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春季积雪融水是古尔班通古特沙漠土壤水分的重要补给源之一,为早春植物的萌发和生长创造了有利的条件。为掌握该地区春季沙丘的土壤水分分布状况,采用探地雷达测量技术,于2010年4月进行了多次野外测量,并通过对地面直达波信号的提取和分析,初步获得了一致的测量结果。结果表明:(1)探地雷达地面直达波测量的土壤平均含水量与20 cm深同步TDR的测量结果非常接近,两者总体相差在0.02 cm3/cm3以内,充分反映了GPR地面直达波测量结果的有效性和精确性;(2)春季积雪完全融化后,沙丘/沙垄顶部土壤水分明显低于垄间低地,这与前人的研究一致,反映了积雪和冻土层在消融过程中,沙丘表面融水在坡面重力作用下,沿难以透水的冻土层上界自坡上向坡下迁移,形成了垄间最高、坡部次之和垄顶最少的分布格局;(3)垄间低地的土壤水分明显受到低矮灌草丛的影响进行再分布,这是由于积雪最初沿植丛基部开始消融,并以植丛为中心形成漏斗状融洞,从而形成以植丛为中心汇集较多融雪水的格局,而垄间低地中较为高大的梭梭乔木对融雪水的再分布影响明显不如低矮的灌草丛,这与其地表茎基过少有关。此外,探地雷达测量实验提供了详实可靠的表层土壤含水量分布信息,可为荒漠生态系统的空间尺度研究提供真实可靠的数据基础。
Spring snow meltwater is one of the important sources of soil moisture in the Gurbantunggut Desert, creating favorable conditions for early spring plant germination and growth. In order to understand the distribution of soil moisture in the spring sand dunes in the area, several field surveys were conducted in April 2010 using GPR measurement techniques. Through the extraction and analysis of ground direct wave signals, consistent measurements were obtained . The results show that: (1) The average soil water content measured by GPR ground penetrating radar is very close to that of 20 cm deep synchronous TDR, and the difference between them is less than 0.02 cm3 / cm3, which fully reflects the GPR terrestrial direct wave measurements (2) After the spring snowmelt completely melted, the soil moisture at the top of sand dune / sand dune was obviously lower than that of the ridge land. This is consistent with the previous studies, which reflect the process of snow melting and permafrost ablation , The surface melt of sand dunes migrated along the gravity of the slope surface along the upper boundary of the pervious permafrost layer from slope to slope, forming the distribution pattern with the highest ridge height, the second lowest ridge extent and the lowest ridge height; Soil moisture in the lowland of the ridge was apparently redistributed due to the influence of low shrubs and grasslands. This is because the snow began to ablate along the basal part of the plantation and formed a funnel-shaped cave around the plantation, In the center, more snowmelt water was collected, while the tall Haloxylon ammodendron in the lowland of the ridge was significantly less affected by the redistribution of snowmelt than the low shrubs, which was related to the infrequent stem base. In addition, GPR measurement experiments provide detailed and reliable information on the distribution of surface soil moisture, which can provide a true and reliable data foundation for the spatial scale study of desert ecosystems.