云南热区森林生态系统水分条件的空间分异规律

Spatial Differentiation of Water Conditions of Forest Ecosystems in Hot Region of Yunnan Province

根据101个气象站点30a的观测资料,用标准差分级和线性回归分析方法,对云南热区的主要气象指标进行量化,研究这些指标的空间分异规律。结果表明,云南热区森林生态系统水分条件具有高度的时空异质性,其规律性表现在:①多雨区除金沙江流域外,均集中于其余5大水系的下游地区,即东南季风和西南季风的迎风面上,而较多降雨的地区则处于东南季风和西南季风的通道上,呈越往北降雨量越少的变化趋势。②在降雨量水平分异影响下,海拔每升高100m,各地区降雨量的增加量有很大差异,充分表现了地貌因素在决定降雨量再分配及垂直分异中的重要作用。③湿润度呈现出与降雨量相似的分异规律,且能较好的反映出各地区降雨量的有效性。④在典型的季风气候条件下,旱季降雨的空间分异表明,冬春干旱威胁是热区造林事业和林业生态恢复和建设中最突出的矛盾。

Three main meteorological indicators of annual rainfall, moisture degree and dry season rainfall are quantitatively evaluated and their spatial differentiations are studied using the analytical methods of standard error and linear regression based on the meteorological data for 30 years from 101 meteorological stations in the tropical and subtropical regions of Yunnan Province. Significant spatial and time differentiations in water conditions were found in forest ecosystems. The regularity manifests that aside from Jinsha river, rainfall-rich areas are mostly located at the downstream of the five large rivers, or in the windward side of southeast and southwest monsoons, while relatively rainfall-rich areas are located along the passageway of southeast and southwest monsoons, and northward rainfall is getting less. The rainfall increments of an increase of 100 meters in altitude are different due to the horizontal rainfall differentiation, which suggests that landform plays an important role in rainfall and its vertical distribution. Moisture is similar to rainfall in differentiation, and it is able to indicate the effectiveness of rainfall. The spatial differentiation of rainfall in dry season suggests that drought is the most important factor affecting the afforestation in typical monsoon areas, especially in the tropical and subtropical regions of Yunnan.