Category Archives: Weather & Sky

Check the Air for DNA

Musings & News, Weather & Sky
DNA of giraffe and elephant were both detected in the air outside Copenhagen Zoo (photos from Wikimedia Commons)

18 July 2023

We’ve been paying attention to air quality this summer as Canadian wildfire smoke blows into town. The smoke that reaches us, called smog or soot in the chart below, is labelled PM2.5 by air monitors (the particles are less than 2.5 micrometers in diameter). As you can see there’s a lot of other stuff in the air that the monitors are not analyzing — but they could. In the past few years scientists have discovered that we can check the air for DNA.

Atmospheric particulate matter, types and sizes in micrometres (?m) (diagram from Wikipedia) The diagram has been updated to show PM2.5 with a red line

In 2020 an environmental DNA (eDNA) study in water led to eDNA studies in the air when a fish inventory compared trawling surveys (shown below) to DNA analysis of seawater samples. Science Magazine reported, “Overall, the team found about a 70% match between species abundance recorded by eDNA and trawls.”

Fishery biologists and deckhands working up a big tow on the F/V Excalibur. All catches
are first divided into baskets by species. Photo: NOAA Fisheries

In 2021 Mark Johnson, a graduate student at Texas Tech, realized that pollen and plant fragments are such a big component of air quality that he decided to compare manual plant surveys to eDNA measurements at Texas Tech University’s Native Rangeland.

The two methods complemented each other. Manual surveys detected 80 species while eDNA found 91 using the devices pictured below. According to Science Magazine, “eDNA was better at finding easily overlooked species with small flowers, such as weakleaf bur ragweed. But people were better at spotting plants too rare to release much eDNA, particularly when they had showy flowers, such as the chocolate daisy.”

The Big Spring Number Eight dust traps that were used to collect airborne eDNA (photo from Mark Johnson’s studay at Texas Tech)

It was only a matter of time before similar air monitoring was used to detect animals.

Two recent studies — one in the UK, the other in Copenhagen — collected and analyzed air samples for animal DNA. And they found it. To prove their equipment, each study located air samplers near a zoo and both found zoo animal DNA. According to NPR, the Copenhagen study “picked up 49 animal species including rhinos, giraffes and elephants. ‘We even detected the guppy that was living in the pond in the rainforest house.'”

Guppy (photo from Wikimedia Commons)

And so we’ve come full circle from detecting fish DNA in water to detecting it in the air.

Read more about the animal eDNA studies at WESA-FM: Scientists vacuum zoo animals’ DNA out of the air.

p.s. There is speculation that this technique could help us inventory endangered species.

(photo credits are in the captions; click on the links to see the originals)

Bad Air Returns

Weather & Sky
  • Cathedral of Learning from CMU, 29 June 2023 (photo by Kaleem Kheshgi)

17 July 2023

When Canadian wildfire smoke swept into Pittsburgh in late June it gave us two and a half days of terrible air quality, then dissipated suddenly on 30 June. Kaleem Kheshgi captured the stark contrast from smoke to clear in photos on 29 and 30 June. Even as the smoke dispersed meteorologists warned that it could and would return because the fires are still burning.

Today their prediction comes true. Wildfire smoke from Alberta and British Columbia has blown into the U.S. and caused Code Red air quality alerts yesterday from Montana to Michigan and Kentucky.

AirNow interactive air quality map on Sunday 17 July 2023 as of 4pm EDT (screenshot from AirNow.gov)

Pittsburgh was in the clear at the time but not anymore. At 5am today Pittsburgh was already in Code Orange and the red zone was approaching. Cleveland and Buffalo are among the many locations in red. (Pittsburgh is marked with a * on these maps.)

Regional air quality on 17 July 2023 at 5am from AirNow.gov (Wisconsin to Kentucky, Missouri to Cape Cod)

Code Orange will force some of my friends indoors today. Code Red is bad for everyone.

A code ORANGE air quality alert means that air pollution concentrations within the region may become unhealthy for sensitive groups. Sensitive groups include children, the elderly, and people suffering from asthma, heart disease, or other lung diseases. The effects of air pollution can be minimized by avoiding outdoor exercise or strenuous activity.

A code RED air quality alert means that air pollution concentrations are unhealthy for the general population.
— National Weather Service Alert

A look at some individual monitors on the AirMatters app tells the story at 6:30am. I’ve set my app to look at Pittsburgh, plus local monitors near Frick Park (“Forest Glen”), Carlow University and one of several monitors in Homestead.

screenshot from AirMatters app, 17 July 6:30am (my data focus is on Pittsburgh)

Today’s forecast says we’ll be in Code Orange but the Red Zone is so close that we will probably see Red spikes before rain and thunderstorms clear it out late this afternoon/evening.

Check your own air quality at AirNow https://www.airnow.gov/. Download the AirMatters app at the Apple Store or Google Play.

(photos by Kaleem Kheshgi, maps from AirNow.gov)

Drought: The Long and Short of It

Climate Change, Weather & Sky
View of South Mountain from Queen Creek, AZ (photo from Wikimedia Commons)

12 July 2023

Short term:

Last Friday, 7 July, Pennsylvania was placed under a statewide drought watch by the PA Department of Environmental Protection. They evaluated four factors to make the decision: precipitation, surface water flow, groundwater level, and soil moisture. The most worrisome was low groundwater in 16 counties and a 90-day rain deficit in Elk and Warren.

And then it rained in central and eastern PA and the Drought Condition map changed. Most of the state is now in the green (good) or yellow zone. Except for low groundwater in 14 of our 67 counties, the drought appears to be short term because a good rain can clear it up. See the Before and After, July 9 and 11, in this slideshow.

USGS Pennsylvania Drought Condition monitoring as of July 9 and 11, 2023

Long term:

Meanwhile, Arizona is not in a drought right now but it’s a desert, its water supply is limited, and it suffered a long term drought for many years. Water allocation has to be planned in Arizona so they won’t run out. This prompted Phoenix put the brakes on development last month in places that rely on ground water.

Arizona will not approve new housing construction on the fast-growing edges of metro Phoenix that rely on groundwater thanks to years of overuse and a multi-decade drought that is sapping its water supply. …

Officials said developers could still build in the affected areas but would need to find alternative water sources to do so — such as surface or recycled water.

Driving the state’s decision was a projection that showed that over the next 100 years, demand in metro Phoenix for almost 4.9 million acre-feet of groundwater would be unmet without further action, Hobbs said. An acre-foot of water is roughly enough for two to three U.S. households per year. …

Hobbs added that there are 80,000 unbuilt homes that will be able to move forward because they already have assured water supply certificates within the Phoenix Active Management Area, a designation used for regulating groundwater.

— TribLive: Drought, water overuse prompt Arizona to limit construction in some fast-growing parts of Phoenix

I’ve marked up this Google map of Phoenix to show the fastest growing areas circled in red.

Map of Phoenix, AZ metro with circles added: 5 fastest growing suburbs (screenshot from Google Maps)

Back in the 1990s I had a friend in the City of Phoenix’s economic development department who was proud to predict that, based on the city’s projected level of development, they had 75 years of water. In other words, they were OK until approximately 2070. My thought at the time was “Only 75 years?? Then what??”

Now we know. It took only 30 years to put the brakes on.

p.s. Phoenix, in Maricopa County, is one of the fastest growing areas of the U.S.; Maricopa grew 20.55% since 2010. Being from Pittsburgh, where Allegheny County grew 2.89% in the same time period, I marveled at the notion of 80,000 unbuilt homes.

(photo and map credits are in the captions, click on the links to see the originals)

Speaking of the Tilted Earth

Weather & Sky
Sunrise on the summer solstice, Pittsburgh, 21 June 2023 (photo by Kate St. John)

Wednesday 21 June 2023

Two days ago we learned how humans are changing the tilt of the Earth(*). Today we celebrate the most important Tilted Earth Day in the northern hemisphere when the summer solstice occurs at 10:57am EDT and gives us the longest day.

Sunlight on Earth on the northern summer solstice (diagram from Wikimedia Commons)

Three years ago meteorologist Bill Kelly made this video at WJLA in Washington, DC explaining how the Earth’s tilt is the key to the solstice. Only one fact has changed: The solstice is on a different date and time. Sunrise, sunset, and day length are the same in DC today as they were on the solstice in 2020.

Bill Kelly video on YouTube

In Pittsburgh today the sun rose at 5:49am, we’ll have 15 hours, 3 minutes and 50 seconds of daylight, and the sun will set at 8:53pm. Thanks to the tilted Earth.

(*) p.s. How much have humans changed the tilt of the Earth? The study highlighted in Monday’s blog calculated that we’ve already moved it 80 cm (31.5?) in just 17 years (1993-2010). Click here to read more.

(photo and video credits: Click on the captions to see the originals)

Thunderstorms in Training

Weather & Sky
Thunderstorm (photo by “jcpjr” from Shutterstock.com)

Occasionally during the May-to-August storm season, the National Weather Service warns of flash flooding because of potential “training thunderstorms.”

Training thunderstorms? Are they getting in shape for a big competition? Are they practicing to be better thunderstorms? Are they learning from older, wiser storms?

No. “Training” in this case means the storms are lined up in a row, moving one after the other like railcars in a train. The Philadelphia Area Weather Book describes it:

Most of the year, thunderstorms, steered by speedy winds a few miles above the ground, move along quickly enough so that flooding is not a problem. But those high-altitude winds are typically much weaker in summer and, at times, nearly calm. When this happens, thunderstorms can sit over the same spot for hours. Even if the steering winds are not that lazy, flooding can still occur if the winds blow parallel to a line of storms. When that happens, one thunderstorm after another passes over the same location like railroad cars in a train passing over a track. Appropriately meteorologists call this process training.

— The Philadelphia Area Weather Book, 2002

From the ground we experience them as storm after storm and downpour after downpour, but on radar they look like a moving train seen from above.

Marked up radar image showing training thunderstorms (image from Wikimedia Commons)

When radar-watching meteorologists saw this phenomenon they turned the concept of “moving like a train” into an adjective describing thunderstorm behavior. The new use of an old word did not catch on. Though it’s been around at least 30 years it’s not in the dictionary.

definition of training from Google

And so when “training thunderstorms” occur, which is thankfully rare, weather forecasters must explain the term.

video about training thunderstorms from KHOU-TV on YouTube

Learn more about the complex cauldron of air that churns out training thunderstorms in Forbes Magazine: Thunderstorm Training Can Turn an Average Storm into a Flash Flood Emergency.

(photos by “jcpjr” from Shutterstock.com and from Wikimedia Commons, dictionary screenshot from Google)

Humans Are Changing the Tilt of the Earth

Musings & News, Weather & Sky
Windmill pumping groundwater in Texas (photo from Wikimedia Commons)

19 June 2023

Compared to the size of our planet we humans aren’t particularly large but with billions of us pumping groundwater we have changed the tilt of the Earth. Slightly.

The angle of Earth’s axial tilt varies over a period of 26,000 years (precession) from 22.1 to 24.5 degrees, but within that it wobbles due to sloshing liquids like molten lava, ocean currents, and massive air currents such as hurricanes.

This very short video shows the North Pole wandering as the axis wobbles.

video from climate.nasa.gov

Earth’s spin axis wobbles, its North Pole tracing out a roughly 10-meter-wide circle every year or so. The center of this wobble also drifts over the long term; lately, it has been tilting in the direction of Iceland by about 9 centimeters per year. …

Now, scientists have found that a significant amount of the polar drift results from human activity: pumping groundwater for drinking and irrigation.

— Science Magazine: Humanity’s groundwater pumping has altered Earth’s tilt

Local water abundance, on the surface and underground, changes a region’s gravitational pull. This principle was used by the GRACE and GRACE-FO satellites as they rode the “hills” and “valleys” of gravity and recorded the presence and absence of groundwater.

To find out what affected Earth’s axial tilt, Clark R. Wilson at the University of Texas at Austin and his colleagues built a model of polar wander factoring in all the sloshing over time, including changes to surface water. But the model was missing something.

When the researchers also put in 2150 gigatons of groundwater that hydrologic models estimate were pumped between 1993 and 2010, the predicted polar motion aligned much more closely with observations. Wilson and his colleagues conclude that the redistribution of that water weight to the world’s oceans has caused Earth’s poles to shift nearly 80 centimeters during that time, reported Thursday in Geophysical Research Letters.

— Science Magazine: Humanity’s groundwater pumping has altered Earth’s tilt

The GRACE satellites detected groundwater changes that produced this map. Notice how groundwater dropped in the U.S. Southeast and the Central Valley of California.

NASA GRACE data shows trends in global groundwater storage, 2003-2013 (map from NASA)

How did we pump so much groundwater? We used machines like these.

Groundwater pumping station at water facility (photo from Wikimedia Commons)

Watch the groundwater come and go in India 2002-2008 in this NASA video. (Click on the image to access the video.)

Groundwater depletion in India (video from NASA Goddard Space Flight Center)

Who knew that we could make the planet move!? 80 cm (31.5″) in just 17 years.

(photos from Wikimedia Commons, maps from NASA, click on the captions to see the originals)

Goatsbeard, Insects and a Smoky Sunrise

Insects, Phenology, Plants & Fungi, Weather & Sky
Goatsbeard gone to seed, SGL 117, 6 June 2023 (photo by Kate St. John)

10 June 2023

Goatsbeard (Tragopogon dubius) lived up to its name this week as it showed off its huge fluffy seed head at SGL 117 in Washington County, PA.

Nymphal froghoppers known as spittlebugs hid under foam while sucking plant juice at Frick Park.

Spittlebugs, Frick Park, 8 June 2023 (photo by Kate St. John)

A fluffy white substance that looked like fungus may well be insects — perhaps woolly aphids (“boogie woogie” aphids) sipping sap from a cut branch.

Are these aphids

Canadian wildfire smoke made for eerie an sunrise on Thursday morning. My photos of it were anemic. Check out Dave DiCello’s instead. Click on a photo to enlarge it.

(photos by Kate St. John, tweet embedded from @DaveDiCello)

Yes, It’s a Drought

Climate Change, Weather & Sky
White snakeroot (Ageratina altissima) wilting in Schenley Park, 7 June 2023 (photo by Kate St. John)

9 June 2023

Plants are drooping, water levels are low, and clouds of dust engulf dirt roads in western Pennsylvania. It hasn’t rained for almost three weeks at a time of year that’s usually wet. Yesterday it became official. We’re in a drought.

Every week the U.S. Drought Monitor at University of Nebraska-Lincoln issues a nationwide drought assessment. Pennsylvania is labeled “SL” on this week’s map for evidence in both Short term and Long term indicators. (Click here for the latest Drought Map.)

Pennsylvania is in Short-and-Long Term Drought, 6 June 2023 (map from US Drought Monitor at UNL)

Most of Pennsylvania, including Allegheny County, is in Moderate Drought.

Much of PA is in Moderate Drought, 6 June 2023 (map from US Drought Monitor at UNL)

The drought seems sudden but it’s been building for a while. Precipitation was above normal last year through January 2023 but starting in February it fell off. April and May were seriously below normal. June has been bone dry so far. As of today Pittsburgh has a year-to-date precipitation deficit of 4.55 inches.

Monthly precipitation in Pittsburgh: Normal 1991-2020 (green) and 2023 actual (red) (graph from Climate for PBZ at weather.gov )

Even the hardiest invasive plants are wilting in the city parks …

Mugwort drooping from lack of water, Hays Woods, 3 June 2023 (photo by Kate St. John)

… small tributaries are completely dry …

High water and no water at waterfall, Schenley Park, 7 June 2023 (photo by Kate St. John)

… and the cascade pools in Schenley Parks’ Phipps Run are stagnant. Unfortunately stagnant water is a breeding ground for mosquitos, an unexpected consequence of drought.

Low water in cascade pool, Phipps Run, Schenley Park, 7 June 2023 (photo by Kate St. John)

The forecast calls for rain on Monday 12 June, but one day’s rain can’t overcome the 4.5+ inch deficit.

Hoping for more rain soon. Meanwhile check out these drought tips for lawns and camping at TribLive: Dry conditions expected to continue in Western Pennsylvania.

(photos by Kate St. John, maps from U.S. Drought Monitor)

Bad Air Today, Fewer Warblers This Fall?

Climate Change, Weather & Sky
Sunset in Pittsburgh 3 June 2023. Pink sun due to Canada’s wildfire smoke (photo by Jonathan Nadle)

6 June 2023

On Saturday evening Jonathan Nadle took a photo of the setting sun glowing pink with threads of smoke across its face. The color was the result of wildfire smoke drifting in from western Canada.

Today Pittsburgh and much of the northeastern U.S. are under an air quality alert because the smoke is now at ground level. We don’t see it as smoke — it looks like haze — but the particles have put our air quality forecast into Code Orange = “Unhealthy for Sensitive Groups.” Young children, seniors, and those with respiratory problems should limit outdoor activities.

AirNow forecast for Pittsburgh PA on 6 June 2023

NBC News explains:

Millions of people across the Midwest are under dangerous air quality conditions Monday, as smoke from wildfires in eastern Canada wafts over the region.

Hazy skies have blanketed a wide swath of the country from the Ohio Valley to as far south as the Carolinas. Air quality advisories are in effect Monday in southeastern Minnesota and parts of the Upper Peninsula of Michigan, as well as in more than 60 counties in Wisconsin.

The spike in air pollution comes from wildfires that have been raging in the Canadian provinces of Quebec and Nova Scotia.

… Canada is experiencing one of the worst starts to its wildfire season ever recorded.

— NBC News: Air quality levels in parts of the U.S. plunge as Canada wildfires rage, 5 June 2023

There are wildfires across much of Canada right now — west and east — but the fires affecting Pittsburgh today are mostly in Quebec and nearly all are out of control, displayed as red dots on Canada’s interactive wildfire map. Click here or on the screenshot below to see the interactive map.

Active wildfires in Canada, Quebec wildfires circled in pink, 6 June 2023 (map from Canadian Wildland Fire Information System)

For Pittsburgh the smoke is mostly an inconvenience but for Canadians it is dangerous and for the birds that nest in these forests it is deadly. The fires are happening where northern warblers breed including bay-breasted, blackpoll, palm, Cape May and Tennessee.

When we see fewer of these migrating warblers in the fall, the fires will be partly to blame.

Tennessee warbler (photo by Donna Foyle)

Unfortunately as climate change heats up the Earth and reduces rainfall, we can also expect more fires in North America’s forests.

Click here to see AirNow’s interactive air quality map centered on Pittsburgh, PA

(see photo and map credits in the captions)

Air Quality UPDATES

28-30 June 2032:

Wildfire smoke is back again, worse than before.

6-7 June 2023:

7 June 2023, 5:00am: The winds have changed. Pittsburgh air is still Unhealthy for Sensitive Groups this morning but it is much worse elsewhere. It is Very Unhealthy from Harrisburg to Philadelphia (purple), and Hazardous to breathe in a wide swath of Ontario including Ottawa (brown).

6 June satellite map:

AirNow interactive map as of 7 June 2023, 5:00am

Saturn and The Moon

Weather & Sky
Four of Saturn’s moons transit the planet (image from Hubble Space telescope via Wikimedia Commons)

12 May 2023

From Earth, Saturn is tiny and the Moon is large. You can see the huge size difference in Paul Byrne’s (@ThePlanetaryGuy) video of Saturn rising behind the Moon.

In reality Saturn is 95 times larger than our Moon and has 83 moons of its own plus thousands of moonlets. Only seven of Saturn’s moons can be seen through a telescope from Earth.

(photo from Wikimedia Commons, click on the caption to see the original)