Thermal response of Moroccan lakes to climatic warming: first results

Abstract

Water temperature plays a primary role in controlling a wide range of physical, geochemical and ecological processes in lakes, with considerable influences on lake water quality and ecosystem functioning. In this paper, we report on the ability of the one-dimensional lake model to simulate the water temperature of Moroccan lakes, i.e., Sidi Boughaba and Sidi Ali lakes, over a 35 yrs period from 1979 to 2014, affected by climate change and based on a freshwater lake model (FLake). During the study periods, two variables are studied, the epilimnion and metalimnion temperatures. The result analysis shows that epilimnion temperatures increased, while metalimnion temperatures decreased. Additionally, we calculate significant air temperature, wind speed and water temperature variation and illustrate, using a sequential t test analysis of regime shifts (STARS) based on the Rodionov method, a substantial increase in annually averaged of all variables, in response to an abrupt shift in the climate. Schmidt stability showed a significant increase for Sidi Ali Lake and near 0 for Sidi Boughaba Lake. On the other hand, the sensitivity analysis (i.e., one-at-a-time (OAT) method) of the atmospheric variable is discussed. The results show good agreement with water temperature observations that suggests that the predictive model can be used to obtain a firstorder estimation of water temperature in Moroccan lakes. Hence, it is possible to apply this model in other Moroccan lakes to simulate the behavior of temperature and to investigate the potential future warming of the water column in lakes, affected by climate change.

The increasing of maximum lake water temperature in lowland lakes of central Europe: case study of the Polish Lakeland

“…Kangur et al (2013) observed an increase in maximum water temperature in the summer period for Lake Peipsi (Estonia/ Russia). In a broader perspective the response of lakes to climatic changes in this part of Europe is similar to many other cases located in different regions of the world (Austin and Colman, 2007;Hampton et al, 2008;Shimoda et al, 2011;Groß-Wittke et al, 2013;Zhong et al, 2016;Haddout et al, 2018). For instance, for the summer period (July-September) the surface water temperature in the Great Lakes in North America experienced a warming trend at a rate of 1.1 °C dec -1 (Austin and Colman, 2007).…”

Effect of climate warming on a change in thermal and ice conditions in the largest lake in Poland – Lake Śniardwy

“…A study by Li et al, (2019) conducted in four lakes in the Yangtze River catchment showed that over the 39-year study period, the surface water temperature increased at a rate of 0.26-0.28°C dec -1 . Mean annual temperatures in the epilimnion in two lakes in Morocco (Sidi Ali and Sidi Boughaba) in the years 1979-2014 increased by 0.198 and 0.013°C dec -1 , respectively (Haddout et al, 2018). It is worth emphasising that the rate of increase in water temperature in Lake Śniardwy was higher than that for air temperatures for the nearby meteorological station in the analogical period.…”

Long-term water temperature changes in Seneca Lake and their nexus to climate change and human activities

“…It is interesting to note that as shown in figure 2(b), the rate of temperature increase in the metalimnion layer was notably higher than that in the epilimnion layer. The temperatures of the epilimnion layer are strongly correlated with air temperature and are directly affected by climate warming (Haddout et al 2018). But the heightened vertical mixing occurring within the epilimnion and metalimnion layers due to warming (Wahl and Peeters 2014) can push the thermocline slightly downward, causing faster warming at the metalimnion layer.…”