本文首次计算并分析了我国亚热带东部山区坡面辐射平衡各分量，重点讨论了净辐射的地理分布特征及其变化规律。结果表明，本区各坡向年均净辐射的分布都具有南北高、中间低的特点，湘鄂西部为最低值区。夏季因受副高控制的影响，净辐射分布形势差别较大。净辐射在各坡向间的差异以冬季最大，夏季最小。夏季南、北坡净辐射随坡度的变化形式基本相同，冬季则完全相反。净辐射的年变幅以南坡最小，东、西坡次之，北坡最大。本文计算结果还揭示出冬季在本地区北坡的坡面净辐射可出现负值的新事实。

Each of the components of the radiation budget on sloping fields in the eastern subtropi-cal mountainous regions is calculated and analysed for the first time, dealing emphaticallywith the geographical distributions and variation rules of net radiation (NR). It is foundthat the value of annual average net radiation is greater in both south and north than in themiddle of the area, and the smallest value appears in the west of both Hunan and Hubei pro-vinces. The distribution of NR in summer is quite different from that mentioned above be-cause of the effect of the subtropical high. The variation of the NR with orientation is thegreatest in winter and smallest in summer. The variation pattern of NR with slope is appro-ximately the same on both north and south sides in summer, but it is extremely different inwinter. Annual range of NR is the greatest on north side and smallest on south side. Asfor cast and west sides, the annual range is between north and south. In addition, it is revea-led from the results of the calculation in this paper that the NR on north side may fall intominus value, and this is a new significant fact.