Technical description of the modulated UV field site in Sodankylä, Hanne Perälä, FMI-ARC

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1 Technical description of the modulated UV field site in Sodankylä, Hanne Perälä, FMI-ARC The first research field for the FUVIRC project was established during the spring 2002 in the Tähtelä area close to the meteorological mast. Lamp frames Prof. Satu Huttunen provided the bases of the frames from the Pallas area. The frames were modified by adding a fourth lamp. The stands were painted gray. In that way, additional radiation can be avoided. The modified lamp frame is shown in photo 1. Picture 1. Lamp frame in Sodankylä Lamps As we can see from photo 1, the lamp frame has four lamps in a circle. The lamps are approximately one meter above the ground. The lamp model is Philips TL 40W/12 RS, and they were supplied by Onninen Oy. The lamps are covered by sheet metal. The purpose of the metal is to protect the lamps against the impacts of weather and to prevent extra radiation upwards and to the side.

2 Figure 2 shows the power distribution of the lamp according to the manufacturer. As we can see in figure 2, the peak is located slightly above 300 nm. There also appears to be some additional UVC radiation. Figure 2. Power distribution of Philips TL40W/12RS lamps. The extra radiation is excluded with filters. Cellulose-acetate is used for filtering only UV-C radiation. UV-C and UV-B radiations are filtered away with Melinex polyester. Cellulose-acetate is obtained from Expopak Oy, tel Melinex was supplied by KTA yhtiöt Oy, tel The size of the cellulose-acetate film was 0.1 mm x 1290 mm, and it was cut as required. Melinex was delivered as a roll of 370 x 460 x mm. Faders Along two sides of the frame there are tubes that contains faders. The faders direct the current of the lamps. The faders are model Quictronic HF 2x36/ V DIM from Osram Oy. The faders operate at the normal mains voltage V. The control voltage should be direct current of 1-10 V. That allows an adjustment scale from 1% up to 100% to be reached. Each fader is used to control two lamps simultaneously. Sensors Solar Light CO s PMA1102 and PMA1111 sensors are used in the field. PMA1102 is an analog UV-B sensor, whose spectral response follows the erythema action spectrum within nm, which is shown in figure 3. In addition to the UV sensors, there are internal temperature sensors. The temperature is also determined by a formula which reduces the error of the dependency on temperature. A Teflon diffuser ensures an angular response close to a cosine function for incident angles up to 50. The functioning of the sensor is based on the phosphorus technology used in Robertson-Berger meters as well as SL501A meters. PMA1111 differs from PMA1102 almost exclusively by its measuring range. PMA1111 can measure radiation in the range of nm, as in the response graph shown in figure 4.

3 Figure 3. PMA1102 response graph. Figure 4. PMA1111 response graph. The power of the lamps is controlled along with the PMA1102 sensors. There are 10 UV-B sensors in the field. Seven of them operate in the enhanced UV-B treatment, one in the UV-A treatment, and two are for reference. The seven sensors operating in the enhanced UV-B treatment are compared with the two reference sensors. Sensors with a similar shading environment are usually used for reference. There are three UV-A sensors, of which one operates in the UVA treatment, one in the UV-B treatment and the third in the reference area. The control voltage is calculated for the enhanced UV-B treatment. In the UV-A treatment, the control voltage is the same as in the nearest enhanced UV-B treatment. NILU-UV is situated in one reference area. This sensor measures UV radiation in five different wavelength channels with 10 nm bandwidth, while the PAR channel measures the spectrum of visible light between 400 and 700 nm. The middle wavelengths for the five channels are 305, 312, 320, 340 and 380 nm. The instrument includes a temperature sensor and internal thermal resistance. They can be used to attain temperature stabilization. NILU-UV can record for three weeks the minute averages of irradiance and temperature. It can store the daily averages of the whole year. In the research field, minute averages are used, which are stored in the computer every second or third week. The temperatures in each area are measured and collected by a TinyTalk TK temperature logger. Sensors measure the temperature on the surface of the area at 15-minute intervals for approximately 18 days. Therefore, the

4 measurements are stored in the computer every second week as NILU-UV s data. The measurement range for TinyTalk is between 30 and +50 C. Data logging The data recorded by the PMA sensors are collected with a QLI50-data logger and transferred to a computer with a Windows 2000 Professional UK operating system. In the computer, an application based on National Instruments LabView processes the data further. QLI50 is a product by Vaisala Oy. It has been designed for harsh conditions. It needs to be interfaced between the sensors and the computer which stores the data. QLI50 reads the sensors at every five seconds and sends the data automatically via a serial channel to a computer, which reads the results. The purpose of this LabView application is to collect data from the sensors, to save that data in the correct format, to calculate the control voltage for the faders of the lamps and to feed the voltage to an analogous output card. For one minute, the application reads data strings from QLI50 at five-second intervals and saves them in a tabular form. When a minute has passed, the minute average, the standard deviation, the minimum and the maximum are calculated from the table. The results are saved in the file of the day. The control voltage of the lamps is based on the averages. If the fluctuation is not too big, the control voltage is not adjusted. The application inputs the voltage reading to the PCI-6216V card connected to the computer. PCI-6216V is multi-channel analogous output card. There are 16 channels, whose voltages can vary between -10 and +10 V. Resolution on each channel is 16 bits. The settling time of the channel is two microseconds from -10 to +10 V. The PCI-6216V card is coupled to a buffer box with four identical printed boards with four channels in each. These boards shield the computer and especially the output card against electronic peaks caused by lightnings. At the same time, the buffer amplifies the small signal coming from the output card.

5 Flow chart of the mast field s low-voltage current PMA sensors and NILU need 3 pairs, control voltage needs one pair. Hut pr Krone bushpar Out: Control voltages 7 pc. In: QLI1, QLI2 and NILU data. Pair cable 100x2x m QLI1 and 2 BOX 1 input sensors Out: QLI1, QLI2 and NILU In: Control voltages 7 pc Box and 60pr Krone bushpars - WHP 24V power - +/- 5V power IN - 3 sensors IN - 4 sensors - NILU IN -Sensors 5842,5840, 6385,5844, 6384,5845 OUT - Controls 1-2,4, ,18-24V to chopper - from chopper to sensors+/- 5V Lampframes OUT - 1 control - 24 V OUT - 2 controls - 24 V Pair cable 30x20x m Pair cable 30x20x m OUT:PMA sensors IN:Control voltages Box 3-50 pr Krone bushpar - +/- 5V power OUT: PMA sensors and NiLU IN:Control voltages Boxi 2: - 50 pr Krone bushpar - 12 V power - +/- 5V power IN: Sensors 5839,6386,5846 OUT: Control voltage V to chopper - From chopper to sensors +/-5V IN: Sensors 5838, 5843, 5841, 5837, NILU OUT: Control voltages 16-21, V to chopper - From chopper to sensors +/-5V

6 Flow chart of the mast field s operating voltage First area of the research field, the same principle as later in the emplacements 2. and 3. 3x1,5S Output of the operating voltage in the hut Power plug 32 Amps 5x6 S 80 m 1. emplacement: - 32 A in - 2x16 A out - 12xschuko sockets 5x2,5 S 40 m 5x2.5 S 40 m 2. emplacement: - 16 A in - 6xschuko socket 3. emplacement: - 16 A in - 6xschuko socket 3x1.5 S 3x1.5 S n pc - two-piece branch box n pc - two-piece branch box 3x0.75S 3x0.75S F a d e r F a d e r F a d e r F a d e r

7 Information about equipment Device Manufacturer Importer Price [ ] PMA 1102 sensor Solar Light Co. Pietiko Oy 1650 PMA m cable Solar Light Co. Pietiko Oy 1907 PMA 1111 sensor Solar Light Co. Pietiko Oy 1236 PMA m cable Solar Light Co. Pietiko Oy 1493 QLI50 Vaisala Oy Vaisala Oy 1620 PCI-6216V D/A card ADLink Dosesoft Oy 1281 PC Data-Systems 1770 Quictronic HF 2x36/ V DIM Osram Oy Osram Oy 37 TL 40W/12 RS lamp Philips Oy Onninen Oy 59 Power supply WHP25 Vaisala Oy Vaisala Oy 560 PSM-ME-RS232/RS485- P interface converter Phoenix contact Phoenix contact 324 +/- 5V Chopper Farnell Oy 94.93

8 Material used Material Supplier Price Need Causeway and fence Oraniemi reindeer owners 5432 association Hut for a peatland Rovaniemi City 756 experiment Lamp holder 770/38 PPO-elektroniikka Oy Polyester 150m roll KTA-yhtiöt Cellulose-acetate Expopak Oy Rubber Schuko plug Lapin sähkö ja turva Two-piece RVP branch box Lapin sähkö ja turva Krone 100 pr terminal Teletekno 98,90 2 Krone 50 pr terminal Teletekno 67,10 2 Cabels Supplier Unit price/m Need [m] [ ] VSKB-Aton 3x0,75S Lapin sähkö ja turva VSB-Aton 3x1,5S Lapin sähkö ja turva VMOHBU 100x2x0,6 SLO Oy 8,30 60 VMOHBU 30x3x0,6 SLO Oy 2, VMOHBU 5x2x0,5 SLO Oy 0,78 925