Thursday, 30 June 2011

Useful Internet sites for boaters.

Useful Internet sites for boaters, an occasional series of snippets.
MetCheck, supports the most popular small talk subject for the British, on a boat or ashore, the weather. The big conversation subject on a boat being, the merits of cassette toilets -v- pump-out.

I find that MetCheck is a good site for wasting away the hours when its raining, snowing, hailing, or blowing. Our very variable British weather means that now I am quite adept at setting all the on-line MetCheck options.

There are however times when even MetCheck reports the kind of weather for the next millennium that you would like to avoid. So its always useful to have an alternative weather checking location which may be able to supply the required weather prediction. That’s one of the good things about weather prediction standards, there are so many different ones to choose from.

Billions of pounds are spent every year on weather forecasting. One curious thing about our brand of weather is, statistically, if you predict that the weather tomorrow will be the same as it was today you will get it right more often than predicting a change in the pattern of the weather.

I thought you might find of interest the following weather research paper extract. The research was aimed at the "Effect of cloud-scattered sunlight on the earth's energy balance" I know its a catchy little piece and would make for ideal bedtime reading for insomniacs. But for years I’ve thought that insomnia was nothing to lose any sleep over.

Abstract: The spectral changes of the shortwave total, direct and diffuse cloud radiative forcing (CRF) at surface are examined for the first time using spectrally resolved all-sky flux observations and clear-sky fluxes. The latter are computed applying a physically based approach, which accounts for the spectral changes of aerosol optical properties and surface albedo. Application of this approach to 13 summertime days with single-layer continental cumuli demonstrates: (i) the substantial contribution of the diffuse component to the total CRF, (ii) the well-defined spectral variations of total CRF in the visible spectral region, and (iii) the strong statistical relationship between spectral (500 nm) and shortwave broadband values of total CRF. Our results suggest that the framework based on the visible narrowband fluxes can provide important radiative quantities for rigorous evaluation of radiative transfer parametrisation and also can be applied for estimation of the shortwave broadband CRF.

Researchers after long periods of study discovered:-
  • The amount of the Sun's energy that reaches the Earth's surface is the main driver of the Earth's temperature.
  • Comparing values for cloudy sky to the values for a clear sky, the researchers found that, on average, puffy fair-weather clouds cool down the earth's surface by blocking sunlight.
  • Sunlight is scattered by clouds and is the reason why beach-goers can get sunburned even on overcast days.

Kassianov one of the researchers in a moment of pure genius said "If you want to study how aerosols and clouds interact, you need to look in the region of the spectrum where aerosol effects are significant. If you want to fish, you go where the fish are biting."

Kassianov, E., J. Barnard, L. K. Berg, C. N. Long, and C. Flynn (2011), Shortwave spectral radiative forcing of cumulus clouds from surface observations, Geophys. Res. Lett., 38, L07801, doi:10.1029/2010GL046282.

Like astrologers there are many cranks out on the streets making predictions on everything from the end of the world to tomorrows weather. Their predictions are made from such sources as the scattering chicken entrails, reading tea leaves, positions of the planets on the background of stars and listening to the voices in their head. I prefer the chicken entrails for the accuracy.

I heard a story about one such long term prediction of the weather. A couple of years ago, the autumn was fast approaching and a narrow boater was wondering if the winter this year would be as bad as the last winter. The seasoned boater looked at the sky, checked his seaweed and pine cone, but he did not have any chicken entrails and so was unable to predict what the weather was going to be.

The boater chose to err on the safe side and so he rang up British Waterways to find out what they knew. He figured that British Waterways would need accurate long term predictions of the weather so that the carefully organised winter stoppage program could be planned in advance. Speaking to one of the British Waterways Board members he asked "Is the coming winter going to be cold?" "It looks like this winter is going to be quite cold indeed," the board member replied.

So the old boater started to collect wood in order to be prepared. A week later he called British Waterways again to enquire if there had been any change in the long term weather forecast. The British Waterways Board member replied, "it's still predicted to be a very cold winter." The old boater started to collect every scrap of wood he could find. He even told every other boater he knew and everyone passing by about the British Waterways long term weather predictions.

A month later he called British Waterways again. He asked "Are you absolutely sure that the winter is going to be very cold?" the Board member replied "Absolutely, it's going to be one of the coldest winters on record." "But how can you be so sure?" the old boater asked. The Board member replied, "Take it from me, we know, after all its what we get paid for. Our few remaining staff and dwindling numbers of volunteers are reporting that the boaters everywhere on the system are collecting wood like crazy! Take it from me, we know, it's going to be one of the coldest winters on record."


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