scholarly journals Potential climate forcing of land use and land cover change

2014 ◽  
Vol 14 (8) ◽  
pp. 12167-12234 ◽  
Author(s):  
D. S. Ward ◽  
N. M. Mahowald ◽  
S. Kloster
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Land Cover Change ◽  
Surface Albedo ◽  
Arable Land ◽  
Climate Impacts ◽  
Radiation Budget ◽  
Worst Case ◽  
Fire Emissions ◽  
Community Land Model

Abstract. Pressure on land resources is expected to increase as global population continues to climb and the world becomes more affluent, swelling the demand for food. Changing climate may exert additional pressures on natural lands as present day productive regions may shift, or soil quality may degrade, and the recent rise in demand for biofuels increases competition with edible crops for arable land. Given these projected trends there is a need to understand the global climate impacts of land use and land cover change (LULCC). Here we quantify the climate impacts of global LULCC in terms of modifications to the balance between incoming and outgoing radiation at the top of the atmosphere (radiative forcing; RF) that are caused by changes in long-lived and short-lived greenhouse gas concentrations, aerosol effects and land surface albedo. We simulate historical changes to terrestrial carbon storage, global fire emissions, secondary organic aerosol emissions, and surface albedo from LULCC using the Community Land Model version 3.5. These LULCC emissions are combined with estimates of agricultural emissions of important trace gases and mineral dust in two sets of Community Atmosphere Model simulations to calculate the RF from LULCC impacts on atmospheric chemistry and changes in aerosol concentrations. With all forcing agents considered together, we show that 45% (+30%, −20%) of the present-day anthropogenic RF can be attributed to LULCC. Changes in the emission of non-CO2 greenhouse gases and aerosols from LULCC enhance the total LULCC RF by a factor of 2 to 3 with respect to the LULCC RF from CO2 alone. This enhancement factor also applies to projected LULCC RF, which we compute for four future scenarios associated with the Representative Concentration Pathways. We calculate total RFs between 1 to 2 W m−2 from LULCC for the year 2100 (relative to a preindustrial state). To place an upper bound on the potential of LULCC to alter the global radiation budget we include a fifth scenario in which all arable land is cultivated by 2100. This "worst-case scenario" leads to a LULCC RF of 4.3 W m−2 (±1.0 W m−2), suggesting that not only energy policy but land policy is necessary to minimize future increases in RF and associated climate changes.

scholarly journals Potential climate forcing of land use and land cover change

2014 ◽  
Vol 14 (23) ◽  
pp. 12701-12724 ◽  
Author(s):  
D. S. Ward ◽  
N. M. Mahowald ◽  
S. Kloster
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Land Cover Change ◽  
Surface Albedo ◽  
Arable Land ◽  
Global Radiation ◽  
Climate Impacts ◽  
Radiation Budget ◽  
Fire Emissions ◽  
Community Land Model

Abstract. Pressure on land resources is expected to increase as global population continues to climb and the world becomes more affluent, swelling the demand for food. Changing climate may exert additional pressures on natural lands as present-day productive regions may shift, or soil quality may degrade, and the recent rise in demand for biofuels increases competition with edible crops for arable land. Given these projected trends there is a need to understand the global climate impacts of land use and land cover change (LULCC). Here we quantify the climate impacts of global LULCC in terms of modifications to the balance between incoming and outgoing radiation at the top of the atmosphere (radiative forcing, RF) that are caused by changes in long-lived and short-lived greenhouse gas concentrations, aerosol effects, and land surface albedo. We attribute historical changes in terrestrial carbon storage, global fire emissions, secondary organic aerosol emissions, and surface albedo to LULCC using simulations with the Community Land Model version 3.5. These LULCC emissions are combined with estimates of agricultural emissions of important trace gases and mineral dust in two sets of Community Atmosphere Model simulations to calculate the RF of changes in atmospheric chemistry and aerosol concentrations attributed to LULCC. With all forcing agents considered together, we show that 40% (±16%) of the present-day anthropogenic RF can be attributed to LULCC. Changes in the emission of non-CO2 greenhouse gases and aerosols from LULCC enhance the total LULCC RF by a factor of 2 to 3 with respect to the LULCC RF from CO2 alone. This enhancement factor also applies to projected LULCC RF, which we compute for four future scenarios associated with the Representative Concentration Pathways. We attribute total RFs between 0.9 and 1.9 W m−2 to LULCC for the year 2100 (relative to a pre-industrial state). To place an upper bound on the potential of LULCC to alter the global radiation budget, we include a fifth scenario in which all arable land is cultivated by 2100. This theoretical extreme case leads to a LULCC RF of 3.9 W m−2 (±0.9 W m−2), suggesting that not only energy policy but also land policy is necessary to minimize future increases in RF and associated climate changes.

scholarly journals An Urban Parameterization for a Global Climate Model. Part I: Formulation and Evaluation for Two Cities

2008 ◽  
Vol 47 (4) ◽  
pp. 1038-1060 ◽  
Author(s):  
K. W. Oleson ◽  
G. B. Bonan ◽  
J. Feddema ◽  
M. Vertenstein ◽  
C. S. B. Grimmond
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Land Cover Change ◽  
Land Surface ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Surface Model ◽  
Land Use Land Cover ◽  
Community Land Model

Abstract Urbanization, the expansion of built-up areas, is an important yet less-studied aspect of land use/land cover change in climate science. To date, most global climate models used to evaluate effects of land use/land cover change on climate do not include an urban parameterization. Here, the authors describe the formulation and evaluation of a parameterization of urban areas that is incorporated into the Community Land Model, the land surface component of the Community Climate System Model. The model is designed to be simple enough to be compatible with structural and computational constraints of a land surface model coupled to a global climate model yet complex enough to explore physically based processes known to be important in determining urban climatology. The city representation is based upon the “urban canyon” concept, which consists of roofs, sunlit and shaded walls, and canyon floor. The canyon floor is divided into pervious (e.g., residential lawns, parks) and impervious (e.g., roads, parking lots, sidewalks) fractions. Trapping of longwave radiation by canyon surfaces and solar radiation absorption and reflection is determined by accounting for multiple reflections. Separate energy balances and surface temperatures are determined for each canyon facet. A one-dimensional heat conduction equation is solved numerically for a 10-layer column to determine conduction fluxes into and out of canyon surfaces. Model performance is evaluated against measured fluxes and temperatures from two urban sites. Results indicate the model does a reasonable job of simulating the energy balance of cities.

scholarly journals Pairing FLUXNET Sites to Validate Model Representations of Land Use/Land Cover Change

2017 ◽  
Author(s):  
Liang Chen ◽  
Paul A. Dirmeyer ◽  
Zhichang Guo ◽  
Natalie M. Schultz
Keyword(s):  
Land Use ◽  
Heat Flux ◽  
Land Cover ◽  
Land Cover Change ◽  
Land Surface ◽  
Surface Fluxes ◽  
Late Winter ◽  
Land Use Land Cover ◽  
Community Land Model ◽  
Ground Heat Flux

Abstract. Land surface energy and water fluxes play an important role in land-atmosphere interactions, especially for the climatic feedback effects driven by land use/land cover change (LULCC). These have long been documented in model-based studies, but the performance of land surface models in representing LULCC-induced responses has not been well investigated. In this study, measurements from proximate paired (open versus forest) flux tower sites are used to represent observed deforestation-induced changes in surface fluxes, which are compared with simulations from the Community Land Model (CLM) and the Noah Multi-Parameterization (Noah-MP) land model. Point-scale simulations suggest CLM can represent the observed diurnal and seasonal changes in net radiation (Rnet) and ground heat flux (G), but difficulties remain in the energy partitioning between latent (LE) and sensible (H) heat flux. CLM does not capture the observed decreased daytime LE, and overestimates the increased H during summer. These biases are mainly associated with deficiencies over forest land-cover types and the parameterization of soil evaporation. Global gridded simulations with CLM show uncertainties in the estimation of LE and H at the grid level for regional and global simulations. Noah-MP exhibits a similar ability to simulate the surface flux changes, but with larger biases in H, G, and Rnet change during late winter and early spring, which are related to a deficiency in estimating albedo. Differences in meteorological conditions between paired sites is not a factor in these results. Attention needs to be devoted to improving the representation of surface heat flux processes in land models to increase confidence in LULCC simulations.

scholarly journals Land-Use Change Related to Topography and Societal Drivers in High-Mountains – A Case Study in the Upper Watershed of the Tergi (Kazbegi Region), Greater Caucasus

2019 ◽  
Vol 11 (3) ◽  
pp. 317-340 ◽  
Author(s):  
Tim Theissen ◽  
Annette Otte ◽  
Rainer Waldhardt
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Land Cover ◽  
Land Cover Change ◽  
Cultural Landscapes ◽  
Regional Scale ◽  
Arable Land ◽  
High Mountain ◽  
Development Trends ◽  
Greater Caucasus

Abstract High mountain ecosystems, with strong topographic and climatic gradients, are fragile and particularly sensitive to changes in land use. The abandonment of historic cultural landscapes has often led to changes in the pattern of land cover and thus, to a shift in the functions of high mountain landscapes, like fresh water supply, productivity or erosion control. In order to understand the effects of land-use change on the land-cover pattern at the local and regional scale, we analyzed and classified the mountainous landscape structure in the Kazbegi region in Georgia, located in the Central Greater Caucasus. For 13 settlements, we determined the land cover as present in 1987 and 2015, and quantified the changes over time to detect land-cover development trends for each settlement. Using a cluster analysis, the study area was analyzed regarding to topography (altitude, aspect, slope) and distance to settlements at the regional scale to gain six groups with separating conditions. Furthermore, each settlement was classified according to topography and land-cover change to obtain site-specific, comparative development trends. Our results show that this Caucasian high-mountain landscape is characterized by open grassland (67%) used as pasture and hay meadow, and natural birch forests (7%) in patches in the upper half of the subalpine belt. Within the settlements but also in their surroundings, field vegetables are cultivated in home gardens (1%). Land-cover change during the observation period mainly affected the cultural grassland with hay meadow abandonment. Moreover, shrubbery and forest expanded considerably on abandoned pastures. We further detected a strong relationship to topography that considerably varied between settlements resulting in specific trends in land-use change. Hay-making and arable land cultivation are focused today on sun-exposed and gentle slopes near the settlements. Shrub encroachment and reforestations were localized on farther distances and mostly on north-exposed slopes. Besides providing basic information about the historic and current land-use and land-cover patterns, our results quantify the landscape change during almost 30 years. A spatio-temporal analysis revealed an understanding of how land-use decisions influence the landscape pattern. In the context of societal development, regional socioeconomic processes, like shifts in the agricultural structure and population outmigration, seem to be societal drivers of changes. Our findings reveal linkages and interrelationships between natural, human-induced environmental and socioeconomic processes within high-mountain socio-ecological systems. Moreover, we suggest that sustainable land-use strategies for spatial development on sub-regional level, especially in marginal high-mountain regions, should consider topography and its influence on land-use change.

scholarly journals Pairing FLUXNET sites to validate model representations of land-use/land-cover change

2018 ◽  
Vol 22 (1) ◽  
pp. 111-125 ◽  
Author(s):  
Liang Chen ◽  
Paul A. Dirmeyer ◽  
Zhichang Guo ◽  
Natalie M. Schultz
Keyword(s):  
Land Use ◽  
Heat Flux ◽  
Land Cover ◽  
Land Cover Change ◽  
Land Surface ◽  
Surface Fluxes ◽  
Late Winter ◽  
Land Use Land Cover ◽  
Community Land Model ◽  
Ground Heat Flux

Abstract. Land surface energy and water fluxes play an important role in land–atmosphere interactions, especially for the climatic feedback effects driven by land-use/land-cover change (LULCC). These have long been documented in model-based studies, but the performance of land surface models in representing LULCC-induced responses has not been investigated well. In this study, measurements from proximate paired (open versus forest) flux tower sites are used to represent observed deforestation-induced changes in surface fluxes, which are compared with simulations from the Community Land Model (CLM) and the Noah Multi-Parameterization (Noah-MP) land model. Point-scale simulations suggest the CLM can represent the observed diurnal and seasonal changes in net radiation (Rnet) and ground heat flux (G), but difficulties remain in the energy partitioning between latent (LE) and sensible (H) heat flux. The CLM does not capture the observed decreased daytime LE, and overestimates the increased H during summer. These deficiencies are mainly associated with models' greater biases over forest land-cover types and the parameterization of soil evaporation. Global gridded simulations with the CLM show uncertainties in the estimation of LE and H at the grid level for regional and global simulations. Noah-MP exhibits a similar ability to simulate the surface flux changes, but with larger biases in H, G, and Rnet change during late winter and early spring, which are related to a deficiency in estimating albedo. Differences in meteorological conditions between paired sites is not a factor in these results. Attention needs to be devoted to improving the representation of surface heat flux processes in land models to increase confidence in LULCC simulations.

Analysis of Land Use/Land Cover Change in Yangzhou City Based on CLUE-S Model

2011 ◽  
Vol 13 (5) ◽  
pp. 695-700
Author(s):  
Zhihua TANG ◽  
Xianlong ZHU ◽  
Cheng LI
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Land Cover Change ◽  
Land Use Land Cover ◽  
S Model

scholarly journals An Automatic and Operational Method for Land Cover Change Detection Using Spatiotemporal Analysis of MODIS Data: A Northern Ontario (Canada) Case Study

2021 ◽  
Vol 10 (5) ◽  
pp. 325
Author(s):  
Ima Ituen ◽  
Baoxin Hu
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Change Detection ◽  
Land Cover Change ◽  
Basic Unit ◽  
Operational Method ◽  
Northern Ontario ◽  
Modis Data ◽  
Forest Fire Management ◽  
Land Cover Change Detection

Mapping and understanding the differences in land cover and land use over time is an essential component of decision-making in sectors such as resource management, urban planning, and forest fire management, as well as in tracking of the impacts of climate change. Existing methods sometimes pose a barrier to the effective monitoring of changes in land cover and land use, since a threshold parameter is often needed and determined based on trial and error. This study aimed to develop an automatic and operational method for change detection on a large scale from Moderate Resolution Imaging Spectroradiometer (MODIS) data. Super pixels were the basic unit of analysis instead of traditional individual pixels. T2 tests based on the feature vectors of temporal Normalized Difference Vegetation Index (NDVI) and land surface temperature were used for change detection. The developed method was applied to data over a predominantly vegetated area in northern Ontario, Canada spanning 120,000 sq. km from 2001–2016. The accuracies ranged between 78% and 88% for the NDVI-based test, from 74% to 86% for the LST-based test, and from 70% to 86% for the joint method compared with manual interpretation. Our proposed method for detecting land cover change provides a functional and viable alternative to existing methods of land cover change detection as it is reliable, repeatable, and free from uncertainty in establishing a threshold for change.

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