华北地区夏季水量丰枯年气候特征对比分析

利用 NCEP/ NCAR的 4 0 a再分析资料 ,对比分析了华北地区夏季水量丰、枯年气候特征差异 .结果发现 ,干旱年我国大部分地区海平面气压场为弱低压 ,湿润年为较强低压 ;干旱年印度夏季风、南海季风及西太平洋副热带高压南侧的东南风均弱于湿润年 ;干旱年北半球中高纬度槽脊发展较弱 ,冷空气活动较弱 ,华北地区位于弱脊区 .湿润年北半球大气环流指数为低指数 ,中高纬度冷空气活动频繁 ,华北地区位于槽前脊后 ;干旱年西太平洋副热带高压南北向发展较弱 ,位置偏南 ,而东西向发展强盛 ,在我国南部地区形成狭长的高压脊 .湿润年副热带高压南北向发展较强 ,位置偏北 ,东西向发展较弱 ;干旱年华北地区为弱下沉运动 ,在 6 0 0～ 4 0 0 h Pa层之间 ,形成了闭合径圈环流 .而湿润年华北地区上空为上升气流 。

秦岭-淮河地区降水空间聚类分析

秦岭-淮河地区受复杂地形与多变季风气候影响,降水在年际和年内波动较大,空间分布呈明显区域性。通过分析不同时间尺度降水量,年降水量丰平枯状态和相邻年份年降水量变化的增平减趋势,对秦岭-淮河地区进行降水空间聚类。结果表明:根据候降水量指标可将秦岭-淮河地区分为江淮、黄淮、秦岭以南、秦岭以北4个区,据年降水量丰平枯状态联系数指标可将该地区分为江淮、黄淮、秦岭-淮河交界附近、秦岭以北高原和秦岭以南西段4个区,据相邻年份年降水量变化增平减趋势联系数指标可将该地区分为江淮、黄淮、秦岭3个区;融合3个降水指标的区域划分结果,可将秦岭-淮河地区划分为6个区:江淮、黄淮、秦岭以南、秦岭以北西段和高原区、关中区、秦岭-淮河交界过渡区。基于线性矩法的分区一致性检验表明分区内无奇异站点。

Assessment of Saline Water Intrusion into Huong River in Dry Season

Most rivers in Vietnam flow directly to the sea where the interaction between fresh and salt water occurs. Because of uneven flow distribution through the year with only 20% annual flow in the dry season, while fresh water requirement for socio-economic activity in this season is much higher. With this situation, the simulation and finding out the mechanism of saline water intrusion into the estuary in general will help to suggest suitable solutions to control the situation. This paper presents results done at the Huong river estuary. Based on the data collected in current years and using MIKE11 softwave, number scenarios were simulated and found out the intruded process of saline water into the river. They will be very important parameters for which solutions to control negative effects to serve socio-economic development at the downstream of Huong river will be recommended and implemented in the later stage.