Monitoring Lake Water Temperature and Estimating Evaporation in Western Iraq Using Ground-based Meteorological Observations and Satellite Remote Sensing

Abdulqader Mahdi Salh (Higher Institute of Desert Sciences, University of Anbar, Ramadi, 31001, Iraq)
Bilal Bardan Ali (Department of Geography, College of Education for Humanities, University of Anbar, Anbar, Iraq)
Ahmed M. El Kenawy (Instituto Pirenaico de Ecologia, Campus de Aula Dei, 1005, 50059, Zaragoza, Spain Department of Geography, Mansoura University, Mansoura, 35516, Egypt)
Khamis Daham Muslih (University of Baghdad, College of Arts, Department of Geography & GIS)
Sara Ismail Chiad (Higher Institute of Desert Sciences, University of Anbar, Ramadi, 31001, Iraq)

Forum Geografi
Vol. 41 No. 1 (2027): April 2027

Monitoring and estimating water loss rates from lakes in arid regions is challenging due to the scarcity of climate data. Therefore, this study aimed to investigate the spatiotemporal variation of lake surface temperature and evaporation for Tharthar Lake (western Iraq) using ground meteorological observations and satellite remote sensing technique. Three meteorological parameters—air temperature, humidity, and wind—were used in this study to conduct temporal analysis from January–December 2023. These parameters are available in the dataset of Tikrit weather station. Land Surface Temperature (LST) was obtained by processing thermal and infrared data of Landsat 9. Further, evaporation was calculated by the METRIC (Mapping Evapotranspiration at High Resolution with Internalized Calibration) model by solving the surface energy balance and scaling the instantaneous surface fluxes to daily and seasonal totals. The METRIC model was validated by an independent machine learning-based validation. The results demonstrate that the temperature of the air in contact with the lake surface varies seasonally, ranging between 3.2 °C (January) and 47 °C (July). Additionally, relative humidity displays a seasonal pattern: declining from approximately 79% (winter) to 19% (summer). Evaporation during winter and summer was less than 1 mm /day and over 4 mm /day, respectively. The evaporation rate exhibited a clear spatial discontinuity where the evaporation loss was relatively higher along the shallow periphery and southern parts of the lake compared to the deep central areas. Evaporation dynamics and seasonal variation of the lake are primarily governed by atmospheric forces. Notably, the evident seasonal evaporation indicates that Tharthar Lake is vulnerable to considerable seasonal water loss. The approach used in this study is a flexible method for evaporation monitoring at lakes in arid and data-scarce regions and can be applied in Iraq, where similar conditions are prevalent, to support the sustainable management of water resources.