Monthly Changes in the Influence of the Arctic Oscillation on Surface Air Temperature over China

Partial Least Squares Regression （PLSR） is used to study monthly changes in the influence of the Arctic Oscillation （AO） on spring, summer and autumn air temperature over China with the January 500 hPa geopotential height data from 1951 to 2004 and monthly temperature data from January to November at 160 stations in China. Several AO indices have been defined with the 500-hPa geopotential data and the index defined as the first principal component of the normalized geopotential data is best to be used to study the influence of the AO on SAT （surface air temperature） in China. There are three modes through which the AO in winter influences SAT in China. The influence of the AO on SAT in China changes monthly and is stronger in spring and summer than in autumn. The main influenced regions are Northeast China and the Changjiang River drainage area.

Long-term and monthly changes in abundance,size composition and spatial distribution of the mantis shrimp Oratosquilla oratoriainthe BohaiSea

With the decline in fish resources worldwide,the ecological dominance and economic importance of crustaceans have obviously increased.Among crustacean species,mantis shrimps are increasingly dominant in many coastal waters of the world.In China,Oratosquilla oratoria is the most widely distributed and productive species of mantis shrimp,and its relative resource density is the highest in the Bohai Sea.In this study,we analysed the long-term and monthly population characteristics of O.oratoria in the Bohai Sea,including its relative resource density,body size and spatial distribution.The results showed that the relative resource density of O.oratoria in the Bohai Sea increased from 3.59 kg/h in 1982 to 14.48 kg/h in 2018,and the percentage of this species that serves as a fishery resource increased from 4.22%in 1982 to 35.27%in 2018,based on the mean relative resource density in May and August.The relative resource density of O.oratoria in the fishing moratorium season from May to August was significantly higher than that in the other months of fishing season,and the relative resource density decreased rapidly after the fishing moratorium ended.The relative resource density of O.oratoria was the highest in summer(August),followed by in autumn(October)and spring(May),and it was the lowest in winter(January).The relative resource density of O.oratoria in the western Bohai Sea was higher than that in the eastern Bohai Sea.The mean body weight of O.oratoria in the Bohai Sea decreased from 21.95 g in 1982 to 14.34 g in 2018,based on the mean body weight in May and August.The body size of O.oratoria in the fishing moratorium season was significantly higher than that in the fishing season,and the body size decreased rapidly after the fishing moratorium ended.Overall,in the context of declining resources of most fishery species,the relative resource density of O.oratoria increased due to its hardiness and adaptability,and its body size decreased under intensive fishing over the past 30 years.The fishing moratorium system had a great influence on the population dynamics of O.oratoria in terms of the relative resource density and body size in the Bohai Sea.

Analysis of the Correlation between Tourism and Climate in the Ancient City of Langzhong

Based on the meteorological data of Langzhong from 1981 to 2016,a comprehensive comfort index model of tourism climate suitable for Langzhong is established by calculating the meteorological and climatic factors affecting tourism in the ancient city of Langzhong.The model is used to evaluate the climate comprehensive comfort of Langzhong,and its grades and suitable tourism periods are divided.Based on the monthly index of passenger flow volume in the ancient city of Langzhong from 2013 to 2015,a mathematical model is established through OLS regression analysis to analyze the correlation between changes in monthly passenger flow volume in a year and the comprehensive comfort of tourism climate in the ancient city of Langzhong.The results show that the climate in Langzhong is suitable for tourism in spring and autumn.It is suitable for tourism from February to June and from September to December,of which it is most suitable for tourism from April to May and from September to October.It is less suitable for tourism in only January and from July to August,and there is no unsuitable period.The changes in monthly passenger flow volume in a year are mainly affected by the meteorology and climate.The changes of climate comprehensive comfort in various month have an extremely significant impact on passenger flow volume.The elastic coefficient of impact of climate comprehensive comfort index on the monthly index of passenger flow volume is 0.9614%.