Archives par mot-clé : Radiation

Sun spotless for 33 days straight – airline travelers getting dosed with up to 70 times more radiation

by A. Watts, June 21, 2019 in WUWT


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.

 

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 . [Courtesy climate4you.com]

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A Second Look At Radiation Versus Temperature

by Willis Eschenbach, June 14, 2019 in WUWT


I kept going back and looking at the graphic from my previous post on radiation and temperature. It kept niggling at me. It shows the change in surface temperature compared to the contemporaneous change in how much energy the surface is absorbing. Here’s that graphic again:

 

Figure 1. From my previous post. It is a scatterplot showing the dependence of temperature on the total downwelling radiation (longwave plus shortwave) absorbed by the surface.

What I found botheracious were the outliers at the top of the diagram. I knew what they were from, which was the El Nino/La Nina of 2015-2016.

After thinking about that, I realized I’d left one factor out of the calculations above. What the El Nino phenomenon does is to periodically pump billions of cubic meters of the warmest Pacific equatorial water towards the poles. And I’d left that advected energy transfer out of the equation in Figure 1. (Horizontal transfer of energy from one place on earth to another is called “advection”).

And it’s not just advection of energy caused by El Nino. In general, heat is advected from the tropics towards the poles by the action of the ocean and the atmosphere. Figure 2 shows the average amount of energy exported (plus) or imported (minus) around the globe.

Radiation versus Temperature

by Willis Eschenbach, June 8, 2019 in WUWT


Due to the recent posts by Lord Monkton and Nick Stokes, I’ve been thinking about the relationship between radiation and temperature. So I turned to the CERES dataset. Here is a scatterplot of the monthly global average surface temperature versus the monthly global average downwelling total radiation absorbed by the surface. The total radiation is the sum of the net solar radiation at the surface and the downwelling longwave radiation at the surface. I’ve removed the seasonal variations from the data.

Note that 3.7 W/m2 is the increase in downwelling longwave radiation expected from a doubling of CO2 …

When I saw that, I thought well, maybe the increase is small because there’s a lag between the absorption of the radiation and the warming. To see if that was the case, I did a cross-correlation analysis of the relationship.