Dr. Eddy Graham

For all James Joyce fans around the world - today, 16 June, is 'Bloomsday'!

Bloomsday is named after Leopold Bloom, the central character in Ulysses, the novel by James Joyce, arguably one of the greatest works of literature of all-time . The novel follows the life and thoughts of Leopold Bloom and a host of other characters – real and fictional – from 8am on 16 June 1904 through to the early hours of the following morning, in Dublin, Ireland.

Ulysses is riddled with enigmata (plural of enigma), tricks and conundra (plural of conundrum). Joyce even got the weather right on the day in question (it was a warm summer's day in Dublin, with a high temperature of 23-24degC, but there was a thunderstorm in the evening!

After a little bit of detective work (sorry, only a little), I have uncovered the following weather gems in Joyce's magnum opus:

"Warm sunshine merrying over the sea"

"His frocktails winked in bright sunshine to his fat strut"

"Thunder in the air. Was washing at her ear with her back to the fire too. He felt heavy, full: then a gentle loosening of his bowels"

"The deafening claps of thunder and the dazzling flashes of lightning which lit up the ghastly scene testified that the artillery of heaven had lent its supernatural pomp to the already gruesome spectacle"

"past ten of the clock, one great stroke with a long thunder"

OK, ok, next time I'll use 20th century reanalyses by NOAA-CIRES or ERA20C by ECMWF - sorry time does not allow today.

Happy Bloomsday 2017 to all!

@eddy_weather

The sub-tropical trade winds have been blowing more strongly than normal across the Canary Isles in recent weeks. Here is an (otherwise) rare example of a foehn waterfall cloud, captured in time-lapse mode (at 1/50 hertz) by @eddy_weather on 2 June 2017, from Santa Cruz de Tenerife - wow!

If you cannot see the animation here - click here!

Today in the #CanaryIslands as seen by the NASA Terra sensor (713km above us): Lovely 'bow waves' appear in the trade wind cloud layer as it approaches the mountainous isles from the N/NE. But Aha! How does the wind know each island is ahead of it? Can the wind itself predict what is ahead of it? (answer below)

Answer: Much like the way a motorway traffic jam propagates backwards against the flow of traffic, the velocity and air pressure fields change considerably in the airflow ahead of the Isles

@eddy_weather

#NASA MODIS Terra

There were some spectacular trails of 'sunglint' to the lee of Canary Islands yesterday (18 May 2017), as seen by NASA MODIS Terra satellite sensor. Sunglint is the isotropic reflection of the sun's rays from a still water surface (isotropic means it has a preferred direction). In this case, the wind was blowing strongly from the north/north-east, and in the lee of the mountainous islands, the sea is more sheltered from the wind. Thus it is smoother and hence reflects more sunlight back to the satellite sensor.

Looking more closely, one can see the actual impression of the lee atmospheric gravity waves on the sea surface (these are not regular ocean waves - instead these have wavelengths of several kilometres).

@eddy_weather, San Cristóbal de La Laguna, 19 mayo 2017

Eddy is presently on sabbatical leave from the University of the Highlands and Islands and is currently working at El Instituto de Astrofísica de Canarias, San Cristóbal de La Laguna, Tenerife (Canary Islands). Here are a few photographs of his new surroundings:

The view from el Mirador de San Roque (~725m) in La Laguna, down to the city of Santa Cruz de Tenerife, with the island of Gran Canaria beyond across the sea in the distance.

View to the Guajara campus of the University of La Laguna.

View across towards La Vega de las Mercedes

San Cristóbal de La Laguna is a UNESCO World Heritage Site, with many beautiful buildings dating back to 17th century and earlier.

Eddy on his first day of work at the Instituto de Astrofísica de Canarias in La Laguna.

The view from my workplace to the Anaga mountains in the distance. The large satellite dish sits on top of the roof of the nearby Museo de la Ciencia y el Cosmos.

Of course, a trip to Tenerife would not be complete without a visit to desert landscape of Mt Teide, the world's 3rd highest volcano at 3,718m in altitude

Inside the huge volcanic crater, many different coloured and solidified lava flows can be seen (the black ones on the mountain slope are thought to date from the late Middle Ages)

@eddy_weather, April/May 2017

A very happy #WorldMetDay to you today (23 March 2017) from @eddy_weather in the Hebrides, Scotland!

Based on long-term Met Office records for Stornoway (which digitally stretch back to 1873, one of the longest such series in Scotland), the winter of 2016-2017 so far in Stornoway is the 2nd mildest (out of 144 years), 21st driest (out of 144 years) and 48th sunniest (out of 88 years), according to the latest data from @eddy_weather.

Let's look at the data with the aid of a few charts. Firstly,  air temperature: Up to the end of January 2017, the current winter's mean air temperature of +6.9C has only be exceeded once before, in 1989:

Next, precipitation (rainfall & snowfall): We are having a dry winter, the driest in 6 years (since 2011) and the 21st driest in the whole 144-year record (so about a 1:6 or 1:7 year event):

And finally, days with air frost: There have been only 3 air frosts this December and January, which is the joint 10th lowest total since 1873. Overall, there's been a decrease of about 25% in the number of days of air frost since 1873 for these months (see trend line).

@eddy_weather, Stornoway, 5 February 2017.

Flying from Edinburgh to Stornoway recently, I captured the following stunning views of the Highlands. Fog and low cloud filled into the glens like a rising and invading ocean, but the Munro peaks remained glorious and resplendent in the sunshine, just like Greenland nunataks. Here I have identified some of the mountain summits:

1) Looking south across Rannoch Moor

2) North-west across The Trossachs to Ben Lui and Ben Cruachan (near Oban).

3) The Nevis Range and the Great Glen.

4) Now looking eastwards (from the other side of the aeroplane): Fog winds its way through the Pass of Drumochter

5) The Fara and Dalwhinnie (the bow waves indicate the fog is flowing upwards from the south, and perhaps is sloshing in seiche fashion e.g. https://youtu.be/liwEP03SgVw?t=4 and https://youtu.be/bWKiRsHSBFw?t=1)

6) A Broken Spectre 'Glory' from the fog top indicates that the fog droplets were 'old', with a variation in size of more than 20%.

7) And finally, out of the clouds: Carn Eighe / Sgurr na Lapich with a rather thin snow cover for the time of year.

A radiosounding taken at Abermarle, Northumberland (which was also lying under the fog layer) at 12z on this day shows a strong temperature and humidity inversion at 700-800m. The air temperature was -1.1degC at 766m with 99% relative humidity, whereas at 1050m it was a shocking +8.2degC but with a relative humidity of only 30%.

@eddy_weather, Stornoway, Scotland, 24 January 2017

Flying north from Heathrow to Stornoway (via Edinburgh) on Friday 20 January 2017, I was able to spot a plethora of local cloud features. It's all thanks to (a) the quasi-permanent high pressure and temperature inversion across the British Isles lately, and (b) humans.

Firstly, let's look and see what two of the biggest power stations in the UK are up to (from a viewing height of 32,000 feet):

Oh dear, it's looks like some stratocumulus or stratus undulatus pyrocumulugenitus!

Let's look more closely:

Drax is the bigger plant marked 'A' (with presumably a greater emission of water vapour); Ferrybridge is 'B'. Drax's cumulus thermal (pyrocumulus, as it is caused by an anthropogenic heat source) is so powerful, that when it hits the inversion, the cloud oscillates up-and-down downwind (north) in a wave train - that's the undulatus bit.

Now, let's consider the NASA Terra 721 satellite image of the same time. The Drax plume again is most apparent - I wonder if its total water vapour emissions are proportionate to the cloud liquid water extent across the north of England that day? There is surely a link, whether minor or major, as shown by Graham (2007) for the Energie Wasser Bern (EWB) incinerator in Bern Switzerland.

Reference: 

Graham, E. (2007). Clouds - Nature's Landscape? Montagsseminar, Institut Fuer Angwandte Physik, Universitaet Bern.

NASA's Terra satellite flew over Scotland this morning at a height of 705km and captured the following two images:

There's a near complete snow cover over the country but it's all very ephemeral I'm afraid - it'll disappear as quickly as it came!

(False colours: Left: red=snow; Right: cyan=snow).

@eddy_weather, 14 January 2017