Sunday, September 2, 2018

Weather Radar, Birds, and Smoke

Taking a nice walk in Seattle's Magnuson park tonight, I saw and heard a lot of geese in the air, and, of course, I thought about bird migration.   So I wanted to check the Doppler weather radar when I got home to see which way the birds were moving aloft.

The  (9:08 PM) Doppler weather radar from Langley Hill on the the WA coast was fairly dramatic, showing strong southward motion for our feathered friends.  How can I tell?   The colors tell the speed of the air towards (green or blue) or away (yellow or red) from the radar.  The couplet of green to the NW and red to the SE tell us that the birds of flying south/southeast.  The don't like flying offshore.



Compare this to the pattern in May....just the opposite, birds flying north.


Then I started to muse about smoke and birds, and took a look at the Doppler velocity imagery during the period of greatest smoke (roughly August 21-22) at 9:09 PM--and I was surprised what I saw (see below).   It appears that the radar was picking up the smoke offshore (all the gray colors, little velocity), in contrast to the birds over land, who were heading to the south.



A few days later when the smoke was much less (August 25th), the offshore radar returns were gone.


The birds kept flying to the smoky periods, perhaps they were high enough to be above the worst of it.  I did notice less birds singing in my backyard during the worst of the smoke. 

Finally, today I learned about another impact of the wildfire smoke---regional stores were stripped of the better quality furnace filters.  Absolutely none in the local Fred Meyer store.  This may be a big business opportunity for someone-- imagine starting an Air Quality Store.  Imagine-- a wide selection of filter masks,,home air quality filtration systems, particle sensors, and yes, even furnace filters.  Could even run tours to places with clean air.


7 comments:

Maxine said...

Great article. I smell smoke at times even when the Dept of Ecology air monitoring site fortress.wa.gov/ecy/enviwa for smoke shows Green (healthy). Is there a more accurate site? How can I tell when the air is healthy and when it isn't? We have neighbors that burn illegally in the summer, and I was wondering if that could be the cause when I can't see any smoke, or if the smoke is from the forest fires. My chest hurts even thought I'm healthy. I live in N. Thurston County.

John Bower said...

I love your posts on birds and radar. Not many people know this, but you can quite easily go outside on these big migration nights and hear the sharp chirps of birds migrating hundreds of feet overhead (probably not high enough to avoid the smoke, but flying through smoke is not something they probably know to avoid as it is a rare occurrence, too rare for natural selection to select for the ability to avoid it). Quieter places are better for hearing the birds, but you can hear the birds' calls even in moderately noisy environments. Listen for short, sharp chirps. I find that once folks have figured out the sound, they hear a lot of them.

Another great trick is to use binoculars and look at the moon as it is rising - you can actually see the birds fly across the front of the moon. Best to do this earlier in the evening, as the brightness of the moon later on probably isn't great for one's eyes. Works best with the full moon. Next full moon, September 24, there should still be lots of birds migrating.

Biggest migrations are on clear nights when there is a wind out of the north. The very best is the first clear night after the wind has been from the south for a few days as the birds are backed up, waiting to migrate.

As Cliff notes, birds do not like to migrate over the ocean because the air rising over the land provides them lift, which the air over the ocean does not. (The exception is places where there is a strong tailwind, such as the tradewinds that blow into South America over the Atlantic.) I've been listening to migrating birds for many years since I was a graduate student at the Cornell Lab of Ornithology (which has done some of the best research on night migrant acoustics), and having heard them all over the country, I can attest that we have tremendous numbers of night migrants, which, I believe, is due to two main factors. First, we live south of a tremendous amount of wild land (BC, Yukon, Alaska, etc.). Second, the birds pile up along the coast avoiding flying over the water.

A classic book for getting a feel of what migration must be like for birds is "Last of the Curlews" by Dodsworth. Fiction, it tells the story of the migration of the last Eskimo Curlews, a species now thought to be extinct or nearly extinct.

John Marshall said...

To Maxine... why don't you just buy a PurpleAir sensor and place it on your property? That way you'll always know what the air quality is at your house.

Having objective, extremely localized data may make it easier to have discussions with your neighbors about burning illegally all summer. As in, "I know what you did last night at 6pm. Here's the data."



Eric Blair said...

For all of the talk about reducing carbon imprints, I'm continually surprised that the PNW hasn't banned the use of wood stoves for being used for home heating purposes. In many other areas of the country this policy was implemented decades ago, and has contributed to the improved air quality, particularly during the winter months. Perhaps pellet - burning stoves could still be used, for those who cannot do without.

Maya said...

Another comment for Maxine... I have asthma so I have a need to keep a regular eye on the AQI and have found that both aqicn.org and airnow.gov have what seem to be pretty reliable readings (i.e., my own symptoms track pretty well to elevated readings on their sites). Both offer the ability to enter in your zipcode to get localized readings.

John Marshall said...

The problem with government sources for AQ in north Thurston is that the only nearby sensors are at Lacey, Shelton, Aberdeen and Chehalis. Next closest is the other side of JBLM.

Unfortunately, no one in your area appears to have installed a PurpleAir sensor either (equivalent to a Personal Weather Station) except at North Yelm.

Thanks to terrain, smoke can vary greatly over short distances. It's fine to enter a zipcode into some software and get an extrapolated number, but without enough sensors and too much terrain, the resting AQI might not be accurate.

Nothing beats having your own sensor on your house or in backyard, whatever. They aren't very expensive or hard to install.

Greg F said...

Thanks, Cliff, for bringing up bird migration. The backyard has been unusually quiet the last few days. Crows, doves, sparrows, Oregon juncos -- they're all gone! I didn't see or hear the geese leaving, but your article confirms Summer is officially over, at least for my local birds. It seemed really eerie all day with no 'tweets'.

I have also enjoyed reading your articles on smoke weather (including the newest one). Let's hope we get a clearer (and safer) smokeless Summer next year. I'm about to turn 66, and I don't recall forest fire smoke ever being so bad as the last few years. I also live near Olympia, and the AQI crossed 190+ for a while. Not healthy for walking.

Thanks again for your interesting posts.