Jingfeng Wang

Georgia Institute of Technology | GT · School of Civil & Environmental Engineering

Ocean evaporation (latent heat flux, LE) plays a crucial role in global precipitation patterns, water cycle dynamics, and energy exchange processes. However, current bulk methods for quantifying ocean evaporation are subject to significant uncertainties. The Maximum Entropy Production (MEP) theory offers a novel approach for estimating surface heat...

The inverse temperature layer (ITL) beneath water‐atmosphere interface within which temperature increases with depth has been observed from measurement of water temperature profile at an inland lake. Strong solar radiation combined with moderate wind‐driven near‐surface turbulence leads to the formation of a pronounced diurnal cycle of the ITL pred...

Plain Language Summary This paper represents a synthesis of conceptual analyses, case study analyses, and practical thoughts on the application of convergence science in Arctic change studies. During a virtual workshop in 2020, a diverse, multi‐national team of authors consisting of social scientists, engineers, earth system scientists, and ecologi...

Evapotranspiration (ET) links water, energy, and carbon balances, and its magnitude and patterns are changing due to climate and land use change in the southeastern U.S. Quantifying the environmental controls on ET is essential for developing reliable ecohydrological models for water resources management. Here, we synthesized eddy covariance data f...

A theory of maximum entropy production (MEP) for electromagnetic wave propagation in dielectric materials is proposed and applied to simultaneously retrieving soil moisture (SM) and vegetation water content (VWC) from L‐band microwave brightness temperature (TB). One representation of the MEP principle states that a non‐equilibrium system correspon...

Ground heat flux (G0) is a key component of the land‐surface energy balance of high‐latitude regions. Despite its crucial role in controlling permafrost degradation due to global warming, G0 is sparsely measured and not well represented in the outputs of global scale model simulation. In this study, an analytical heat transfer model is tested to re...

Plain Language Summary The seasonally thawed layer on top of the permafrost (active layer) is a key component of the Arctic system affected by the strong warming trend over the past decades. This soil layer experiences a pronounced seasonal cycle of freezing and thawing processes caused by the availability of Sun's energy. Mathematical modeling of...

An “inverse‐temperature layer” (ITL) of water temperature increasing with depth is predicted based on physical principles and confirmed by in situ observations. Water temperature and other meteorological data were collected from a fixed platform in the middle of a shallow inland lake. The ITL persists year‐around with its depth on the order of one...

The 21st century evapotranspiration (ET) trends over the continental U.S. are assessed using innovative, energy‐based principles. Annual ET is projected to increase with high confidence at the rate of 20 mm for every 1℃ of rise in near‐surface air temperature, or 0.45 or 0.98 mm/year/year, depending on the emission scenario. The ET trajectory is do...

A physically based analytical model is formulated to simulate the thaw depth of active layer under changing boundary condition of soil heat flux. The energy conservation statement leads to a nonlinear integral equation of the thaw depth using an approximate temperature profile as an analytical solution of the diffusion equation describing the heat...

The calculation of surface sensible heat (SH) and latent heat (LE) fluxes using the bulk transfer models for complex terrains, tall vegetation regions, and morning and evening transition periods remains a challenging problem in numerical weather and climate models. The maximum entropy production (MEP) model, a new method of calculating surface heat...

Efforts to develop effective climate strategies necessitate a better understanding of the relationship between terrestrial water and carbon cycles. Water use efficiency (WUE) has been often used to characterize this relationship , while the role of transpiration (T) in the variation of ecosystem WUE has been less investigated. Here, we partitioned...

Plain Language Summary Surface temperature of the Earth is a primary indicator of Earth climate system. Change of surface temperature depends on conductive and turbulent heat transport processes at either side of Earth surface and the media (soil, air, water, snow, etc.) specific absorption of solar radiation. Understanding and simulating surface t...

An accurate estimation of evapotranspiration (ET) is vital for understanding the global hydrological cycle. However, large uncertainties in the present global ET products originate from the distinct model structures, assumptions, and inputs. The maximum entropy production (MEP) model provides a novel method for modeling ET based on parsimonious inp...

Evaporation (E) from about 300 million lakes worldwide without plant physiological constraints directly reflects hydrological response to atmospheric forcings. However, it remains inadequately understood about what regulate spatial variability of global lake E across seasons. Here we show that vertical vapor pressure difference (e D )accounts for 6...

Water demand growth coupled with its high spatial-temporal mismatch of water resources will lead to an increasing water scarcity worldwide. In order to investigate a robust long-term water stress for ecosystems and regions across China, the improved maximum entropy production (MEP) method was utilized to obtain a reliable evapotranspiration (ET) pr...

Previous studies discovered a spatially heterogeneous expansion of Siberian larch into the tundra of the Polar Urals (Russia). This study reveals that the spatial pattern of encroachment of tree stands is related to environmental factors including topography and snow cover. Structural and allometric characteristics of trees, along with terrain elev...

This study investigates the drivers of water use efficiency (WUE), a key metric of water resources management, and its changes over eight regions across China from 1982 to 2015 based on gross primary production (GPP) and actual evapotranspiration (AET) datasets. The order of seasonal change of WUE from large to small is autumn, summer, spring and w...

The maximum entropy production (MEP) approach has been little used to simulate evaporation in forests and its sensitivity to input variables has never beenyet to be systematically evaluated. This study addresses these shortcomings. First, we show that the MEP model performed well in simulating evaporation during the snow-free periods at six sites i...

Characterizing physical relationships between the sensible, latent and ground heat flux at the Earth surface is of crucial importance in studying the global energy, water, and carbon cycles. Here we demonstrate an analogy between the daily mean turbulent heat transfer in the atmospheric surface layer and conductive-advective heat transfer in soil....

Evapotranspiration (ET) is a vital part of the hydrological cycle and the water–energy balance. To explore the characteristics of five typical remote sensing evapotranspiration datasets and provide guidance for algorithm development, we used reconstructed evapotranspiration (Recon) data based on ground and GRACE satellite observations as a benchmar...

Snow cover plays a key role in the water and energy budgets over cold regions. Understanding and parameterizing water and heat exchange over snow surfaces in hydrologic models remains a major challenge. An innovative approach based on the theory of maximum entropy production (MEP) was developed for modeling energy budgets for snow‐covered surfaces....

Flash floods-caused losses are rapidly increasing due to climate change induced extreme weather events and economic development in the world. The WRF-Hydro-RAPID model coupled with land surface model and a vector-based flow routing module is able to simulate discharge at any reach of a watershed, making it a good tool for flood simulation and forec...

The well-known conceptual Xin'anjiang model (XAJ) has limited capability for application in the basins with limited data due to two major runoff routing problems: relying on the observed flow data to estimate the parameters of the Muskingum method and lack of physics-based representation of spatial heterogeneity in key routing parameters such as th...

It is challenging to accurately differentiate and simulate different runoff components yielded under the saturation-excess and infiltration-excess mechanisms in semi-arid and semi-humid watersheds. Fixed model structures and runoff generation modes in most of the existing conventional hydrological models limit their ability to account for respectiv...

River width is an essential physical variable for the simulation of rainfall-runoff processes using distributed hydrologic models. In this paper, a model of river width integrating the effects of an upstream drainage area and terrain topography is proposed for the derivation of a spatial variation of a river width of medium-sized mountainous waters...

The Weather Research and Forecasting (WRF)-Hydro model as a physical-based, fully-distributed, multi-parameterization modeling system easy to couple with numerical weather prediction model, has potential for operational flood forecasting in the small and medium catchments (SMCs). However, this model requires many input forcings, which makes it diff...

The Tibetan Plateau (TP) has been experiencing warming and wetting since the 1980s. Under such circumstances, we estimated the summer latent heat flux (LE) using the maximum entropy production model driven by the net radiation, surface temperature, and soil moisture of three reanalysis datasets (ERA5, JRA-55, and MERRA-2) at the Ali site over the w...

Entropy and Information are key concepts not only in Information Theory but also in Physics: historically in the fields of Thermodynamics, Statistical and Analytical Mechanics, and, more recently, in the field of Information Physics. In this paper we argue that Information Physics reconciles and generalizes statistical, geometric, and mechanistic v...

This study analyzed summer observations of diurnal and seasonal surface energy budgets across several monitoring sites within the Arctic tundra underlain by permafrost. In these areas, latent and sensible heat fluxes have comparable magnitudes, and ground heat flux enters the subsurface during short summer intervals of the growing period, leading t...

Surface heat fluxes over the central Tibetan Plateau have been estimated using the maximum entropy production (MEP) model with the surface energy balance and the observation data from the Third Tibetan Plateau Atmospheric Scientific Experiment (TIPEX‐III). The MEP surface heat fluxes are highly correlated with those of the TIPEX‐III observations. T...

Plain Language Summary Classical methods for estimating vapor flow from vegetated surfaces, known as the process of evapotranspiration, require input data on water vapor gradient, wind speed, and surface roughness as well as model parameters that are often difficult to obtain from in situ and remote sensing observations. The uncertainty of these va...

In semi-humid regions, accurate prediction of flood processes is challenging. The goal of this study is to gain more insights into the runoff generation mechanism in semi-humid regions using multiple-model comparison method and explore the Bayesian model averaging (BMA) approach to improve flood prediction. This study compares seven runoff generati...

Hydrological modelling is a critical tool for preventing and mitigating severe flood disasters. This study aims to assess the applicability of a physically based distributed hydrological model, CASC2D‐SED, for flood forecasting in four typical medium and small watersheds across three hydro‐climatic zones (semi‐arid, semi‐humid, and humid) in China....

The maximum entropy production (MEP) model based on nonequilibrium thermodynamics and the theory of Bayesian probabilities was recently developed to model land surface fluxes, including soil evaporation and vegetation transpiration. This model requires few input data and ensures the closure of the surface energy balance. This study aims to test the...

Real-time precipitation data with high spatiotemporal resolutions are crucial for accurate hydrological forecasting. To improve the spatial resolution and quality of satellite precipitation, a three-step satellite and gauge precipitation merging method was formulated in this study: (1) bilinear interpolation is first applied to downscale coarser sa...

The recently developed maximum entropy production (MEP) model, an alternative parameterization of surface heat fluxes, is incorporated into the Weather Research and Forecasting Model (WRF). A pair of WRF cloud-resolving experiments (5 km grids) using the bulk transfer model (WRF default) and the MEP model of surface heat fluxes are performed to hin...

The maximum-entropy-production (MEP) model of surface heat fluxes, based on contemporary non-equilibrium thermodynamics, information theory, and atmospheric turbulence theory, is used to re-estimate the global surface heat fluxes. The MEP model predicted surface fluxes automatically balance the surface energy budgets at all time and space scales wi...

Developing high-quality long-term data sets at uniform space–time resolution is essential for improved climate studies. This article processes the outputs from two global and regional climate models, the Community Climate System Model (CCSM3) and the Regional Climate Model driven by the Hadley Centre Coupled Model (RegCM3). The results are bias-cor...

This study characterizes the space-time structure of soil moisture background error covariance and paves the way for the development of a soil moisture variational data assimilation system for the Noah land surface model coupled to the Weather Research and Forecasting (WRF) model. The soil moisture background error covariance over the contiguous Un...

Remote sensing is an indispensable tool for monitoring and detecting the evolution of the Earth's hydrometeorological processes. Fast-growing remote sensing observations and technologies have been a primary impetus to advancing our knowledge of hydrometeorological processes and their extremes over the last decades. Meanwhile, integrating the hydrol...

A coupled force-restore model of surface soil temperature and moisture (FRMEP) is formulated by incorporating the maximum entropy production model of surface heat fluxes and including the gravitational drainage term. The FRMEP model driven by surface net radiation and precipitation are independent of near-surface atmospheric variables with reduced...

Agricultural models, such as the Decision Support System for Agrotechnology Transfer – Cropping Systems Model (DSSAT-CSM), have been developed for predicting crop yield at field and regional scales and to provide useful information for water resources management. A potentially valuable input to agricultural models is soil moisture. Presently, no ob...

The objective of this study is to develop a framework for dynamically downscaling spaceborne precipitation products using the Weather Research and Forecasting (WRF) Model with four-dimensional variational data assimilation (4D-Var). Numerical experiments have been conducted to 1) understand the sensitivity of precipitation downscaling through point...

A new algorithm is formulated for retrieving hourly time series of surface hydrometeorological variables including net radiation, sensible heat flux, and near-surface air temperature aided by hourly visible images from the Geostationary Operational Environmental Satellite (GOES) and in situ observations of mean daily air temperature. The algorithm...

There is considerable interest in understanding the fate of the Amazon over the coming century in the face of climate change, rising atmospheric CO2 levels, on-going land transformation, and changing fire regimes within the region. In this analysis, we explore the fate of Amazonian ecosystems under the combined impact of these four environmental fo...

Recent investigations on scale-invariant processes such as topography and modeling evapotranspiration demonstrate the usefulness and potential of the principles of maximum entropy (MaxEnt) and maximum entropy production (MaxEP) in the study of Earth systems. MaxEnt allows theoretical predictions of probability distributions of geophysical multifrac...

A conceptual model is proposed to express freshwater flux (evaporation minus precipitation) as a function of sea surface salinity (and vice versa). The model is formulated using an idealized one-dimensional diffusion equation in the ocean surface layer.It is shown to provide good agreement with existing freshwater flux estimates and salinity observ...

The recently formulated maximum entropy production (MEP) model over land surfaces has been generalized to water-snow-ice surfaces. Analytical solutions of energy budget in terms of the partition of surface radiative fluxes into (turbulent and/or conductive) heat fluxes at the earth-atmosphere interface are derived as functions of surface temperatur...

A mosaic of protected areas, including indigenous lands, sustainable-use production forests and reserves and strictly protected forests is the cornerstone of conservation in the Amazon, with almost 50 per cent of the region now protected. However, recent research indicates that isolation from direct deforestation or degradation may not be sufficien...

Assignment of ignorance prior distributions in the Bayesian statistics has been a controversial matter. We argue that it is caused by the ambiguity in the probability distribution defined directly on continuous variables. Use of the concept of Limiting Density of Discrete Points (LDDP) may remove such ambiguity so that Laplace's Principle of Indiff...

We have demonstrated that the Maximum Entropy (ME) principle in the context of Bayesian probability theory can be used to derive the probability distributions of those processes characterized by its scaling properties including multiscaling moments and geometric mean. We started from a proof-of-concept case of a power-law probability distribution,...

A model of evaporation, sensible and ground heat fluxes over land surfaces is proposed based on the theory of maximum entropy production (MEP). A key element of the proposed MEP model is the formulation of a dissipation (or entropy production) function, whose extremization under the constraint of conservation of energy leads to a unique partition o...

Abstract Available from http://www.agu.org

We have demonstrated that the maximum entropy (ME) principle can be used as a general inference algorithm to derive the probability distributions at different scales of a multifractal process characterized by its scaling properties such as multiscaling moments and geometric mean. In a case study, the ME distributions of topography have been tested...

Prior research has shown that deforestation in the southwestern Amazon enhances the formation of non-precipitating shallow cumulus clouds, while deep cumulus convection was favored over forested land. The research presented here further investigates the trends of hydrometeors in the area by examining how precipitation frequency changes as a functio...

Building on a proof-of-concept study of energy balance over dry soil, a model of evapotranspiration is proposed based on the theory of maximum entropy production (MEP). The MEP formalism leads to an analytical solution of evaporation rate (latent heat flux), together with sensible and ground heat fluxes, as a function of surface soil temperature, s...

A new model, based on the theory of maximum entropy production (MEP), is proposed for remote sensing of evapotranspiration over land surfaces. According to the MEP formalism, extremization of a dissipation (or entropy production) function under the constraint of conservation of energy leads to an analytical expression of evaporation (as well as sen...

There is growing evidence of the potential of the Principle of Maximum Entropy (MaxEnt) and the Principle of Maximum Entropy Production (MEP) as frameworks for modeling complex, far-from equilibrium, thermodynamic systems. Here we report new results of the applications of the MaxEnt and MEP method in characterizing multi-scaling processes and model...

There is growing evidence of the potential of the Principle of Maximum Entropy (MaxEnt) and the Principle of Maximum Entropy Production (MEP) as frameworks for modeling complex, far-from equilibrium, thermodynamic systems. Here we report new results of the applications of the MaxEnt and MEP method in characterizing multi-scaling processes and model...

Organizations of many variables in nature such as soil moisture and topography exhibit patterns with no dominant scales. The maximum entropy (ME) principle is proposed to show how these variables can be statistically described using their scale-invariant properties and geometric mean. The ME principle predicts with great simplicity the probability...

Organizations of many variables in nature such as soil moisture and topography exhibit patterns with no dominant scales. The maximum entropy (ME) principle is proposed to show how these variables can be statistically described using their scale-invariant properties and geometric mean. The ME principle predicts with great simplicity the probability...

A simple method for estimating thermal inertia using daily amplitude of surface soil heat flux and temperature is proposed. Based on an analytical solution of the diffusion equation where the soil temperature is idealized as a sinusoidal function, the thermal inertia is expressed as a proportional coefficient in a linear equation relating the ampli...

The objective of this proposal is to explore the idea of Maximum Entropy (MaxEnt) as a unifying principle to characterize multi-scaling hydrometeorological parameters such as rainfall and soil moisture, and develop a MaxEnt-based design of data collection networks for the sampling of multiscaling processes. The approach we follow is to relate the s...

An extremum hypothesis of turbulent transport in the atmospheric surface layer is postulated. The hypothesis has led to a unique solution of Monin–Obukhov similarity equations in terms of simple expressions linking shear stress (momentum flux) and heat flux to mean wind shear and temperature gradient. The extremum solution is consistent with the we...

The Ecosystem Demography Model 2 is a dynamic ecosystem model and land surface energy balance model. ED2 discretizes landscapes of particular terrain and meteorology into fractional areas of unique disturbance history. Each fraction, defined by a shared vertical soil column and canopy air space, contains a stratum of plant groups unique in function...

A simple method for estimating thermal inertia using daily amplitude of surface soil heat flux and temperature is proposed. Based on an analytical solution of the diffusion equation where the soil temperature is idealized as a sinusoidal function, the thermal inertia is expressed as a proportional coefficient in a linear equation relating the ampli...

[1] A model of heat fluxes over a dry land surface is proposed based on the theory of maximum entropy production (MEP) as a special case of the maximum entropy principle (MaxEnt). When the turbulent heat transfer in the atmospheric boundary layer is parameterized using a Monin-Obukhov similarity model, a dissipation function or entropy production f...

Shallow clouds are prone to appear over deforested surfaces whereas deep clouds, much less frequent than shallow clouds, favor forested surfaces. Simultaneous atmospheric soundings at forest and pasture sites during the Rondonian Boundary Layer Experiment (RBLE-3) elucidate the physical mechanisms responsible for the observed correlation between cl...

This study explores the possibility of using the principle of maximum entropy production (MEP) as a predictive tool in modeling heat fluxes over the land surface. Following the MEP formalism built on the Bayesian probability theory, an entropy production function (or dissipation function), not related to the thermodynamic entropy and its production...

It is well-known that the structures of river networks show self-similar behavior characterized by power-law distributions. In this study, we demonstrate that the power- law distributions can be derived by maximizing the information entropy under a certain constraint using the maximum entropy principle (MaxEnt). The MaxEnt solution of power-law dis...

The Ecosystem Demography Model 2 is a land-surface model with full energy and hydrologic balan