The research on transfer funcotion of the chemical constituents in snow layer

已有报道表明，在极地地区，雪层中的化学成分浓度在积累后会发生变化。但是，很难找到浓度变化的原因。我们在实验室进行了重现实验，以检查化学成分的扩散过程。为了做这个实验，我们创造了一个新的设备，可以改变雪的温度。该装置可将雪样温度降至-31℃，并可产生0.71℃的温度梯度。由于在实验室中难以人工制作雪块供实验使用，我们从三个地区的雪层中采集了雪样，其中北海道的两个点和长野县的一个点。然后，我们还观察了地层，密度和雪温度，以调查初始雪条件。第一次实验使用了在北海道采集的雪样。在约一周的时间内，将该样品（密度：0.35 × 0.37g/cm^3）的上部温度设定为-20℃，下部温度设定为-30℃。实验后雪样中化学成分浓度呈现出上部上升、下部下降的趋势。试验结束后，全层的氧同位素比值下降。这种变化可能是由于雪粒的升华和凝结而发生的。

It is already reported that the chemical constituents concentration in the snow layer changes after accumulation in the polar region. However, it finds the cause of the concentration change hardly. We experimented in the reappearance at the laboratory to examine the diffusion processes of the chemical constituents. To do this experiment, we created the new equipment that can change a snow temperature. This equipment can lower the temperature of snow sample to -31℃, and can create the temperature inclination of 0.71℃. We collected snow samples from snow layers at the three regions, two points of Hokkaido and one of Nagano Prefecture because it was difficult to create snow blocks artificially to be used by the experiment in laboratory. Then we also observed stratigraphy, density and snow temperature to investigate the initial snow condition. The snow sample which was collected in Hokkaido was used for the first experiment. For about one week, this sample (density : 0.35〜0.37g/cm^3) set a temperature in the upper part to -20℃ and in the lower part to -30℃. After experiment, the concentration of chemical constituents in snow sample increased in the upper part and decreased in the lower part. And oxygen isotope ratio decreased in whole layers after experiment. It is possible that this change have occurred with the sublimation and condensation of snow grain.