应用气象学报
應用氣象學報
응용기상학보
QUARTERLY JOURNAL OF APPLIED METEOROLOGY
2013年
6期
686-694
,共9页
延伸期预报%检验%PPS方法
延伸期預報%檢驗%PPS方法
연신기예보%검험%PPS방법
extended-range forecast%verification%PPS approach
基于延伸期过程性天气气候事件预报评估的特点,结合实际科研和业务工作的需求,提出了一种适用于延伸期过程预报的检验方法(简称PPS方法)。该方法参考了常用的预报评分方法准则,借鉴了命中率、假警报率、欧式距离和动态时间弯曲距离等评估检验方法。利用命中率、假警报率和该方法对实际预报中可能出现的有漏报没有空报和既有漏报也有空报这两类情况的多个实例进行对比分析,表明该方法既能考虑大气随着时间的延长预报效果急剧降低的特性,也考虑了相似时间序列度量不精确匹配和形变的问题。利用该方法对1999-2010年冬季冷空气过程业务预报进行检验,结果表明:该方法能清晰表征延伸期预报时段内冷空气过程预报的准确程度,真实反映了目前延伸期预报准确率较低的现状,有较好的适用性。同时,该方法也适用于其他延伸期过程事件预报的评分,具有较好的应用前景。
基于延伸期過程性天氣氣候事件預報評估的特點,結閤實際科研和業務工作的需求,提齣瞭一種適用于延伸期過程預報的檢驗方法(簡稱PPS方法)。該方法參攷瞭常用的預報評分方法準則,藉鑒瞭命中率、假警報率、歐式距離和動態時間彎麯距離等評估檢驗方法。利用命中率、假警報率和該方法對實際預報中可能齣現的有漏報沒有空報和既有漏報也有空報這兩類情況的多箇實例進行對比分析,錶明該方法既能攷慮大氣隨著時間的延長預報效果急劇降低的特性,也攷慮瞭相似時間序列度量不精確匹配和形變的問題。利用該方法對1999-2010年鼕季冷空氣過程業務預報進行檢驗,結果錶明:該方法能清晰錶徵延伸期預報時段內冷空氣過程預報的準確程度,真實反映瞭目前延伸期預報準確率較低的現狀,有較好的適用性。同時,該方法也適用于其他延伸期過程事件預報的評分,具有較好的應用前景。
기우연신기과정성천기기후사건예보평고적특점,결합실제과연화업무공작적수구,제출료일충괄용우연신기과정예보적검험방법(간칭PPS방법)。해방법삼고료상용적예보평분방법준칙,차감료명중솔、가경보솔、구식거리화동태시간만곡거리등평고검험방법。이용명중솔、가경보솔화해방법대실제예보중가능출현적유루보몰유공보화기유루보야유공보저량류정황적다개실례진행대비분석,표명해방법기능고필대기수착시간적연장예보효과급극강저적특성,야고필료상사시간서렬도량불정학필배화형변적문제。이용해방법대1999-2010년동계랭공기과정업무예보진행검험,결과표명:해방법능청석표정연신기예보시단내랭공기과정예보적준학정도,진실반영료목전연신기예보준학솔교저적현상,유교호적괄용성。동시,해방법야괄용우기타연신기과정사건예보적평분,구유교호적응용전경。
Based on the features of forecast and assessment for extended-range weather and climate events,a verification approach named PPS (process-event prediction score)for process event forecast is proposed,which is combined with the actual requirements of extended-range forecast operation.This approach considers not only the criteria of event forecast scores including hit rate,false alarm rate commonly used in weather forecast operation,but also the advantages of other approaches such as Euclidean distance and dynamic time warping distance. <br> As the forecast period is relatively long,it is very difficult to forecast a process event completely and accurately.Therefore,it is terrifically valuable for adjacent hit,denoting the forecast with one to two days lead or lag,in operational application.Based on the above-mentioned features,the periods of forecast and observation for process events are extended,respectively,and the virtual events are transformed into simi-lar imaginary events.In terms of the accordance extent between forecast and observation,classified score table is constructed.Moreover,weight is used to show the influence of false alarm on forecast score. <br> The features of PPS approach are assessed by couples of cases including “no false alarm but missing”and “missing and false alarm”,and the relations of PPS to hit rate and false alarm rate are analyzed.Under the condition of “no false alarm but missing”,scores of PPS and hit rate increase with the correct forecast number of days.The PPS score is generally higher than hit rate score,which indicates the increasing score effect from the expansion for process events of observation and forecast.In the case of missing and false alarm, PPS scores are higher than the hit rate score when false alarm rate is low.However,PPS scores will be lower than the hit rate score when false alarm rate significantly increases,which shows the influence of false alarm to PPS score.Combined with the features of process event forecast and the possible influence of false alarm on forecast skill,PPS score objectively reflects the actual skill of forecast.Compared with hit rate and false alarm rate,it is more efficient to represent the process event information involved in a forecast.Therefore,it is more applicable for assessing the skills of process event forecast. <br> By this approach,skills of operational cold air process forecast are assessed during winters from 1999 to 2010.The results show that the PPS score reflects the accuracy of cold air process forecast well.Moreo-ver,the verification actually indicates relatively low accuracy of extended-range forecast today.Above all, this approach can be used to assess extended-range process forecast and shows good prospect for operation-al application.