Climate trends of the North American prairie pothole region 1906-2000
Climate trends of the North American prairie pothole region 1906-2000
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DOI：
10.1007/s10584-008-9543-5
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发表时间：
2009-03-01
期刊：
影响因子：
4.8
通讯作者：
Guntenspergen, Glenn
中科院分区：
文献类型：
--
作者：
Millett, Bruce;Johnson, W. Carter;Guntenspergen, Glenn
大草原坑洼区（PPR）是北美独有的。其数以百万计的湿地和丰富的生态系统产品和服务对强烈大陆性气候所特有的温度和降水在时间和空间上的广泛变化非常敏感。PPR上的降水和温度梯度相互正交。降水量从西到东几乎增加了两倍，从大约300毫米/年增加到900毫米/年，而年平均气温从北部的大约1A摄氏度到南部的近10A摄氏度。代表6个生态区的18个PPR气象站的20世纪天气记录显示了几个趋势。气候总体上变得越来越温暖和潮湿，昼夜温差已经减少。日最低气温上升1.0A摄氏度，而日最高气温下降0.15A摄氏度。最低气温冬季增温大于夏季，最高气温夏季降温，冬季增温。年平均降水量增加49毫米，增幅9%。帕尔默干旱严重程度指数（PDSI）的趋势反映了大多数气象站的水分供应增加，但是，在加拿大西部大草原的几个站记录有效干燥的条件。东西部湿度梯度在20世纪变陡，西部站点变得干燥，东部站点变得湿润。如果湿度梯度继续变陡，湿地生态系统的生产面积将缩小。如果未来的气候不提供补充水分来抵消更高的蒸发需求，湿地的后果将特别严重。
The Prairie Pothole Region (PPR) is unique to North America. Its millions of wetlands and abundant ecosystem goods and services are highly sensitive to wide variations of temperature and precipitation in time and space characteristic of a strongly continental climate. Precipitation and temperature gradients across the PPR are orthogonal to each other. Precipitation nearly triples from west to east from approximately 300 mm/year to 900 mm/year, while mean annual temperature ranges from approximately 1A degrees C in the north to nearly 10A degrees C in the south. Twentieth-century weather records for 18 PPR weather stations representing 6 ecoregions revealed several trends. The climate generally has been getting warmer and wetter and the diurnal temperature range has decreased. Minimum daily temperatures warmed by 1.0A degrees C, while maximum daily temperatures cooled by 0.15A degrees C. Minimum temperature warmed more in winter than in summer, while maximum temperature cooled in summer and warmed in winter. Average annual precipitation increased by 49 mm or 9%. Palmer Drought Severity Index (PDSI) trends reflected increasing moisture availability for most weather stations; however, several stations in the western Canadian Prairies recorded effectively drier conditions. The east-west moisture gradient steepened during the twentieth century with stations in the west becoming drier and stations in the east becoming wetter. If the moisture gradient continues to steepen, the area of productive wetland ecosystems will shrink. Consequences for wetlands would be especially severe if the future climate does not provide supplemental moisture to offset higher evaporative demand.