Not until Gerbert Roerink brought in the images from his green monitor. Suddenly, mice are hot.
Roerink receives the latest satellite images from the Disaster Monitoring Constellation four times a week. These images, with a resolution of 25×25 metres, show the Netherlands at plot level. Roerink processes the images into pictures for the green monitor. And of course he always has a quick look for signs of anything unusual.
Mid-December he saw some. ‘Hey, the vegetation in Friesland is dying. How can that be?’ A colleague at Livestock Research knew the answer straightaway. ‘That is mouse damage. It’s a big problem there. The farmers are very keen to get it on the agenda, but they are not succeeding.’
Roerink did. Pretty much to his own amazement. He sketched the scale of the problem, looked for a detailed satellite image and sent a message to De Boerderij magazine and the Frisian daily, Het Friesch Dagblad. That was on Friday 9 January. When the Dutch press bureau ANP got hold of it the next Monday it became ‘world news’ in the Netherlands.
PREDICTING MILK YIELD
The mouse plague is a nice example of what can be done with the green monitor. The monitor literally reveals the greenness of the landscape. The technique has existed for some time. But only recently on a weekly basis and with a plot-level resolution.
With the green monitor Roerink can literally see grass growing. ‘You can quantify the length of grass with the green index up to about 20 centimetres. Above that, the signal is saturated so you don’t see differences anymore.’
A company like FrieslandCampina uses this information to improve the models with which the supply of milk is forecast. Does more grass mean more milk? That question is even more interesting, says Roerink, now that the milk quota are being scrapped. Everyone can see the green monitor at www.groenmonitor.nl. Now accurately to the nearest 25 metres, but soon perhaps with a resolution of five metres. Back garden level, in other words. Roerink: ‘That appeals to the imagination even more. We are working on it. But the satellite only passes by once a month.’