Using the sea surface temperature and wind anomalies(SSTA and SSWA for short)of the tropical Pacific from January 1970 to December 1989,main spatial patterns of tropical Pacific SSTA and SSWA coupling features in the ...Using the sea surface temperature and wind anomalies(SSTA and SSWA for short)of the tropical Pacific from January 1970 to December 1989,main spatial patterns of tropical Pacific SSTA and SSWA coupling features in the transform course from the warm phase to the cold phase of El Nino-southern Oscillation(ENSO)cycles are discussed. The main conclusions are as follows:(1)air-sea coupling patterns at the mature stage of El Nino(La Nina)are main spatial ones of tropical Pacific SSWA and SSTA coupling:(2)at the mature stage of El Nino,the interaction of the anticyclonic anomaly wind,generated by the forcing of distinct meridional SSTA gradient in the Northern Hemisphere tropical central Pacific.with the California cold current and SSTA is mainly responsible for weakening of El Nino;(3)the second sea temperature increase along the South American coast in the decaying course of El Nino results from the eastward movement of the weakened positive SSTA in the tropical central-eastern Pacific forced by anomalous west wind stress:(4)La Nina results from the joint effect of Walker circulation,Ekman drift and negative SSTA in the tropical central-eastern Pacific.展开更多
利用常规气象观测资料和NCEP再分析资料,对2013年4月18日到20日河南出现的一次区域性寒潮天气过程的环流背景、影响系统及寒潮期间降水多相态转换的成因进行了分析。结果表明:本次寒潮过程属于横槽转竖型,冷锋迅速南下,导致寒潮暴发;此...利用常规气象观测资料和NCEP再分析资料,对2013年4月18日到20日河南出现的一次区域性寒潮天气过程的环流背景、影响系统及寒潮期间降水多相态转换的成因进行了分析。结果表明:本次寒潮过程属于横槽转竖型,冷锋迅速南下,导致寒潮暴发;此次寒潮天气的大气温度层结存在逆温层结构特征,温度廓线的变化会导致降水相态发生变化;受低层冷空气持续影响,暖层强度即融化层遭到一定程度的破坏或消失,冷层即冻结层强度增强,0℃层高度下降,以致降水相态发生相应的改变;降水相态的变化与暖层温度及0℃层高度密切相关。根据本次寒潮过程中NCEP再分析数据得到:当降水相态为雨时,暖层温度≥2℃,0℃层高度≤975 h Pa;当降水相态为雪时,暖层温度≤-1℃,0℃层高度≌1000 h Pa;当降水相态为冰粒时,2℃≥暖层温度≥-1℃,1000 h Pa≥0℃层高度≥975 h Pa。展开更多
采用差示扫描量热法(DSC)热分析设备进行了奥氏体相变激活能的研究,通过测定10Mn5试验钢冷轧和温轧两种状态下的热流-温度曲线计算了逆相变激活能和相变激活能。绘制了相变体积分数与温度之间的关系曲线。结果表明,钢温轧态奥氏体逆相...采用差示扫描量热法(DSC)热分析设备进行了奥氏体相变激活能的研究,通过测定10Mn5试验钢冷轧和温轧两种状态下的热流-温度曲线计算了逆相变激活能和相变激活能。绘制了相变体积分数与温度之间的关系曲线。结果表明,钢温轧态奥氏体逆相变激活能(788.5 k J/mol)小于冷轧态奥氏体逆相变的激活能(1030 k J/mol);温轧态奥氏体逆相变能量门槛低,转变较容易。当相变体积分数大于50%后,冷轧和温轧的奥氏体相变激活能的变化趋势是随着奥氏体体积分数的增加而逐渐减小。展开更多
基金This work was supported by the National Natural Science Foundation of China under the Grants 49375242.
文摘Using the sea surface temperature and wind anomalies(SSTA and SSWA for short)of the tropical Pacific from January 1970 to December 1989,main spatial patterns of tropical Pacific SSTA and SSWA coupling features in the transform course from the warm phase to the cold phase of El Nino-southern Oscillation(ENSO)cycles are discussed. The main conclusions are as follows:(1)air-sea coupling patterns at the mature stage of El Nino(La Nina)are main spatial ones of tropical Pacific SSWA and SSTA coupling:(2)at the mature stage of El Nino,the interaction of the anticyclonic anomaly wind,generated by the forcing of distinct meridional SSTA gradient in the Northern Hemisphere tropical central Pacific.with the California cold current and SSTA is mainly responsible for weakening of El Nino;(3)the second sea temperature increase along the South American coast in the decaying course of El Nino results from the eastward movement of the weakened positive SSTA in the tropical central-eastern Pacific forced by anomalous west wind stress:(4)La Nina results from the joint effect of Walker circulation,Ekman drift and negative SSTA in the tropical central-eastern Pacific.
文摘利用常规气象观测资料和NCEP再分析资料,对2013年4月18日到20日河南出现的一次区域性寒潮天气过程的环流背景、影响系统及寒潮期间降水多相态转换的成因进行了分析。结果表明:本次寒潮过程属于横槽转竖型,冷锋迅速南下,导致寒潮暴发;此次寒潮天气的大气温度层结存在逆温层结构特征,温度廓线的变化会导致降水相态发生变化;受低层冷空气持续影响,暖层强度即融化层遭到一定程度的破坏或消失,冷层即冻结层强度增强,0℃层高度下降,以致降水相态发生相应的改变;降水相态的变化与暖层温度及0℃层高度密切相关。根据本次寒潮过程中NCEP再分析数据得到:当降水相态为雨时,暖层温度≥2℃,0℃层高度≤975 h Pa;当降水相态为雪时,暖层温度≤-1℃,0℃层高度≌1000 h Pa;当降水相态为冰粒时,2℃≥暖层温度≥-1℃,1000 h Pa≥0℃层高度≥975 h Pa。
文摘采用差示扫描量热法(DSC)热分析设备进行了奥氏体相变激活能的研究,通过测定10Mn5试验钢冷轧和温轧两种状态下的热流-温度曲线计算了逆相变激活能和相变激活能。绘制了相变体积分数与温度之间的关系曲线。结果表明,钢温轧态奥氏体逆相变激活能(788.5 k J/mol)小于冷轧态奥氏体逆相变的激活能(1030 k J/mol);温轧态奥氏体逆相变能量门槛低,转变较容易。当相变体积分数大于50%后,冷轧和温轧的奥氏体相变激活能的变化趋势是随着奥氏体体积分数的增加而逐渐减小。
