暖温带落叶阔叶林辐射能量环境初步研究

A PRELIMINARY STUDY ON THE ENVIRONMENT OF RADIATION ENERGY OF DECIDUOUS BROAD-LEAVED FOREST IN THE WARM TEMPERATE ZONE

本文对暖温带落叶阔叶林辐射能量环境进行了初步探讨，文中对林、灌、草各层次的总、反、净、光台有效及吸收、透射等辐时因子的变化分别进行了系统分析。主要结论如下：（１）在生长季（５─１０日）期间，抵达林冠的太阳总辐射为３０９５．４５ＭＪ·ｍ￣（－２），抵达灌草层的为３８８．３４ＭＪ·ｍ￣（－２）。峰值出现在５月，谷值在８月。（２）生氏季内，抵达群落的太阳总辐射主要集中于５、６两月，占整个生长季的４０．９９％。（３）生长季内，林冠上方净辐射总值为１６５８．７４ＭＪ·ｍ￣（－２）。（４）林冠反射主要受入射光的光谱特性及群落发育状况共同影响，反射率的变化主要与群落发育状况相关；灌草层的反射及后射率主要受群落发育状况的影响。（５）整个生长季，林冠所接收的光台有效辐时为１３０８．３ＭＪ·ｍ￣（－２），灌草层为１９４．２１ＭＪ·ｍ￣（－２）。（６）净辐射日进程受气候因素影响十分强烈。（７）群落内光能资源的时空分布存在很大差异。

his paper is the first one to study the environment of radiation energy of deciduousbroad-leaved forest in the warm temperate zone, North China. In this paper,we systematical-ly analysed the course of gross radiation,reflection radiation,net radiation,photosynthetic ac-tive radiation and absorptance radiation and transmittance radiation both above conopy andshrub-herbous layer. The major conclusions are as follows :1. During the growing season, the amounts of gross solar radiation reaching the canopyand shrub-herbous layer were 3095. 45MJ/m￣2 and 388 34MJ/m￣2, respectively. The monthlymaximum appered in May,minimum in August.2. During the growing season,the gross radiation reaching the canopy mainly appeared inMay and Jun. The amount of the two months was 40. 99%of total gross radiation. 3. During growing season, the amount of net radiation above the canopy was1658.74MJ/m￣2.4. The reflection radiation above the canopy was affected both by the characters of spec-trum of incident light and the growing situation of the community. The albedo of the canopyrelated mainly to the growing situation of the community. The reflection and albedo of theshrub-berbous layer were affected mainly by the growing situation of the community. 5. During the whole growing seaso, the photosynthetic active radiation(PAR)reachingthe canopy and the shrub-herbous layer were 1308. 3MJ/m￣2 and 194. 21MJ/m￣2,respectivily. 6.Daily course of the net radiation above the canopy was strongly affected by weatherconditions. 7. There were great differences in time and spatial distribution of solar radiation reachingeach layer.