摘要:利用区域数值模式WRF-ARW（V3.9）开展高分辨率数值模拟试验，研究了东北地区大兴安岭和长白山地形对该地区夏季降水的单独和共同影响。结果表明，东北地区两大山脉地形可以显著影响东北及其周边区域的大气环流和降水。大兴安岭和长白山地形的阻挡作用使得夏季偏南气流在两个山脉的迎风坡一侧堆积，引起局地水汽增加并产生上升运动，因此两个山脉的迎风坡一侧降水增加；而在两个山脉的背风坡一侧，局地水汽减少并伴随下沉运动，因此两个山脉的背风坡一侧降水减少。大兴安岭地形的存在使得其东侧到松嫩平原地区夏季降水增加1.09 mm d?1（相较参照试验增幅为30%），而使其西侧蒙古东部地区夏季降水减少0.69 mm d?1（相较参照试验减幅为24%）；长白山地形的存在使得长白山南侧到朝鲜半岛地区夏季降水增加1.76 mm d?1（相较参照试验增幅为26%），而使其北侧三江平原地区夏季降水减少0.81 mm d?1（相较参照试验减幅为22%）。当大兴安岭与长白山同时存在时，两者的协同作用会减弱蒙古东部、松嫩平原和朝鲜半岛地区夏季降水的响应，而增强三江平原地区夏季降水的响应。该研究结果对于理解东北地区当代气候的形成具有重要的科学意义。
关键词:区域数值模式/
地形影响/
大兴安岭/
长白山/
夏季降水/
东北
Abstract:The separate and joint effects of the Great Khingan Strip (GKS) and Changbai Mountain (CM) on summer rainfall in Northeast China are investigated based on high resolution simulations using a regional numerical model WRF–ARW (V3.9). The results indicate that the GKS and CM can significantly influence rainfall and atmospheric circulation in Northeast China. The two mountains block the southerly winds at the windward slopes, leading to moisture convergence and upward movement over the regions; therefore, summer rainfall increase on the windward slopes of the two mountains. On the leeward slopes, there are moisture divergence and downward motion of winds, which results in decreased precipitation over the regions. The existence of the GKS can increase summer rainfall by about 1.09 mm d?1 (30% of climatological mean summer precipitation in control run) in the region from the eastern slope of the GKS to the Songnen Plain, but decrease it by about 0.69 mm d?1 (24% of climatological mean summer precipitation in control run) over Eastern Mongolia. The existence of the CM can increase summer rainfall by about 1.76 mm d?1 (26% of climatological mean summer precipitation in control run) in the region from the southern slope of the CM to the Korean Peninsula, but decrease it by about 0.81 mm d?1 (22% of climatological mean summer precipitation in control run) over the Sanjiang Plain. The combined effect of the GKS and CM has an offset effect on summer rainfall in Eastern Mongolia, the Songnen Plain, and the Korean Peninsula, but has an enhancement effect on the Sanjiang Plain. The results of this study are important to better understand the formation of the current summer climate in Northeast China.
Key words:Regional numerical model/
Topographical effect/
Great Khingan Strip/
Changbai Mountain/
Summer rainfall/
Northeast China
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