This study examines the seasonal variations of tropical cyclogenesis over the South China Sea (SCS) using a genesis potential (GP) index developed by Emanuel and Nolan. How different environmental factors (including l...This study examines the seasonal variations of tropical cyclogenesis over the South China Sea (SCS) using a genesis potential (GP) index developed by Emanuel and Nolan. How different environmental factors (including low-level vorticity, mid-level relative humidity, vertical wind shear, and potential intensity) contribute to these variations is investigated. Composite anomalies of the GP index are produced for the summer and winter monsoons separately. These composites replicate the observed seasonal variations of the observed frequency and location of tropical cyclogenesis over the SCS. The degree of contribution by each factor in different regions is determined quantitatively by producing composites of modified indices in which only one of the contributing factors varies, with the others set to climatology. Over the northern SCS, potential intensity makes the largest contributions to the seasonal variations in tropical cyclogenesis. Over the southern SCS, the low-level relative vorticity plays the primary role in the seasonal modulation of tropical cyclone (TC) genesis frequency, and the vertical wind shear plays the secondary role. Thermodynamic factors play more important roles for the seasonal variations in tropical cyclogenesis over the northern SCS, while dynamic factors are more important in the seasonal modulation of TC genesis frequency over the southern SCS.展开更多
To investigate the seasonal changes in physiological and biochemical indexes of Tibetan sheep in Hongyuan area,we measured the physiological and biochemical indexes of Tibetan sheep at four different seasons. The resu...To investigate the seasonal changes in physiological and biochemical indexes of Tibetan sheep in Hongyuan area,we measured the physiological and biochemical indexes of Tibetan sheep at four different seasons. The results showed that the body temperature,respiration and heart rate of Tibetan sheep at four seasons were 39. 18- 39. 60 ℃,27. 20- 49. 04 times / min,91. 87- 106. 25 times / min,respectively. The indexes of WBC,MCV,MCH and MCHC in autumn and winter were significantly higher than those in spring and summer（ P 〈 0. 01）,while the indexes of RBC,HCT and RDW-CV in spring and summer were significantly higher than those in autumn and winter（ P 〈 0. 01）. The PLT did not vary greatly in spring,summer or autumn,but were all extremely higher than that in winter（ P〈 0. 01）. The HGB maintained stable in the four seasons. The indexes of TP,ALB and GLO in summer and autumn were extremely higher than those in winter and spring（ P 〈 0. 01）,while the indexes of ALP and PCHE in summer and autumn were extremely lower than those in winter and spring（ P 〈 0. 01）. The indexes of AST,ALT,LDH,GLU,CHOL and CA maintained stable in all seasons.展开更多
植被物候直接影响其生物量,调控生态系统碳循环过程。目前,气候变化(尤其干旱)对中国中高纬度植被物候的影响依然不清楚。因此,文章基于GIMMS NDVI3g数据集,提取中国30°N以北地区中多种植被类型生长季的开始日期(Start of the Seas...植被物候直接影响其生物量,调控生态系统碳循环过程。目前,气候变化(尤其干旱)对中国中高纬度植被物候的影响依然不清楚。因此,文章基于GIMMS NDVI3g数据集,提取中国30°N以北地区中多种植被类型生长季的开始日期(Start of the Season,SOS)与结束日期(End of the Season,EOS)两物候参数。然后结合野外观测数据,验证提取物候参数结果可靠性,并结合饱和水汽压差(Vapor Pressure Deficit,VPD)与改进后的标准化降水蒸散指数(Standardized Precipitation Evapotranspiration Index,SPEI)探究植被物候对干旱的响应特征规律。结果表明:(1)不同地区的植被物候变化呈现明显的差异性,单季植被与双季植被第1个生长季的SOS集中在每年的第30~180天,而双季植被第2个生长季的SOS集中在每年的第200~220天。单季植被与双季植被第1个生长季的EOS主要集中在每年的第180~300天,双季植被第2个生长季的EOS主要集中在每年的第260~300天。(2)森林季前VPD的上升导致植被的SOS提前及EOS延迟;草地季前VPD上升导致植被的SOS滞后以及EOS提前。(3)研究区内大部分地区的SPEI与植被的SOS、EOS均呈正相关,即干旱促使该地区植被的SOS、EOS提前。展开更多
基金funded by the tropical marine meteorology fund from the Institute of Tropical and Marine Meteorology CMAthe National Basic Research Program of China(2011CB403500)+2 种基金SOED1108LED1002the Fundamental Research Funds for the Central Universities (No.11lgpy13)
文摘This study examines the seasonal variations of tropical cyclogenesis over the South China Sea (SCS) using a genesis potential (GP) index developed by Emanuel and Nolan. How different environmental factors (including low-level vorticity, mid-level relative humidity, vertical wind shear, and potential intensity) contribute to these variations is investigated. Composite anomalies of the GP index are produced for the summer and winter monsoons separately. These composites replicate the observed seasonal variations of the observed frequency and location of tropical cyclogenesis over the SCS. The degree of contribution by each factor in different regions is determined quantitatively by producing composites of modified indices in which only one of the contributing factors varies, with the others set to climatology. Over the northern SCS, potential intensity makes the largest contributions to the seasonal variations in tropical cyclogenesis. Over the southern SCS, the low-level relative vorticity plays the primary role in the seasonal modulation of tropical cyclone (TC) genesis frequency, and the vertical wind shear plays the secondary role. Thermodynamic factors play more important roles for the seasonal variations in tropical cyclogenesis over the northern SCS, while dynamic factors are more important in the seasonal modulation of TC genesis frequency over the southern SCS.
基金Supported by Achievement Transformation Project of Science & Technology Department of Sichuan Province "Hybridization Improvement and Demonstration Promotion of Tibetan Sheep with White Suffolk Sheep"
文摘To investigate the seasonal changes in physiological and biochemical indexes of Tibetan sheep in Hongyuan area,we measured the physiological and biochemical indexes of Tibetan sheep at four different seasons. The results showed that the body temperature,respiration and heart rate of Tibetan sheep at four seasons were 39. 18- 39. 60 ℃,27. 20- 49. 04 times / min,91. 87- 106. 25 times / min,respectively. The indexes of WBC,MCV,MCH and MCHC in autumn and winter were significantly higher than those in spring and summer（ P 〈 0. 01）,while the indexes of RBC,HCT and RDW-CV in spring and summer were significantly higher than those in autumn and winter（ P 〈 0. 01）. The PLT did not vary greatly in spring,summer or autumn,but were all extremely higher than that in winter（ P〈 0. 01）. The HGB maintained stable in the four seasons. The indexes of TP,ALB and GLO in summer and autumn were extremely higher than those in winter and spring（ P 〈 0. 01）,while the indexes of ALP and PCHE in summer and autumn were extremely lower than those in winter and spring（ P 〈 0. 01）. The indexes of AST,ALT,LDH,GLU,CHOL and CA maintained stable in all seasons.
文摘植被物候直接影响其生物量,调控生态系统碳循环过程。目前,气候变化(尤其干旱)对中国中高纬度植被物候的影响依然不清楚。因此,文章基于GIMMS NDVI3g数据集,提取中国30°N以北地区中多种植被类型生长季的开始日期(Start of the Season,SOS)与结束日期(End of the Season,EOS)两物候参数。然后结合野外观测数据,验证提取物候参数结果可靠性,并结合饱和水汽压差(Vapor Pressure Deficit,VPD)与改进后的标准化降水蒸散指数(Standardized Precipitation Evapotranspiration Index,SPEI)探究植被物候对干旱的响应特征规律。结果表明:(1)不同地区的植被物候变化呈现明显的差异性,单季植被与双季植被第1个生长季的SOS集中在每年的第30~180天,而双季植被第2个生长季的SOS集中在每年的第200~220天。单季植被与双季植被第1个生长季的EOS主要集中在每年的第180~300天,双季植被第2个生长季的EOS主要集中在每年的第260~300天。(2)森林季前VPD的上升导致植被的SOS提前及EOS延迟;草地季前VPD上升导致植被的SOS滞后以及EOS提前。(3)研究区内大部分地区的SPEI与植被的SOS、EOS均呈正相关,即干旱促使该地区植被的SOS、EOS提前。
