Analysis Of Extreme Climate Change Characteristics And Hydrological Response In Shandong Province

The fifth report of the Intergovernmental Panel on Climate Change(IPCC)points out that the world is continuing to warm,and extreme climate events are showing more abnormal and sudden trends in this context.This paper chooses Shandong Province and the Dawen River Basin in its territory as the research areas,and determines 16 extreme climate indices based on long series of measured dates from 95 Meteorological Stations and Beiwang Hydrological Station,which focuses on the analysis results about the temporal and spatial characteristics of the extreme climate indices and the impact of extreme climate on the total of extreme flood and dry water in the basin in Shandong Province and its inland coastal areas.The followings are the main research results:(1)The maximum and minimum monthly average temperature and inter-annual precipitation in Shandong Province all shows upward trends,which have a warming trend.The minimum monthly average temperature passes the significance test of 0.05,and its rate(0.59?/10a)is 3.3 times the maximum monthly average temperature,and the rising rate of inter-annual precipitation is 21.22mm/10a.In terms of the rate of change,the inland areas and coastal areas are consistent with the performance of Shandong Province,which show upward trends.The increase rate of the maximum monthly average temperature is the largest in the inland area,while the increase rate of precipitation is the largest in the coastal area(34.91 mm/10a),which is much higher than that in the inland area(24.32 mm/10a).(2)In the extreme low temperature indices,TN10p and FD0 show downward trends,-0.48%d/10a and-6.42d/10a respectively,while TNn shows an upward trend(0.72?/10a),and only TN10p(Z=-0.04)does not pass the significance test of 0.05.In the extreme high temperature indices,TX90p,SU25 and TXx all show upward trends,which are 4.06d/10a,2.31d/10a and 0.32?/10a respectively,and only TX90p(Z=4.10)passes the significance test.In terms of the rate of change,only TN10p of the extreme low temperature indices is larger in the inland area than coastal area;the extreme high temperature indices in the inland area are smaller than that in the coastal area,and Shandong is between them.(3)The extreme precipitation indices show upward trends.The rising rates of CWD,R25and R20 are smaller,0.12d/10a,0.37mm/10a and 0.42mm/10a respectively.The rising rates of RX5day,R99p and R95p are larger,10.55mm/10a,10.83mm/10a and 22.16mm/10a respectively,which pass the significance test of 0.05.The PRCPTOT has the largest ascent rate(26.48mm/10a),which fails the significance test of 0.05.In terms of rate of change,except for CWD,the other seven extreme precipitation indices are smaller in inland areas than in coastal areas,and Shandong is between them.(4)The correlations between extreme climate indices and longitude,latitude and altitude are weak in Shandong Province,inland area and coastal area,and the correlation coefficients are between-0.7—0.8.Only CDD and latitude are significantly correlated in all three areas.There are fewer indices pairs with strong correlations between extreme temperature indices and more extreme precipitation indices.In terms of spatial distribution,the extreme climate indices has obvious spatial heterogeneity.TNn generally shows a gradual upward trend from southwest to northeast.The distribution trends of TX90p and TNn are roughly opposite;SU25 has no obvious spatial distribution law,and the high value center is mainly in Weihai region and part of Qingdao;CDD and R20 have obvious trends of decreasing from southeast to northwest in space;R99p and RX5day have similar spatial distribution rules,and the high value centers are in Weihai and Qingdao.(5)The interannual variation rate of total extreme floods in the Dawen River Basin is-7.29×10~5 m~3/10a,showing an insignificant downward trend,and the value is the largest in 2004(1.06×10~9 m~3).The interannual variation rate of the total extreme dry water is 1.99×10~6 m~3/10a,showing an insignificant upward trend.The lag effect of extreme hydrological events on precipitation is poor.Through correlation analysis and principal component analysis,extreme flood events are mainly affected by precipitation intensity indices(R95p,R99p,RX5day and PRCPTOT),and precipitation frequency indices(R20 and R25)have some effects,while extreme dry water events are affected by extreme temperature indices to some extent.