We realised that huge areas of the snowpack in the sierra went down to 15 per cent of today ‘ s values , says michael dettinger , a research hydrologist at the scripps institution of oceanography in la jolla , california 加利福尼亚拉霍亚市斯克里普斯海洋研究所的一位水文学家迈克尔?德廷杰说,我们发现,在谢拉地区积雪场的大部分面积已在目前的基础上缩小了15 。