Studies On Microclimate And Protective Effects Of River Shelterbelt Along Huaihe River

Study the microclimatic factors of the river shelterbelt in Huaihe, especially the wind effects ofshelterbelts; it is very important to estimate the waves-up due to the wind and to protect the plain onboth sides of the strait industrial and agricultural production and people’s lives and property in theperiod of high water in Huaihe River.Three kinds of river shelterbelts were selected for field study in Tian jia an in Huai Nan, whichcalled tightly willow, sparse form willow and the poplar. Using the method of combining conventionalobservations and gradient observations to analysis the microclimatic factors internal and external offorests.To study the diurnal variation of the forest microclimatic internal and external. Compare theeffect of different shelterbelts to the environment. To choice of existing shelterbelts reasonability andprovide the basis for evaluation and transformation of the shelterbelt.This article utilized Putianformula, the TOMAS curve formula, wind obstruct the water formula, embankment works normsmethod and ultra-high method to estimate and analysis the high-water period of storm waves-up andthe ultra-high of the dam five regions in Tian jia an in Huai Nan. The main research results are asfollows:(1) There is a certain difference among the three kinds of shelterbelts inside and outside on airtemperature, the average air temperature in the shelterbelts are higher than the average temperatureof the shore. Relative humidity of the air, soil surface temperature, soil moisture content and lightintensity in the shelterbelts are lower than the mean of the shore. The air temperature, soil surfacetemperature, soil moisture content and light intensity in six different times of day has emerged as a lowlevel of the parabolic trend, relative humidity showed a high level of the parabolic trend. Airtemperature and relative humidity of the air within the shelterbelts showed smaller as the heightincreases mean trend in the vertical level (0.5m,1m and2m) and the light intensity showed itsopposite trend. Soil temperature in0cm,5cm,10cm,15cm and20cm vertical levels had decreasedwith the depth in the shelterbelts; the rate of change is getting smaller and smaller with the depthincreased. Soil moisture content in0~10cm10~20cm levels is very close in the shelterbelts, is22.7%and22.9%respectively.(2) There is a certain difference among the three kinds of shelterbelts on the wind effects,windbreak ratio increased with the height increases. The best wind effect belongs to weeping willowshelterbelts, sparse weeping willow shelterbelts in the middle and the wind effect of poplar is theworst. There is a certain difference among the three kinds of shelterbelts on the wind effects at thesame height. The windbreak effect of the tightly willow shelterbelt is the best, too.(3) There is a certain difference among the average wave height，average period and effective period in the revisions of wind speed1(21.4m/s)and revisions of wind speed2（23.3m/s). The averagewave height can reach up to0.58m, average period and effective period can reach up to3.4s and3.9sseparately. Wind obstruct water in each region are less than1cm in the two different revisions of windspeed. The R2%can reach up to2.99m in regions; the average wavelength can reach7.83m. It happenthe overtopping dam in five regions except the3region under the revise wind speed2in the dam ultraanalysis.(4) There is a certain reduce among the average wave height，average period and effective periodunder windbreak effect of the tightly willow shelterbelt in regions; The reducing of R2%is0.7mapproximately, the deforestation rate of R2%between27.7%-29.3%; the average wavelength canreduce53.5%-56.9%under the revise wind speed1. The reducing of R2%is0.62m-0.96m approximately,the deforestation rate of R2%between21.7%-32.1%; the average wavelength can reduce54.2%-55.9%under the revise wind speed2. Each region of ultra-high dam accounted for a maximum height ofpercentage has to reduce under the revise wind speed1. The dam ultra-high accounted for the largestdam height percentage was decreased by19.5%,19.0%,17.3%,19.2%and18.6%under the revisewind speed1in the five regions. The dam ultra-high accounted for the largest dam height percentagewas decreased by22.9%,17.2%,23.9%,23.3%and17.5%under the revise wind speed2in the fiveregions. It doesn’t have the overtopping phenomenon in each region.