Coverages
Spatial coverage :
- Sud de Gansu: latitude between 34° 36' N and 34° 28' 47" N, longitude between 104° 20' 24" E and 104° 37' 47" E, between 2200m and 2600m of altitude
Time coverage :
- 1ère période: between 1996 and 1997
- 2e période: between 2005 and 2006
- 3e période: between 2014 and 2015