A new CSIRO blog and a new MNF ship – and she’ll be equipped for solar measurements

CSIRO has a new blog in its cyber-armamentarium, and it’s called Investigator@CSIRO. It was unveiled to the public today and it’s already full of images, videos and information about CSIRO’s Future Research Vessel Project and the new ship Investigator, which is currently under construction in Singapore. The team has even made LEGO® models that’ll be up for grabs!

When construction finishes next year, Investigator will be a scientific ship operated by the Marine National Facility (MNF) based in Hobart. Funded by the Australian Government and run by CSIRO, the MNF is available to all Australian scientists and international collaborators who are researching our oceans and atmosphere.

Graphic of RV Investigator, a new research vessel currently under construction.

Investigator will replace an old warhorse of Australian marine and atmospheric research, Southern Surveyor. Southern Surveyor is a former North Sea trawler that’s served Australian science for over 20 years. She’s carried out 111 voyages as the Marine National Facility vessel in this time and chalked up an astonishing 481,550 kilometers of travel. (That’s equivalent to going around the equator 12 times – further than the distance from the Earth to the Moon!) You can get a flavour of the research and discoveries the ship and its scientists have contributed to in the very reader-friendly set of annual reports, which also include maps of where the ship’s travelled in any given year. This year’s schedule is also there for you to check out, of which today’s departure to study the East Australian Current (yes, the one of Finding Nemo fame) is a part.

111 research voyages as the Marine National Facility vessel and counting: RV Southern Surveyor

Here on the solar blog we’re particularly interested to see that Investigator, like Southern Surveyor before it, will have a pyranometer on board similar to the one we have here at Newcastle. While we use ours to monitor how much solar energy is going into our solar towers and photovoltaic systems, theirs will gather data about how much sunlight shines onto the oceans and will help scientists learn about ocean heating.

Meteorology equipment on board Southern Surveyor (image courtesy Eric Schultz)

Subscribe to Investigator@CSIRO to read all about the Future Research Vessel Project and stay updated about the new ship’s progress.

Perfect day for solar power

You know you’re a solar scientist when you’re outside on a Saturday, looking at the beautiful blue skies and perfect weather, and you find yourself thinking, “If only today was a work day.”

It may sound crazy, but this has been know to happen — usually when experiments have been delayed for a few days because of cloud only to have it clear up on the weekend. Luckily we’ve been having stunning solar conditions every day recently, and Thursday in particular had flawlessly clear skies. We know exactly how good the conditions were, because we have instruments here on site that record the amount of sunshine hitting the ground at all times. It’s obviously important to have this data when you’re testing solar technology.

The graph above shows the intensity of sunlight at our site on Thursday. The red curve is the data we’re interested in for concentrated solar power, because it’s the ‘direct irradiance’ — the intensity of direct (shadow-casting) sunlight on a surface that’s tilted to face the sun. Because there was no cloud it’s almost a perfectly smooth curve, starting at sunrise (just before 7 am) and dropping off at 5 pm. The little dip just after 7 am is where the shadow of Solar Tower 2 passes over the measuring instrument.

The green ‘total horizontal’ irradiance curve, on the other hand, is what you’d be interested in if you wanted to measure all the light falling on a surface lying flat on the ground — say, a book you’re reading. It includes the direct sunlight as well as the indirect rays—the ones that arrive on the page after having been scattered off clouds or other objects—and also takes into account the fact that the angle between the sun and the book changes throughout the day. The blue ‘diffuse horizontal’ curve shows just the indirect rays. This is how much light you’d still have available to read by if someone cast a shadow over your book.

If you’re following along, you may be wondering why the curves don’t add up – specifically, why the ‘direct’ plus the ‘diffuse’ curves don’t equal the ‘total irradiance’ curve. The answer is simply because here the ‘direct’ curve refers to shadow-casting light on a surface tilted to face the sun. The other curves refer to a surface lying flat on the ground. That’s all.

Below are the three instruments we use to take these measurements. The two pyranometers measure the sunlight falling onto a flat surface. One of them is kept shaded by a little black disc that tracks the sun, so it can measure the diffuse (non-direct) rays only. The pyrheliometer measures the direct radiation only, and a tracking mechanism makes sure that it always faces the sun directly.

These little gizmos are probably the most important solar instruments we have on site. Without them we’d have no idea how much energy was available for use in our solar facilities.


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