海南岛橡胶林辐射通量特征

热带橡胶人工林作为我国热带地区最重要的生态系统，在森林辐射研究中扮演着重要角色。随着橡胶林在我国热带地区大面积地种植，对其生态效应的质疑也在增加，有必要对其辐射通量进行研究。基于海南岛橡胶林2010年1 a的辐射观测数据，分析了其时序变化和分配等规律。结果表明：研究区橡胶林的太阳总辐射（DR）、反射辐射（UR）和净辐射（NR）通量日变化呈典型的单峰曲线，大气逆辐射（DLR）、森林长波辐射（ULR）、长波有效辐射（Ln）呈波浪形；各辐射总量除Ln 外，均为雨季大于旱季；海南岛橡胶林DR年总量为5 356.99 MJ/m2，NR、UR和Ln占其比例分别为67%、15%和18%；NR通量分配率日变化呈倒“U”型曲线，Ln和UR通量分配率则呈“U”型曲线。另外，文章还研究了各辐射通量间的关系。2010年全年反射率均值为14.18%，全年DLR与ULR之比为92.89%，净辐射NR与太阳总辐射DR关系最为密切。

Characteristics of Radiation Fluxes of Rubber Plantation Forest in Hainan Island

Tropical rubber plantation forest is the most important ecosystem in tropical China, and it plays an important and representative role in the study of solar radiation in tropical forest. It is necessary to study the radiation flux of rubber plantation forest because of the increasing questions about the ecological effects of the large-scale cultivation of rubber trees in tropical China. Solar radiation is the primary energy source for ecosystems, and the net radiation (NR) energy drives the ecosystem's life activities and energy flows. This study analyzed temporal variations and distributions of solar radiation and its components based on radiation fluxes observations on an iron tower of 50 m high in Hainan Island in 2010. The results showed that the diurnal variations in global solar radiation (DR), reflected radiation (UR) and NR all were represented by typical single-peak curves. Atmospheric inverse-radiation (DLR), forest long-wave radiation (ULR) and effective long-wave radiation (Ln) were represented by an undulating curve. Gross radiations, except Ln，in rainy season, were greater than those in dry season. Diurnal variation in the NR/DR ratio showed an inverted U-shaped curve while the Ln/DR and UR/DR ratios showed U-shaped curves. In addition, the relationship between the radiation fluxes was studied, too. And the annual mean reflectivity was 14.18%, the ratio of DLR/ULR 92.4% in 2010. Net radiation (NR) and global solar radiation (DR) was most closely related.