NUMERICAL SIMULATION OF METHANE EMISSION FROM SUBARCTIC LAKE IN KOMI REPUBLIC (RUSSIA)

Abstract

During last decades, a special attention has been paid to methane emission from lakes [Bastviken et al., 2004; Wik et al., 2016 and etc.] as one of the significant sources of this important greenhouse gas to the atmosphere. However, attempts to simulate methane production and efflux at the air-water interface are scarce [Stepanenko et al., 2011; Tan et al., 2015a; Tan et al., 2015b] and models proposed so far need further validation using observation datasets. In this study, we use the 1D + numerical model LAKE [Stepanenko et al., 2011; Stepanenko et al., 2016]. The LAKE model was applied to a small subarctic lake in the Seida study site (Komi Republic, Russia) for identification of the key factors influencing the surface CH4flux and its concentration in the lake. We carried out a calibration of biogeochemical constants involving qualitative considerations of the character of biogeochemical and physical processes occurring in the lake and aiming at a satisfactory agreement with observations, performed by the University of Eastern Finland (UEF) [Lind et al., 2009; Marushchak et al., 2016]. Comparing our model calibration results to earlier studies suggest that the crucial parameter of the model – methane production rate constant (Pnew, 0) – has similar values for lakes of different types in high latitudes.