###### Abstract
Some work has presented research on hybrid wind-solar systems. For instance, based on the long-term recorded data of wind speed and irradiance, a calculation methodology of a PV array for a standalone hybrid wind/PV system was developed to improve the ability to find the optimum size of the PV array [11]. A report by Reference [12] indicates methodologies to model components and designs of hybrid renewable energy systems, and evaluates them. A case study of isolated site Potou in the northern coast of Senegal also described methodology based on a multiobjective genetic algorithm to realize the optimization of a hybrid solar-wind-battery system, and indicates the influence of load profiles on optimal configuration [13]. More accurate mathematical models for characterizing the PV module, wind generator, and battery were used to achieve the configurations of various types and capacities of system devices by changing the type and size of the devices' systems [14]. A hybrid system was proposed and applied in many cities in Iraq, which can be considered a renewable resource of power generation. The simulation calculation of this system was done by software based on local meteorological data and the sizes of PV and wind turbines. The results illustrate that it is useful to utilize the solar and wind energy to generate power in harsh environments [15]. Wind and solar energy are unpredictable and weather-dependent in the polar regions. An energy-storage system (ESS) is necessary as a reliable back-up to the observing system in order to store excess energy and then release the power to guarantee periods when a net load occurs. Some integrated wind-PV-battery hybrid systems and power-management strategies were proposed to offer a lower cost and higher efficiency [16]. Isolated power systems built by hybridizing renewable-power sources (wind and solar) in Indian used a battery as appropriate energy storage [17]. Studies [18; 19] have developed an energy-management strategy and new photovoltaic solar structure for a renewable-energy system for rural communities to meet load demands. The observation equipment used in cold regions often uses batteries as power storage. However, batteries are sensitive to low temperatures, which can decrease their capacity. Therefore, a hybrid wind- and solar-energy system is also temperature-dependent. In this study, a new observing system was designed to observe multiple parameters of polar environments based on analysis of the previous deployment of the observing system in the Arctic Ocean. Mathematical models of the PV array, wind turbine, and low-temperature characteristics of a PV panel are proposed. A lead-acid battery was selected for the standalone hybrid wind-solar system. Since battery capacity varies at different ambient temperatures, battery capacities must be calibratedbased on charging and discharging experiments at low temperatures. Charging strategy for a battery in polar environments was also designed. A hybrid wind-solar charging circuit was developed to provide a reliable power supply to the observing system by adapting to the low ambient temperature in the Arctic Ocean and Antarctica. This hybrid wind-solar charging circuit is composed of a solar charging circuit, a wind-turbine charging circuit, a detection circuit, an analog-to-digital converter ADC circuit, and an auxiliary circuit [20]. We have comprehensively evaluated the temperature dependence of the circuit with laboratory experiments from \(-50\)\({}^{\circ}\)C to \(30\)\({}^{\circ}\)C. The monthly average energy production from the PV panel and the wind turbine were simulated using monthly average meteorological data. A case study of the operational results of the power system during field observations in Zhongshan Station, East Antarctica was examined to evaluate the technical feasibility and stability of the hybrid wind-solar system. In these contexts, this paper focused on exploring a standalone hybrid wind-solar system for automatic observation systems designed to be used in the polar regions.