Sensible Heat Transfer Research Articles

High-resolution maps of carbon dioxide and moisture fluxes over an urban neighborhood

Mapping fluxes of CO2 and moisture at building to block scale is necessary to take informed action to mitigate climate change and reduce urban warming. This study used the aerodynamic resistance approach to build maps at fine spatial resolution.

Impact of urban morphology on the microclimatic regulation of water bodies on waterfront in summer: A case study of Wuhan

Urban water bodies reduce urban heat through evaporation and transfer of sensible heat. However, today's highly intense urban construction patterns cause poor urban air mobility and excessive residual heat accumulation, and weaken water bodies' regulating effects. This study examines the relationship between urban morphology and water bodies' microclimatic regulation during summer in the water-network city, Wuhan, using remote sensing data and the weather research and forecasting (WRF). This study found (1) on the waterfront, the key impact indicators for microclimate in the waterfront are building density (BD) and floor area ratio (FAR), both of which can lead to higher temperatures and lower humidity, (2) BD significantly warmed the waterfront on the large lakes, while FAR impacted the urban main windway areas, (3) urban development with high FAR significantly suppressed the water's cooling ability in the downtown and main windway areas, with the cooling intensity decreased by 28.7% and 20.6%, respectively, and the cooling distance decreased by 13.5% and 15%. These findings provide insights for the practice of climate adaptive planning and design on the water network-related urban areas of Wuhan and other places with similar environments.

Performance analysis and efficiency enhancement of cooling tower in 210 MW thermal unit

Heat exchangers, condensers plays a vital role in any kind of power cycle like modified Rankin cycle, these components involves transfer of both sensible and latent heat and have great influence over the power plant performance. The condenser employed in MTPS involves transfer of latent heat into steam. Yet it as to induce a phase change in thereby forming water. Increase in the effectiveness of condenser resulted in the increase of vacuum in the condenser. Thereby work done by steam is increased and coal saving (per ton of steam production) is achieved. This condensation process results in the formation of sludge’s (temporary) and (permanent). Along the inner periphery of the condenser tubes. These permanent scales have decreased thermal conductivity and inhibit the heat transfer rate. The more the thickness of the scale the less the heat is removed from the steam. This scale formation limits the life of the condenser tubes with maximum performance. In this project the thickness of the scale formed in the condenser tubes is calculated theoretically and the performance is analysed before and after scale formation in the condenser. Different materials which involve less scale formation, different ways of reducing scales and various scale removing methods are suggested.

CMIP5 Models Predict Rapid and Deep Soil Warming Over the 21st Century

AbstractDespite the fundamental importance of soil temperature for Earth's carbon and energy budgets, ecosystem functioning, and agricultural production, studies of climate change impacts on soil processes have mainly relied on air temperatures, assuming they are accurate proxies for soil temperatures. We evaluated changes in soil temperature, moisture, and air temperature predicted over the 21st century from 14 Earth system models. The model ensemble predicted a global mean soil warming of 2.3 ± 0.7 and 4.5 ± 1.1 °C at 100‐cm depth by the end of the 21st century for RCPs 4.5 and 8.5, respectively. Soils at 100 cm warmed at almost exactly the same rate as near‐surface (~1 cm) soils. Globally, soil warming was slightly slower than air warming above it, and this difference increased over the 21st century. Regionally, soil warming kept pace with air warming in tropical and arid regions but lagged air warming in colder regions. Thus, air warming is not necessarily a good proxy for soil warming in cold regions where snow and ice impede the direct transfer of sensible heat from the atmosphere to soil. Despite this effect, high‐latitude soils were still projected to warm faster than elsewhere, albeit at slower rates than surface air above them. When compared with observations, the models were able to capture soil thermal dynamics in most biomes, but some failed to recreate thermal properties in permafrost regions. Particularly in cold regions, using soil warming rather than air warming projections may improve predictions of temperature‐sensitive soil processes.

Negative feedback processes following drainage slow down permafrost degradation.

The sustainability of the vast Arctic permafrost carbon pool under climate change is of paramount importance for global climate trajectories. Accurate climate change forecasts, therefore, depend on a reliable representation of mechanisms governing Arctic carbon cycle processes, but this task is complicated by the complex interaction of multiple controls on Arctic ecosystem changes, linked through both positive and negative feedbacks. As a primary example, predicted Arctic warming can be substantially influenced by shifts in hydrologic regimes, linked to, for example, altered precipitation patterns or changes in topography following permafrost degradation. This study presents observational evidence how severe drainage, a scenario that may affect large Arctic areas with ice‐rich permafrost soils under future climate change, affects biogeochemical and biogeophysical processes within an Arctic floodplain. Our in situ data demonstrate reduced carbon losses and transfer of sensible heat to the atmosphere, and effects linked to drainage‐induced long‐term shifts in vegetation communities and soil thermal regimes largely counterbalanced the immediate drainage impact. Moreover, higher surface albedo in combination with low thermal conductivity cooled the permafrost soils. Accordingly, long‐term drainage effects linked to warming‐induced permafrost degradation hold the potential to alleviate positive feedbacks between permafrost carbon and Arctic warming, and to slow down permafrost degradation. Self‐stabilizing effects associated with ecosystem disturbance such as these drainage impacts are a key factor for predicting future feedbacks between Arctic permafrost and climate change, and, thus, neglect of these mechanisms will exaggerate the impacts of Arctic change on future global climate projections.

Influence of urban form on the cooling effect of a small urban river

Urban warming due to increased urbanization is becoming a serious environmental problem, requiring urban planners to consider heat mitigation strategies that reduce urban air temperature. Urban rivers play an important role in reducing urban heat through evaporation and transfer of sensible heat, known as the river cooling effect (RCE). We used detailed field measurements to calculate the river cooling intensity (RCI) and river cooling distance (RCD) for the Cheonggye River in Seoul, Korea in order to determine the relationship between RCE and urban form at different times of day during summer. Our results showed that the Cheonggye River had a mean RCI of 0.46 °C and a mean RCD of 32.7 m at 2 p.m. and a mean RCI of 0.37 °C and a mean RCD of 37.2 m at 10 p.m. Spatial variations in RCE were negatively correlated with street width and mean building height at 2 p.m., indicating that narrower streets and lower buildings would improve the RCE. In addition, temporal variations in RCE were related to changes wind speed at similar humidity levels. Our results show that the urban form surrounding a river can affect the local RCE, suggesting that landscape and urban planners should consider urban form as a variable affecting urban heat and RCE.

Thermal Load Reduction with Green Building Envelope

Various studies have confirmed that high thermal resistance in roof & wall can reduce the heat transfer load of the buildings. In this study, experimental investigation of the effects of some sustainable features (such as green roof, reflective coated roof & Fly ash brick (FAB) etc.) on the building has been conducted in the Indian context. For the purpose, two scaled building models i.e. Model I (conventional design) & Model II (green design) have been examined with different design configurations. The sensible heat transfer (SHT) load of the building is reduced by 21% - 29% through the use of FAB with cavity wall in place of Fired clay brick (FCB) wall. The load reduction increases to 26% - 44% by using FAB cavity wall with reflective coating on the roof. This reduction further increases to 64% - 68% with FAB cavity wall along with green roof. In this final scenario, the monthly electrical energy saving for air-conditioning is approximately 5.1 kWhe/m2 per unit envelope area, with associated reduction in GHG emissions up to 6.36 kg CO2eq/m2 per unit envelope area, assuming continuous operation of HVAC systems.

Air-sea transfer of gas phase controlled compounds

Gases in the atmosphere/ocean have solubility that spans several orders of magnitude. Resistance in the molecular sublayer on the waterside limits the air-sea exchange of sparingly soluble gases such as SF6 and CO2. In contrast, both aerodynamic and molecular diffusive resistances on the airside limit the exchange of highly soluble gases (as well as heat). Here we present direct measurements of air-sea methanol and acetone transfer from two open cruises: the Atlantic Meridional Transect in 2012 and the High Wind Gas Exchange Study in 2013. The transfer of the highly soluble methanol is essentially completely airside controlled, while the less soluble acetone is subject to both airside and waterside resistances. Both compounds were measured concurrently using a proton-transfer-reaction mass spectrometer, with their fluxes quantified by the eddy covariance method. Up to a wind speed of 15 m s-1, observed air-sea transfer velocities of these two gases are largely consistent with the expected near linear wind speed dependence. Measured acetone transfer velocity is ∼30% lower than that of methanol, which is primarily due to the lower solubility of acetone. From this difference we estimate the “zero bubble” waterside transfer velocity, which agrees fairly well with interfacial gas transfer velocities predicted by the COARE model. At wind speeds above 15 m s-1, the transfer velocities of both compounds are lower than expected in the mean. Air-sea transfer of sensible heat (also airside controlled) also appears to be reduced at wind speeds over 20 m s-1. During these conditions, large waves and abundant whitecaps generate large amounts of sea spray, which is predicted to alter heat transfer and could also affect the air-sea exchange of soluble trace gases. We make an order of magnitude estimate for the impacts of sea spray on air-sea methanol transfer.

Antarctic and Southern Ocean Surface Temperatures in CMIP5 Models in the Context of the Surface Energy Budget*

Abstract This study examines the biases, intermodel spread, and intermodel range of surface air temperature (SAT) across the Antarctic ice sheet and Southern Ocean in 26 structurally different climate models. Over the ocean (40°–60°S), an ensemble-mean warm bias peaks in late austral summer concurrently with the peak in the intermodel range of SAT. This warm bias lags a spring–summer positive bias in net surface radiation due to weak shortwave cloud forcing and is gradually reduced during autumn and winter. For the ice sheet, inconsistencies among reanalyses and observational datasets give low confidence in the ensemble-mean bias of SAT, but a small summer warm bias is suggested in comparison with nonreanalysis SAT data. The ensemble mean hides a large intermodel range of SAT, which peaks during the summer insolation maximum. In summer on the ice sheet, the SAT intermodel spread is largely associated with the surface albedo. In winter, models universally exhibit a too-strong deficit in net surface radiation related to the downward longwave radiation, implying that the lower atmosphere is too stable. This radiation deficit is balanced by the transfer of sensible heat toward the surface (which largely explains the intermodel spread in SAT) and by a subsurface heat flux. The winter bias in downward longwave radiation is due to the longwave cloud radiative effect, which the ensemble mean underestimates by a factor of 2. The implications of these results for improving climate simulations over Antarctica and the Southern Ocean are discussed.

COOLING CONDENSERS WITH COLD AIR FLOW OR AIR ELIMINATION IN POWER PLANT TOWERS

Abstract. Evaporative cooling mechanism and specific heat exchange are principles of cooling happening in towers. Air/water mixture releases enthalpy of vaporization. Vapor rises from consumed hot water to cold air flow and water evaporation energy is 1000 Btu per kilogram. This endothermic process from water decreases water temperature. Water loss is the drawback of this process which enters the air from tower in the form of vapor. The vapor is approximately 1.2 percent for each 5.5 Centigrade degrees of tower range in normal condition .Sensible heat which changes temperature also plays an important role in this process. When water is warmer than air, air consequently cools water, leading to increased air temperature .Since water sensible heat transfers to air, released enthalpy of vaporization enjoys cooling effect and this effect forms almost 75 percent of total cooling process of tower and the remaining 25 percent is related to specific heat exchange .Cooling towers are not away from general rules of protection.

Estimation of the Water Temperature Influence on Direct Evaporative Cooler Operation

In the present paper a study is conducted of the mass and heat transfer phenomena which rule the function of a direct evaporative cooler. A comprehensive mathematical model is developed, which is based on the latent and sensible heat transfer and can predict the effectiveness of such a cooler under any circumstances of operation and water supply. As a development of the existing simulation models of direct evaporative coolers, the model presented here is general, as far as the temperature of the supply water is concerned. In addition, direct evaporative cooling is valued according to its efficiency, the quality of outcoming air and the specific consumption of water while working in Mediterranean climates.

The energy balance of a US Class A evaporation pan

Concurrent with the trend of rising global average air temperature, there have been worldwide observations of a decline in pan evaporation over the last 30–50 years. This global phenomenon has since received much attention from the scientific community. Better interpretation of the long-term trend of pan evaporation (involving seasonal and inter-annual variations) requires rigorous experimental investigation of the physics of pan evaporation. To do that, we constructed an instrumented US Class A pan that replicated an operational pan at Canberra Airport in Australia. We subsequently monitored pan evaporation and associated meteorological variables at half-hourly intervals over a three-year period (Oct 2007–Jan 2010).Extending our earlier work on the aerodynamics of pan evaporation, we conducted a theoretical and experimental study on the energy balance of the pan under non-steady state conditions. The theory considers heat exchanges at both the pan water surface and the pan wall. We formulate the radiative balance based on the geometry of the system (the pan diameter, the height of the water level, the height of the rim and solar zenith angle) and account for differences in albedo and emissivity between the pan water surface and the pan wall. The theory is used to compute all relevant energy fluxes and thereby close the energy balance. Integration of the half-hourly fluxes to a daily basis showed that we were able to close the energy budget with a RMSE of ∼18Wm−2 or 7.5% of the net short-wave radiation. We find that evaporation from our pan is dominated (∼80%) by the radiative exchanges at the pan water surface; those at the pan wall are smaller but also important. Contrary to expectation, there was little if any sensible heat exchange across the pan wall. Instead we found that the major sensible heat flux occurs across the pan water surface. Importantly, evaporative cooling at the pan water surface can result in a transfer of sensible heat from the (warmer) air to the (cooler) surface of the water body. The sensible heat flux from the overlying air to the pan water surface is minimal at low evaporation rates, but at higher evaporation rates (e.g., >300Wm−2) it contributes the equivalent of up to 15% of the total evaporative flux.

Nonequilibrium thermodynamics of circulation regimes in optically thin, dry atmospheres

An extensive analysis of an optically thin, dry atmosphere at different values of the thermal Rossby number Ro and of the Taylor number Ff is performed with a general circulation model by varying the rotation rate Ω and the surface drag τ in a wide parametric range. By using nonequilibrium thermodynamics diagnostics such as material entropy production, efficiency, meridional heat transport and kinetic energy dissipation we characterize in a new way the different circulation regimes. Baroclinic circulations feature high mechanical dissipation, meridional heat transport, material entropy production and are fairly efficient in converting heat into mechanical work. The thermal dissipation associated with the sensible heat flux is found to depend mainly on the surface properties, almost independent from the rotation rate and very low for quasi-barotropic circulations and regimes approaching equatorial super-rotation. Slowly rotating, axisymmetric circulations have the highest meridional heat transport. At high rotation rates and intermediate-high drag, atmospheric circulations are zonostrophic with very low mechanical dissipation, meridional heat transport and efficiency. When τ is interpreted as a tunable parameter associated with the turbulent boundary layer transfer of momentum and sensible heat, our results confirm the possibility of using the Maximum Entropy Production Principle as a tuning guideline in the range of values of Ω. This study suggests the effectiveness of using fundamental nonequilibrium thermodynamics for investigating the properties of planetary atmospheres and extends our knowledge of the thermodynamics of the atmospheric circulation regimes.

Sensitivity of simulated short-range high-temperature weather to land surface schemes by WRF

The simulations of a heat wave occurring in southern Yangtze-Huaihe valley and southern China during late July, 2003 were conducted to examine the sensitivity of simulated surface air temperature (SAT) to different land surface schemes (LSSs) using the Weather Research and Forecasting Model (WRF) Version 2.2 in the short-range mode for 24-h integrations. Initial and boundary conditions employed a National Centers for Environmental Prediction (NCEP) analysis. The results showed that, overall, simulated high-temperature weather is sensitive to different LSSs. Large differences in simulated SAT intensity, threat score, and simulated error under different schemes are identified clearly. In addition, some systematic differences are also induced by the LSSs. In terms of threat score from the three LSSs, SLAB is the best, and RUC is better than NOAH. SLAB gives the lowest absolute error for area-averaged SAT, and tends to depict the western Pacific subtropical high with the easternmost position at low levels. The LSSs modify the simulated SAT, primarily via the transfer of sensible heat from the land surface to the atmosphere. The physical mechanism of the positive feedback between atmospheric circulation and the SAT is unimportant, with “negative” feedback over most of the simulated areas. This study emphasizes the importance of improving LSSs in SAT forecasting by numerical models.

Application of a three-dimensional model for assessing effects of small clear-cuttings on radiation and soil temperature

A three-dimensional model Mixfor-3D of soil–vegetation–atmosphere transfer (SVAT) was developed and applied to estimate possible effects of tree clear-cutting on radiation and soil temperature regimes of a forest ecosystem. The Mixfor-3D model consists of several closely coupled 3D sub-models describing: forest stand structure; radiative transfer in a forest canopy; turbulent transfer of sensible heat, H 2O and CO 2 between ground surface and the atmospheric surface layer; evapotranspiration of ground surface vegetation and soil; heat and moisture transfer in soil. The model operates with the horizontal grid resolution, 2 m × 2 m; vertical resolution, 1 m and primary time step, 1 h. The model was tested against meteorological data obtained at a small clear-cutting area in Otterbach in central Germany during summer 2005. The meteorological data including air temperature and humidity, precipitation, solar radiation, wind speed and direction, soil temperatures at 10 and 20 cm depth were measured by five automatic stations within the clear-cut area. One reference station was placed about 100 m from the clear-cut inside the forest stand. Comparisons of modelled and measured solar radiation fluxes and soil temperature profiles showed that the model adequately describes the spatial heterogeneity and dynamics of these variables under different weather conditions. The model can be used to explore solar radiation and soil temperature patterns within heterogeneous forest plots, with applications to various silvicultural tasks.

A One-Layer Satellite Surface Energy Balance for Estimating Evapotranspiration Rates and Crop Water Stress Indexes

Daily evapotranspiration fluxes over the semi-arid Catania Plain area (Eastern Sicily, Italy) were evaluated using remotely sensed data from Landsat Thematic Mapper TM5 images. A one-source parameterization of the surface sensible heat flux exchange using satellite surface temperature has been used. The transfer of sensible and latent heat is described by aerodynamic resistance and surface resistance. Required model inputs are brightness, temperature, fractional vegetation cover or leaf area index, albedo, crop height, roughness lengths, net radiation, air temperature, air humidity and wind speed. The aerodynamic resistance (rah) is formulated on the basis of the Monin-Obukhov surface layer similarity theory and the surface resistance (rs) is evaluated from the energy balance equation. The instantaneous surface flux values were converted into evaporative fraction (EF) over the heterogeneous land surface to derive daily evapotranspiration values. Remote sensing-based assessments of crop water stress (CWSI) were also made in order to identify local irrigation requirements. Evapotranspiration data and crop coefficient values obtained from the approach were compared with: (i) data from the semi-empirical approach “Kc reflectance-based”, which integrates satellite data in the visible and NIR regions of the electromagnetic spectrum with ground-based measurements and (ii) surface energy flux measurements collected from a micrometeorological tower located in the experiment area. The expected variability associated with ET flux measurements suggests that the approach-derived surface fluxes were in acceptable agreement with the observations.

Flux contribution of coherent structures and its implications for the exchange of energy and matter in a tall spruce canopy

Thefluxcontributionofcoherentstructurestothetotalexchangeofenergy and matter is investigated in a spruce canopy of moderate density in heterogeneous, complex terrain. The study deploys two methods of analysis to estimate the coherent exchange: conditional averages in combination with wavelet analysis, and quadrant analysis. The data were obtained by high-frequency single-point measurements using sonic anemometers and gas analysers at five observation heights above and within the canopy and subcanopy, and represent a period of up to 2.5months. The study mainly addresses the momentum transfer and exchange of sensible heat throughout the roughness sublayer, while results are provided for the exchange of carbon dioxide and water vapour above the canopy. The magnitude of the flux contribution of coherent structures largely depends on the method of analysis, and it is demonstrated that these differences are attributed to differences in the sampling strategy between the two methods. Despite the differ- ences, relational properties such as sweep and ejection ratios and the variation of the flux contribution with height were in agreement for both methods. The sweep phase of coherentstructures is the dominantprocess close to and within the canopy, whereas the ejections gain importance with increasing distance to the canopy. The efficiency of the coherent exchange in transporting scalars exceeds that for momentum by a factor of two. The occurrence of coherent structures results in a flux error less than 4% for the eddy-covariance method. Based on the physical processes identified from the analysis of the ejection and sweep phases along the vertical profile in the rough- ness sublayer, a classification scheme for the identification of exchange regimes is developed. This scheme allows one to estimate the region of the canopy participat- ing in the exchange of energy and matter with the above-canopy air under varying environmental conditions.

Numerical Analysis of Coupled Water, Vapor, and Heat Transport in the Vadose Zone

Vapor movement is often an important part in the total water flux in the vadose zone of arid or semiarid regions because the soil moisture is relatively low. The two major objectives of this study were to develop a numerical model in the HYDRUS‐1D code that (i) solves the coupled equations governing liquid water, water vapor, and heat transport, together with the surface water and energy balance, and (ii) provides flexibility in accommodating various types of meteorological information to solve the surface energy balance. The code considers the movement of liquid water and water vapor in the subsurface to be driven by both pressure head and temperature gradients. The heat transport module considers movement of soil heat by conduction, convection of sensible heat by liquid water flow, transfer of latent heat by diffusion of water vapor, and transfer of sensible heat by diffusion of water vapor. The modifications allow a very flexible way of using various types of meteorological information at the soil–atmosphere interface for evaluating the surface water and energy balance. The coupled model was evaluated using field soil temperature and water content data collected at a field site. We demonstrate the use of standard daily meteorological variables in generating diurnal changes in these variables and their subsequent use for calculating continuous changes in water contents and temperatures in the soil profile. Simulated temperatures and water contents were in good agreement with measured values. Analyses of the distributions of the liquid and vapor fluxes vs. depth showed that soil water dynamics are strongly associated with the soil temperature regime.

A Synoptic Climatology of Summertime Heat and Humidity in the Piedmont Region of North Carolina

Abstract The synoptic patterns and boundary layer conditions over a range of antecedent periods associated with the summertime hot events for the years 1951–93 are examined. A hot event is defined as a single day with the highest average daily temperature within a surrounding 5-day window. Among these events, four event subtypes were determined on the basis of extreme values of temperature and/or dewpoint. Composite synoptic maps and vertical profiles of atmospheric variables are produced to distinguish the hottest and moistest events. The hot events, including the extreme categories, are influenced by similar large-scale circulation features. The region is under the control of the Bermuda high, which is centered off the coast of Florida and in the Atlantic Ocean. An upstream 500-hPa ridge produces subsidence and adiabatic warming in the midlevels of the troposphere. Composite patterns of the hottest and moistest events indicate stronger upstream 500-hPa ridging and upper-level subsidence, which suggest greater suppression of local convection and reduction in the upward turbulence transfer of surface sensible heat and water vapor. The moistest events are tied to considerably greater antecedent precipitation, which suggests increased evapotranspiration and accumulation of water vapor near the ground. The extreme hot and humid events are also associated with greater accumulated precipitation hours in the antecedent periods, especially on a 30-day scale. The hottest events also have less sky cover in the 30-day antecedent period, allowing more insolation and surface heating. The extreme events also have greater atmospheric thickness, lighter winds, and greater westerly component in the winds. Synoptic analysis shows that low-level thermal and moisture advection are not significant contributors to the heat and moisture in the extreme events of the Piedmont region.

Temperature–Humidity Dissimilarity and Heat-to-water-vapour Transport Efficiency Above and Within a Pine Forest Canopy: the Role of the Bowen Ratio

Over the past 15 years atmospheric surface-layer experiments over heterogeneous canopies have shown that the vertical transfer of sensible heat and water vapour exhibit a strong dissimilarity. In particular, the sensible-heat-to-water-vapour transport efficiencies generally exceed unity. One of the main consequences is that evaporation (latent heat flux) computed by the flux-variance method is overestimated, as persistently demonstrated by comparisons with evaporation obtained with the eddy-correlation method. Various authors proposed to take into account the temperature–humidity dissimilarity to extend the applicability of the flux-variance method in order to compute evaporation from non-uniform surfaces. They attempted to connect the sensible-heat-to-water-vapour transport efficiency (λ) to the correlation coefficient between temperature and humidity turbulent fluctuations (R Tq ). This approach was found to be successful over ‘wet’ surfaces for which λ can be approximated by R Tq and ‘dry’ surfaces for which λ can be approximated by 1/R Tq . However, no solution has been proposed until now for intermediate hydrological conditions. We investigated this question using eddy-correlation measurements above and inside a pine forest canopy. For both levels, our data present a strong likeness with previously published results over heterogeneous surfaces. In particular, they confirm that λ is R Tq in wet conditions and 1/R Tq in dry conditions. Moreover, we defined the range of the Bowen ratio (Bo) values for which those two approximations are valid (below 0.1 and greater than 1, respectively) and established a relationship between λ, R Tq and Bo for the intermediate range of Bo. We are confident that this new parameterization will enlarge the applicability of the flux-variance method to all kinds of heterogeneous surfaces in various hydrological conditions