图  1   利用3种不同的大气改正方法获取的同一时刻同一区域的流体静力学延迟(a)和湿延迟(b)

Figure  1.   Hydrostatic delay (a) and wet delay (b) for the same area at the same time based on three different atmospheric correction methods (MERIS, ERA-Ⅰ and WRF)

图  2   对比3种大气改正方法的流程图

Figure  2.   Process flowchart for comparing three different atmospheric correction methods

图  3   基于3种大气改正方法的残差相位直方图

黑色叉号表示每幅图残差的频率分布(共7幅)，红色曲线表示基于7幅图残差分布拟合的正态曲线

Figure  3.   Histograms of residual phase from the results corrected by three different atmospheric correction methods

Black crosses are the frequency for each interferogram (seven in total), and red curves stand for the fitted normal curve of the residuals of the seven interferogams

图  4   海原断裂带的地质构造图和试验数据分布

背景为来自SRTM (Shuttle Radar Topography Mission)的高程，黑色虚线表示Envisat ASAR数据和MERIS数据的覆盖范围，黑色实线矩形框表示WRF第三层嵌套的范围，红色方块表示ERA-Ⅰ的数据分布

Figure  4.   Tectonic map of the Haiyuan fault zone and distribution of test data

Fault traces are superimposed on SRTM DEM. The black dashed rectangle shows the coverage of Envisat ASAR data and MERIS data. The black solid rectangle stands for the coverage of WRF simulation. Red squares represent data from ERA-Ⅰ. And the epicenter of two large historical earthquakes are marked as magenta points

图  5   降轨数据061条带覆盖老虎山断裂的ASAR数据时空分布

红色圆圈表示条带内的雷达数据，其中红色实心圆表示无云情况.红线表示可由MERIS数据改正的长时间基线干涉图，绿线表示可由ERA-Ⅰ数据改正的长时间基线干涉图

Figure  5.   Spatio-temporal baseline plot of Envisat ASAR acquisitions for descending track 061 covering the Laohushan fault

Acquisitions are numbered time sequentially, and 11 of them marked with red solid circle are largely cloud-free. The two long-temporal-baseline inter-ferograms denoted by red line are corrected for atmospheric effects using MERIS data, and the four long-temporal-baseline interferograms marked by green lines are corrected by using ERA-Ⅰ data

图  6   利用长时间基线干涉图获取震间形变场的流程

Figure  6.   Flowchart of deriving interseismic deformation field based on long-temporal-baseline interferograms

图  7   以一个基于MERIS改正的干涉对(040522-100116，上)和基于ERA-Ⅰ改正的干涉对(041218-100116，下)为例展示图 6所示的形变速率场获取过程

从左至右分别为原始干涉图、湿延迟、流体静力学延迟、经过大气改正的干涉图、拟合得到的轨道误差和轨道改正后的残余误差

Figure  7.   Deriving process of the deformation field from one interferogram pair (040522-100116, upper panels) corrected by MERIS data and the other one (041218-100116, lower panels) corrected by ERA-Ⅰ data as shown in Fig.6

From left to right, shown are original interferograms, the wet delay from MERIS and ERA-Ⅰ data, the hydrostatic delay from MERIS and ERA-Ⅰ data, the atmosphere-corrected interferograms, linear orbital ramp, and residual interferograms after orbital correction

图  8   InSAR震间形变场和形变场剖面线

(a)和(b)分别表示基于MERIS改正和ERA-Ⅰ改正的震间形变场，其中红色实线矩形框内的断层为老虎山断裂，红色虚线矩形框内的断层为景泰断裂；(c)和(d)分别表示速度场剖面线AA′和BB′平行于断层的水平运动速率，其中黄点和绿点分别表示基于MERIS和ERA-Ⅰ大气改正后的形变场在剖面线上的投影，而红线和黑线分别表示对应其平均值

Figure  8.   Interseismic velocity field of study area and its two profiles across the fault

(a) The MERIS-corrected rate map; (b) The ERA-Ⅰ-corrected rate map. The red solid rectangle covers the Laohushan fault, and the red dashed rectangle covers the Jingtai fault; (c) The fault-parallel velocity of the AA′ profile from two rate maps; (d) The fault-parallel velocity of the BB′ profile from two rate maps. Black and green points are the projection of MERIS-corrected and ERA-Ⅰ-corrected rate map on the profile, and red line and black line are their mean values