The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B7. Beijing 2008 
104 
4. DATSETS AND TESTING RESULTS 
The western part of Phoenix (in Arizona, USA) consists of Deer 
Valley and the west Salt River Valley (Buckley, 2000), where 
several towns are included, i.e., Glendale, Peoria and Sun City. 
The excessive pumpage of groundwater in the areas has resulted 
in a large extent of land subsidence. The early interferometric 
study with a limited set of ERS C-band SAR images reported 
that several subsiding bowls exhibit across the towns (Buckley, 
2000). We attempt to detect the spatio-temporal subsidence 
distribution in Phoenix by the method presented in section 2 
and 3. For this study, we use 39 ERS SAR images acquired 
from 1992 to 2000, which are combined to form 86 
interferometric pairs by thresholding of spatial and temporal 
baseline shorter than 120 m and 4 years, respectively. Table 1 
lists the information of all the interferometric pairs. Figure 1 
shows the study site and all the PSs superimposed onto the SAR 
amplitude image averaged from all the datasets. 
Master/Slave 
Dates, YMD a 
B L 
(m) 
T 
(days) 
Master/Slave 
Dates, YMD 
B 1 
(m) 
T 
(days) 
Master/Slave 
Dates, YMD 
B L 
(m) 
T 
(days) 
920710/930521 
24 
315 
950827/960916 
104 
386 
961230/970519 
-35 
140 
920710/931008 
-78 
455 
950827/980330 
52 
946 
961230/981130 
-86 
700 
920710/950827 
-85 
1143 
950827/981130 
88 
1191 
961230/990802 
-65 
945 
920814/930205 
-25 
175 
950827/990802 
109 
1436 
961230/991220 
-21 
1085 
920814/950514 
80 
1003 
951105/951210 
-68 
35 
961230/001030 
54 
1400 
920814/960603 
36 
1389 
951105/961021 
106 
351 
970310/970519 
-91 
70 
920918/951106 
-79 
1144 
951106/951211 
-51 
35 
970310/990315 
73 
735 
920918/951210 
64 
1178 
951106/980504 
16 
910 
970310/991220 
-76 
1015 
921023/960812 
113 
1389 
951106/990628 
-65 
1330 
970310/001030 
-2 
1330 
930205/950514 
105 
828 
951211/980504 
67 
875 
970519/980330 
-88 
315 
930205/960603 
60 
1214 
951211/990628 
-15 
1295 
970519/981130 
-51 
560 
930521/931008 
-101 
140 
960218/960219 
53 
1 
970519/990802 
-31 
805 
930521/950827 
-109 
828 
960218/961021 
-35 
246 
970519/991220 
14 
945 
930521/960916 
-5 
1214 
960218/980608 
-5 
841 
970519/001030 
89 
1260 
930521/961230 
65 
1319 
960219/960428 
87 
69 
980223/980713 
90 
140 
930521/970519 
31 
1459 
960219/961021 
-88 
245 
980330/981130 
37 
245 
930903/961230 
-98 
1214 
960219/980608 
-58 
840 
980330/990802 
57 
490 
930903/970310 
-42 
1284 
960603/980223 
31 
630 
980330/991220 
103 
630 
931008/950827 
-8 
688 
960812/971215 
-112 
490 
980504/990628 
-81 
420 
931008/960812 
-41 
1039 
960812/980330 
85 
595 
980608/000508 
13 
700 
931008/960916 
97 
1074 
960916/961230 
70 
105 
981130/990802 
21 
245 
931217/960218 
-73 
793 
960916/970519 
36 
245 
981130/991220 
65 
385 
931217/960219 
-19 
794 
960916/980330 
-52 
560 
990315/990524 
50 
70 
931217/960428 
68 
863 
960916/981130 
-16 
805 
990315/001030 
-75 
595 
931217/961021 
-107 
1039 
960916/990802 
5 
1050 
990524/990628 
110 
35 
950514/960603 
-44 
386 
960916/991220 
50 
1190 
990802/991220 
46 
140 
950514/980223 
-13 
1016 
961021/980608 
29 
595 
990802/001030 
119 
455 
950514/980713 
76 
1156 
961021/000508 
42 
1295 
991220/001030 
75 
315 
950827/960812 
-33 
351 
961230/970310 
56 
70 
a YMD: year, month, day; Read 920710 as July 10, 1992, and 001030 as October 30, 2000. 
Table 1. Summary information for 86 short baseline interferometric pairs 
Figure 1. The study site and PS pixels superimposed onto the SAR amplitude image averaged from all the datasets.