中国地质灾害气象预警模型研究

地质灾害气象预警是指对气象因素(主要为降雨)引发的地质灾害发生可能性大小的预测预报。中国大陆的地质灾害气象预警工作始于2003年, 逐步形成了国家级、省级、市县级的分级运行业务模式, 预警模型及可靠性问题是这项工作的核心科学技术问题和研究难点。考虑到各级地质灾害气象预警的时空尺度与预警时效, 形成了两代预警模型并行运算、相互校验与补充的运行模式。第一代隐式统计预警模型, 也称为临界降雨判据法, 基于不同地质环境区域引发地质灾害的临界雨量不同, 分区建立临界降雨判据, 该模型2003年起在预警业务中使用, 因其只涉及一个或一类参数, 使用广泛, 近年来又在模型参数、判据修正等方面不断完善。但单一的临界雨量指标很难准确反映地质环境的变化以及地质灾害的成生规律, 且预警区划、判据更新与准确性提高等也限制了其进一步发展。第二代显式统计预警模型, 耦合了地质环境变化与降雨参数等多因素建立预警判据, 地质环境指标在模型中显式表达, 在模型原理、空间精度、升级能力等方面表现了其优越性, 显著提高了预警精细度和准确度, 2008年开始在国家级预警业务使用, 并逐步向省级推广。两代预警模型均是基于统计方法建立, 一定程度上均受到统计样本的选择、地质环境条件的精细程度、实况降雨数据的精确匹配等因素控制和影响。多年来, 两代预警模型在中国地质灾害气象预警业务中成功运行并不断升级完善, 为中国大陆的地质灾害防灾减灾工作做出了重要贡献。

STUDY OF EARLY WARNING MODELS FOR REGIONAL GEO-HAZARDSIN CHINA

Early-warning of geo-hazards in China, refers to analyze and forecast the probability of regional geo-hazards induced by meteorological factors(mainly rainfall).It has gradually formed a grading business model since 2003, and is classified into national level, provincial level, city and county level. The technological keys and research difficulties of the business are the study on early-warning model and its reliability problem. Considering time-space scale and technical difficulty, early warning models are modeled mainly on the basis of statistical method. Up to now, two generation models have been formed and include mutually calculation, checking and supply. This paper systematically presents the principle, technical method, business application and improved technique of two generation models. The first generation model is named the implicit statistics models, and also named the critical rainfall criterion. It is established on the basis of different rainfalls in different geological environment areas. The model is widely used for involving only one or a group of parameters. It has been improved in model parameters and correcting criterion recently. But, it has difficulty in showing changes of geo-environment and causes of geo-hazards. The first model is also limited by improvement of warning division, accuracy and renewal of criteria. The second generation model is named explicit statistics models and established by taking into consideration of geo-environment and rainfall multi-parameters. In the model, explicit expression of geo-environmental factors, and the advantages of model principle, spatial precision and improving ability are shown. It significantly improves precision and accuracy of early-warning. The second generation model was developed in 2008 and used in national early-warning business, gradually to provincial business. Both are established on statistical method. The two generation early-warning models were influenced by selection of statistical samples, knowing degree of geological environmental conditions and accurate matching of rainfall data in some degree. Over years, the two generation models are operated successfully and improved continuously. Important contributions to geo-hazards mitigation have been made.