求助一段积雪变质物理过程方面的英文文献段落的翻译
AnewsnowfalloccurredonDecember18followedbyaclearnight,andonDecember19thesnowpack,32cmdeep,wascomposedofsurfacehoar(E=3.0mm)overlayingalayeroffreshsnow6cmdeep,formedbydecomposedprecipitationparticlesandroundedparticles(E=0.3mm),aswellasacrustduetorefreezingofthepreviouslymeltedlayerandotherlayerswithfacetedcrystals(insomecasesroundedparticleswithfewfaceted,E=0.5mm),andsomeroundedpolycrystalscausedbytheheatingofsnowpackonDecember17.Thecrustwastheresultofthestrongnocturnalirradiation.
疑惑如下：
1.surfacehoar(E=3.0mm)是formedbydecomposedprecipitationparticlesandroundedparticles(E=0.3mm)?
2.thesnowpack,32cmdeep,是由surfacehoar(E=3.0mm)、acrust和someroundedpolycrystals组成的吗?
3.最后一句“Thecrustwastheresultofthestrongnocturnalirradiation.”不知怎么理解,文章前后貌似没有讲什么是nocturnalirradiation.
