Validation of an application for forecasting blowing snow
Validation of an application for forecasting blowing snow
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DOI：
10.3189/1998aog26-1-138-143
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发表时间：
1998
影响因子：
2.9
通讯作者：
G. Guyomarc'h;L. Mérindol
中科院分区：
文献类型：
--
作者：
G. Guyomarc'h;L. Mérindol
风对雪分布的影响和雪崩危险的增加是众所周知的。预测这种现象是基于经验规则和经验。两年来，CEN已经测试了一个新的分析程序，用于预测阿尔卑斯山的吹雪事件。目的是改进雪崩预报工具，以提高雪崩灾害预报的准确性。我们对吹雪机制的理解始于强风期间在高海拔地区的观察和实地测量。使用经验的方法，雪粒形态，雪颗粒和粒度之间的凝聚力已被结合起来，定义一个函数的计算“漂移指数”。通过与野外观测的风阈值比较，定义了一个吹雪指数。使用一个名为PROTÉON的应用程序分析了由SAFRAN（雪模型相关气象参数估计）和Crocus（积雪演变模型）计算的积雪剖面。风速和降雪廓线的预报已被用来区分有或没有降雪的时期。对于随后的24小时和每个雪层，计算该积雪指数的值并显示在图表上。验证包括一个比较预测的吹雪期与现场观察和测量的通行证位于海拔2700米。气象和雪参数数据可在此网站上获得。
Wind effects on snow distribution and increasing avalanche hazard are well known. Forecasting such phenomena is based on empirical rules and experience. For two years, the CEN has tested a new analysis program for forecasting blowing-snow events at an Alpine site. The aim is to improve avalanche-forecasting tools so as to increase the accuracy of avalanche-hazard forecasts. Our understanding of blowing-snow mechanisms began with observations and field measurements at a high altitude site during periods of strong wind. Using an empirical approach, snow-grain morphology, cohesion between snow particles and grain-size have been combined to define a function for the calculation of a “driftabilily index”. By comparing this index with the wind thresholds observed in field, a snowdrifting index has been defined. Snow profiles calculated by SAFRAN (estimation of relevant meteorological parameters for snow models) and Crocus (snowpack-evolution model) were analysed using an application called PROTÉON. Forecasts of wind velocity and snow profiles have been used to discriminate between periods with or without snow transport. For the subsequent 24 hours and for each snow layer, the value of this snowdrifting index is calculated and displayed on a graph. Validation consists of a comparison of forecasted blowing-snow periods with the field observations and measurements at a pass situated at 2700 m a.s.l. Meteorological and snow-parameter data are available at this site.