The oasis transition during 1990 and 2020 was exhibited in Figure 6,
which illustrated the distribution features of various oasis types in
Tuha Basin. Totally, the area of oasis converted to non-oasis was
3940.70 km2; and 9570.38 km2 of
non-oasis converted to oasis, which demonstrated the oasis expansion in
Figure 3. Specifically, as an almost transfer-in type, the converted
area from non-oasis to artificial oasis was 1418.18
km2, distributing in the southeast of Gaochang
district, surrounding of Yizhou district and northern Balikun county.
Natural oasis converted 3520.84 km2 to non-oasis,
mainly occurred in northern and eastern Balikun; as an important
transfer-in oasis, non-oasis converted 8152.20 km2 to
natural oasis, mainly concentrating in northern part of Balikun county.