spotless sun June 2019

Solar Dynamics Observatory HMI Continuum image for June 21, 2019
Are we in a solar grand minimum? We've seen this before, but now predictions are for an extremely weak solar cycle ahead.

Today is the summer solstice in the northern hemisphere. The sun has been without a single observable sunspot now for over a month - 33 days according to NOAA and SIDC data. Spaceweather.com says:
"This is a sign of Solar Minimum, a phase of the solar cycle that brings extra cosmic rays, long-lasting holes in the sun's atmosphere, and a possible surplus of noctilucent clouds. "
There's been sightings of the electric blue noctilucent clouds as far south as Joshua Tree, near Los Angeles, and many many other locations. But one of the most interesting things is due to the fact that the Sun's magnetic field has weakened, more cosmic rays are now bombarding Earth and some airline flights are seeing doses of radiation up to 73 times that which we'd see at ground level.

noctilucent clouds southern california
© Don Davis
Noctilucent clouds seen near the city of Joshua Tree not far from Los Angeles CA, on June 14, 2019
For example, a flight from Chicago, IL to Teterboro, NJ which flies at 45,000 feet gets 73.3 times the radiation dosage than a traveler would experience at ground level. A typical commercial flight across the United States gives you about 40x exposure - about the same amount of radiation as a typical dental x-ray. The Chicago-Teterboro flight is almost double that. Frequent air travelers during the solar minimum like we have now would get an even more elevated dose of cosmic rays.

Spaceweather.com is monitoring passenger flights:
We are constantly flying radiation sensors onboard airplanes over the US and and around the world, so far collecting more than 22,000 gps-tagged radiation measurements. Using this unique dataset, we can predict the dosage on any flight over the USA with an error no worse than 15%.

E-RAD lets us do something new: Every day we monitor approximately 1400 flights criss-crossing the 10 busiest routes in the continental USA. Typically, this includes more than 80,000 passengers per day. E-RAD calculates the radiation exposure for every single flight.

The Hot Flights Table is a daily summary of these calculations. It shows the 5 charter flights with the highest dose rates; the 5 commercial flights with the highest dose rates; 5 commercial flights with near-average dose rates; and the 5 commercial flights with the lowest dose rates. Passengers typically experience dose rates that are 20 to 70 times higher than natural radiation at sea level.
Here is a table of recent "hot flights" arranged by radiation dosage level:
radiation measurments airline flights
© Hotflights/SpaceWeather.com
Column definitions: (1) The flight number; (2) The maximum dose rate during the flight, expressed in units of natural radiation at sea level; (3) The maximum altitude of the plane in feet above sea level; (4) Departure city; (5) Arrival city; (6) Duration of the flight.
There's now a dedicated website setup for monitoring this https://www.radsonaplane.com/

Meanwhile, the sun seems to be in a deep slumber, PerspectaWeather reports:

The sun continues to be very quiet and it has been without sunspots this year 62% of the time as we approach what is likely to be one of the deepest solar minimums in a long, long time. In fact, all indications are that the upcoming solar minimum may be even quieter than the last one which was the deepest in nearly a century.
sunspot cycle
© Courtesy climate4you.com
Daily observations of the number of sunspots since 1 January 1977 according to Solar Influences Data Analysis Center (SIDC). The thin blue line indicates the daily sunspot number, while the dark blue line indicates the running annual average. The recent low sunspot activity is clearly reflected in the recent low values for the total solar irradiance. Compare also with the geomagnetic Ap-index. Data source: WDC-SILSO, Royal Observatory of Belgium, Brussels. Last day shown: 31 May 2019. Last diagram update: 1 June 2019 .
In addition, there are now forecasts that the next solar cycle, #25, will be the weakest in more than 200 years. The current solar cycle, #24, has been the weakest with the fewest sunspots since solar cycle 14 peaked in February 1906. Solar cycle 24 continues a recent trend of weakening solar cycles which began with solar cycle 21 that peaked around 1980 and if the latest forecasts are correct, that trend will continue for at least another decade or so.

Full story by Paul Dorien here