地表植被分布对0604“碧利斯”台风暴雨的影响

SENSITIVITY OF HEAVY RAINFALL TO LOCAL VEGETATION TYPES IN SOUTHEASTERN HU'NAN

湖南省三面环山,山坡上混合林分布密集,面积较大,山坡下的地表植被以草地和庄稼地为主。利用AREM中尺度数值预报模式,以0604号"碧利斯"台风暴雨为例,用不同的地表植被和陆面过程方案的试验,研究了湖南这种特殊的地表植被分布对"碧利斯"台风暴雨中心位置和强度的影响。试验结果表明,混合林可产生相对较大的陆气通量,增强了局地大气不稳定度,导致降水强度加大;同时混合林与草地的区域大气之间形成次级环流,引导降水中心向陆气通量大的地区偏移。

Southeastern Hu＇nan is surrounded on three sides by mountains,with an open plain in the north.Mixed woodland dominates mountainous regions,while short grass and irrigated crop occupy the basin.This special vegetation distribution was studied in this paper with the AREM mesoscale numerical model,and its effects on local heavy rainfall are demonstrated by the case of Typhoon Bilis（2006）.The numerical experiments showed that the surface covered with mixed woodland can produce relatively large land-air flux,strengthen atmospheric instability and therefore result in stronge rainfall.In addition,a secondary circulation forced between the regions of mixed woodland and short grass draged the rain center toward the regions with large land-air flux.