scholarly journals A 1 km global cropland dataset from 10 000 BCE to 2100 CE

2021 ◽  
Vol 13 (11) ◽  
pp. 5403-5421
Author(s):  
Bowen Cao ◽  
Le Yu ◽  
Xuecao Li ◽  
Min Chen ◽  
Xia Li ◽  
...  
Keyword(s):  
Land Use ◽  
Spatial Information ◽  
Large Area ◽  
Cropland Area ◽  
Geographical Regions ◽  
Long Time ◽  
Cropland Change ◽  
History Database ◽  
Mapping Result

Abstract. Cropland greatly impacts food security, energy supply, biodiversity, biogeochemical cycling, and climate change. Accurately and systematically understanding the effects of agricultural activities requires cropland spatial information with high resolution and a long time span. In this study, the first 1 km resolution global cropland proportion dataset for 10 000 BCE–2100 CE was produced. With the cropland map initialized in 2010 CE, we first harmonized the cropland demands extracted from the History Database of the Global Environment 3.2 (HYDE 3.2) and the Land-Use Harmonization 2 (LUH2) datasets and then spatially allocated the demands based on the combination of cropland suitability, kernel density, and other constraints. According to our maps, cropland originated from several independent centers and gradually spread to other regions, influenced by some important historical events. The spatial patterns of future cropland change differ in various scenarios due to the different socioeconomic pathways and mitigation levels. The global cropland area generally shows an increasing trend over the past years, from 0×106 km2 in 10 000 BCE to 2.8×106 km2 in 1500 CE, 6.2×106 km2 in 1850 CE, and 16.4×106 km2 in 2010 CE. It then follows diverse trajectories under future scenarios, with the growth rate ranging from 16.4 % to 82.4 % between 2010 CE and 2100 CE. There are large area disparities among different geographical regions. The mapping result coincides well with widely used datasets at present in both distribution pattern and total amount. With improved spatial resolution, our maps can better capture the cropland distribution details and spatial heterogeneity. The spatiotemporally continuous and conceptually consistent global cropland dataset serves as a more comprehensive alternative for long-term earth system simulations and other precise analyses. The flexible and efficient harmonization and downscaling framework can be applied to specific regions or extended to other land use and cover types through the adjustable parameters and open model structure. The 1 km global cropland maps are available at https://doi.org/10.5281/zenodo.5105689 (Cao et al., 2021a).

scholarly journals A 1 km global cropland dataset from 10000 BCE to 2100 CE

2021 ◽  
Author(s):  
Bowen Cao ◽  
Le Yu ◽  
Xuecao Li ◽  
Min Chen ◽  
Xia Li ◽  
...  
Keyword(s):  
Land Use ◽  
Spatial Information ◽  
Large Area ◽  
Cropland Area ◽  
Geographical Regions ◽  
Long Time ◽  
Cropland Change ◽  
History Database ◽  
Mapping Result

Abstract. Cropland greatly impacts food security, energy supply, biodiversity, biogeochemical cycling, and climate change. Accurately and systematically understanding the effects of agricultural activities requires cropland spatial information with high resolution and a long time span. In this study, the first 1 km resolution global cropland proportion dataset for 10000 BCE–2100 CE was produced. With the cropland map initialized in 2010 CE, we first harmonized the cropland demands extracted from the History Database of the Global Environment 3.2 (HYDE 3.2) and the Land-Use Harmonization 2 (LUH2) datasets, and then spatially allocated the demands based on the combination of cropland suitability, kernel density, and other constraints. According to our maps, cropland originated from several independent centers and gradually spread to other regions, influenced by some important historical events. The spatial patterns of future cropland change differ in various scenarios due to the different socioeconomic pathways and mitigation levels. The global cropland area generally shows an increasing trend over the past years, from 0 million km2 in 10000 BCE grows to 2.8 million km2 in 1500 CE, 6.2 million km2 in 1850 CE, and 16.4 million km2 in 2010 CE. It then follows diverse trajectories under future scenarios, with the growth rate ranging from 18.6 % to 82.4 % between 2010 CE and 2100 CE. There are large area disparities among different geographical regions. The mapping result coincides well with widely-used datasets at present in both distribution pattern and total amount. With improved spatial resolution, our maps can better capture the cropland distribution details and spatial heterogeneity. The spatiotemporally continuous and conceptually consistent global cropland dataset serves as a more comprehensive alternative for long-term earth system simulations and other precise analyses. The flexible and efficient harmonization and downscaling framework can be applied to specific regions or extended to other land use/cover types through the adjustable parameters and open model structure. The 1 km global cropland maps are available at https://doi.org/10.5281/zenodo.5105689 (Cao et al., 2021a).

scholarly journals Cropland Abandonment in Slovakia: Analysis and Comparison of Different Data Sources

Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 334
Author(s):  
Juraj Lieskovský ◽  
Dana Lieskovská
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Spatial Data ◽  
Data Sources ◽  
Communist Regime ◽  
Corine Land Cover ◽  
Cropland Area ◽  
Cropland Abandonment ◽  
Multi Temporal

This study compares different nationwide multi-temporal spatial data sources and analyzes the cropland area, cropland abandonment rates and transformation of cropland to other land cover/land use categories in Slovakia. Four multi-temporal land cover/land use data sources were used: The Historic Land Dynamics Assessment (HILDA), the Carpathian Historical Land Use Dataset (CHLUD), CORINE Land Cover (CLC) data and Landsat images classification. We hypothesized that because of the different spatial, temporal and thematic resolution of the datasets, there would be differences in the resulting cropland abandonment rates. We validated the datasets, compared the differences, interpreted the results and combined the information from the different datasets to form an overall picture of long-term cropland abandonment in Slovakia. The cropland area increased until the Second World War, but then decreased after transition to the communist regime and sharply declined following the 1989 transition to an open market economy. A total of 49% of cropland area has been transformed to grassland, 34% to forest and 15% to urban areas. The Historical Carpathian dataset is the more reliable long-term dataset, and it records 19.65 km2/year average cropland abandonment for 1836–1937, 154.44 km2/year for 1938–1955 and 140.21 km2/year for 1956–2012. In comparison, the Landsat, as a recent data source, records 142.02 km2/year abandonment for 1985–2000 and 89.42 km2/year for 2000–2010. These rates, however, would be higher if the dataset contained urbanisation data and more precise information on afforestation. The CORINE Land Cover reflects changes larger than 5 ha, and therefore the reported cropland abandonment rates are lower.

scholarly journals Land Use Issues: The Last Settler's Syndrome

2010 ◽  
Vol 42 (2) ◽  
pp. 357-365 ◽  
Author(s):  
Peter A. Groothuis
Keyword(s):  
Land Use ◽  
North Carolina ◽  
Interesting Case ◽  
Western North Carolina ◽  
Long Time

In the last settler's syndrome, each new settler wants the area to remain as it was on their arrival. Newcomers' preferences often differ from long-term residents, and conflicts arise. To explore land use issues among various groups, a survey of opinions on mountain views was developed and administered to Watauga County residents in western North Carolina. Watauga County provides an interesting case study, because it is a growing area with an influx of newcomers along with long-time residents. The results suggest that agreements can be achieved on some land use issues, whereas disagreements will arise on others.

scholarly journals Land Change Prediction using Markov Change Multi-Layer Perceptron in Navi Mumbai, Maharashtra, India

2019 ◽  
Vol 8 (10) ◽  
pp. 484-490
Keyword(s):  
Land Use ◽  
Satellite Images ◽  
Change Model ◽  
Land Use Management ◽  
Land Change ◽  
Large Area ◽  
Human Need ◽  
Future Prediction ◽  
Term Evaluation

Long-term evaluation of land change and future prediction change is extremely important for planning and land use management. This research conducted for the analyze future prediction change in the study area Navi Mumbai. For this prediction analysis used satellite images year from 1998, 2008 and 2018 are taken. Thus, the change detection obtained from land use and land cover assist in most favourable solutions for the choice, planning, implementation, and observance of development schemes. To meet the increasing demands of human need, land management is required. In this work for upcoming predict year, Markov change model is used for simulating 2028 year. It will give vital and useful information on future development and planning. And also, is easy for continuing to monitor land change for the large area due to natural human activities and the effect of natural resources.

scholarly journals Remote Sensing Analysis In RUSLE Erosion Estimation

2018 ◽  
Author(s):  
Ketut Wikantika
Keyword(s):  
Remote Sensing ◽  
Vegetation Cover ◽  
Soil Loss ◽  
Spatial Information ◽  
Universal Soil Loss Equation ◽  
Large Area ◽  
Coverage Area ◽  
Erosion Processes ◽  
Long Time ◽  
Soil Loss Equation

Soil erosion is a major issue in various hemispheres. It is because erosion affects the survival of ecosystem. Diverse human actions, e.g., bushes burning and illegal logging, play a role in accelerating erosion. Climate factor such as rain intensity has also an influence in the release of soil particles. Therefore, a regular identification of those factors that affect erosion processes is highly needed in order to keep an environmental sustainable. Different areas in Indonesia have different erosion variable characteristics. One of the characteristics is indicated by the varieties ofvegetation cover, where a loose vegetation cover causes soil surfaces open for a long time period. Till now, researches dealing with the modeling of erosions with wide area coverage are few, since erosion observations have always been conducted by direct observations in the field, hence time consuming. Therefore, an erosion mapping model that is applied in a wide coverage area and the up to date of data is needed. Spatially, erosions can be depicted in a form of spatial information system model describing their potential class levels. There are several erosion models that can be used to find out the erosion occurring on a land, among others Universal Soil Loss Equation (USLE) model or its modification Revised Universal Soil Loss Equation (RUSLE). RUSLE erosion model consists of rainfall, soil erodibility, vegetation cover, slope gradient and length, and support practice factors. Recent technology in remote sensing allowed vegetation cover to beanalysed from satellite imagery, make the possibility of erosion analysis in large area in shorter time.

Deep drainage rates of Grey Vertosols depend on land use in semi-arid subtropical regions of Queensland, Australia

Soil Research ◽  
2011 ◽  
Vol 49 (5) ◽  
pp. 424 ◽  
Author(s):  
D. M. Silburn ◽  
P. E. Tolmie ◽  
A. J. W. Biggs ◽  
J. P. M. Whish ◽  
V. French
Keyword(s):  
Land Use ◽  
Steady State ◽  
Time Lag ◽  
Native Vegetation ◽  
Deep Drainage ◽  
Groundwater Response ◽  
Long Time ◽  
Matrix Flow ◽  
Normal Shape

Changes in land use can affect the soil water balance and mobilise primary salinity. This paper examines changes in soil chloride (Cl) and deep drainage under pasture and annual cropping on five gilgaied Grey Vertosols in southern inland Queensland, Australia, comparing them to remnant native vegetation. Transient soil Cl mass-balance (CMB) was used for crop and pasture sites, as it is suitable for determining the long-term, low rates of drainage since clearing some 40–50 years ago. Steady-state CMB was used for native vegetation. Large masses of salts and Cl were stored under native vegetation (31–103 t/ha of Cl to 3.2 m), and deep drainage was low (0.10–0.27 mm/year). The Cl profiles were generally of a normal shape for matrix flow (e.g. no bypass flow). Soil Cl was lost under cropping (average 65% lost to 1.4 m) and pasture (32%) compared with native vegetation. This lost Cl was not stored within the top 4–5 m of soil, indicating movement of water below 4–5 m. Deep drainage averaged 10 mm/year under cropping for both gilgai mounds and depressions (range 2.7–25 mm/year), and 3.3 and 5.1 mm/year under pasture for mounds and depressions, respectively. Subsoil (depth 1.5–4+ m) was generally dry under native vegetation and wetter under cropping and pasture. Deep drainage over the last 40–50 years was stored in the unsaturated zone (to deeper than 4+ m), indicating a long time lag between land-use change and groundwater response. Steady-state CMB greatly underestimated drainage for crop and pasture sites.

scholarly journals Property studies of “loner” flares of gamma-ray blazars

2019 ◽  
Vol 72 (1) ◽  
Author(s):  
Gege Wang ◽  
Zhongxiang Wang ◽  
Liang Chen ◽  
Jianeng Zhou ◽  
Yi Xing
Keyword(s):  
Spectral Properties ◽  
Gamma Ray ◽  
Light Curves ◽  
Sharp Peak ◽  
Physical Origin ◽  
Large Area ◽  
Flare Event ◽  
Photon Index ◽  
Long Time

Abstract We search through $\gamma$-ray data obtained with the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope and find 24 blazars (or candidates) that have a single clear flare event in their 9.5 yr long-term light curves. We define these events as loner flares since each flare stands out significantly above the relatively stable, low-flux light curve. We analyze the LAT data in detail for these 24 sources. The flares in 10 of them are primarily due to a single sharp peak, for which we study by fitting with two different analytic functions. The time durations thus determined for the sharp peaks are in a range of 4–$25\:$d. The $\gamma$-ray spectra of the 24 blazar sources can be described with a power-law or a log-parabola function. We obtain their spectral properties in the flaring and quiescent states, and find that in the flares 16 of the sources have harder emission, three have softer emission, and the other five keep the same emission. We discuss a possible correlation between the differences in photon index in the quiescent and flaring states and photon indices in quiescence. In addition, the sharp peak flares seem to have a tendency of having long time durations and hard emission, possibly related to their physical origin in a blazar jet. Studies of more similar flares will help establish these possible features.

scholarly journals Long Time-Series Mapping and Change Detection of Coastal Zone Land Use Based on Google Earth Engine and Multi-Source Data Fusion

2021 ◽  
Vol 14 (1) ◽  
pp. 1 ◽  
Author(s):  
Dong Chen ◽  
Yafei Wang ◽  
Zhenyu Shen ◽  
Jinfeng Liao ◽  
Jiezhi Chen ◽  
...  
Keyword(s):  
Land Use ◽  
Time Series ◽  
Change Detection ◽  
Coastal Zone ◽  
Google Earth ◽  
Coastal Zones ◽  
Long Time Series ◽  
Coastal Aquaculture ◽  
Long Time

Human activities along with climate change have unsustainably changed the land use in coastal zones. This has increased demands and challenges in mapping and change detection of coastal zone land use over long-term periods. Taking the Bohai rim coastal area of China as an example, in this study we proposed a method for the long time-series mapping and change detection of coastal zone land use based on Google Earth Engine (GEE) and multi-source data fusion. To fully consider the characteristics of the coastal zone, we established a land-use function classification system, consisting of cropland, coastal aquaculture ponds (saltern), urban land, rural settlement, other construction lands, forest, grassland, seawater, inland fresh-waters, tidal flats, and unused land. We then applied the random forest algorithm, the optimal classification method using spatial morphology and temporal change logic to map the long-term annual time series and detect changes in the Bohai rim coastal area from 1987 to 2020. Validation shows an overall acceptable average accuracy of 82.30% (76.70–85.60%). Results show that cropland in this region decreased sharply from 1987 (53.97%) to 2020 (37.41%). The lost cropland was mainly transformed into rural settlements, cities, and construction land (port infrastructure). We observed a continuous increase in the reclamation with a stable increase at the beginning followed by a rapid increase from 2003 and a stable intermediate level increase from 2013. We also observed a significant increase in coastal aquaculture ponds (saltern) starting from 1995. Through this case study, we demonstrated the strength of the proposed methods for long time-series mapping and change detection for coastal zones, and these methods support the sustainable monitoring and management of the coastal zone.

Enhancing the power generation of Rhodopseudomonas palustris-based MFC

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1261-1268
Author(s):  
Shu Otani ◽  
Dang-Trang Nguyen ◽  
Kozo Taguchi
Keyword(s):  
Activated Carbon ◽  
Rhodopseudomonas Palustris ◽  
Ozone Treatment ◽  
Maximum Power Density ◽  
On Demand ◽  
Long Time ◽  
Dry Conditions ◽  
Carbon Sheet ◽  
Uv Ozone

In this study, a portable and disposable paper-based microbial fuel cell (MFC) was fabricated. The MFC was powered by Rhodopseudomonas palustris bacteria (R. palustris). An activated carbon sheet-based anode pre-loaded organic matter (starch) and R. palustris was used. By using starch in the anode, R. palustris-loaded on the anode could be preserved for a long time in dry conditions. The MFC could generate electricity on-demand activated by adding water to the anode. The activated carbon sheet anode was treated by UV-ozone treatment to remove impurities and to improve its hydrophilicity before being loaded with R. palustris. The developed MFC could generate the maximum power density of 0.9 μW/cm2 and could be preserved for long-term usage with little performance degradation (10% after four weeks).

Central Otago - Built on gold, growing on grass.

2014 ◽  
Vol 76 ◽  
pp. 15-23
Author(s):  
Barrie J. Wills
Keyword(s):  
Economic Growth ◽  
Land Use ◽  
National Economy ◽  
Local Community ◽  
Central Government ◽  
Future Generations ◽  
Economic Potential ◽  
District Council ◽  
Definition Of

A warm welcome to our "World of Difference" to all delegates attending this conference - we hope your stay is enjoyable and that you will leave Central Otago with an enhanced appreciation of the diversity of land use and the resilient and growing economic potential that this region has to offer. Without regional wellbeing the national economy will struggle to grow, something Central Government finally seems to be realising, and the Central Otago District Council Long Term Plan 2012-2022 (LTP) signals the importance of establishing a productive economy for the local community which will aid in the economic growth of the district and seeks to create a thriving economy that will be attractive to business and residents alike. Two key principles that underpin the LTP are sustainability and affordability, with the definition of sustainability being "… development that meets the needs of the present without compromising the ability of future generations to meet their own needs."

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