## 1 Introduction
From the aforementioned review of SEB models, we know that both single-source and two-source models are based on the energy balance equation (Equation (1)) that is founded on the premise of ignoring the energy transported by horizontal advection and consumed by photosynthesis [16; 17]. Nevertheless, the presence of horizontal advection always characterizes exchanges in the near surface layer and contributes to the uncertainty of energy influxes [23; 24]. Neglecting systematic sampling errors, systematic instrument bias, low and high frequency loss of turbulent fluxes and energy sinks, horizontal advection of heat and water vapor is regarded as the primary reason for the non-closure ofthe surface energy balance [25; 26; 27]. To a certain region, uncertainties from horizontal advection on the surface energy balance have two aspects. One is the horizontal advection itself, which develops on heterogeneous surfaces and exerts profound influence on the energy balance equation. This has been reported in many previous studies [28; 29]. Therefore, horizontal advection should be discussed as one reason for energy imbalances and regarded as a necessary item to add to the energy balance equation. The other uncertainty refers to the ground-based meteorological variables of air temperature, humidity and other auxiliary surface measurements inputted to the energy balance equation. These meteorological variables are actually measured and thus characterize the practical circumstance rather than describe the environment under the condition of energy balance closure, which means that the actually observed meteorological variables have already contained effects from the horizontal advection and would affect the energy balance equation when they are used as inputs. In conclusion, horizontal advection affects the energy balance equation directly through energy inputs or outputs, whereas ground-based observations impact the energy balance equation indirectly by including the effects of advection. In view of the prevalence of the horizontal advection and its influence on the energy balance system, it is of great necessity to take into account the horizontal advection when applying SEB models to estimate ET. The objective of this paper is to propose an innovative method, the surface energy balance-advection (SEB-A) method, which is based on the energy balance equation and considers the horizontal advection as well to derive ET. The SEB-A method assumes that the energy consumed in the actual ET consists of two parts; one part is provided by the energy balance system and the other part is brought in by the horizontal advection. The former, called local ET, can be obtained by the modified energy balance equation (Equation (3)), and the calculation method of it is similar to previous studies that are on the SEB models; the latter, called exotic ET, can be calculated with the help of ground-based EC observations. Section 2 describes the datasets used to assess the method. Section 3.1 presents a description on the theory of calculating the local ET that is regulated by the energy balance system, and Section 3.2 introduces approaches for deriving the exotic ET that is driven by the horizontal advection. Section 4 shows the results of the SEB-A method that was applied on a regional scale by using variables retrieved from ASTER imagery and HJ-1A/B imagery and measured at meteorological and EC stations. Section 5 discusses the advantages and limitations of the SEB-A method. Section 6 concludes the work.