以水文循环基本原理为基础, 从流域径流水汽来源影响因素角度明确了中长期径流预报基本概念及分类, 即 以气象( 中期) 、气候( 长期) 和天文因素( 超长期) 为预报因子, 针对流域出口断面( 或典型断面) 的旬、月、季( 汛期) 或 年径流, 以及流域旱涝趋势进行预报。通过比较不同时间尺度下的水汽系统物理运动机理, 论证了/ 短期气候预测0 作为中长期径流预报理论基础的合理性, 并将流域径流来源影响因素及其表现概括为三大规律: 天文因素表现出的 周期性是主要规律, 反映了水文气候过程的基本状态; 大气环流表现出的随机性对水文气候基本状态存在干扰, 导 致了波动; 流域特征性规律反映了各种因素综合作用结果, 具有流域的特殊性。最终, 将流域中长期径流预报分为 正常年份的径流过程预报和异常灾变年份的大旱大涝预测, 其中前者的预报因子为水文气象与气候要素, 后者为天 文因素; 在服务对象上, 前者为水利工程常规运行调度服务, 后者为防洪抗旱部门防灾减灾提供灾情预测; 在结果发 布上, 前者提供定量的径流过程预报, 后者提供丰、平、枯等3 级( 或5 级) 定性预测, 并给出相似年份; 在预报方法 上, 前者采用数理统计方法或物理成因相关分析法, 后者采用周期性、随机性和流域特殊性识别等综合预报方法。

Based on the basic pr inciple o f hydr olo gic cycle, the basic concept and classificatio n of mid2 to long2term r unof f fo recast are defined from the perspect ive of impact factor s of water vapor so ur ces o f riv er basin r unoff, the met eo ro lo gical fact ors ( mid2 term) , climate facto rs ( long2term) , and ast ronomica l f acto rs ( v ery long2term) ar e selected as the pr edict ors, and the ten2day, monthly, seaso nally ( floo d) or annual runoff tar geting to the outlet sect ion of riv er basin ( or ty pical section) and dro ught and floo d t rend are f orecasted. Thro ug h the compar ison o f the differ ence in the physical mo vement mechanism of w ater vapo r sy st em under different time scales, the r ationality of / shor t2term climate prediction0 as the theo retical basis fo r mid2 to long2term r unoff forecast is demo nstr ated. The impact factor s fo r the r unoff sources in r iver basin and their performance are summar ized as thr ee law s: the per io dic law o f astr onomical facto rs is the main rule, which r eflects the basic st ate of hydro log ical and climat ic pro cess; the r andom law o f atmospher ic cir culation has interference on the basic state o f hydro lo gy and climate, which leads to fluctua2 tion; and the character istic law o f riv er basin reflects the compr ehensiv e effects fr om var ious facto rs, which has par ticular ity . Fi2 nally, the mid2 t o long2term r unoff forecast can be divided into t wo catego ries: runoff pr ocess forecast in no rmal y ear and dr ought and floo d for ecast in abno rmal calamity y ear. T he fo rmer takes the hy dr olog ical and climatic elements as predictor s whereas the latt er takes t he astro nomical factor s as predictor s. In terms of service objects, the fo rmer serv es fo r the regular op2 er ation and scheduling of wat er pr ojects whereas the latt er pr ov ides disaster fo recast fo r disaster preventio n and reduct ion in floo d co nt rol and dr ought resistance departments. In terms o f publicatio n of results, t he former pr ovides the quant itativ e fo recast of r unoff pr ocess whereas the latt er pr ovides t he qualitative for ecast of level 3 ( or level 5) and similar year s. In terms o f fo recast met ho ds, t he fo rmer adopts mathematical statistics met ho d or physical cause co rrelatio n analy sis w hereas the latter ado pts com2 prehensive for ecasting ident ificatio n method of per iodicity , r andomness, and w atershed particularit y.

国家自然科学基金项目( 51379088) ; 吉林省科技厅科技支撑项目( 20130206088SF)