Study On The Water Evaporation Salinity Effect And The Influencing Factors

The northwest region is arid and semi-arid climate in our country,the climate is dry, strong evaporation, low rainfall. There are many salt lakes. so research under the condition of different salinity water body in the natural evaporation of experiments can be yantian baysalt, the change of salt lake water level to provide basic data, and reasonable estimate of different salinity water surface evaporation, integration of the meteorological factors to analysis of different salinity of the water evaporation is of great significance.Through carrying out field experiment, the paper looks into the evaporation from water surface and the changes of temperature about four Na Cl solutions with different concentrations in the evaporator under the same weather conditions, analyzes the salinity effect on different time scales and the change rule of temperature on the profile, combined with the structure characteristics of the experiment itself, based on energy conservation principle, analyzes from where and to where the energy in the experiment comes and goes, and analyzes the physical process of evaporation of the evaporator. The paper selects the evaporation capacity and the related meteorological data, analyzes the response situation of fresh water and salt water to the main meteorological factors, using statistical methods, compares the effects of four main meteorological elements(air temperature, wind speed, air humidity, and water surface net radiation) on the evaporation process of the evaporator, and using grey correlation degree, analyzes the meteorological factors which affect the evaporation capacity of fresh water and salt water on different time scales(day, ten days, month). The main conclusions are summarized below:(1)As a whole, the change trends with the time of the evaporation from water surface of the four Na Cl solutions with different concentrations in the evaporator have a certain similarities, but there exists the salinity effect(on the day scale, when the evaporation is strong, the salinity effect is obvious) on the time scales of day, month and season, the salinity of water body and evaporation capacity present a negative correlation relationship, and the statistical research finds that there may exist index relations between them.(2)The change of day : when the salinity changes and the evaporation is strong, the time when the maximum average daily evaporation intensity in each evaporator appears lags behind: fresh water between 13:00-14:00; 2.4% saline solution, about 13:00-14:00; 6.5% saline solution, about 14:00; 9% saline solution, between 14:00-15:00, and the maximum average daily evaporation intensity is not very significant. And when the concentration is more than 11%, the evaporation is very weak on the day scale.The change of mounth :it more apparent than the scale of day,when the solution concentration increased 1% months evaporation fall within the range of 2.2 mm to 2.2 mm;Seasonal change process: in summer, when the salinity increases to 11%, the evaporation is very weak, and inautumn, when the concentration of salt solution reaches 9%, the evaporation is not very obvious.(4) When the salinity increases, the water surface temperature in each evaporator decreases gradually, and the water temperature changes is basically similar, but with the increase of the salinity, the constant temperature zone in the lower part of the water has a tendency to move up gradually. In fresh water, there is a positive correlation between water-gas temperature difference and evaporation capacity at night, and there is a significant negative correlation relationship in the day.(5) The main meteorological factors which affect fresh water and salt water are all: air temperature(x1), wind speed(x2), relative humidity(x4) and net radiation(x3), and air temperature and evaporation capacity are positively correlated; evaporation capacity and wind speed are positively correlated; relative humidity and evaporation capacity are negatively correlated; net radiation and evaporation capacity are negatively correlated. Aiming at the response of the meteorological factors above, compared with fresh water, salt water evaporation lags behind.(6)By using multiple regression analysis it is concluded that between the fresh water(y1),salt water(y2)and the main meteorological elements necessarily relations are:y1=1.331+0.175x1+0.415x2-0.054x3+0.002x4y2=-1.883+0.158x1+0.275x2-0.017x3+0.001x4...