PRECIPITATION CHANGES FROM 1956 TO 1996 ON THE WALNUT GULCH EXPERIMENTAL WATERSHED 1
PRECIPITATION CHANGES FROM 1956 TO 1996 ON THE WALNUT GULCH EXPERIMENTAL WATERSHED 1
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核桃峡谷实验流域 1956 年至 1996 年降水量变化 1
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
H. Osborn
中科院分区：
文献类型：
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作者：
M. Nichols;K. Renard;H. Osborn
摘要：亚利桑那州南部的气候以夏季降水为主，占全年降水量的60%以上。对美国农业部-农业研究所核桃沟实验流域的夏季和非夏季降水数据进行了分析，以确定1956年至1996年降水特征的趋势。在此期间，年降水量增加。年降水量的增加可以归因于非夏季月份降水量的增加，并被非夏季月份贡献的年降水量比例的增加所抵消。这一发现与先前报道的美国西南部非夏季降水增加一致。详细的事件数据进行了分析，以提供洞察在这段时间内的降水事件的特征。根据事件数量、事件降水量、30分钟事件强度和事件持续时间对降水事件数据进行表征。非夏季降水的趋势似乎是事件频率增加的结果，因为事件数量在非夏季月份增加，尽管每个事件的平均数量，平均事件强度和平均事件持续时间没有增加。在夏季“季风”季节，记录的降水事件的频率增加，但每次事件的平均降水量减少。了解降水趋势和构成降水时间序列的事件特征是了解和管理半干旱生态系统水资源的关键的第一步。
ABSTRACT: The climate of Southern Arizona is dominated by summer precipitation, which accounts for over 60 percent of the annual total. Summer and non‐summer precipitation data from the USDA‐ARS Walnut Gulch Experimental Watershed are analyzed to identify trends in precipitation characteristics from 1956 to 1996. During this period, annual precipitation increased. The annual precipitation increase can be attributed to an increase in precipitation during non‐summer months, and is paralleled by an increase in the proportion of annual precipitation contributed during non‐summer months. This finding is consistent with previously reported increases in non‐summer precipitation in the southwestern United States. Detailed event data were analyzed to provide insight into the characteristics of precipitation events during this time period. Precipitation event data were characterized based on the number of events, event precipitation amount, 30‐minute event intensity, and event duration. The trend in non‐summer precipitation appears to be a result of increased event frequency since the number of events increased during nonsummer months, although the average amount per event, average event intensity, and average event duration did not. During the summer “monsoon” season, the frequency of recorded precipitation events increased but the average precipitation amount per event decreased. Knowledge of precipitation trends and the characteristics of events that make up a precipitation time series is a critical first step in understanding and managing water resources in semiarid ecosystems.