| Under the background of global warming,climate change has attracted wide attention from all walks of life.Different regions have different responses to global climate change.Regional climate change research is of great significance for a comprehensive understanding of climate change laws and future climate change trends.Based on the monthly measured data of average temperature,extreme maximum temperature,extreme minimum temperature,precipitation and precipitation days of Lhasa and Jinghong two meteorological stations from 1956 to 2017,the meteorological elements of Lhasa and Jinghong are discussed in depth by using linear tendency estimation,Mann-Kendall mutation test,wavelet analysis and R/S analysis methods in order to clarify the climate change characteristics of Lhasa and Jinghong areas in the past 62 years.,and the response to global climate change.Research shows that in recent years,the climate in Lhasa has a trend of warming and humidifying,while Jinghong climate has a trend of warming and drying.The main conclusions are as follows:(1)In the past 62 years,the annual average temperature in Lhasa and Jinghong has shown an upward trend,and will continue to rise in the future.The climatic tendency rate of annual average temperature in Lhasa is 0.443 ?/10 a,and the Jinghong is 0.29 ?/10 a.Lhasa annual average temperature increase rate is greater than Jinghong,Lhasa is more sensitive to global warming response.There is no obvious mutation in the average temperature of the two places.The annual average temperature time series of Lhasa has a main oscillation period of 20 a and 31 a,and the average temperature time series of Jinghong has the main oscillation period of 9a,16 a,22a and 32 a.(2)The average temperature in wet and dry seasons of Lhasa showed a warming trend from 1956 to 2017.There was no obvious mutation time in the dry and wet seasons.The time series of average temperature in wet season had 17 a and 28 a oscillating main periods,and the time series of average temperature in dry season had 11 a,17a and 28 a oscillating main periods.The mean temperature of Jinghong in wet season and dry season also showed a warming trend.There was no obvious mutation time in the study period.The mean temperature time series of wet season had 6a,11 a,31a oscillation main period,and the mean temperature time series of dry season had 9a,16 a,33a oscillation main period.(3)In recent years,the annual extreme maximum temperature in Lhasa has a significant warming trend.The linear trend of the time series of Jinghong annual extreme maximum temperature is not obvious,and the interannual variation is relatively large.The annual extreme maximum temperature in Lhasa changed abruptly from cold to warm in 1983,but the annual extreme maximum temperature of Jinghong did not change significantly.The time series of annual extreme maximum temperature in Lhasa has a main oscillation period of 14 a and 30 a,and the time series of annual extreme maximum temperature in Jinghong has a main oscillation period of 3a,12 a and 27 a.(4)The extreme minimum temperature time series of Lhasa and Jinghong years have a tendency to increase temperature in the near 62 a,and the annual minimum temperature increase rate of Lhasa is greater than Jinghong.The Lhasa annual extreme minimum temperature time series did not significant mutations,and the Jinghong annual extreme minimum temperature time series occurred in 1979 by a cold-warming mutation.The time series of annual extreme minimum temperature in Lhasa has a main period of variation of 7a and 31 a,while the time series of annual extreme minimum temperature in Jinghong has a main period of oscillation of 7a and 29 a.(5)The annual precipitation in Lhasa has not increased significantly in the past 62 years,while the annual precipitation in Jinghong has not decreased significantly in the study period.The annual precipitation in Lhasa will still increase slightly in the future,while the annual precipitation in Jinghong will decrease slightly.The annual precipitation in Lhasa has 3a,5a,13 a and 45 a oscillation periods,while Jinghong has 2a,6a,17 a and 36 a oscillation periods.During the study period,the precipitation in wet and dry seasons of Lhasa showed an increasing trend,and the increasing rate of precipitation in wet season was higher than that in dry season.The wet season precipitation time series has the main periods of 3a,5a,13 a and 45 a,while the dry season precipitation time series has the main periods of 5a,8a,14 a and 28 a oscillation.The precipitation in wet season of Jinghong showed a slight downward trend,while the precipitation in dry season showed a slight upward trend.The time series of precipitation in wet season had the main oscillating periods of 4a,6a,12 a and 39 a,and the time series of precipitation in dry season had the main oscillating periods of 2a,5a,10 a,16a and 31 a.(6)In the past 62 years,the annual precipitation days in Lhasa showed no significant increase trend,while the annual precipitation days in Jinghong showed a significant decrease trend.The precipitation days in Lhasa will continue to increase in the future,and Jinghong precipitation days will continue to decrease in the future.There is no obvious mutation time in the annual precipitation days of the two places.The main oscillation periods of Lhasa annual precipitation days time series are 3a,13 a and 28 a.The main oscillation periods of Jinghong annual precipitation days time series are 20 a and 32 a.Precipitation days in Lhasa showed a decreasing trend in wet season and an increasing trend in dry season.There was no obvious sudden change in wet season.The sudden change of precipitation days from less to more occurred in dry season around 1990.The time series of precipitation days in wet season has the main periods of 3a,12 a and 28 a,while the time series of precipitation days in dry season has the oscillating main periods of 5a,12 a and 25 a.The time series of precipitation days in Jinghong wet season and dry season showed a significant downward trend,and the downward rate in dry season was higher than that in wet season.The time series of precipitation days in Jinghong wet season had abrupt change from 1986 to 1994,and there was no obvious mutation time in the dry season.The time series of precipitation days in Jinghong wet season has 3a,5a,20 a,32a main periods,and the oscillation signal in dry season is weak. |
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