SWIPS (Shallow Water Ice Profiling Sonar)：Peace河淺水冰剖面聲納數據分析及其對冰凍河流中潛冰和原位錨冰生長作用的影響
Abstract
Peace River SWIPS (Shallow Water Ice Profiling Sonar) data were analyzed to quantify the roles of frazil ice and riverbed anchor ice grown in situ during the initial buildup of a seasonal ice cover. Data were derived through quasi-continuous monitoring of frazil parameters throughout the water column, providing direct and indirect measures of anchor ice volume and mass growth rates. Analyses utilized water level and air and water temperature information in conjunction with acoustic volume backscattering coefficient data to track and interpret spatial and temporal changes in riverbed and water column ice. Interest focused on four frazil intervals characterized by anomalously low levels of frazil content (relative to simulations with an anchor-icefree river ice model) as distinguished by two strikingly different types of time dependences. A simple physical model was proposed to quantitatively account for discrepancies between measured and simulated results in terms of the pronounced dominance of anchor ice as an initial source of river ice volume and mass. The distinctive differences in temporally variable water column frazil content are attributed, in this model, to corresponding differences in the stabilities of riverbed anchor ice layers against detachment and buoyancydriven movement to the river surface. In accord with earlier observations, the stability of in situ grown riverbed ice layers appears to be inversely proportional to cooling rates. The strength of the coupling between the two studied ice species was shown to be strong enough to detect changes in the anchor ice constituent from variations in water column frazil content.
摘要：
對Peace河SWIPS（淺水冰剖面聲納）數據進行了分析，以量化在季節性冰蓋初始形成期間原位生長的潛冰和河床錨冰的作用。數據是通過對整個水柱的潛冰參數進行準連續監測得出的，提供了錨冰體積和質量增長率的直接和間接測量。分析利用水位、空氣和水溫信息以及聲體積后向散射系數數據來跟蹤和解釋河床和水柱冰的空間和時間變化。興趣集中在四個潛冰間隔上，其特征是潛冰含量異常低（相對于錨無冰河冰模型的模擬），這兩個間隔的時間依賴性截然不同。提出了一種簡單的物理模型，定量解釋了測量結果和模擬結果之間的差異，即錨冰作為河流冰量和質量的初始來源具有明顯的優勢。在該模型中，時變水柱潛冰含量的顯著差異歸因于河床錨冰層對分離和浮力驅動的河流表面運動的穩定性的相應差異。根據早期的觀察，原位生長的河床冰層的穩定性似乎與冷卻速率成反比。兩種研究冰種之間的耦合強度被證明足夠強，可以從水柱潛冰含量的變化中檢測到錨冰成分的變化。
關鍵詞：IPS冰剖面儀，SWIPS淺水冰剖面儀，冰聲學回聲探測，后向散射，ASL冰剖面聲吶
