In GPR profiles, ice is usually imaged as a mostly electromagnetic transparent facies. However, diffraction events, as well as internal layering, can be also observed. In some cases, the bedrock below glaciers is masked by dense diffractions usually interpreted as the effect of liquid water pockets inside the so-called warm ice. However, the actual physical meaning of such GPR facies is not always obvious, because it can be related also to mixed debris and ice deposits.

We adopted a strategy well known in medical sciences and referred as “differential diagnosis” in order to infer which is the actual meaning of a high scattering facies imaged within the Eastern Gran Zebrù glacier (Central Italian Alps) and, more generally, of all the internal glacier features. In fact, in many cases, there is no direct information to limit the subjectivity of geophysical interpretation; therefore, we provide all the discriminative hypotheses based on both independent and integrated criteria including GPR attribute analysis, imaging effects, reflection analysis, GPR frequency evaluations combined with geomorphological and remote sensing data obtained by two photogrammetric UAV and thermal infrared surveys.

On the basis of the differential diagnosis, we concluded that the high scattering zone embedded within the studied glacier is most likely related to a mixture of ice and debris probably formed during a past shrinking phase. Beside this case study, this approach could be helpful in other GPR glaciological surveys, in which the target is related not only to the bedrock detection, but also to a detailed analysis of the internal facies of a glacier.

在 GPR 剖面中，冰通常被成像为主要是电磁透明相。然而，也可以观察到衍射事件以及内部分层。在某些情况下，冰川下方的基岩被密集的衍射掩盖，通常被解释为所谓的暖冰内部液态水袋的影响。然而，这种探地雷达相的实际物理意义并不总是很明显，因为它也可能与混合碎片和冰沉积物有关。

我们采用了医学科学中众所周知的策略，称为“鉴别诊断”，以推断东格兰泽布鲁冰川（意大利中部阿尔卑斯山）内成像的高散射相的实际含义，更一般地说，所有内部冰川特征。事实上，在很多情况下，并没有直接的信息来限制地球物理解释的主观性；因此，我们提供了基于独立和综合标准的所有判别性假设，包括 GPR 属性分析、成像效果、反射分析、GPR 频率评估，结合两个摄影测量无人机和热红外调查获得的地貌和遥感数据。

在鉴别诊断的基础上，我们得出结论，嵌入在研究冰川内的高散射区很可能与过去收缩阶段形成的冰和碎片的混合物有关。除了这个案例研究之外，这种方法可能有助于其他 GPR 冰川学调查，其中目标不仅与基岩检测有关，而且与冰川内部相的详细分析有关。