Study On Urban Climate Change And Heat Island Effect In ZhaoYang District

With the acceleration of urbanization,in the context of global warming,high intensity human activities have caused abnormal changes in local climate.Therefore,the research on the urban climate and heat island effect in ZhaoYang district can provide scientific basis for the development of agriculture and social economy in ZhaoYang district.Based on ZhaoTong station average temperature,highest temperature,lowest temperature,precipitation,relative humidity(1951-2013),sunshine hours,the lowest average surface temperature,ground temperature(1954-2013),the highest surface temperature(1959-2013),and other climate elements month by month and day by day data,and LuDian station,mark,YiLiang stand,QiaoJia,HuiZe station,YongShan stand temperatures(1959-2012)monthly data,using linear regression analysis,Mann-Kendall mutation test,Morlet wavelet analysis,gray prediction model,The research on the urban climate change,extreme temperature and precipitation(1951-2013)and heat island effect(1959-2012)in zhaoyang district provides theoretical basis for the suburban agricultural production,urban waterlogging,drought,frost,consumption and allocation of energy resources,and construction of ecological livable city in zhaoyang district.The results show that:(1)Climate factor change: the average temperature and minimum temperature in zhaoyang district show a warming trend in both year and season;The maximum temperature in spring(-0.047?/10a)showed a cooling trend,while the temperature in other periods showed a warming trend.From the analysis of mutation,the mean temperature,maximum temperature,minimum temperature,annual and seasonal mutation all occurred after 1990 s,and there was a main change cycle of more than 20 years.In the future 10 a,the average temperature,maximum temperature and minimum temperature will continue to increase.Except for the winter(0.643mm/10a)and the dry season(1.439mm/10a),the precipitation showed a decreasing trend in other periods.Except for no abrupt change in precipitation in dry season,all the abrupt changes in other periods occurred after 1980 s.The main cycles of annual,spring,summer,autumn and rainy season were shorter than 15 a,while the main cycles of winter and dry season were longer than 27 a and 25 a,respectively.In the future,precipitation of 10 a will show a decreasing trend.The number of hours of sunshine increased in autumn(2.178h/10a)and winter(2.863 h /10a),but decreased in other periods.There was no obvious mutation point in the dry season,while the mutation occurred in other periods after 1980 s.The main period of annual and seasonal change is less than 18a;In the future,the sunshine of 10 a will decrease.The relative humidity showed a decreasing trend.All the abrupt changes occurred in the early 21 st century.The main period of annual relative humidity change was about 30 a,and all other periods were within 14 a.The relative humidity of 10 a will decrease in the future.The annual and seasonal variations of geothermal temperature showed an increasing trend.The temperature increase rate was the highest,followed by the average,and the lowest.All the mutations occurred after the late 1990 s.The time scale of the main cycle varies,and the average,minimum and maximum ground temperature of 10 a will be increasing in the future.(2)Extreme temperature change: out of the 16 extreme temperature indexes,11index(monthly maximum temperature Maximum,month lowest minimum,maximum,monthly minimum temperatures thermidor days,summer days and warm nights warm days,days and days,hot day last index and crop growth period,the highest temperature minimum)is on the rise,five index(frost days,frozen days,on average diurnal range and cold cold night stay,continuous index)is on the decline;Except for the number of hot months,the number of cold days,the hot diurnal duration index and the cold diurnal duration index had no obvious mutation points during this period,the other index mutations occurred from 1980 s to the early 21 st century.There are 2~3 cycles of extreme temperature index,with the time between3~52a.Except for the minimum monthly temperature,the number of warm night days and the monthly average daily range,there are no obvious main cycles.The time scale of the main cycle of the index change is 10~20a.(3)Changes in extreme precipitation: 8 of the 11 extreme precipitation indexes showed a downward trend,mainly including days of moderate rain,days of heavy rain,days of precipitation greater than or equal to 25 mm,heavy precipitation,duration of tidal period,total annual precipitation,maximum precipitation of 5 days and precipitation intensity;The three indexes showed an upward trend,which were extremely strong precipitation,continuous dry period and the maximum precipitation of 1 day respectively.Besides strong rainfall no obvious mutation point were the rest of the index point mutation,and year of mutations are mainly concentrated in the1980 s,the moderate rain days,heavy rain days,greater than or equal to 25 mm precipitation days,strong rainfall,sustained boom period,total annual precipitation,such as 1,maximum precipitation index change significantly,beyond the 95%confidence interval;The extreme precipitation index has 2 to 3 change cycles,with the time between 6 and 16 a,and the time scale of the main period is all less than 16 a.(4)Changes of heat island effect: from 1959 to 2012,the annual and seasonal heat island effect in ZhaoYang district showed an upward trend,among which the annual heat island effect was 0.38 ?,the highest was 0.68 ? in summer,and the lowest was 0.11 ? in winter.S change from view,ZhaoYang district 60 s and 70 s of the 20 th century the heat island effect is not obvious,the area even some seasons or period of time,a suburb of city air temperature is lower than the temperature,heat island effect after 70 s gradually strengthen,heat island effect after the 90 s has been a steady increase,by far the largest season ZhaoYang district heat island effect in summer(0.68 ?),but for the winter to heat up the fastest season 0.142 ? / 10a;Month by month,the most obvious heat island effect in ZhaoYang district was0.9 ? in September,followed by 0.8 ? in July,and the least obvious in January and April,when the temperature in urban areas was lower than that in suburban counties.However,the heat island effect increased significantly after the 1980 s.The annual and seasonal heat island effects were both mutated,and the mutated years basically occurred after the 1980 s,and all of them exceeded the 95% confidence interval,with significant increases.In the next 10 a,the annual and seasonal heat island effect will be on the rise,among which the winter heat island effect will rise the most and is expected to surpass the summer in the future,thus making the heat island effect in ZhaoYang district,like most cities,present the strongest phenomenon of winter heat island effect.