Analysis on Climatic Characteristics of High Temperature Weather in Longdong Region

Using meteorological data from 8 national basic meteorological observation stations in Qingyang City of Longdong region from 1972 to 2021,the causes and change characteristics of high-temperature weather were analyzed,and targeted countermeasures and suggestions were proposed for residents' production,life,and energy security supply affected by high-temperature weather.The results showed that①affected by global warming,the annual average temperature,annual average maximum temperature,annual extreme maximum temperature,days of daily maximum temperature≥30℃,and days of daily maximum temperature≥35℃in Longdong region were all showing an upward trend;②due to the different terrain and soil properties of the underlying surface,the increase in high temperature weather varied in different regions.Due to the influence of desert and hilly terrain,the frequency and days of high temperature occurrence were relatively high in the central and northern parts of Qingyang City.Due to the climate regulation of the Ziwuling Mountains,the days of high temperature in the central and southern parts was significantly less than that in the central and northern parts;③if the warm high pressure ridge on the Qinghai-Tibet Plateau developed strongly in summer,the temperature of the closed warm center reached 0-4℃on the 500 hPa of high-altitude weather map.If the warm air mass developed eastward,it often led to sustained high temperature weather in Longdong region;④when the El Nino phenomenon occurred,the subtropical high in the western Pacific developed strongly in summer,with a center located northward,which was stable,with little movement.It was dry,sunny,hot,and rainless in Longdong region,and the high temperature weather was more significant than that in normal years.

Comparative Analysis of Extreme High Temperature Weather in the Summers of 2013 and 2003

The characteristics of regional high temperature(HT) weather in 2013 and 2003 and their causes were studied using daily maximum temperature data, National Center for Environmental Prediction(NCEP) reanalysis data, and outgoing longwave radiation(OLR) data. For these two years of HT weather, there were many similar characteristics, such as their long duration, wide range, high intensity, and severe influence. However, there were also three obvious differences: firstly, in 2013, the major area where HT weather occurred was farther north than in 2003; secondly, the HT weather in South China and the southeast area of Jiangnan in 2013 lasted fewer days than in 2003, but in other areas it lasted for more days than in 2003; thirdly, the intensity of the HT weather in 2013 was also stronger in the north and weaker in the south, similar to that of the duration. A strong and stable western Pacific subtropical high(WPSH), a continental warm high, and the distribution of the warm center in the lower troposphere played important roles in the HT weather formation. Several probable causes for the differences are that the cold air was weaker, the WPSH was farther north, and the tropical convective systems were stronger in 2013 than in 2003. Finally, a preliminary cause analysis of the WPSH anomaly was presented.