融合多源数据构建区域航空重力梯度扰动全张量          下载免费PDF全文

刘金钊  梁星辉  叶周润  刘站科  郎骏健  王国成  柳林涛 《地球物理学报》2020,63(8):3131-3143

通过联合全球重力位模型(EGM2008)、航空重力扰动数据和剩余地形模型(RTM)数据,基于频谱域(二维FFT变换)和空间域(Stokes数值积分)算法对毛乌素测区GT-2A航空重力测量系统采集的空中测线后处理重力扰动数据进行解算,构建了该地区的航空重力梯度扰动全张量.(1)残余航空重力扰动延拓结果表明:残余航空重力扰动经向下延拓至大地水准面,再向上延拓至航空高度后与原数据差值的标准差为1.0078 mGal,考虑边缘效应后,内缩计算范围得到的差值标准差减小至0.1269 mGal.(2)基于残余重力扰动数据(原航空高度数据及向下延拓数据),通过不同方案解算得到的梯度扰动结果表明:两种方案得到的研究区域重力梯度扰动各分量之差的最大标准差为6.4798E(Γ_(yz)分量),最小标准差为2.6968E(Γ_(xy)分量),内缩计算范围后得到的差值标准差最大值为1.8307E(Γ_(zz)分量),最小值为0.7223E(Γ_(yz)分量).本文的思路和方法可为未来我国自主构建航空重力梯度标定场提供参考.  相似文献   

风浪扰动对太湖水体悬浮物重金属含量的影响   总被引：10，自引：2，他引：8  

池俏俏  朱广伟  张战平  秦伯强 《湖泊科学》2006,18(5):495-498

通过离心浓缩的方法,获取太湖梅梁湾口东岸处(即梅梁湾与贡湖湾的交界处)不同风浪条件下的悬浮颗粒物．冷冻干燥,微波消解,ICP-AES的方法测定了其中Co、Cr、Cu、Ni、Pb、Zn等重金属元素及Al、Ca、Fe、Mn等相关金属元素的含量．结果发现,小风浪(2 m/s)、中风浪(7 m/s)和大风浪(11 m/s)下：①水体总悬浮颗粒态金属的量依次大幅度增加;②单位悬浮颗粒物中各金属元素的含量在不同风浪下变化不同．Ca在小、中、大风浪下含量依次增大;Zn在小、中、大风浪下含量依次减少;Mn和Cu的含量变化趋势相同：与小风浪相比,中风浪下Mn、Cu的含量显著增大;与中风浪相比,大风浪下含量显著减少;其它元素Al、Fe、Ni、Pb、Co、Cr等在单位悬浮物中,中风浪与小风浪相比含量减少,大风浪与中风浪相比含量略微增加．研究表明：①金属元素在水体总悬浮物中的含量主要受风浪影响,但风浪对单位悬浮物中金属含量的影响则因元素而异;②除Cu、Mn、Zn外,悬浮物中重金属含量随粒径增大含量减少．  相似文献   

Impact of forest degradation on streamflow regime and runoff response to rainfall in the Garhwal Himalaya,Northwest India     

Nuzhat Q. Qazi  L. Adrian Bruijnzeel  Shive Prakash Rai  Chandra P. Ghimire 《水文科学杂志》2017,62(7):1114-1130

Baseflows have declined for decades in the Lesser Himalaya but the causes are still debated. This paper compares variations in streamflow response over three years for two similar headwater catchments in northwest India with largely undisturbed (Arnigad) and highly degraded (Bansigad) oak forest. Hydrograph analysis suggested no catchment leakage, thereby allowing meaningful comparisons. The mean annual runoff coefficient for Arnigad was 54% (range 44–61%) against 62% (53–69%) at Bansigad. Despite greater total runoff Q_t (by 250 mm year^–1), baseflow at Bansigad ceased by March, but was perennial at Arnigad (making up 90% of Q_t vs. 51% at Bansigad). Arnigad storm flows, Q_s, were modest (8–11% of Q_t) and occurred mostly during monsoons (78–98%), while Q_s at Bansigad was 49% of Q_t and occurred also during post-monsoon seasons. Our results underscore the importance of maintaining soil water retention capacity after forest removal to maintain baseflow levels.