Microclimate of Arctic Tree Line 2. Soil Microclimate of Tundra and Forest
Microclimate of Arctic Tree Line 2. Soil Microclimate of Tundra and Forest
复制标题
北极林线小气候 2. 苔原和森林土壤小气候
DOI：
10.1029/wr020i001p00067
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发表时间：
1984
影响因子：
5.4
通讯作者：
W. Rouse
中科院分区：
文献类型：
--
作者：
W. Rouse
森林和苔原土壤在丘吉尔的气候正常年份显示出独特的小气候。森林土壤的活动层比冻土带的活动层温暖得多，但冻土带的活动层更深。森林的土壤比苔原的土壤湿润得多。这是由于深冬的积雪为已经解冻的土壤提供了充足的融水。土壤全年保持湿润，大量的潜热释放延迟了森林土壤的冻结，直到积雪形成。因此，土壤在整个冬季保持相对温暖，并在春季积雪融化之前迅速融化。在树木生根区的解冻期约为6个月，而在冻土带的相同深度为4个月。土壤热储量的大小是很大的，包括18%和16%的净辐射在冻土和森林，分别在解冻季节。在回冻期间，它是主要的热交换过程。80%~ 90%的土壤热储存是在融化和冻结过程中进行的潜热交换。土壤热通量板严重低估了地面热交换，在多年冻土区是不可靠的。
Forest and tundra soils display distinctive microclimates for a climatically normal year at Churchill. Forest soils are substantially warmer in the active layer than those of the tundra but the tundra active layer is deeper. Forest soils are much wetter than those of the tundra. This results from the deep winter snow pack, which provides abundant meltwater to already thawed soils. The soils remain wet throughout the year, and the large latent heat release delays the freezing of forest soils until a snow pack is established. As a result, soils stay relatively warm throughout winter and thaw rapidly and deeply before snow pack melting in the spring. The thaw period in the tree rooting zone is about 6 months, compared to 4 months at the same depth in tundra. The magnitude of soil heat storage is large, comprising 18% and 16% of net radiation in tundra and forest, respectively, during the thaw season. During freeze back it is the dominant heat exchange process. Between 80% and 90% of the total soil heat storage is involved in the latent heat exchange accompanying thawing and freezing. Soil heat flux plates strongly underestimate the ground heat exchange and are unreliable in permafrost terrain.