1. # Температура почвы

## Summing up the results of the September Freeze in 2015/2016 academic year

Dear Colleagues!

In measuring the temperature of the soil participated Petrozavodsk and St. Petersburg, Moscow and Izhevsk, Republic of Tatarstan, Rostov region and the Astrakhan region.

Of the participants with a high temperature in the day freeze frame start analysis profiles Cherkov-Grishensky school. When the air temperature 26 ° C, the surface of the air warmed to 29 ° C. Thus, when the air temperature measured at a depth of 10 cm, was quite significant difference - 18 ° C. At a depth of 20 cm has a total of 14 ° C.

The group from the village Melikhovo Lazoriki initial data seems to be similar. High temperatures - 30 ° C, the surface temperature of the soil - 31 ° C. But then begin strangeness: at a depth of 10 cm - 31 ° C, and at a depth of 20 cm - 30 ° C. It seems to be intuitively clear that the soil warms up slowly and under a layer of earth is colder than on the ground. Man enjoyed this property, digging cellars. I think that in this case should be clarified how well the group Lazoriki complied with the study protocol.

But the results of the participants from the village. Red Barricades can understand one of the reasons resulting in measuring errors. Look at the picture, which they placed in the questionnaire.

When measuring only part of the "probe" sensor is immersed in the soil, it can be assumed that the participants did not pre-groove in the soil, as required by the protocol of the project and tried to plug the sensor directly into the soil. This gives rise to resistance, so it seems that you can not continue to stick to not to break the sensor. However, these temperature sensors have one unexpected property - is the measure of the entire length of the sensor. Therefore, half of the sensor measures the actual temperature of the soil at the desired depth, and half of the sensor is located in a warm outdoor air. As a result, there is a strong distortion of the measurement result.

The same pattern can be seen from the other participants in the project, working with digital temperature sensors.

I am very interested in the results of a member from St. Petersburg. This is the only form in which it is noted that the deeper the soil temperature is higher, although the difference is small. However, and in St. Petersburg temperature is lower than most of the other participants. The conclusion, which made the student with the nickname alice30701, coincides with the conclusions that have made my own students in stop-frame last year. In the autumn the soil cools rapidly from the surface, and at depths of more stores heat. In the spring, on the contrary, the deeper the cooler because the soil warms up gradually, starting from the surface. (This can be read in the article below, dedicated to the analysis of the March freeze-frame of the last school year).

Maybe you can share with us their own findings and observations?

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