Elevation‐dependent responses of streamflow to climate warming
Elevation‐dependent responses of streamflow to climate warming
复制标题
水流对气候变暖的依赖海拔的响应
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
S. Godsey
中科院分区：
文献类型：
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作者：
C. Tennant;B. Crosby;S. Godsey
气候变暖将影响雪线海拔，可能改变山间水流的时间和大小。目前，评估潜在的海拔相关响应是困难的，因为许多测量的流域整合了以雪和雨为主的排水区域。为了预测雪线上升对河流流量的影响，我们绘制了萨蒙河流域（美国爱达荷州）当前的雪线（1980米），并预测了升温3°C后的雪线高度（2440米）。这一增加导致冬季积雪面积减少40%。我们通过收集一个新的、海拔分层的流域测量网络的流量记录来扩展这一分析，该网络包含在高海拔（2250-3800米）、中海拔（1500-2250米）和低海拔（300-1500米）的流域，这些流域隔离了雪、混合和雨为主的降水制度。结果表明，低海拔地区降水和流量百分位数之间的滞后比中、高海拔流域短得多。低海拔流域年流量百分位数（Q25和Q75）比高海拔流域早30-50天。低海拔极端事件以低流和无流事件为主，而中、高海拔极端事件主要是大震级洪水。只有中海拔和高海拔流域与萨蒙河流域的流量有强烈的交叉相关，这表明低海拔流域的贡献变化可能不能很好地用主流测量表来表示。随着雪线的上升，中高海拔流域可能会表现出目前仅在低海拔地区观察到的行为。为业务决策或变化检测而设计的河流监测网络可能需要修改，以捕获河流对变暖的依赖于海拔的响应。版权所有©2014 John Wiley & Sons， Ltd。
Warming will affect snowline elevation, potentially altering the timing and magnitude of streamflow from mountain landscapes. Presently, the assessment of potential elevation‐dependent responses is difficult because many gauged watersheds integrate drainage areas that are both snow and rain dominated. To predict the impact of snowline rise on streamflow, we mapped the current snowline (1980 m) for the Salmon River watershed (Idaho, USA) and projected its elevation after 3 °C warming (2440 m). This increase results in a 40% reduction in snow‐covered area during winter months. We expand this analysis by collecting streamflow records from a new, elevation‐stratified gauging network of watersheds contained within high (2250–3800 m), mid (1500–2250 m) and low (300–1500 m) elevations that isolate snow, mixed and rain‐dominated precipitation regimes. Results indicate that lags between percentiles of precipitation and streamflow are much shorter in low elevations than in mid‐ and high‐elevation watersheds. Low elevation annual percentiles (Q25 and Q75) of streamflow occur 30–50 days earlier than in higher elevation watersheds. Extreme events in low elevations are dominated by low‐ and no‐flow events whereas mid‐ and high‐elevation extreme events are primarily large magnitude floods. Only mid‐ and high‐elevation watersheds are strongly cross correlated with catchment‐wide flow of the Salmon River, suggesting that changes in contributions from low‐elevation catchments may be poorly represented using mainstem gauges. As snowline rises, mid‐elevation watersheds will likely exhibit behaviours currently observed only at lower elevations. Streamflow monitoring networks designed for operational decision making or change detection may require modification to capture elevation‐dependent responses of streamflow to warming. Copyright © 2014 John Wiley & Sons, Ltd.