Spatial and temporal variability of freshwater discharge into the Gulf of Alaska
Spatial and temporal variability of freshwater discharge into the Gulf of Alaska
复制标题
阿拉斯加湾淡水排放的时空变化
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
J. Beamer
中科院分区：
文献类型：
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作者：
D. Hill;N. Bruhis;S. Calos;A. Arendt;J. Beamer
对流入阿拉斯加湾（果阿）的淡水进行了研究。利用现有的流量计数据，建立了月流量的回归方程。这些方程将流量表示为流域物理特性（如面积、平均海拔和土地覆盖）和流域气象特性（如温度、降水量和积水年降水量）的函数。为了提供必要的输入气象数据，使用气象站数据、PRISM气候学和统计降尺度方法，在高空间分辨率网格上开发了40年后播期的温度和降水数据。从方程的径流预测被发现同意与观测。回归方程一经开发，就应用于跨越整个果阿流域的划定流域网络。该地区被分为北方地区和南方地区，前者从阿留申山脉到东南狭长地带的阿拉斯加/加拿大边境，后者从那里到弗雷泽河。进入北方果阿地区的平均年径流量为792 ± 120 km 3 yr−1。水平衡使用基于MODIS的蒸散率产生的季节性存储量与GRACE卫星的估计是一致的。GRACE数据表明，由于近年来冰川体积损失（GVL），北方地区的径流量增加了57 ± 11 km 3/年。由此得出的总价值为849 ± 121 km 3 yr−1。推导出的回归方程易于应用，为量化任何感兴趣的未测量流域径流的年平均值、季节变化和年际变化提供了一种易于使用的工具。
A study of the freshwater discharge into the Gulf of Alaska (GOA) has been carried out. Using available streamgage data, regression equations were developed for monthly flows. These equations express discharge as a function of basin physical characteristics such as area, mean elevation, and land cover, and of basin meteorological characteristics such as temperature, precipitation, and accumulated water year precipitation. To provide the necessary input meteorological data, temperature and precipitation data for a 40 year hind-cast period were developed on high-spatial-resolution grids using weather station data, PRISM climatologies, and statistical downscaling methods. Runoff predictions from the equations were found to agree well with observations. Once developed, the regression equations were applied to a network of delineated watersheds spanning the entire GOA drainage basin. The region was divided into a northern region, ranging from the Aleutian Chain to the Alaska/Canada border in the southeast panhandle, and a southern region, ranging from there to the Fraser River. The mean annual runoff volume into the northern GOA region was found to be 792 ± 120 km3 yr−1. A water balance using MODIS-based evapotranspiration rates yielded seasonal storage volumes that were consistent with GRACE satellite-based estimates. The GRACE data suggest that an additional 57 ± 11 km3 yr−1 be added to the runoff from the northern region, due to glacier volume loss (GVL) in recent years. This yields a total value of 849 ± 121 km3 yr−1. The ease of application of the derived regression equations provides an accessible tool for quantifying mean annual values, seasonal variation, and interannual variability of runoff in any ungaged basin of interest.