Impact of different types of ENSO conditions on seasonal precipitation and streamflow in the Southeastern United States
Impact of different types of ENSO conditions on seasonal precipitation and streamflow in the Southeastern United States
复制标题
DOI：
10.1002/joc.5257
复制
发表时间：
2018-03
期刊：
影响因子：
--
通讯作者：
Hui Wang;T. Asefa
中科院分区：
文献类型：
--
作者：
Hui Wang;T. Asefa
气候科学的最新进展发现了两种不同类型的El Niño事件，即东太平洋El Niño （EP‐El Niño）和中太平洋El Niño （CP‐El Niño）。确定流域如何响应不同的El Niño‐南方涛动（ENSO）事件，包括El Niño和La Niña条件，对于理解海洋遥相关如何可能影响当地降水和水流至关重要。本研究选取了1950-2010年期间美国东南部70个人类影响最小的流域，研究EP‐和CP‐El Niño条件下以及La Niña事件中水流是否表现出不同的模式。对SEUS的187个气象站进行了类似的分析。分析表明，EP‐El Niño和CP‐El Niño年12 - 1 - 2月（DJF）的季节平均流量和降水量均高于长期平均值。然而，CP‐El Niño减弱了传统EP‐El Niño带来的润湿效应，导致SEUS大多数站点的季节性降水/流量增加百分比较小。在ENSO信号衰减季节（MAM）， EP‐和CP‐El Niño的流量都高于相应的气候学。与DJF季节相比，MAM季节的增幅更大。在La Niña事件期间，SEUS大部分台站的降水和流量都减少，特别是在DJF和MAM季节。ENSO在水资源管理中的使用通常仅限于SEUS的北方冬季，因为它的信号在水文响应中得到了很好的反映。研究发现，在6 - 7 - 8月（JJA）季节，随着MAM ENSO信号的衰减，EP‐El Niño和CP‐El Niño事件的降水和流量存在显著差异。
Recent advancement in climate sciences has discovered two different types of El Niño events, namely the eastern Pacific El Niño (EP‐El Niño) and central Pacific El Niño (CP‐El Niño). Identifying how watershed responses to different El Niño‐Southern Oscillation (ENSO) events, including both El Niño and La Niña conditions, is critical in understanding how the oceanic teleconnections possibly affect local precipitation and streamflow. In this study, 70 watersheds with minimum human impact during the period 1950–2010 in the Southeastern United States (SEUS) were selected to examine whether streamflow exhibits different patterns in EP‐ and CP‐El Niño conditions, and La Niña events. Similar analyses were applied to 187 precipitation stations in SEUS. Analyses reveal that for the peak season of both EP‐El Niño and CP‐El Niño years, December–January–February (DJF), seasonal average streamflow and precipitation is higher than long‐term average. CP‐El Niño, however, weakens the wetting effect brought by traditional EP‐El Niño, leading to smaller percentage of increases in seasonal precipitation/streamflow for most stations in the SEUS. In the decaying season March–April–May (MAM) of ENSO signals, streamflow for both EP‐ and CP‐El Niño is higher than its corresponding climatology. The increased amplitude is even greater in MAM compared to that of the DJF season. During La Niña events, reduced precipitation and streamflow are observed for large portion of stations in SEUS, especially for the DJF and MAM season. The use of ENSO in water resources management is often limited to boreal winter season for the SEUS, as its signal is well reflected in hydrological responses. This study finds that for the June–July–August (JJA) season followed by the decay of ENSO signals in MAM, there is striking difference in the magnitude of precipitation and streamflow for EP‐El Niño and CP‐El Niño events.