Under A1B, A2, and B1 emissions scenarios, there is great uncertainty in simulation of temperature and precipitation of the 21st century with climate models on product information the Tibetan Plateau. Temperature and precipitation of GCMs will all increase with different ratios. Precipitation under A2 scenario will increase most significantly while there is the least increase under A1B scenario. Based on evaluation of simulation performance with 22 climate models from IPCC AR4, there are great differences in the simulated values while only a few models have well simulated temperature and precipitation on the Tibetan Plateau. It is obvious that simulation with GCMs still needs to be further improved. Because of the low resolution of GCMs, parameters of physical process of climate models are also needed to be further improved, so there are great uncertainties in the simulation of temperature and precipitation.
In the future, we could think of downscaling methods to predict climate changes in order to find proper method for China and provide more reliable prediction results with multi-model ensembles method. view of many uncertainties of climate models, it is of great importance to investigate climate changes in China with GCMs to reduce those uncertainties.AcknowledgmentsThis work was financially supported by the National Basic Research Program of China (2010CB951101), the National Natural Science Foundation of China (40830639, 41101015), the ��Strategic Priority Research Program��Climate Change: Carbon Budget and Relevant Issues�� of the Chinese Academy of Sciences (XDA05110102), and the Special Fund of State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering (1069-50985512).
Recently, lots of hydraulic servo systems have been replaced by electric motor-driven systems to overcome the drawbacks of traditional hydraulic servo systems such as oil leakage, maintenance, and laying complex pipe. In spite of these drawbacks, hydraulic systems are still used in fields that require large force and high power. Brefeldin_A In order to solve these issues, electrohydrostatic actuator (EHA) systems are in the process of being developed for industrial use. The EHA systems can also be referred to as a direct drive volume controlled (DDVC) actuator [1�C3] or valveless hydraulic servo (VHS) actuator [4].The EHA systems generally consist of an electric motor, hydraulic pump, hydraulic cylinder, accumulator, check valves, and relief valves for safety. An electric motor that is directly tied to the hydraulic pump controls the cylinder, whose directional change depends upon the electric motor’s rotation direction.