Physically based morphostructural land surface segmentation: Case of the Alps and Western Carpathians

2021 ◽  
Author(s):  
Peter Bandura ◽  
Jozef Minár ◽  
Miroslav Bielik
Keyword(s):  
Land Surface ◽  
Western Carpathians ◽  
Surface Segmentation ◽  
Physically Based ◽  
The Alps

scholarly journals Physically-based land surface segmentation: Theoretical background and outline of interpretations

2018 ◽  
Author(s):  
Jozef Minar ◽  
Peter Bandura ◽  
Juraj Holec ◽  
Anton Popov ◽  
Lucian Drăguţ ◽  
...  
Keyword(s):  
Steady State ◽  
Potential Energy ◽  
Equilibrium State ◽  
Land Surface ◽  
Theoretical Background ◽  
Gravitational Potential Energy ◽  
Surface Segmentation ◽  
Physically Based ◽  
Input Variables ◽  
Definition Of

Incorporation of a physically-based general geomorphological theory directly into the segmentation algorithm is fundamental to physically-based land surface segmentation. Topographical steady state for morphostructural segmentations with five types of elementary forms defined by the principle of equilibrium provides a basis for definition of input variables. Examples of application introduce two new physically-based geomorphometric variables: Index of Steady State (ISS) quantifying the closeness of regions to a topographic steady state; and Index of Slope Disequilibrium (ISD), expressing percentage deviation from an equilibrium state of gravitational Potential Energy of Surface (PES) for mass flow.

scholarly journals Physically-based land surface segmentation: Theoretical background and outline of interpretations

2018 ◽  
Author(s):  
Jozef Minar ◽  
Peter Bandura ◽  
Juraj Holec ◽  
Anton Popov ◽  
Lucian Drăguţ ◽  
...  
Keyword(s):  
Steady State ◽  
Potential Energy ◽  
Equilibrium State ◽  
Land Surface ◽  
Theoretical Background ◽  
Gravitational Potential Energy ◽  
Surface Segmentation ◽  
Physically Based ◽  
Input Variables ◽  
Definition Of

Incorporation of a physically-based general geomorphological theory directly into the segmentation algorithm is fundamental to physically-based land surface segmentation. Topographical steady state for morphostructural segmentations with five types of elementary forms defined by the principle of equilibrium provides a basis for definition of input variables. Examples of application introduce two new physically-based geomorphometric variables: Index of Steady State (ISS) quantifying the closeness of regions to a topographic steady state; and Index of Slope Disequilibrium (ISD), expressing percentage deviation from an equilibrium state of gravitational Potential Energy of Surface (PES) for mass flow.

Toward a Robust Canopy Hydrology Scheme with Precipitation Subgrid Variability

2007 ◽  
Vol 8 (3) ◽  
pp. 439-446 ◽  
Author(s):  
Dagang Wang ◽  
Guiling Wang
Keyword(s):  
Land Surface ◽  
Surface Characteristics ◽  
Hydrological Processes ◽  
Canopy Interception ◽  
Time Step ◽  
Covered Area ◽  
Surface Models ◽  
Physically Based ◽  
Interception Loss ◽  
The Impact

Abstract Representation of the canopy hydrological processes has been challenging in land surface modeling due to the subgrid heterogeneity in both precipitation and surface characteristics. The Shuttleworth dynamic–statistical method is widely used to represent the impact of the precipitation subgrid variability on canopy hydrological processes but shows unwanted sensitivity to temporal resolution when implemented into land surface models. This paper presents a canopy hydrology scheme that is robust at different temporal resolutions. This scheme is devised by applying two physically based treatments to the Shuttleworth scheme: 1) the canopy hydrological processes within the rain-covered area are treated separately from those within the nonrain area, and the scheme tracks the relative rain location between adjacent time steps; and 2) within the rain-covered area, the canopy interception is so determined as to sustain the potential evaporation from the wetted canopy or is equal to precipitation, whichever is less, to maintain somewhat wet canopy during any rainy time step. When applied to the Amazon region, the new scheme establishes interception loss ratios of 0.3 at a 10-min time step and 0.23 at a 2-h time step. Compared to interception loss ratios of 0.45 and 0.09 at the corresponding time steps established by the original Shuttleworth scheme, the new scheme is much more stable under different temporal resolutions.

scholarly journals Inter-comparison of two land-surface models applied at different scales and their feedbacks while coupled with a regional climate model

2012 ◽  
Vol 16 (3) ◽  
pp. 1017-1031 ◽  
Author(s):  
F. Zabel ◽  
W. Mauser ◽  
T. Marke ◽  
A. Pfeiffer ◽  
G. Zängl ◽  
...  
Keyword(s):  
Land Use ◽  
Land Surface ◽  
Regional Climate ◽  
Moderate Increase ◽  
Net Radiation ◽  
Land Surface Models ◽  
Near Surface ◽  
Temporal Behaviour ◽  
Surface Models ◽  
The Alps

Abstract. Downstream models are often used in order to study regional impacts of climate and climate change on the land surface. For this purpose, they are usually driven offline (i.e., 1-way) with results from regional climate models (RCMs). However, the offline approach does not allow for feedbacks between these models. Thereby, the land surface of the downstream model is usually completely different to the land surface which is used within the RCM. Thus, this study aims at investigating the inconsistencies that arise when driving a downstream model offline instead of interactively coupled with the RCM, due to different feedbacks from the use of different land surface models (LSM). Therefore, two physically based LSMs which developed from different disciplinary backgrounds are compared in our study: while the NOAH-LSM was developed for the use within RCMs, PROMET was originally developed to answer hydrological questions on the local to regional scale. Thereby, the models use different physical formulations on different spatial scales and different parameterizations of the same land surface processes that lead to inconsistencies when driving PROMET offline with RCM output. Processes that contribute to these inconsistencies are, as described in this study, net radiation due to land use related albedo and emissivity differences, the redistribution of this net radiation over sensible and latent heat, for example, due to different assumptions about land use impermeability or soil hydraulic reasons caused by different plant and soil parameterizations. As a result, simulated evapotranspiration, e.g., shows considerable differences of max. 280 mm yr−1. For a full interactive coupling (i.e., 2-way) between PROMET and the atmospheric part of the RCM, PROMET returns the land surface energy fluxes to the RCM and, thus, provides the lower boundary conditions for the RCM subsequently. Accordingly, the RCM responses to the replacement of the LSM with overall increased annual mean near surface air temperature (+1 K) and less annual precipitation (−56 mm) with different spatial and temporal behaviour. Finally, feedbacks can set up positive and negative effects on simulated evapotranspiration, resulting in a decrease of evapotranspiration South of the Alps a moderate increase North of the Alps. The inconsistencies are quantified and account for up to 30% from July to Semptember when focused to an area around Milan, Italy.

scholarly journals Land Surface Temperature Retrieval from Passive Microwave Satellite Observations: State-of-the-Art and Future Directions

2020 ◽  
Vol 12 (16) ◽  
pp. 2573
Author(s):  
Si-Bo Duan ◽  
Xiao-Jing Han ◽  
Cheng Huang ◽  
Zhao-Liang Li ◽  
Hua Wu ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Important Variable ◽  
Satellite Observations ◽  
Passive Microwave ◽  
Empirical Methods ◽  
Physically Based ◽  
Temperature Retrieval ◽  
Semi Empirical

Land surface temperature (LST) is an important variable in the physics of land–surface processes controlling the heat and water fluxes over the interface between the Earth’s surface and the atmosphere. Space-borne remote sensing provides the only feasible way for acquiring high-precision LST at temporal and spatial domain over the entire globe. Passive microwave (PMW) satellite observations have the capability to penetrate through clouds and can provide data under both clear and cloud conditions. Nonetheless, compared with thermal infrared data, PMW data suffer from lower spatial resolution and LST retrieval accuracy. Various methods for estimating LST from PMW satellite observations were proposed in the past few decades. This paper provides an extensive overview of these methods. We first present the theoretical basis for retrieving LST from PMW observations and then review the existing LST retrieval methods. These methods are mainly categorized into four types, i.e., empirical methods, semi-empirical methods, physically-based methods, and neural network methods. Advantages, limitations, and assumptions associated with each method are discussed. Prospects for future development to improve the performance of LST retrieval methods from PMW satellite observations are also recommended.

scholarly journals Extracting the temporal signal from a winter and summer mass-balance series: application to a six-decade record at Glacier de Sarennes, French Alps

2011 ◽  
Vol 57 (201) ◽  
pp. 134-150 ◽  
Author(s):  
N. Eckert ◽  
H. Baya ◽  
E. Thibert ◽  
C. Vincent
Keyword(s):  
Mass Balance ◽  
Temporal Trends ◽  
Analysis Model ◽  
Glacier Surface ◽  
Climatic Fluctuations ◽  
Data Variability ◽  
Physically Based ◽  
Physically Based Models ◽  
The Alps ◽  
Interannual Fluctuations

AbstractTemporal trends related to recent climatic fluctuations are extracted from the longest glacier-wide winter and summer mass-balance series recorded in the Alps, at Glacier de Sarennes, France. For this, all point balances measured at the glacier surface are used, and different statistical models are developed and tested. First, Lliboutry’s linear variance analysis model is extended to the two seasonal components of the balance. The explicit modelling of variability sources and correlations is proved useful for appropriately quantifying uncertainties in the different components of the balance and estimating missing data. Next, a non-exchangeable structure is added to model the winter and summer balance time series. Two change points separating different underlying trends are thus detected. The first change was in 1976, with a shift of +23% in the winter balance. The second was in 1982 for the summer balance series. These systematic changes explain 20–30% of the variability of the different components of the balance, the rest being made up of random interannual fluctuations. Simplified and/or less physically based models are less efficient in capturing data variability. As a result, the cumulative glacier-wide balance shows systematic parabolic trends, which result in an accelerated mass loss for Glacier de Sarennes over the last 25 years.

scholarly journals A New Physically-Based Spatially-Distributed Groundwater Flow Module for SWAT+

Hydrology ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 75
Author(s):  
Ryan T. Bailey ◽  
Katrin Bieger ◽  
Jeffrey G. Arnold ◽  
David D. Bosch
Keyword(s):  
Water Balance ◽  
Groundwater Flow ◽  
Land Surface ◽  
Assessment Tool ◽  
Swat Model ◽  
Watershed Model ◽  
Groundwater Head ◽  
Physically Based ◽  
Spatially Distributed ◽  
Modeling Code

Watershed models are used worldwide to assist with water and nutrient management under conditions of changing climate, land use, and population. Of these models, the Soil and Water Assessment Tool (SWAT) and SWAT+ are the most widely used, although their performance in groundwater-driven watersheds can sometimes be poor due to a simplistic representation of groundwater processes. The purpose of this paper is to introduce a new physically-based spatially-distributed groundwater flow module called gwflow for the SWAT+ watershed model. The module is embedded in the SWAT+ modeling code and is intended to replace the current SWAT+ aquifer module. The model accounts for recharge from SWAT+ Hydrologic Response Units (HRUs), lateral flow within the aquifer, Evapotranspiration (ET) from shallow groundwater, groundwater pumping, groundwater–surface water interactions through the streambed, and saturation excess flow. Groundwater head and groundwater storage are solved throughout the watershed domain using a water balance equation for each grid cell. The modified SWAT+ modeling code is applied to the Little River Experimental Watershed (LREW) (327 km2) in southern Georgia, USA for demonstration purposes. Using the gwflow module for the LREW increased run-time by 20% compared to the original SWAT+ modeling code. Results from an uncalibrated model are compared against streamflow discharge and groundwater head time series. Although further calibration is required if the LREW model is to be used for scenario analysis, results highlight the capabilities of the new SWAT+ code to simulate both land surface and subsurface hydrological processes and represent the watershed-wide water balance. Using the modified SWAT+ model can provide physically realistic groundwater flow gradients, fluxes, and interactions with streams for modeling studies that assess water supply and conservation practices. This paper also serves as a tutorial on modeling groundwater flow for general watershed modelers.

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