- Buckets of fun in trout release
- Record returns for green growers
- Port accident record defended
- Coastguard co-founder passes away
- Push to light up Bay Oval
- Accused bank robber arrested
- Keeping safe this Halloween
- Stranded whale might be euthanised
- Trial for alleged 'vicious' attack
- Whale stranded in Maketu
- Flanker reaches Chiefs dream
- Seagulls a dying breed
- Hall fire confirmed as arson
- Rain and wind batter the Bay
- Celebrating some 'pretty big odds'
- Papamoa Hall up in flames
- Armed police called to Judea
- Man crushed by car dies
- Man injured on bouncy castle
- Girl hit by motorcycle
- Balloon release for Jack
- International flights a no go
- Tourists' van found on fire
- Changes to work breaks sought
- Fatal crash victim named
- Clothes used in deliberate fire
- Fatal crash driver twice the limit
- Father and son arrested for theft
- Dangerous fugitive on the run
- Mount store sells lucky spin
Sunspots and solar activity
The connection between solar activity and the earth's climate is an area of ongoing and sometimes controversial research.
A sunspot is a relatively dark, sharply defined region on the solar disc – marked by an umbra (dark area), which is 2000 degrees Celsius cooler than the effective photosphere temperature.
The average diameter of a sunspot is 4000 km, but can exceed 200,000km.
The NASA Solar Physics website (and other websites, such as the Royal Observatory of Belgium), includes information on sunspot numbers, the Maunder Minimum, and sunspot cycle predictions.
The sunspot index is updated monthly and available from 1749. The last time the monthly sunspot number was above 100 for any significant period of time was September 2002 when the value was 109.6 and the last time the value was above 200 was in August 1990 when the value was 200.3.
Reading University's professor of Space Environmental Physics Mike Lockwood thinks the current period of solar activity is likely to become the first “grand solar minimum” for four centuries.
During a grand minimum, the normal 11-year solar cycle is suppressed and the sun has virtually no sunspots for several decades.
Lockwood thinks there is now a 25 per cent chance of a repetition of the last grand minimum, the late 17th Century Maunder Minimum, when there were no sunspots for 70 years.
But Mike says we should not expect a new grand minimum to bring on a new little ice age. There may, however, still be noticeable consequences. For instance, long-term cold winters in the UK are common when solar activity is low. And less solar activity can slow the jet stream, triggering a suite of interlinked extreme weather events.
There have been 24 grand solar minima in the last 10,000 years. Their history is reconstructed by looking for isotopes like carbon-14 that cosmic rays generate in the atmosphere.
The recent decline in solar activity may have helped cause the current ‘hiatus' in the pace of global warming.
The chart (from the Royal Observatory of Belgium) below shows the monthly (and 13-month smoothed number) values of the sunspot number since 1955.
For further information on climate matters see https://sites.google.com/site/climatediceandthebutterfly/
Post a CommentYou must be logged in to make a comment.
- Global Monthly Temperatures: January 1979 - August 2014
- Skinny love - Support network for sacked mannequins
- Tauranga’s September average afternoon temperatures: 1913-2014
- A rash of curious ailments
- Tauranga: September Rainfalls 1898-2014
- Ailment of the week: Viking Finger
- UN Climate Summit 2014
- Promoting freedom of expression... and lingerie as projectiles
- Is Global Warming taking a break?
- MegaFatload: Control+Alt+Delete - Bring on the extradition
- Tauranga’s August average afternoon temperatures 1914-2014
- Driven mad in Tauranga
- Tauranga August rainfalls –1898-2014
- Gym etiquette - Outrageous uses for shared hair dryers
- 1816: The year without a summer