't got water!! Well ok the Columbia, but that's Rocky Mnt. water not desert water lol.

Seriously though how did we go from "how does the Sound heat up?" to how it cools off!

[airsix]

Seriously though how did we go from "how does the Sound heat up?" to how it cools off!

If you measure an increase in temp you are seeing the NET effect of all factors, not just the sum of the positive contributors. To understand the impact of the positive contributors you have to measure the negative factors too.

And it doesn't just heat up. It cycles.

-Ben

ps- Interesting trivia: The Columbia actually exceeds drinking water quality standards. I don't subject it to a personal taste-test though.

[CaptnJack]

Seriously though how did we go from "how does the Sound heat up?" to how it cools off!

If you measure an increase in temp you are seeing the NET effect of all factors, not just the sum of the positive contributors. To understand the impact of the positive contributors you have to measure the negative factors too.

And it doesn't just heat up. It cycles.

-Ben

ps- Interesting trivia: The Columbia actually exceeds drinking water quality standards. I don't subject it to a personal taste-test though.

Ummm the factors providing it heat are not the same factors that taketh away. We don't have to quantify evaporation to know that radiant sunlight is (net) heating it up in the spring and summer.

While Lake WA is also "drinkable" relative to maximum contaminant limits (MCLs) from the Safe Drinking Water act its not even close if you consider common risk based limits (like no greater than 1 per million cancer incidence). I imagine the Columbia is similar.

[airsix]

Ummm the factors providing it heat are not the same factors that taketh away. We don't have to quantify evaporation to know that radiant sunlight is (net) heating it up in the spring and summer.

I don't disagree in the least. In fact, that's exactly my point. I guess I'm just not expressing myself clearly. Sun makes the water warm. So lets go diving. That sounds really good to me. Followed by pie and icecream. Mmmmm.... :smt038

[Nwbrewer]

Ummm the factors providing it heat are not the same factors that taketh away. We don't have to quantify evaporation to know that radiant sunlight is (net) heating it up in the spring and summer.

I don't disagree in the least. In fact, that's exactly my point. I guess I'm just not expressing myself clearly. Sun makes the water warm. So lets go diving. That sounds really good to me. Followed by pie and icecream. Mmmmm.... :smt038

Don't forget Mac and Jacks. It's good in the summer....

[Pez7378]

Don't forget Mac and Jacks. It's good in the summer....

http://www.youtube.com/watch?v=8i5k4I1AOEI

[CaptnJack]

I don't disagree in the least. In fact, that's exactly my point. I guess I'm just not expressing myself clearly. Sun makes the water warm. So lets go diving. That sounds really good to me. Followed by pie and icecream. Mmmmm.... :smt038

Damn global warming and all that jazz, warmer is good!

[Sounder]

Don't forget Mac and Jacks. It's good in the summer....

http://www.youtube.com/watch?v=8i5k4I1AOEI

How many times are you going to post the beer song?!

http://youtube.com/watch?v=Yu_moia-oVI&feature=related

[Aquanautchuck]

well, at a SWAG:

assuming the insolation here is about 150 W/m^2 and looking at a 10 m^3 vertical shaft of water, in order to bring that up 5.5 K ( 45F to 55 F) it takes:

4.1484 J / cm^3 / K * 5.5 K * 10,000,000 cm^3 = 228,162,000 J

so about 228 mega-joules to warm up the top 33 feet of a 1-meter square column.

228,162,000 J / 150 (J/s) = 1,521,080 sec = 17 days

i need to dig up a better number for solar insolation for puget sound in the summertime... i think that might be closer to our yearly average...

Huh?????????????????????????????

[smike]

I was really surprised Sunday at Muk, the surface temp was 50 deg already, dropped to 47 @ 40' - 60' or so. So much warmer than 43 back in December.

I only started diving back in November, so I don't know how the temperature normally fluctuates, but I didn't expect that rise already.

S'Mike

[dsteding]

Good opportunity to find out how fast things warm with this warm stretch of weather starting.

Anyone do a dive at, say Cove 2 last night? What was the temp on your computer (at surface/depth if you have it). Next time you dive there check it again.

[airsix]

Good opportunity to find out how fast things warm with this warm stretch of weather starting.

Anyone do a dive at, say Cove 2 last night? What was the temp on your computer (at surface/depth if you have it). Next time you dive there check it again.

Remember, that's right at the mouth of a river too, so there's a big factor.
-Ben