Study on outside radiation flux of coniferous and broad-leaved mixed forest ecosystem at Dinghushan in south China
The characters of outside radiation fluxes of coniferous and broad-leaved mixed forest were studied, including the distribution of upwelling shortwave radiation (R<sub>Su</sub>), upwelling longwave radiation (R<sub>Lu</sub>), upwelling total radiation (R<sub>Tu</sub&...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Zhejiang University Press
2007-05-01
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| Series: | 浙江大学学报. 农业与生命科学版 |
| Subjects: | |
| Online Access: | https://www.academax.com/doi/10.3785/1008-9209.2007.03.0328 |
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| Summary: | The characters of outside radiation fluxes of coniferous and broad-leaved mixed forest were studied, including the distribution of upwelling shortwave radiation (R<sub>Su</sub>), upwelling longwave radiation (R<sub>Lu</sub>), upwelling total radiation (R<sub>Tu</sub>), and the relationship between these components and the environmental factors. The major results were as follows: At middle and small temporal scales (≤1 month), the coefficient of variation (CV) of outside radiations fluxes were R<sub>Lu</sub><R<sub>Tu</sub>≪Rs<sub>u</sub>. In wet and dry season, the average diurnal processes of Rs<sub>u</sub> presented normal peak type curves, the processes of R<sub>Lu</sub> presented undee curve, however the R<sub>Tu</sub> presented anomalous peak type curves. Among the total energy input to the ecosystem, R<sub>Tu</sub> was the largest fraction (82.93%), which indicated that outside radiation fluxes were very important to the energy balance of ecosystem. In the total upside energy, R<sub>Lu</sub> was the largest fraction (97.36%), proving that R<sub>Lu</sub> was more important than R<sub>Su</sub> which was disagreed with the usually considering. The average daily reflect coefficient (η) was 8.3%. The regression equation between monthly η(y) and precipitation x was: y=-0.385lnx+9.3376, R<sup>2</sup>=0.6762. The main factor which influences daily η might be precipitation. The regression analysed between R<sub>Lu</sub> and temperatures, including air temperatures of different height and canopy infrared temperature of the forest ecosystem, indicated that the second layer air temperature (9 m high) had the most closely related to the true surface temperature. The being using Stefan-Boltzmann equation must be revised. In a longer temporal-scale (≥1 month), for example, there existed very obvious correlation between monthly R<sub>n</sub> and monthly R<sub>Lu</sub>, monthly R<sub>n</sub> and monthly R<sub>Tu</sub>. However, the correlation between R<sub>n</sub> and R<sub>Su</sub>, was not significant. In a shorter temporal-scale (≤1 d), this correlation is significant, it seems that the shorter the temporal-scale is, the better the correlation between R<sub>n</sub> and R<sub>Su</sub> is, indicating that the influence of temporal-scale can't be ignored in research of radiation balance. |
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| ISSN: | 1008-9209 2097-5155 |