“Totally unacceptable” is the feeling we have when we look at the SMOS soil moisture retrievals over Europe corresponding to the last month … and who knows for how long it will last ?
Radio Frequencies Interferences (RFIs) is a sensitive topic we have regularly addressed in the SMOS blog. General messages and warnings have been sent to many National entities on illegal emissions in the protected L-Band and this with some success. More than 200 sources have disappeared and we should thank all the individuals involved in this action, including the countries awareness which is, at the end, a necessary step to see regulations applied. If we can understand that reducing and/or switching off the existing sources is a long, but necessary, way to go, we would have thought that, now that the countries awareness exists, the setting up of new equipments or services would be done bearing in mind teh regulations and abiding them.
So naive are we, as the following sad pictures show.
Mid July 2012 a new small RFI spot source appears in mid Poland in the vicinity of an existing one (quite strong by the way). This new source has oscillated in power until around August 22, 2012, when it become a steady and strong beamer, of its own or in conjunction with its neighbor? In this aspect, it follows the bad example of other Eastern countries making strong bursts of emissions acting as large flares for a couple of days before stopping, and going on again, and again … However, for the case depicted here, the source has emitted continuously for a already whole month.
The consequences ? they are easy to understand in the above figure showing soil moisture retrieved values for the three days of September, 2012, the 10th,11th & 12th along with the RFI probabilities maps for ascending orbits (left) and descending orbits (right). The emission is so strong, damaging so much the SMOS observations, that for the last month NO retrieval of soil moisture at all can be obtained for ascending orbits over Western Europe and with a lesser extent for descending orbit but with probably dubious values when obtained (too dry surface), for example over France. The contamination being steady, it breaks the time series of observed soil moisture for the whole Western Europe during the last month and who knows for how long ?
The following image shows how it appears globally for 15 days ascending probabilities map around November the 12th. You are encouraged to click on the map, you will be redirected to the album holding all the RFI probabilities maps since the beginning of the mission. When you are at the album web page, just click then on the right “>” sign to go back in the past, day per day, to understand how steady it-is in time.