Effect Of Solar Radiation On Fine Fuel Mositure

The fuel moisture content is an important factor to determine whether the forest fire will happen, so predicting the fuel moisture content accurately has great significance for foresting fire forecast and fire fighting. Existing method to predict the fuel moisture content don’t describe the solar radiation effect of fuel moisture content definitelyt, the solar radiation effect of fuel moisture content is reinforced through aspect and slope position.In this paper, we take the broad-leaved Pinus koraiensis forest as the study area, the plots were similar in stand type,stand density and elevation.By analying the observed moisture content and weather data of plots(north high, north low, valley bottom, south high, south low). There sults indieate as below:Firstly, in the conventional meteorological data, the difference in temperature and relative humidity between north and south-facing slopes varied diurnally. Two mechanisms drove these differences:overnight, larger elevation driven differences (higher sites were warmer and drier on average) prevailed; during the day, aspect played a greater role in influencing local conditions, with south-facing sites warmer and drier on average. The difference in wind speed between the north and south-facing plots was never more than1km/h.Seeondly. analysis also revealed a substantial decrease in incident solar radiation as it passed through the forest canopies, with the north-facing plots receiving on average only5%of that measured in the open; the south-facing plots received a larger ratio at10%. The south-facing plots received on average5%more solar radiation than the north-facing site at the peak of the day resulting in0.2kw/m2more reaching the forest floor.At the last of this paper, we find that a corresponding difference in observed moisture content was not identified between north and south-facing plots. There may be two reasons: the low transmittance recorded at plots(<10%of open solar radiation measurements); limits on the number of samples. Although this study was not successful in identifying significant differences in observed moisture dynamics in solar radiation, but the effects of solar radiation on the moisture content has been proven. This paper can provide some reference and lesson for the later research.