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Research on Radiation Balance and Environment Energy of the Upper Canopy Space in Chinese Fir Forest

Author: CuiShaSha
Tutor: KangWenXing
School: Central South University of Forestry Science and Technology
Course: Ecology
Keywords: Chinese fir plantation Radiation balance Reflectivity Kinetic energy Latent heat Environment, energy
CLC: S791.27
Type: Master's thesis
Year: 2010
Downloads: 21
Quote: 0
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Abstract


The forest on the redistribution of energy has an important impact on regional and global climate the redistribution results affect the distribution of vegetation photosynthetic productivity, energy redistribution after the balance characteristics is important not only for understanding ecological effects of forest, but also for the The photosynthetic productivity study provides environmental parameters. In conjunction with the the regional Chinese Fir Plantation gradient tower in 2008 measured data in this study based on Hunan fir plantations solar radiation in total radiation, net radiation, reflected radiation, effective radiation, longwave radiation distribution characteristics on different time scales and different seasonal solar radiation distribution rate differences; and fir artificial canopy layer near the upper space is divided into three levels, A-layer from the ground 14.1m, B layer from the ground 22.6m C layer from the ground 32.5m. Analysis of different gradient solar radiation, ambient energy, internal energy, potential energy, potential energy, kinetic energy, latent heat, sensible heat and temperature and humidity can the annual change its vertical distribution, specific findings are as follows: in the day scale the radiation components daily total size order gt of QUL (34.54 MJ · m-d); a QDL (32.59MJ · m-2 · d-1) gt; gt; Q (10.26 MJ · m- 2 · d-1) gt; Qr (0.80 MJ · m-2 · d-1). In addition to the the QDL outside, the remaining three years of radiation change roughly single peak shape changes, Q and Qr rules in different seasons of the diurnal variation showed a single peak curve, while a QDL and QUL the diurnal variation broadly wavy. Two time-scale, long-wave radiation coefficient of variation (CV) are much smaller than the short-wave radiation, wavelength same uplink radiation CV is less than the downward radiance. Day scale, the diurnal variation of the reflectivity curve is U-shaped; monthly scale, the average reflectivity of Chinese Fir Plantation in 2008 was 8.0%, less than the reflectivity of the dry season during the rainy season, and volatile. Affect the solar radiation flux characteristics on different time scales, and the reflectivity of the main factors, we must fully consider the impact of scale effect in the analysis of the relationship between the solar radiation characteristics and radiation flux. Chinese fir plantation ecosystem global solar radiation, the annual total of 3 844.97 MJ · m-2, where the rainy season to 2537.06 MJ · m-2, accounting for 66.0%, only 34.0% of the dry season, to 1 307.91 MJ · m-2 ; annual total of net radiation 2828.02 MJ · m-2, the rainy season, 69.4% is much higher than 30.6% of the dry season; effective radiated and reflected radiation 710.42MJ · m-2 and 288.09 MJ · m-2, respectively, accounted for the rainy season The total value for the full year was 51.1% and 70.0%, respectively. Distribution rate of annual solar radiation, net radiation in each component distribution rate (23.5%), followed by the smallest active radiation (19.0%), the reflected radiation (7.5%). Different seasonal solar radiation distribution rate also reflected radiation and net radiation are less than the rainy season in the dry season, the effective radiated opposite. Seen from the definition of potential energy, potential energy increases with height elevated, selected three spatial levels from the ground only 32.5m, generated by gravity potential energy is small, therefore, woodland environment-bit almost composed of internal energy. Layer B of the internal energy and the potential maximum, the level of C, A layer minimum. These three years of environmental energy changes are unimodal curve, summer maximum and winter minimum. On the wind speed and the size of the kinetic energy, the three levels of bottom-increasing the C layer annual average wind speed of up to 1.175m, s-1, which is inseparable from the canopy layer wind speed weakened, while also shows that the kinetic energy is passed down from the atmosphere over. Temperature and sensible heat of the highest of the three levels of the layer B, seen in the solar radiation is converted to sensible heat of the process, the canopy layer plays the role of a bridge, into a direct heat source. The annual variation of the latent heat of the different levels of performance for the summer gt; fall gt; Spring gt; winter, the main factors affecting the latent heat except canopy interception of precipitation trees transpiration and evapotranspiration of woodland. Temperature and humidity for the sum of sensible heat and latent heat, similar to the annual change latent heat maximum in summer, minimum in winter, which is mainly caused by two reasons, on the one hand, provide temperature and humidity can The energy source is much less in winter than in summer, on the other hand, winter trees in a period of dormancy, the transpiration slow, weak environment evapotranspiration ability to provide a relatively small amount of water vapor. This study stand the fir canopy nearly over the radiation balance, the environment, energy analysis discussion involves not only water, carbon balance study to provide the basis of theoretical methods to such problems, as well as to determine the region hydrothermal structures optimization model and provide a theoretical basis for improving regional climate. And by seeking energy ratio for Chinese fir growth, afforestation and tending to manage and measure the structure of plantations rationality provide an important basis, and also provide a theoretical basis for how to assess the ecological benefits of the plantation.

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CLC: > Agricultural Sciences > Forestry > Forest tree species > Coniferous > Chinese fir
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