Study On Environmental Temperature Effect Of Greenbelts Of Shijiazhuang，Hebei Province In Spring

As an important part of urban ecosystem, urban greenbelt is closely related to the daily life of urban residents. It not only provides the city residents with leisure and entertainment place, but also plays an important role in relieving urban heat island effect and optimizing the living surroundings of urban residents. However, China’s urban ecological environmental construction can’t well adapt to the requirements of the pace of urban development these years. Unreasonable phenomena in planning urban greenbelt structure appear at times, which leads to a series of problems such as insufficient ecological function of greenbelt, increasing urban heat island, and so on. The work and life of urban residents has been influenced a lot.The eco-environmental effect of urban greenbelt was operated on too many studies in the past. But the focus is mainly on summer and autumn, spring is in lack. Spring is the recovering and flourishing season. It is obvious that the studies on eco-environmental effect of greenbelt at the sprouting and growing stages has important theoretical and practical significance.Thus, the author chose seven different parks to monitor atmospheric temperature in greenbelt from the late February to the early May in 2015. Three phases are divided into:before sprouting, sprouting time and flourishing period. Comparatively study the different changing rules between lateral and vertical greenbelt temperature at different time in spring.The analysis on the relationship between temperature effect and greenbelt structure, greenbelt area, water area, surroundings, etc. shows that:First, Before sprouting time during the end of February to early March in spring,(1) In two different parks—with water and without water, the temperature changes most in arbor-grasses, medium in shrub, arbor-shrub-grasses, least in arbor.(2) Average day temperature and temperature changes in parks with water is lower than the ones without water.The parks without water have evidently bigger changes in vertical temperature and the temperature layers are also more obvious. In horizontal level, the temperature is higher while the distance is closer to the lake.(3) Greenbelt in these two sorts of parks has higher temperature than the surrounding temperature outside of parks, which shows that some“warming effect” occurs in greenbelt.Second, From the end of February to early March, “warming effect” in parks with water is weaker than the parks without water, which performs the temperature increasing and decreasing in parks with water is lower than parks without water. Also, no matter increasing range or decreasing range are comparatively small.Third, During the sprouting time from the end of March to early April, the greenbelt temperature of both sort of park is still higher than the outer surrounding temperature, which shows that the “warming effect” of environmental temperature in greenbelts is still regarded as “increasing” and “warming effect” is stronger than before sprouting. In comparison,“warming effect” with artificial lake is weaker than the parks without water.Fourth, During flourishing period from the end of April to early May, greenbelt temperature in both sorts of parks is a litter bit lower than the temperature outside, showing some “warming effect” existing in this phase. But decreasing effect in parks with water is stronger than the ones without water.Fifth, No matter “warming effect” increases or decreases in spring, arbor-shrub-grasses with good cubic structure behaves best who has obvious “warming effect” in the whole spring. But “cooling effect” behaves obviously in arbor at the warmer time in the late spring.Sixth, Whether there is artificial lake in parks or not, “warming effect” changes more as more greenbelt areas cover. But in the previous two monitoring phases, greenbelt seems“increasing temperature”. And when the greenbelt area is up to some extent(~0.2 km2),temperature effect is no longer increasing with larger greenbelt area. In the latter phase,“decreasing temperature” occurs in greenbelt whose effect strength has something to do with the scale of greenbelt area.Last, Before sprouting and during sprouting time, “warming effect” in greenbelt constitutes negative relationship with water area. But in flourishing period, “warming effect”in greenbelt has positive relationship with water area. It indicates that the physical properties of comparative more artificial lake water can relieve the changes of surrounding temperature in different spring phases.