Ph as e ( ra d)

Auxiliary Material for Paper 2011GL048757

Systematic InSAR tropospheric phase delay corrections from global meteorological reanalysis data

R. Jolivet

Institut des Sciences de la Terre, UMR 5275, Universite Joseph Fourier, CNRS, Grenoble, France

R. Grandin

Laboratoire de Geologie, UMR 8538, Ecole Normale Superieure, CNRS, Paris, France

C. Lasserre

Institut des Sciences de la Terre, UMR 5275, Universite Joseph Fourier, CNRS, Grenoble, France

M.-P. Doin

Laboratoire de Geologie, UMR 8538, Ecole Normale Superieure, CNRS, Paris, France

G. Peltzer

Department of Earth and Space Science, University of California, Los Angeles, California, USA

Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA

Jolivet, R., R. Grandin, C. Lasserre, M.-P. Doin, and G. Peltzer (2011),

Systematic InSAR tropospheric phase delay corrections from global meteorological reanalysis data, Geophys. Res. Lett., 38, L17311, doi:10.1029/2011GL048757.

Introduction

The auxiliary material contains four figures. Figure S1 provides an additional example of atmospheric correction (similarly to Figure 1 in the paper). Figure S2 provides a comparison of local phase/elevation ratio between data shown in Figure 1 and ERA-I. Figure S3 provides quantification of the fringe rate reduction due to the atmospheric correction. Figure S4 provides an example of the orbital contribution estimated jointly with an empirical atmospheric correction and the orbital contribution estimated after the ERA-I derived correction.

1. 2011gl048757-fs01.eps

Figure S1. Same as Figure 1, but for acquisitions on 07-23-3007 and 08-27-2007.

2. 2011gl048757-fs02.eps

Figure s2. a. Local phase/elevation ratio of interferogram between acquisitions 10-16-2006 and 11-20-2006, in radar geometry. One color cycle is 2pi rad/km. b.

Local phase/elevation ratio on the corresponding stratified delay map predicted by ERA-I. Ratios are estimated on a 10*10 km-square sliding window.

3. 2011gl048757-fs03.eps

Figure S3. Absolute values of average local phase/elevation ratios for wrapped interferograms in the Himalayan area, before correction (black), after

correction with ERA-I delay map (red). Interferograms are sorted by increasing temporal baselines. The black arrow indicates the example shown in Fig.3.

4. 2011gl048757-fs04.eps

Figure S4. a. Residual orbital ramp estimated on the interferogram of Figure 1 corrected with the 2D ERA-I delay prediction. b. Residual orbital ramp estimated by a joint inversion of a linear phase/elevation relationship and orbital

residuals. The inferred orbital contribution is lower when correction of the

atmospheric phase delay predicted by ERA-I is made. Furthermore, orbital ramps are likely to result in an azimuth-parallel warped plane, which is not the case when jointly estimated with a linear phase/elevation relationship, suggesting that atmospheric and orbital contributions are not well separated in the empirical correction. Empirical estimation of an homogeneous phase/elevation linear relationship on the scene lead to underestimate delay at some places, which is compensated by unreasonnably high orbital contribution. Estimation of the tectonic signal, which makes a much smaller contribution to the

interferometric phase, is therefore most likely biased using this approach.

5 10 15 20 25 30

a. b. c.

Ph as e ( ra d)

3000 4000 5000

Elevation (m)

e.

ER A -I P re di ct io n ( ra d)

Phase (rad)

f. d.

−π 0 rad π

Phase

−π 0 rad π

Phase

4000 60005000 m

Elevation

Tibet

Kunlun Pass fault Xidatan fault Qaidam basin

Go

LOS

10 15 20 25 30

10 15 20 25 30

ERA-I

Data Residual DEM _{25 km}

N

−π 0 rad π

Phase

a. b.

−π 0 rad/kmπ

Phase

0 rad/kmπ

Phase

0 1

Absolute value of average phase/elevation ratio (rad/km) ^{0 10 20 30} Interferograms #

2 3 4 5

6 Data

ERA-I

6 months 9 months 1 yr

70 days

35 days 2 yr 3 yr

a. b.

−π 0 rad π

Phase

−π 0 rad π

Phase