Urban and rural dewfall, surface moisture, and associated canopy-level air temperature and humidity measurements for vancouver, canada
Urban and rural dewfall, surface moisture, and associated canopy-level air temperature and humidity measurements for vancouver, canada
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DOI：
10.1007/s10546-004-8947-7
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发表时间：
2005
影响因子：
4.3
通讯作者：
K. Richards
中科院分区：
文献类型：
--
作者：
K. Richards
与乡村环境相比，中纬度城市天气好的时候，夜间树冠的湿度通常较低。这一特征部分归因于城市露水的减少，但这种联系在很大程度上尚未得到证实，因为城市露水数据很少。在这项研究中，1996 年夏季，在加拿大温哥华的农村和城市住宅区测量了表面湿度（即露水 + 吸干滴水）和降露水（通过微型蒸渗仪）。在这两个地点以及从农村到城市的车辆行驶过程中测量了空气温度和湿度。天气和地点的影响是显而易见的。湿度数据表明，在晴朗的夜晚观察到的少量（< 1 g m−3）城市湿度过量与城市露水减少有关。对于草地来说，两个地点的潮湿事件频率和表面湿度量相似。然而，在草地上，农村露水量（平均每晚 0.10 毫米）多于城市露水量（平均每晚 0.07 毫米）。另一方面，“屋顶”蒸渗仪的数据（平均露水量=每晚 0.12 毫米）表明，城市屋顶可以与乡村草地相媲美，成为温哥华降露水的首选位置。
Canopy-level humidity is often less at night during fine weather in a mid-latitude city, compared to its rural surroundings. This feature has been attributed, in part, to reduced urban dew, but links are largely unproven, because urban dew data are rare. In this study, surface moisture (i.e., dew + guttation by blotting) and dewfall (by mini-lysimeter) were measured at rural and urban residential sites in Vancouver, Canada, during the summer of 1996. Air temperature and humidity were measured at both sites, and on rural-to-urban vehicle traverses. Weather and location effects were evident. Humidity data suggested the small (< 1 g m−3) urban moisture excess observed on fine nights was linked to reduced urban dew. For grass, the frequency of moisture events, and surface moisture amounts, were similar for both sites. However, on grass, rural dewfall (mean=0.10 mm per night) was more than urban dewfall (mean=0.07 mm per night). On the other hand, data for a ‘roof’ lysimeter (mean dewfall=0.12 mm per night) showed that an urban roof could rival rural grass as a favoured location for dewfall in Vancouver.