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利用中国通量网(ChinaFLUX)4个森林台站(长白山、千烟洲、鼎湖山和西双版纳)2003—2008年总辐射和光合有效辐射(PAR)观测资料,研究了CNR1总辐射表和Li-190SB光量子仪在长期观测中可能出现的不确定性和仪器性能变化等问题.结果表明:98%以上的CNR1总辐射观测精度满足技术标准,但在西双版纳站,CNR1观测的总辐射(QCNR1)比高精度短波辐射仪CM11观测的总辐射(QCM11)平均低7%;虽然温度对CNR1观测的总辐射有一定影响,但其影响大都在仪器允许的精度范围内,在西双版纳站,CNR1除了受温度影响外,还受到热带雨林特有的季节性雾的影响;通过分析光合有效辐射数据(特别是其与总辐射比值)的长期变化发现,光量子仪Li-190SB的性能衰减较明显,平均年衰减率达4%左右.为了校正PAR仪器性能衰减产生的系统误差,本文尝试给出了PAR的后期补偿校正方法,该方法可基本消除由于野外长期使用所造成的Li-190SB性能衰减.
Using total solar radiation and photosynthetically active radiation (PAR) observations from 4 forest stations (Changbai Mountain, Qianyanzhou, Dinghushan and Xishuangbanna) of ChinaFLUX from 2003 to 2008, the effects of CNR1 pyranometer and Li- 190SB optical quantum instrument in the long-term observation of uncertainties and changes in instrument performance and other issues.The results show that: 98% of CNR1 total radiation observation accuracy to meet the technical standards, but in Xishuangbanna station, CNR1 observed total radiation (QCNR1) ratio The total radiation (QCM11) measured by CM11 is 7% lower on average. Although the temperature has some influence on the total radiation observed by CNR1, most of the effects are within the precision range of the instrument. In Xishuangbanna Station, CNR1 is affected by temperature But also affected by the seasonal seasonal fog of rainforest. By analyzing the long-term changes of photosynthetically active radiation data (especially its ratio to total radiation), it is found that the performance degradation of Li-190SB is obvious, and the average annual decay rate Up to about 4% .In order to correct the system error caused by the performance degradation of PAR instrument, this paper attempts to give a post-compensation correction method for PAR, which can basically eliminate the long- Caused by the Li-190SB performance degradation.