Report on Flux-AWS installation


Shenggong Li




1) Underground sensors placement at the forest site


We dug a 1.0 m hole near the tower base at the Mongonmorit mountain forest site for placing underground sensors. We could not dig it as deep as 1.5 m as planned just because we met rocks. Thus, we slightly adjusted the sensor array depths as follows:


(a) TDR sensor of 150 cm was placed at a depth of 10 cm, thus we have two TDR sensors at 10 cm deep;


(b) two SHPs were placed respectively at 5 and 10 cm depth;


(c) We only found 5 Pt sensors in the suitcase and they were put into soil at the depths of 5, 10, 20, 30, and 50 cm, respectively, which have corresponding tag marks of 2, 3, 5, 7 and 8;


(d) One suction tube was at the depth of 40 cm rather than 50 cm;


(e) No sensor was buried beneath 100 cm so that the tension meter of 120 cm was not placed;


(f) The sensor placement area was about 2 m away from one corner of the tower base, and


(g) The arrangement of the underground sensors see attached digiphotos.




2) The tower at the Mongonmorit forest site


As we went the site, we found the concrete tower base was completed, but the scaffolding tower has not yet been constructed as planned. We were supposed to have met the workers, who were responsible for the construction, but during our field work period, they did not show up. In this case, we are worrying about the bad influence possibly imposed on the placed sensors by both fence building and tower erecting. With this concern, we talked to Dr. Dawaa. He said he would try to contact the construction company and inform them our concern and tell them to pay close attention to the sensor area during the construction of the tower and fence.




3) Start of the measurements at KBU site


The work at the Kerlenbayan-Ulaan Grassland was not as smooth as we had expected. When we went the site, we found the power line was extended to the site. One technician from the power company said we could not use electricity without a permit issued by the local government. Processing the application for the permit might take one to two weeks and be available by mid November. With our insistence, they agreed to offer two to three hour power for our temporary use. We connected the cable attached to the logger box at the site to the power line after checking the voltage (ca. 217 V), then switched on the switch at the other end (the power substation). However, the fuse was burned even we tried several times. We suspected that the voltage transformer inside the logger box (upper box) might have dew water accumulated, leading to burning of the fuse. Therefore, we gave up both testing the data logger and starting the measurements. This would avoid damage possibly caused by sudden switching on of the power by the power company person without our presence. There should be a power supply box on the power pole near the site, but Dr. Dawaa said the box was still in Ondorhaan and would be sent to the KBU site recently. We suggest that we should have a power socket with switch inside the box to both control power supply and extend power for other use, e.g. data downloading by computer. A concern in mind is that extreme coldness aroused in deep winter may bring about an influence on the measurements. 




4) Measurements of earth resistance at KBU and forest sites


We measured the earth resistance both at the forest and KBU sites, but reading panel always showed outflow data, implying that the earth resistance might be too large. But the major reason is potentially due to low temperature, which exceeded the application temperature range of the resistance meter (0-40 oC), or due to snow cover, which might also affect the measurements. We should do this measurement next year when soil temperature is higher (above 0 oC).