Amid the Dimmest Sun Since 1978 – a Month Without Sunspots

By Anthony Watts – Re-Blogged From WUWT

The sun today is cue-ball blank, a perfect unmarred sphere:

Solar Dynamics Observatory HMI Continuum


The sun has just passed an entire calendar month with no sunspots. The last time this happened, in August 2008, the sun was in the nadir of a century-class Solar Minimum. The current stretch of blank suns shows that Solar Minimum has returned, and it could be as deep as the last one.

The last time a full calendar month passed without a sunspot was August 2008. At the time, the sun was in the deepest Solar Minimum of the Space Age. Now a new Solar Minimum is in progress and it is shaping up to be similarly deep. So far this year, the sun has been blank 73% of the time–the same as 2008.

Solar Minimum is a normal part of the solar cycle. Every ~11 years, sunspot counts drop toward zero. Dark cores that produce solar flares and CMEs vanish from the solar disk, leaving the sun blank for long stretches of time. These minima have been coming and going with regularity since the sunspot cycle was discovered in 1859.

Full story at Spaceweather.com


Here’s the sunspot data:

SIDC sunspot data Graph source: http://www.woodfortrees.org/plot/sidc-ssn/from:1975

Meanwhile, the sun is putting out less solar energy towards the Earth, as this graph of PMOD composite monthly total solar irradiance (TSI) data shows:

TSI in watts per square meter Graph source: http://www.woodfortrees.org/plot/pmod/from:1975

What is most interesting is in the PMOD ( Physikalisch-Meteorologisches Observatorium Davos (PMOD) composite ) TSI data, measured by satellites, and endorsed by NOAA, shows a drop of 2 watts per square meter since it’s peak around 2003, to the present in 2019, where in the last month, it has literally dropped like a rock, creating the lowest value in the dataset so far.

The estimate of increased solar forcing from increased carbon dioxide and other GHG’s in Earth’s atmosphere could be up to 3 watts/square meter if model estimates are to be believed:

Changes in radiative forcing of long-lived greenhouse gases between 1979 and 2012.

This graph shows changes in radiative forcing of long-lived greenhouse gases between 1979-2012. These gases are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), chlorofluorocarbon-12 (CFC-12), CFC-11, and fifteen other minor, long-lived, halogenated gases. The 15 other halogenated gases are CFC-113tetrachloromethane (CCl4), trichloromethane (CH3CCl3); hydrochlorofluorocarbons (HCFCs) 22141b and 142bhydrofluorocarbons (HFCs) 134a152a23143a, and 125sulfur hexafluoride (SF6), and halons 12111301 and 2402). The graph does not include other forcings, such as aerosols and changes in solar activity. Summary Total forcing in 1979 was 1.712 watts per square metre (W.m-2), and has steadily increased over time to 2.873 W.m-2 in 2012. Between 1979-2012, the largest contributors to radiative forcing have been CO2 and CH4. In 2012, the percentage contributions of each gas to total forcing was approximately: CO2: 64% CH4: 18% N2O: 6% CFC-12: 6% CFC-11: 2% 15 minor gases: 4% Forcing data are briefly summarized below. All the data are available in a later section as comma-separated values. The first value is the year, followed by forcing values (in W.m-2) for CO2, CH4, N2O, CFC-12, CFC-11, the 15-minor halogenated gases, and total forcing, respectively: 1979: 1.027, 0.419, 0.104, 0.092, 0.039, 0.031, 1.712 1980: 1.058, 0.426, 0.104, 0.097, 0.042, 0.034, 1.761 1990: 1.293, 0.472, 0.129, 0.154, 0.065, 0.065, 2.178 2000: 1.513, 0.494, 0.151, 0.173, 0.066, 0.083, 2.481 2010: 1.791, 0.504, 0.174, 0.170, 0.060, 0.106, 2.805 2012: 1.846, 0.507, 0.181, 0.168, 0.059, 0.111, 2.873References: Butler, J.H. and S.A. Montzka (2013-08-01) THE NOAA ANNUAL GREENHOUSE GAS INDEX (AGGI)[1], NOAA/ESRL Global Monitoring Division

It seems the sun has dimmed more than the usual amount at the end of solar cycle 24, and it could be a factor in the severe winter we are experiencing in many parts of the northern hemisphere.

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