[Insert Figure 4 about here]
Figure 4: Inter-annual temperature variations of 10 selected typical large lakes from Asia. Please note that LWST is plotted on different scales for each lake.
3.2.2. Typical lakes from Europe
The inter-annual variations of 8 selected typical lakes across Europe during 2001-2015 are shown in Figure 5. An obvious increasing trend for nighttime LWST was observed in Lake Ladoga (Russia) (y = 0.21x -428.07, R² = 0.36, P=0.02), while no definite trend was observed from daytime measurements (y = 0.06x -122.44, R²=0.1, P=0.26) (Figure 5(a)). Lake Onega, Vattern and Vanern are closely located (Figure 1), and exhibited very similar trend in LWST (Figure 5(b-d)), with highest and lowest annual temperatures recorded in 2007-2008 and 2011, respectively. A slight increase trend in LWST was noted for Lake Gevena (Figure 5(e)). Likewise, Lake Neagh and Lake Kuybyshevskoye showed a slight trend in LWST increase, though not significant (Figure 5(f-g)). While the temporal variation in daytime LWST was not significant (y = 0.03x -38.23, R² = 0.11), Lake Bolsena showed a clear trend of increased nighttime LWST (y = 0.05x -82.48, R² = 0.38; Figure 5(h)) during the period of study.