x
uploads/level curve.jpg

level curve level curve = contour line.

level flight

Firstly , the status of our nation ' s water resources , flood and arid hazards is overviewed to illustrate the necessity for study on dynamic control of flood season limited water level . disadvantages in traditional limitsd water level design , static control of limited water level design , static control of limited water level and fuzzy limited water level curve are pointed out , and mending methods for these are introduced . dynamic control and its key problems are analyzed hi next section . the allowable range of limited water level is determined , so as the allowable extreme risk index . the definition of extreme risk is re - illustrated , risk analysis methods in reservoir operation is discussed either . according to the definition of extreme risk rate , the allowable extreme risk rate of reservoir is systematically demonstrated with variant extreme risk indexes and flood season limited water level 本文首先闡述了我國水資源狀況和水旱災害、說明水庫汛期限制水位動態控制研究的必要性;介紹了傳統汛限水位設計、汛限水位靜態控制、模糊汛限水位過程線存在的問題及其初步改進方法;分析汛期限制水位動態控制的方法及關鍵問題;進一步闡述了水庫極限風險率的定義;根據極限風險率定義,詳細敘述了不同極限風險指標時、不同汛期限制水位下起調,水庫所能承受的極限風險率計算方法。然后,基于極限風險率計算方法,以白石水庫為背景,研究“考慮壩體自身安全、考慮壩體安全與下游防護對象控制下泄流量的汛限水位動態控制的極限風險率” 。

By comparing i8o curve with annual growth rate and grey level curve in the stalagmite during the same period , the author brings forward that that climate in shennongjia region mostly embodies matching modes of warm / wet , cold / dry over the past 2000 years , but temperature was out of harmony with precipitation in the course of climate transforming , which shows that shennongjia climate embodies matching modes of cold / wet , warm / dry at part period of time 近2000年中17次太陽活動和1400aad以來29次火山活動對氣候變化影響的印跡在石筍氧同位素中都有明顯的記錄,表明氣候事件與太陽活動、火山活動有較好的相關性。石筍各代用指標譜分析顯示126a 、 100a 、 81a 、 60a 、 40a 、 22a 、 11a等周期成分,也進一步支持了太陽活動對季風區短尺度氣候變化的驅動作用。

Both the annual banding growth rate curve and grey level curve show the evolution processes of the precipitation over the past 2000 years this region and that divide into seven dry / wet cycles 石筍紋層厚度和灰度曲線比較清晰地揭示了本區過去2000年降水演化過程,可劃分7個干濕旋回。

Compared c13 & o18 isotope analysis curve with lake level curve , further analyzed palaeoenvironment 通過分析、對比碳氧同位素曲線與湖平面升降曲線,對古沉積環境的變化規律有了進一步的認識。