Early spring

Date of acquisition

Cloud cover (%)

elevation angle

Satellite azimuth angle

1986/04/31

−10%

59.55

0

1990/04/04

−10%

53.69

0

1992/04/01

−10%

52.05

0

1993/03/04

−10%

49.88

0

1994/04/08

−10%

49.55

0

1995/04/02

−10%

43.43

0

1996/03/12

−10%

54.95

0

1998/03/02

−10%

48.07

0

1999/03/21

−10%

61.01

0

2000/04/31

−10%

52.21

0

2001/03/17

−10%

44.60

0

2003/04/01

−10%

43.92

0

2004/03/09

−10%

47.91

0

2007/03/11

−10%

54.22

0

2008/03/13

−10%

43.07

0

2009/03/16

−10%

47.34

0

2010/03/19

−10%

51.09

0

2011/04/07

−10%

60.24

0