[Insert Figure 8 here]
3.6 Associations of TP lake level and precipitation
changes with El Niño/La Niña
events
We further found the potential associations of lake and precipitation
variations on the TP with El Niño and La Niña events, as illustrated in
Fig. 9, S3 and S4. In the CTP, considerable expansion can be found at
Zhari NamCo, Tangra YumCo and Seling Co during the 2016/2017 and
2017/2018 La Niña events, corresponding well with excessive
precipitation in these two years. On the NTP, dramatic expansions can
also be found at Dogai Coring Lake and Lexiewudan Lake during the
2016/2017 and 2017/2018 La Niña events (Fig. S4). The expansion of Zhari
NamCo was also remarkable due to the dramatic precipitation increase
likely driven by La Niña. Despite some exceptions, we can see that
drastic lake expansion in the TP is very consistent with historical La
Niña incidents, which indicates that La Niña events may exert evident
impact on the hydroclimate of the TP. In addition to ENSO, other climate
variabilities (e.g., the North Atlantic Oscillation, Arctic Oscillation,
and the Indian Ocean Dipole) may also promote the lake expansion in the
TP (Liu and Juárez 2001; Wang et al. 2008). In contrast, considerable
lake shrinkage (in 2011 and 2015) occurred in the TP during El Niño
events (Lei et al. 2019). We here found a phenomenon that is different
from the results of previous studies. In NTP, the lake level changes
have drastically increased relative to 2015 (El Niño event) during the
2016/2017 and 2017/2018 La Niña events (Fig. S4), whereas the
teleconnection between lake dynamics and La Niña appears weaker in NWTP.
The three selected lakes (LumajangdongCo, Jieze Caka and Heishibei Lake)
in NWTP expanded steadily even in 2015, but lake expansion was more
dramatic in 2016 and 2017 (Fig. 5 and Fig. S1).
This
continuous lake expansion is dominated by lake dynamics in NWTP as
reported in previous study (Jiang et al. 2017; Kleinherenbrink et al.
2015; Lei et al. 2017). Since glaciers are widely distributed in NWTP,
the contribution of glacier melt to lake level change may be greater
than the impact of the La Niña event. As indicated above, water level
changes of different lakes showed different spatial and temporal
patterns due to the obvious spatial heterogeneity of climate change.
This anomaly rainfall change is closely associated with El Niño/La Niña
event or other atmospheric circulation events.