The Impact Of Climate Element Change On Meteorological Disasters In Xinyang City

Based on the observation datasets of air temperature,precipitation,sunlight duration during the last 56 years(1961-2016)from the national meteorological stations of Xinyang city,using the analysis methods such as linear trend analysis,M-K mutation test and Morlet wavelet periodic analysis,the characteristics of climate change and its influences on meteorological disaster in Xinyang city were analyzed.The main instructive conclusions are as follows:(1)The temperature in Xinyang city showed a rising trend and the seasonal difference was obvious.The fastest warming appeared in spring and winter,which makes the largest contribution to the increase of annual average temperature,while the negative contribution in summer.The main warming factors include the increase in annual average minimum temperature and annual extreme minimum temperature,and the decrease in the number of cold days.Moreover,the rising temperature in Xinyang city shows a process from slow change to mutation.The mutation point of winter average temperature occurred earliest in 1990,meanwhile the annual average temperature,annual maximum temperature and autumn average temperature all mutated in 1994.There is no obvious mutation in the average summer temperature.In general,Xinyang city experienced a mutation of warming during 1987 to 1998.(2)The annual and seasonal temperatures in Xinyang city both had periodic oscillations with 2 to 5 years,and the annual temperature during 2002 to 2007 existed severe oscillation.In addition,there are annual and decadal oscillations in the last 56 years,including low-frequency oscillations at the quasi-three weeks.The relative cold period of Xinyang city covers 1967,1987 and 2005,and the relative warm period covers 1977,1996 and 2014.(3)The annual precipitation in Xinyang city showed a wavelike decrease without a significant mutation,which was mainly caused by the decrease of precipitation in spring and autumn.The precipitation change obviously appeared regional differences,that is increase in the north and decrease in other regions.There are annual and decadal oscillations,such as the periodic oscillations with 3 to 4 years during 1986-2009 and low-frequency oscillations at the quasi-three weeks.Pluvial period(dry period)and cold period(warm period)are basically synchronous but do not coincide,and pluvial period(dry period)appears 3-4 years earlier than cold period(warm period).(4)The linear trends of seasonal precipitation appeared different.Precipitation in summer and winter was on the rise,and precipitation in spring and autumn was on the decline.There were also regional differences in seasonal precipitation changes.There were mutations of precipitation change in spring,autumn and winter,but no mutation in summer.Seasonal precipitation has violent oscillation of different timescales.Moreover,seasonal precipitation also has interannual and interdecadal periodic changes.(5)The most significant climate change in Xinyang city included a warming mutation occurred from 1987 to 1998 and the violent fluctuation of the annual temperature occurred from 2002 and 2007.The increase in carbon emission is the main cause of rising temperatures.The obvious characters of precipitation change in Xinyang city are violently fluctuated in annual and seasonal change.The abrupt increase in temperature may be related to the violent oscillation of annual and seasonal precipitation.(6)The annual and seasonal sunlight duration of Xinyang city all showed obvious decreasing trends,and the rate of decline in the northwest was significantly higher than that in the southeast.Seasonally,the sunlight duration experienced the biggest drop in summer and the smallest in spring.In addition,the annual and summer average sunlight duration did not exist mutation,and the opposite situation in autumn and winter average sunlight duration.The mutation point was slightly behind that of temperature increase.(7)The meteorological disaster in Xinyang city is characterised by diversity,high frequency and heavy loss.The flood and drought disasters are the most serious disasters in Xinyang city.Meteorological disasters with direct economic losses surpass 400 million yuan occur on average every 3 years.The flood disasters with direct economic losses exceed 600 million yuan occur on average every 6 years.The drought disasters with direct economic losses surpass 100 million yuan occur on average every 4 years.The frequency of wind disaster is high,but the loss is small.The frequency of continuous rain and snow disasters is low,but the loss and impact are large.(8)Climate change has a great influence on meteorological disasters in Xinyang city.The high frequency period of meteorological disasters is slightly lagged behind the mutation of temperature increase,accompanied with the severe oscillation of the annual precipitation.The climate change in Xinyang city has the greatest impact on flood and drought disasters,which greatly increase the occurrence frequency of disasters.We have two innovation points in this paper.Firstly,we have studied the climate characteristic of various meteorological elements and their connection in Xinyang city by using various analysis methods.Second,we also analyzed the impact of climate change on meteorological disasters.The research results will surely play a guiding role for Xinyang city to effectively cope with climate change and disaster prevention and reduction.