叉车双油箱强制温降消泡液压系统的性能分析与改进

介绍了一种叉车双液压油箱结构,且此结构在强制温降消泡功能液压系统得到应用。此系统采用2个独立且串联的独特液压油箱结构,油箱之间通过管路串联组合而成,系统采用增长液压系统油路气泡挥发通道和增加液压油有效整机散热面积,经过样机液压系统热平衡数据测试,证实此强制温降消泡液压系统达到了降低液压系统油温的效果。

Climate state of the Three Gorges Region in the Yangtze River basin in 2022–2023

Based on daily observation data of the Three Gorges Region(TGR)of the Yangtze River basin and global reanalysis data,the climate characteristics,climate events,and meteorological disasters of the TGR in 2022 and 2023 were analyzed.For the TGR,the average annual temperature for 2022 and 2023 was 0.8℃ and 0.4℃ higher than normal,respectively,making them the two warmest years in the past decade.In 2022,the TGR experienced its warmest summer on record.The average air temperature was 2.4℃ higher than the average,and there were 24.8 days of above-average high temperature days during summer.Rainfall in the TGR varied significantly between 2022 and 2023.Annual rainfall was 18.4%below normal and drier than normal in most parts of the region.In contrast,the precipitation in 2023 was considerably higher than the long-term average,and above normal for almost the entire year.The average wind speed exhibited minimal variation between the two years.However,the number of foggy days and relative humidity increased in 2023 compared to 2022.In 2022–2023,the TGR mainly experienced meteorological disasters such as extreme high temperatures,regional heavy rain and flooding,overcast rain,and inverted spring chill.Analysis indicates that the abnormal western Pacific subtropical high and the abnormal persistence of the eastward-shifted South Asian high were the two important drivers of the durative enhancement of record-breaking high temperature in the summer of 2022.

Influence of North Pacific SST on heavy precipitation events in autumn over North China

The characteristics of heavy precipitation occurrence in autumn（the month of September） over North China are investigated using daily observational data.Results indicate that heavy precipitation events experienced a significant decadal increase in 2000/2001.Further investigation reveals a close connection between heavy precipitation occurrence and simultaneous North Pacific SST.The SST anomaly over the North Pacific can result in intensification of the western North Pacific subtropical high and increased water vapor transport from the tropical ocean,which benefits the occurrence of heavy precipitation over North China.However,the key region of North Pacific SST influencing heavy precipitation events over North China was different in the periods 1960-2000 and 2001-2014,being located over the eastern Ocean to China in the first period but more eastward in the second period.This drift in the key region of SST is partly responsible for the decadal increase in heavy precipitation events over North China since 2000/2001.Additionally,the changes in SST variability（a decrease in the eastern Ocean to China and an increase to its east） may have been the main reason for the eastward movement of the key region in the latter period.Certainly,more work is needed in the future to verify the findings of this study.

STUDY ON THE RELATIONSHIP BETWEEN BRIGHTNESS TEMPERATURE FROM GMS-5 INFRARED CLOUD IMAGERY AND SURFACE RAIN RATES DURING THE RAINING SEASONS OF FUJIAN PROVINCE

The GMS-5 infrared cloud imagery for two yearly first raining seasons in 1998 and 1999 are used to study the relationship between brightness temperature and surface rain rates. The result shows that it is likely to have large probability of heavy precipitation with the decrease of brightness temperature and the gradual increase of rainfall intensity; for areas of low temperature, the brightness temperature is better determined for atmosphere above rain gauge stations with multiple points sampling than with single point one; for the yearly first raining season, the threshold brightness temperature is set at 4.6℃ for indication of heavy precipitation in the Fujian area.

Changes in Climate Factors and Extreme Climate Events in South China during 1961-2010

Daily climate data at 110 stations during 1961-2010 were selected to examine the changing characteristics of climate factors and extreme climate events in South China. The annual mean surface air temperature has increased significantly by 0.16℃ per decade, most notably in the Pearl River Delta and in winter. The increase rate of the annual extreme minimum temperature (0.48℃ per decade) is over twice that of the annual extreme maximum temperature (0.20℃ per decade), and the increase of the mean temperature is mainly the result of the increase of the extreme minimum temperature. The increase rate of high-temperature days (1.1 d per decade) is close to the decrease rate of low-temperature days (-1.3 d per decade). The rainfall has not shown any significant trend, but the number of rainy days has decreased and the rain intensity has increased. The regional mean sunshine duration has a significant decreasing trend of -40.9 h per decade, and the number of hazy days has a significant increasing trend of 6.3 d per decade. The decrease of sunshine duration is mainly caused by the increase of total cloud, not by the increase of hazy days in South China. Both the regional mean pan evaporation and mean wind speed have significant decreasing trends of -65.9 mm per decade and -0.11 m s-1 per decade, respectively. The decrease of both sunshine duration and mean wind speed plays an important role in the decrease of pan evaporation. The number of landing tropical cyclones has an insignificant decreasing trend of -0.6 per decade, but their intensities show a weak increasing trend. The formation location of tropical cyclones landing in South China has converged towards 10-19°N, and the landing position has shown a northward trend. The date of the first landfall tropical cyclone postpones 1.8 d per decade, and the date of the last landfall advances 3.6 d per decade, resulting in reduction of the typhoon season by 5.4 d per decade.