Study on the extremely cold winter of 1670 over the middle and lower reaches of the Yangtze River

The snow-cover days over the middle and lower reaches of the Yangtze River （MLRYR） in the winter of 1670 were extracted from Chinese historical documents. By these records, the winter temperature anomalies （compared to the mean of 1961-1990） recorded at seven meteorological stations and the regional mean winter temperature were estimated. The results show that： （1） There was an average of about 30 snow-cover days over the MLRYR region in 1670, ranging from 11-20 days in Shanghai and eastern Zhejiang to 5140 days in eastern Hunan Province. The snow-cover days averaged about 40 days in Anqing and Nan- cheng, and ranged from 30 to 40 days in Quzhou, Jingdezhen, and Nanchang; and （2） the regional mean winter temperature in 1670 was estimated to be approximately 4.0 ℃ lower than that of 1961-1990. The maximum negative anomaly of 5.6℃ occurred in Nanchang and the minimum anomaly of-2.8 ℃ was detected in Quzhou. Both of these were lower than that of the coldest winter during the instrumental observation period of 1951-2010. This research could not only provide a method to es- timate historical climate extremes, but also provide a background to understand the recent instrumentally climate extremes.

Comparison and analysis of skiing injuries at ski resorts in Chongli,China and Japan

Purpose:The rapid development of winter sports requires investigation on injuries in Chongli district,Zhangjiakou city,one of the ski sites of the 2022 Winter Olympics.Careful evaluation is required to observe which injuries are caused under what circumstances,and then we can make corresponding preventive measures and recommendations based on the results.Methods:In this retrospective study,the data of injury cases at ski resorts in China(Chongli district)and Japan were analyzed to provide a reference for the ongoing injury prevention at ski resorts.We collected data on injuries at Wanlong and Fulong ski resorts in Chongli district during the 2017–2018 and 2018-2019 ski seasons.We referred to the skiing injury report issued in February 2020 of a nationwide ski safety statistical service–Japan Ski Safety Association.The causes of injury and specific injured body parts were analyzed based on the data of Chinese and Japanese ski resorts.Statistical significance has been calculated using the Chi-square test.Results:During the 2019–2020 ski season in Japanese ski resorts,the number of reported injuries per 10,000 skiers was 0.93,of which 457(17.3%)were over 50 years old,accounting for a large proportion of injuries,meanwhile in Chongli ski resort,the injury rate of skiers aged 50 and over was 7.1%.The knee joint(23.7%at Wanlong ski resort and 28.4%in Japanese ski resorts)was the most injured body part among Chongli and Japanese skiers.Among snowboarders,shoulder joint injury(17.7%in Japanese ski resorts)was the most common,and injury on hands and fingers(16.3%in Wanlong ski resorts)was the most common.Head injury rates are similar in Chongli,China and Japanese ski resorts(8.2%and 8.7%,respectively).Conclusion:Our analysis demonstrated that injury data recorded among young skiers was higher in Chinese ski resorts(Chongli district)than that in Japanese ski resorts,and elderly skiers made up a larger proportion of skiing injuries in Japanese resorts.Thus,according to our research,the protection of knee joints,shoulder joints,and hands and fingers should be taken seriously.It should pay attention to the teaching of ski poles(for finger protection),and use protective devices such as knee pads,helmets,etc.