Among the most devastating extreme weather events, cold surge(CS) events frequently impact northern China. It has been reported that extreme weather events will increase in the global warming context. However, the dir...Among the most devastating extreme weather events, cold surge(CS) events frequently impact northern China. It has been reported that extreme weather events will increase in the global warming context. However, the direct evidence of this hypothesis is limited. Here, we investigated the changes in frequency, number, duration, and temperature of CS events in northern China using the daily minimum temperature dataset of 331 stations from 1960 to 2016. The results indicate that the annual CS events in terms of frequency and number decreased, and the duration shortened as the starting date was later and the ending date earlier. Meanwhile, the annual CS temperature increased. In addition, spatial trends in the CS events in terms of frequency, number, and duration decreased while the CS temperature increased in most regions of northern China. We interpreted these variations as a response to global warming. However, the extreme CS events in terms of frequency, number and the earliest starting date and the latest ending date showed little change though the extreme CS temperature increased, implying climate warming had not limited extreme CS events. The adverse effect of CS events on agriculture and human health remain concerning.展开更多
The work presented in this paper is a part of the TLP project undertaken in CSSRC(Chins Ship Scientific Research Center). Model tests were performed in seakeeping basin at CSSRC. Wave envelopes are calculated from tim...The work presented in this paper is a part of the TLP project undertaken in CSSRC(Chins Ship Scientific Research Center). Model tests were performed in seakeeping basin at CSSRC. Wave envelopes are calculated from time records of the irregular waves using Hilbert transform.Time histories of surge motions of the model were recorded in long-crested irregular head seas.The low-frequency response was separated from the time history using a low pass filter.The quadratic transfer functions were obtained from ratio of the cross-spectrum(between the low-frequency surge response and the square of the wave envelope)and the auto-spectrum of the square of the wave envelope.展开更多
基金National Natural Science Foundation of China,No.41571062,No.41701592
文摘Among the most devastating extreme weather events, cold surge(CS) events frequently impact northern China. It has been reported that extreme weather events will increase in the global warming context. However, the direct evidence of this hypothesis is limited. Here, we investigated the changes in frequency, number, duration, and temperature of CS events in northern China using the daily minimum temperature dataset of 331 stations from 1960 to 2016. The results indicate that the annual CS events in terms of frequency and number decreased, and the duration shortened as the starting date was later and the ending date earlier. Meanwhile, the annual CS temperature increased. In addition, spatial trends in the CS events in terms of frequency, number, and duration decreased while the CS temperature increased in most regions of northern China. We interpreted these variations as a response to global warming. However, the extreme CS events in terms of frequency, number and the earliest starting date and the latest ending date showed little change though the extreme CS temperature increased, implying climate warming had not limited extreme CS events. The adverse effect of CS events on agriculture and human health remain concerning.
文摘The work presented in this paper is a part of the TLP project undertaken in CSSRC(Chins Ship Scientific Research Center). Model tests were performed in seakeeping basin at CSSRC. Wave envelopes are calculated from time records of the irregular waves using Hilbert transform.Time histories of surge motions of the model were recorded in long-crested irregular head seas.The low-frequency response was separated from the time history using a low pass filter.The quadratic transfer functions were obtained from ratio of the cross-spectrum(between the low-frequency surge response and the square of the wave envelope)and the auto-spectrum of the square of the wave envelope.
