Relationship between the δ 13C of tree ring cellulose from Pinus Koraiensis and climate parameters was investigated. A significantly negative correlation between δ 13C and mean low-cloud amount from May to July was ...Relationship between the δ 13C of tree ring cellulose from Pinus Koraiensis and climate parameters was investigated. A significantly negative correlation between δ 13C and mean low-cloud amount from May to July was discovered, which contributes to reconstructing the mean low-cloud amount from May to July at Antu in recent 200 years. Periodicals of quasi-8-year, quasi-4-year and quasi-2-year were detected both in δ 13C series and in the reconstructed low cloud amount series with 95% confidence level. Quasi-8-year period may reflect the integrated influence of solar activity, monsoon activity and local regional factors. Quasi-4-year and quasi-2-year periods indicate the influences of ENSO and Quasi Biennial Oscillation (QBO) of East Asian monsoon, respectively.展开更多
By using the data set of light rain days and low cloud cover at 51 stations in South China(SC), and the method of linear regression and correlative analysis, we analyze the spatiotemporal characteristics of the light ...By using the data set of light rain days and low cloud cover at 51 stations in South China(SC), and the method of linear regression and correlative analysis, we analyze the spatiotemporal characteristics of the light rain days and low cloud cover including annual variation and long-term seasonal change. The results are as follows:(1) The trends of light rain days and low cloud cover over SC are opposite(light rain days tended to decrease and low cloud cover tended to increase in the past 46 years). The value distributed in east is higher than that in west, and coastal area higher than inland area.(2) The regression coefficients of light rain days and low cloud cover during 1960-2005 are4.88 d/10 years and 1.14%/10 years respectively, which had all passed the 0.001 significance level.(3) Variations of light rain days are relatively small in spring and summer, but their contributions are larger for annual value than that of autumn and winter.(4) There are two regions with large values of aerosol optical depth(AOD), which distribute in central and southern Guangxi and Pearl River Delta(PRD) of Guangdong, and the value of AOD in PRD is up to 0.7.The aerosol index distributed in coastal area is higher than in the inland area, which is similar to the light rain days and low cloud cover over SC. Aerosol indexes in SC kept increasing with fluctuation during the past 27 years. The GDP of the three provinces in SC increased obviously during the past 28 years, especially in Guangdong, which exhibited that there is simultaneous correlation between light rain days with the variables of low cloud cover and release of aerosols over SC during 1960 to 2005.展开更多
At 11:00 am on August 5, 2017, Cangyuan Washan Airport experienced low cloud and low visibility weather, accompanied by aircraft turbulence, which affected the normal operation of flights, which was closely related to...At 11:00 am on August 5, 2017, Cangyuan Washan Airport experienced low cloud and low visibility weather, accompanied by aircraft turbulence, which affected the normal operation of flights, which was closely related to the meteorological conditions at that time. Using the hourly reanalysis data of the European Centre for Medium-range Weather Forecast (ECMWF) Reanalysis 5 (ERA5), including Geopotential height, temperature, precipitation, wind field, specific humidity, vorticity and other elements, with a spatial resolution of 0.25° × 0.25°, this paper focuses on the horizontal distribution and vertical configuration of various physical quantities before and after the occurrence of low cloud and low visibility weather at the airport. The results indicate that the main influencing system of this low cloud and low visibility weather is the westward tropical depression. Before the occurrence of low cloud and low visibility weather, low-level water vapor converges and is accompanied by precipitation. The temperature decreases with precipitation, the near-surface wind direction changes, and the wind speed decreases.展开更多
文摘Relationship between the δ 13C of tree ring cellulose from Pinus Koraiensis and climate parameters was investigated. A significantly negative correlation between δ 13C and mean low-cloud amount from May to July was discovered, which contributes to reconstructing the mean low-cloud amount from May to July at Antu in recent 200 years. Periodicals of quasi-8-year, quasi-4-year and quasi-2-year were detected both in δ 13C series and in the reconstructed low cloud amount series with 95% confidence level. Quasi-8-year period may reflect the integrated influence of solar activity, monsoon activity and local regional factors. Quasi-4-year and quasi-2-year periods indicate the influences of ENSO and Quasi Biennial Oscillation (QBO) of East Asian monsoon, respectively.
基金National Key Project of Research and Development Plan of China(2016YFA0602501)National Natural Science Foundation of China(4163053241275082)
文摘By using the data set of light rain days and low cloud cover at 51 stations in South China(SC), and the method of linear regression and correlative analysis, we analyze the spatiotemporal characteristics of the light rain days and low cloud cover including annual variation and long-term seasonal change. The results are as follows:(1) The trends of light rain days and low cloud cover over SC are opposite(light rain days tended to decrease and low cloud cover tended to increase in the past 46 years). The value distributed in east is higher than that in west, and coastal area higher than inland area.(2) The regression coefficients of light rain days and low cloud cover during 1960-2005 are4.88 d/10 years and 1.14%/10 years respectively, which had all passed the 0.001 significance level.(3) Variations of light rain days are relatively small in spring and summer, but their contributions are larger for annual value than that of autumn and winter.(4) There are two regions with large values of aerosol optical depth(AOD), which distribute in central and southern Guangxi and Pearl River Delta(PRD) of Guangdong, and the value of AOD in PRD is up to 0.7.The aerosol index distributed in coastal area is higher than in the inland area, which is similar to the light rain days and low cloud cover over SC. Aerosol indexes in SC kept increasing with fluctuation during the past 27 years. The GDP of the three provinces in SC increased obviously during the past 28 years, especially in Guangdong, which exhibited that there is simultaneous correlation between light rain days with the variables of low cloud cover and release of aerosols over SC during 1960 to 2005.
文摘At 11:00 am on August 5, 2017, Cangyuan Washan Airport experienced low cloud and low visibility weather, accompanied by aircraft turbulence, which affected the normal operation of flights, which was closely related to the meteorological conditions at that time. Using the hourly reanalysis data of the European Centre for Medium-range Weather Forecast (ECMWF) Reanalysis 5 (ERA5), including Geopotential height, temperature, precipitation, wind field, specific humidity, vorticity and other elements, with a spatial resolution of 0.25° × 0.25°, this paper focuses on the horizontal distribution and vertical configuration of various physical quantities before and after the occurrence of low cloud and low visibility weather at the airport. The results indicate that the main influencing system of this low cloud and low visibility weather is the westward tropical depression. Before the occurrence of low cloud and low visibility weather, low-level water vapor converges and is accompanied by precipitation. The temperature decreases with precipitation, the near-surface wind direction changes, and the wind speed decreases.
