Dataset Development on the Land System and Its Carbon Storage in Sichuan Province, China (2030)
Gao, Y. F.1 Song, C. Q.2 Huang, J. R.2 Wang, Y. H.2 Ye, S. J.2 Gao, P. C.1,2*
1. State Key Laboratory of Earth Surface Processes and Disaster
Risk Reduction, Beijing Normal University, Beijing 100875, China;
2. Center for Geodata and
Analysis, Faculty of Geography, Beijing Normal University, Beijing 100875,
China
Abstract: This study employs
the CLUMondo model to predict changes in Sichuan Province??s land systems from
2020 to 2030 and estimates the region??s carbon storage for 2030 while integrating
land-use intensity under ecological-economic trade-off scenarios. The predicted
land system data and carbon storage estimates form the ??Predicting land system
and carbon storage dataset of Sichuan Province of China in 2030??. The dataset
includes: (1) raster data of land system in Sichuan Province for the years
2010, 2020, and predicted raster data of land system data in 2030 under 9
scenarios; (2) estimated carbon storage of Sichuan Province in 2030 under 9 scenarios;
(3) carbon density. The spatial resolution of the land system raster data is 1
km. The dataset is archived in .tif and .xlsx
data formats, and consists of 18 data files with a data size of 51.4 MB
(Compressed into one file with 1.84 MB).
Keywords: land system data; CLUMondo; carbon storage
assessment; Sichuan Province
DOI: https://doi.org/10.3974/geodp.2025.01.09
Dataset Availability Statement:
The dataset
supporting this paper was published and is accessible through the Digital Journal of
Global Change Data Repository at: https://doi.org/10.3974/geodb.2024.11.04.V1.
1 Introduction
Controlling
the continuous rise in global temperatures has become a core objective of climate
pledges. In 2015, at the 21st Conference of the Parties (COP21) held in Paris,
it was proposed to hold the global average temperature increase to well below 2
??C above preindustrial levels and pursue efforts to limit the temperature
increase to 1.5 ??C[1]. In 2021, at the 26th Conference of the
Parties (COP26) in Glasgow, 154 parties updated or submitted new climate
pledges and reaffirmed the 1.5 ??C climate goal[2]. To mitigate
climate change, China has set the goal of achieving
carbon neutrality by 2060[3], making it a crucial development priority and an essential objective[4]. The
primary driver of global temperature rise is the increasing carbon dioxide
emissions from human activities. The main sources of increasing carbon dioxide
emissions from human activities are fossil fuel combustion and land-use
changes. Since the Industrial Revolution, carbon emissions from land-use
changes have accounted for approximately one-third of the total emissions from
human activities, making them a significant driver of global temperature rise[5].
Sichuan
Province is a critical region in China??s path to carbon neutrality. Sichuan Province is abundant in forest resources, with forest areas covering
approximately 40% of its total land area[6]. Notably, forests are
the largest ??carbon sinks?? in terrestrial ecosystems
and play a key role in absorbing carbon dioxide from the atmosphere[7].
At the same time, future land demands in Sichuan Province show clear ecological-economic trade-offs. For example,
the 14th Five-Year Plan for Economic and Social Development and Vision
for 2035 of Sichuan Province outlined that by 2035, Sichuan Province
needs to achieve ??significant economic growth??. However, it is difficult for
any land type to achieve high ecological and economic benefits simultaneously.
Given
the above background, there is a need for future land data and carbon storage estimates
to provide data support for balancing economic and ecological benefits in land
management for Sichuan Province. This study uses the
CLUMondo model, which incorporates ecological-economic trade-offs and land-use
intensity, to predict land system changes for Sichuan Province in 2030 and
estimate its carbon storage.
2 Metadata of the Dataset
The
name, authors, geographic region, data years, spatial resolution, dataset
composition, data publication and sharing
platform, and data sharing policies for the Predicting
land system and carbon storage dataset of Sichuan Province of China in 2030[8],
are provided in Table 1.
3 Methods
3.1 Data Sources
The
dataset materials used in this study include land cover data, driving factor
data, data for calculating supply capacity, and carbon density spatial
distribution data. The land cover data are used to generate the land system
data. Driving factor data are used as input to calculate location suitability,
which determines the likelihood of changing each land type driven by social,
natural, and economic factors. Supply capacity represents the ability of each
land type to provide different land system services. Carbon density spatial
distribution data are used to calculate the carbon density coefficients for
each land system type. The detailed data are shown in Table 2.
3.2 Algorithm
3.2.1 Land System Modeling Based on Land-Use Intensity
Land
system data are generated by reclassifying land use/land cover types based on
datasets that reflect the natural state of the surface, socioeconomic factors,
or the density of land use/land cover types. Land
system data were first proposed and utilized by
Verburg[15] and have
since been widely applied in land change modeling[16,17]. Compared
with land cover/use data, land
system data reflect not only land use types but also the density or social,
Table
1 Metadata summary
of Predicting
land system and carbon storage dataset of Sichuan Province of China in 2030
Item
|
Description
|
Dataset full name
|
Predicting land system and carbon storage dataset of Sichuan Province of
China in 2030
|
Dataset short name
|
LandSystem&CarbonStorage
|
Authors
|
Gao, Y. F., State Key Laboratory of Earth Surface
Processes and Hazards Risk Governance, Beijing Normal University, Beijing, gaoyifan@mail.bnu.edu.cn
Song, C. Q., Center for Geodata and Analysis,
Faculty of Geography, Beijing Normal University, songcq@bnu.edu.cn
Huang, J. R., Center for Geodata and Analysis,
Faculty of Geography, Beijing Normal University, 202311998223@mail.bnu.edu.cn
Wang, Y. H., Center for Geodata and Analysis,
Faculty of Geography, Beijing Normal University, yuanhuiwang@bnu.edu.cn
Ye, S. J., Center for Geodata and Analysis,
Faculty of Geography, Beijing Normal University, yesj@bnu.edu.cn
Gao, P. C., Center for Geodata and Analysis, Faculty of
Geography/State Key Laboratory of
Earth Surface Processes and Hazards Risk Governance, Beijing Normal
University, gaopc@bnu.edu.cn
|
Geographical region
|
Sichuan Province
|
Year
|
2010, 2020, 2030
|
Spatial resolution
|
Land system data: 1 km; Carbon storage prediction data: provincial scale
|
Data format
|
.tif, .xlsx
|
Data size
|
51.4 MB
|
Dataset files
|
Land system data, carbon storage and carbon density prediction data
|
Foundations
|
National Natural Science Foundation of China (42230106, 42271418); State
Key Laboratory of Earth Surface Processes and Resource Ecology (2022-ZD-04,
2023-WT-02)
|
Computing environment
|
CLUMondo, MATLAB
|
Data publisher
|
Global Change Research Data Publishing & Repository,
http://www.geodoi.ac.cn
|
Address
|
No. 11A, Datun Road, Chaoyang District, Beijing 100101, China
|
Data sharing policy
|
(1) Data are openly available and can be free downloaded via the
internet; (2) End users are encouraged to use Data subject to
citation; (3) Users, who are by definition also value-added service
providers, are welcome to redistribute Data subject to written
permission from the GCdataPR Editorial Office and the issuance of a Data
redistribution license; and (4) If Data are used to compile new
datasets, the ??ten percent principal?? should be followed such that Data records
utilized should not surpass 10% of the new dataset contents, while sources
should be clearly noted in suitable places in the new dataset[9]
|
Communication and
searchable system
|
DOI, CSTR, Crossref, DCI, CSCD, CNKI, SciEngine, WDS, GEOSS, PubScholar,
CKRSC
|
Table 2 Data sources
Type Subtype
|
Name
|
Year
|
Resolution
|
Source
|
Land cover
data
|
Globeland30[10,11]
|
2010, 2020
|
30 m
|
National Geomatics Center of China
http://www.globeland30.org/
|
Driving factor data
|
Soil
|
Bulk density (kg/m3)
|
2017
|
250 m
|
ISRIC-World Soil Information
https://data.isric.org/geonetwork/srv/chi/catalog.search
|
Cation exchange capacity (cmolc/kg)
|
Clay content (%)
|
Coarse fragments content (%)
|
Effective soil water capacity (%)
|
Organic carbon density (kg/m3??10)
|
pH value of water
|
Sand content (%)
|
Silt content (%)
|
Texture content (%)
|
Socioeconomic
|
Market accessibility index
|
2011
|
5 arc-min
|
Instituut voor Milieuvraagstukken (IVM)
http://environmentalgeography.nl/files/data/public/marketinfluence
|
Market influence index ($/person)
|
Market density index
|
(To be continued on the next page)
(Continued)
Type Subtype
|
Name
|
Year
|
Resolution
|
Source
|
|
Socio-
economic
|
Nighttime light index
|
2010
|
30 arc-sec
|
NOAA
https://ngdc.noaa.gov/eog/dmsp/downloadV4composites.html
|
GDP ($)
|
2015
|
Dryad
https://datadryad.org/stash/dataset/doi:10.5061/dryad.dk1j0
|
Population density (%)
|
2010
|
EARTHDATA
https://sedac.ciesin.columbia.edu/data/set/gpw-v4-population-density-rev11/data-download
|
Accessibility
|
Distance to the nearest city (m)
|
2015
|
30 arc-sec
|
Malaria Atlas Project
https://malariaatlas.org/research-project/accessibility-to-cities/
|
Distance to the nearest river (m)
|
N/A
|
1 km
|
Nature Earth
http//www.naturalearthdata.com
|
Distance to the nearest road (m)
|
Distance to the nearest railway (m)
|
Motor vehicle travel time (minutes)
|
2019
|
30 arc-sec
|
Malaria Atlas Project
https://malariaatlas.org/explorer/#/
|
Walking travel time (minutes)
|
Distance to the nearest medical facility (motor vehicle) (minutes)
|
Distance to the nearest medical facility (walking) (minutes)
|
Agriculture and vegetation
|
Yield of 175 major crops per hectare (t/ha)
|
2000
|
5 arc-min
|
EarthStat
http://www.earthstat.org/harvested-area-yield-175-crops/
|
Gross primary productivity (March) (gC/(m2??d))
|
2010
|
0.05 degree
|
The National Tibetan Plateau Data
Center (TPDC) https://data.tpdc.ac.cn/zh-hans/data/d6dff40f-5dbd-4f2d-ac96-55827ab93 cc5/?q=GPP
|
Gross primary productivity (June) (gC/(m2??d))
|
Gross primary productivity (September) (gC/(m2??d))
|
Gross primary productivity (December) (gC/(m2??d))
|
Normalized vegetation index (March)
|
2010
|
1 km
|
The Copernicus Land Monitoring Service
https://land.copernicus.eu/global/
|
Normalized vegetation index (June)
|
Normalized vegetation index (September)
|
Normalized vegetation index (December)
|
Topo- graphy
|
Elevation (m)
|
N/A
|
30 arc-sec
|
WorldClim
https://worldclim.org/data/worldclim21.html
|
Elevation variance (m2)
|
990 m
|
Derived from elevation
|
Slope (??)
|
1 km
|
Aspect
|
Climate
|
Annual precipitation average (mm)
|
2007?C
2018 average
|
30 arc-sec
|
Zenodo
https://zenodo.org/record/3256275#.YGQzHWgzaUl
DOI:10.5281/zenodo.3256275
|
Average precipitation (March)
(mm)
|
Average precipitation (June) (mm)
|
Average precipitation (September) (mm)
|
Average precipitation (December) (mm)
|
Annual temperature average (??)
|
2000?C
2017 average
|
Zenodo
https://zenodo.org/record/1435938#.YGQyyWgzaUk
DOI:10.5281/zenodo.1435938
|
Average temperature (March) (??)
|
Average temperature (June) (??)
|
Average temperature (September) (??)
|
Average temperature (December) (??)
|
(To be continued on the next page)
(Continued)
Type Subtype
|
Name
|
Year
|
Resolution
|
Source
|
|
Livestock
|
Number of buffalo
|
2010
|
5 arc-min
|
Harvard Dataverse
https://dataverse.harvard.edu/
|
Number of cattle
|
Number of chickens
|
Number of ducks
|
Number of goats
|
Number of horses
|
Number of pigs
|
Number of sheep
|
Land cover density
|
Land cover density (%)
|
2010
|
990 m
|
Derived from Globeland30 data
|
Forest density (%)
|
Grassland density (%)
|
Shrubland density (%)
|
Wetland density (%)
|
Waterbody density (%)
|
Built-up area density (%)
|
Bare land density (%)
|
Glacier and permanent snow density (%)
|
Data for calculating supply capacity
|
GDP (raster) (104
CNY//km2)
|
2020
|
1 km
|
Resource and Environmental Science Data Platform
https://www.resdc.cn/DOI/DOI.aspx?DOIID=33
|
GDP total (108
CNY)
|
N/A
|
China
Statistical Yearbook 2020[12]
|
Ecosystem value
raster (104 CNY /km2)
|
1 km
|
Resource and Environmental Science Data Platform
https://www.resdc.cn/DOI/DOI.aspx?DOIID=48
|
Carbon density spatial distribution data
|
Soil carbon density spatial
distribution[13] (MgC/ha)
|
N/A
|
250 m
|
ISRIC - World
Soil Information
SoilGrids250m
2.0
|
Aboveground biomass carbon density spatial
distribution[14] (MgC/ha)
|
2010
|
1 km
|
ORNL DAAC
https://daac.ornl.gov/cgi-bin/dsviewer.pl?ds_id=1763
|
Belowground biomass carbon density spatial
distribution[14] (MgC/ha)
|
2010
|
1 km
|
natural, and economic factors.
In this study, Globeland30 data[10,11] were used to generate land system data in 2010 and 2020 at
a 1 km resolution using upscaling methods[16,18]. The 2010 and 2020
land system data can reflect the local density of the dominant type. The
process for generating the land system data is shown in Figure 1. Specifically, the process of
generating land system data consists of three steps. First, the size of the
sliding window was determined. Next, for each sliding window, the land cover
type with the largest area was identified as the dominant type. This dominant
type determines the system type for the upscaled pixel. For example, in a
sliding window, if the land cover type with the largest area was cropland, the
upscaled pixel would be classified as a ??cropland system??. Third, the density
type for the upscaled pixel was determined
based on natural break thresholds. The method for calculating natural break
thresholds is to slide the global Globeland30 data using a 33??33 sliding
window. For each sliding window, the proportion of the dominant land cover type
was calculated. All proportions of each land cover type were then used to
calculate the natural break thresholds.

Figure
1 Flowchart of the land system data
development
3.2.2 Land System Services
and Scenario Design Considering Ecological‒Economic Trade-offs
The scenario design includes the setup of land
system services and calculating their values in 2030. This study sets 2 land system
services, namely Gross Domestic Product (GDP) and Gross Ecosystem Product
(GEP). The GDP represents economic benefits, whereas
the GEP represents ecological benefits. The total GDP for 2020 was obtained
from statistical yearbooks, and the total GEP for
2020 was derived by calculating the sum of GEP grid data within Sichuan Province. The GEP grid data are
categorized into 4 major services, namely provisioning, regulating, supporting, and
cultural services[19]. To emphasize ecological functions, the
calculation of GEP in this study only focuses on regulating, supporting, and cultural services. Through combinations of 3 different
levels of annual GDP growth rates and 3 different levels of annual GEP growth
rates, 9 scenarios were designed in the study. The GDP growth rates are set at
3.00%, 4.00%, and 5.00%, whereas the GEP growth rates are set at 0.05%, 0.50%,
and 1.00%. The total GDP and GEP for Sichuan Province in 2030 under each scenario
are shown in Table 3.
Table 3 Total GDP and GEP of Sichuan Province in
2030 under nine scenarios
Scenario
|
GDP
annual growth rate (%)
|
Gross
Domestic Product (10,000 CNY)
|
GEP
annual growth rate (%)
|
Gross
Ecosystem Product (10,000 CNY)
|
S1
|
3.00
|
600,642,920.2
|
0.05
|
335,241,496.7
|
S2
|
3.00
|
600,642,920.2
|
0.50
|
350,628,697.8
|
S3
|
3.00
|
600,642,920.2
|
1.00
|
368,468,680.4
|
S4
|
4.00
|
661,572,597.5
|
0.05
|
335,241,496.7
|
S5
|
4.00
|
661,572,597.5
|
0.50
|
350,628,697.8
|
S6
|
4.00
|
661,572,597.5
|
1.00
|
368,468,680.4
|
S7
|
5.00
|
728,009,599.6
|
0.05
|
335,241,496.7
|
S8
|
5.00
|
728,009,599.6
|
0.50
|
350,628,697.8
|
S9
|
5.00
|
728,009,599.6
|
1.00
|
368,468,680.4
|
3.2.3 Land System Change
Simulation Based on the CLUMondo Model
The original
version of the CLUMondo model was developed by van Asselen and Verburg in 2012[15].
The CLUMondo model has been widely used in global and regional land change
simulations[20?C23]. The principle of the CLUMondo model is that
land types change iteratively through land type conversion
rules to respond to changes in all land system services[18,24]. The
core characteristic of the CLUMondo model is its ability to establish the many-to-many relationships between land system types and land system
services[24]. Specifically, each land type
provides multiple services, and each service can be met by multiple land types.
The basic principle of the CLUMondo model is illustrated in Figure 2.

Figure
2 Principles of the CLUMondo model
To simulate land
system changes using CLUMondo, it is necessary to calculate location
suitability, supply capacity, conversion order, resistance, and conversion
matrix. The location suitability reflects the likelihood of each land type
changing into any land type driven by various natural, social, and economic
factors. The resistance indicates the difficulties for one land type to be
converted into others. The conversion matrix indicates restrictions on the
changes that are not allowed between land types. The calculation methods are as
follows.
(1) Location suitability
Before
calculating location suitability, this study normalized the driving factors and
removed those with high correlations. The correlation between the driving
factors was assessed using Spearman??s correlation coefficient, as it does not
require the variables to follow a normal distribution. In this study, the rule
for removing driving factors with high correlations consists of 3 steps. First,
Spearman??s correlation coefficients between all pairs of driving factors were
calculated. Second, driving factors with a coefficient greater than 0.8 were identified. Third, for these pairs, the sum of
their correlation coefficients with all other driving factors was
calculated, and the driving factor with the larger sum was removed.
In the CLUMondo
model, the calculation of location suitability is performed through logistic
regression, as shown in Equation 1. SPSS software was used in this study to
conduct logistic regression for each land system. The sample proportion
selected for regression was 100%, and the regression method used was ??Forward:
Conditional??.
(1)
where
represent the values of the driving factors at the pixel
,
are the coefficients of the driving factors, and
is the constant term.
represents the
local suitability to change to land type j at the pixel
. The value of
ranges from
, with higher values indicating greater suitability.
(2) Supply capacity
Supply capacity
represents the quantity of land system services that each land type can serve.
In this study, the land system services consist of GDP and GEP. The supply
capacities were calculated by overlaying the 2020 land system data with the
2020 GDP raster data and GEP raster data. The overlay analysis calculates the
average GDP and GEP for each land system type. The average GDP and GEP for each
land system type serve as the supply capacity. For GDP, due to discrepancies
between the total amount obtained from raster data and the statistical yearbook
for Sichuan Province, this study calibrated the raster data??s total GDP by
multiplying it with a coefficient. The calculation method for the coefficient
is shown in Equation 2. The supply capacity of each land
system service for Sichuan Province, as calculated in this study, is presented
in Table 4.
(2)
where
is the coefficient,
is the total GDP for Sichuan Province obtained from the GDP
raster data, and
is the total GDP for Sichuan Province as reported in the
statistical yearbook.
(3) Conversion order
The conversion
order reflects the capacity of each land system type to meet each land system
service. The conversion order values are represented by ???C1?? and nonnegative integers. A value of ???C1?? indicates that the land system is unable to serve the land system
service. Nonnegative integers represent the strength of the supply capacity,
with higher values indicating greater capacity to serve the land system
service. In this study, the conversion orders are assigned based on the supply
capacity of land systems[18]. Specifically, the supply capacity
values of the land systems are ranked. For land systems that cannot provide
service, the conversion order value is set to ???C1,?? while for the remaining land system types, it is assigned values
starting from ??0?? based on supply capacity. If there is the same supply capacity
in multiple land systems, they are assigned the same conversion order value.
Additionally, to ensure more reasonable simulation results, this study sets the
conversion order for low-density, medium-density, and high-density water bodies
for GEP to ??0?? to reduce large-scale conversion from other land types to water
bodies. The conversion order settings used in this study are shown in Table 4.
Table 4 Supply capacity
and conversion order statistics
Land type
|
GDP (10,000 CNY/Pixel)
|
Conversion order
|
GEP (10,000 CNY/Pixel)
|
Conversion order
|
Low-density cropland
|
1,504.659
|
19
|
657.359
|
15
|
Medium-density
cropland
|
1,994.615
|
22
|
464.612
|
10
|
High-density cropland
|
2,779.222
|
23
|
301.898
|
7
|
Low-density forest
|
541.916
|
17
|
804.412
|
18
|
Medium-density
forest
|
383.603
|
15
|
945.425
|
21
|
High-density
forest
|
272.148
|
11
|
1,062.804
|
22
|
Low-density grassland
|
370.031
|
12
|
627.427
|
14
|
Medium-density
grassland
|
105.327
|
9
|
527.786
|
12
|
High-density grassland
|
30.327
|
4
|
426.093
|
9
|
Low-density shrubland
|
379.804
|
14
|
606.815
|
13
|
Medium-density
shrubland
|
161.127
|
10
|
489.881
|
11
|
High-density shrubland
|
514.605
|
16
|
738.328
|
17
|
(To be continued on the next page)
(Continued)
Land type
|
GDP (10,000 CNY/Pixel)
|
Conversion order
|
GEP (10,000 CNY/Pixel)
|
Conversion order
|
Low-density wetland
|
378.390
|
13
|
921.447
|
20
|
Medium-density wetland
|
60.424
|
8
|
892.840
|
19
|
High-density wetland
|
18.622
|
0
|
1,204.451
|
23
|
Low-density water
bodies
|
1,910.401
|
21
|
2,545.100
|
0
|
Medium-density
water bodies
|
1,771.468
|
20
|
3,528.336
|
0
|
High-density
water bodies
|
1,058.833
|
18
|
5,112.363
|
0
|
Low-density
artificial surfaces
|
7,271.027
|
24
|
672.572
|
16
|
Medium-density
artificial surfaces
|
11,811.820
|
25
|
376.183
|
8
|
High-density
artificial surfaces
|
42,754.030
|
26
|
149.705
|
0
|
Low-density bare
land
|
23.295
|
3
|
246.358
|
6
|
Medium-density
bare land
|
19.503
|
1
|
205.191
|
2
|
High-density bare
land
|
22.014
|
2
|
200.158
|
1
|
Low-density ice and
permanent snow
|
38.580
|
5
|
231.343
|
5
|
Medium-density
ice and permanent snow
|
39.055
|
6
|
209.031
|
3
|
High-density ice
and permanent snow
|
39.790
|
7
|
215.367
|
4
|
(4) Resistance
The resistances in this study are calculated
based on historical changes in land systems. The easier it is for a land system
type to change into other land system types during a specific historical
period, the smaller its resistance. Conversely, the more difficult the changes,
the larger the resistance. According to the meaning of resistances, the
calculation method of resistances is provided in Equation 3. The results of the
resistances are shown in Table 5.
Table 5 Resistance for each land type
Land type
|
Resistance
|
Land type
|
Resistance
|
Low-density cropland
|
0.876,9
|
High-density wetland
|
0.973,6
|
Medium-density
cropland
|
0.871,5
|
Low-density water
bodies
|
0.771,3
|
High-density cropland
|
0.895,7
|
Medium-density water
bodies
|
0.880,0
|
Low-density
forest
|
0.893,5
|
High-density
water bodies
|
0.897,1
|
Medium-density forest
|
0.906,5
|
Low-density artificial
surfaces
|
0.367,0
|
High-density forest
|
0.964,5
|
Medium-density artificial surfaces
|
0.433,5
|
Low-density grassland
|
0.866,2
|
High-density artificial
surfaces
|
0.951,2
|
Medium-density
grassland
|
0.873,2
|
Low-density bare
land
|
0.627,7
|
High-density grassland
|
0.944,8
|
Medium-density
bare land
|
0.721,1
|
Low-density shrubland
|
0.873,1
|
High-density bare
land
|
0.784,4
|
Medium-density
shrubland
|
0.911,3
|
Low-density ice and permanent snow
|
0.128,4
|
High-density shrubland
|
0.901,1
|
Medium-density ice and permanent snow
|
0.152,4
|
Low-density wetland
|
0.832,6
|
High-density ice
and permanent snow
|
0.546,2
|
Medium-density
wetland
|
0.8952
|
|
|
(3)
where
represents the resistance of land type
.
and
denote 2 historical years, with
.
represents
the number of pixels that remain unchanged as land type
in both years
and
, whereas
represents the number of pixels classified as land type
in year
.
(5) Conversion matrix
The conversion
matrix is also determined based on historical changes in land systems. If land
system type
has been changed into land system type
in historical changes, then the conversion from land type
to land type
is allowed.
3.2.4 Estimation of
Carbon Storage Based on the Carbon Density of Land System Types
The basic principle for
estimating carbon storage is to multiply the area of each land system type by
its corresponding carbon density coefficient and then sum the results. The key
step is to calculate the carbon density coefficient for each land system type[25].
When calculating carbon storage (
),
four carbon pools are considered, namely aboveground carbon storage,
belowground carbon storage, soil carbon storage, and dead biomass organic
carbon storage[26]. Due to the challenges in obtaining data on dead
biomass organic carbon storage, this study follows previous research by excluding dead biomass
organic carbon storage from the calculation. The calculation of carbon storage in
this study is shown in Equation 4. The carbon
density coefficient for each land system type is obtained by overlaying land system
data with spatial distribution data of carbon density. The carbon density
coefficient of each land system type is the average carbon density
corresponding to that land system type, with the calculation methods shown in
Equations 5 to 7. The calculation results for the carbon density coefficients are presented in the
Predicting land system and carbon storage dataset of Sichuan Province of China in
2030[8].
(4)
(5)
(6)
(7)
where
represents the area of the
-th land system type (ha),
represents the aboveground biomass carbon density of the
-th land system type (MgC/ha),
represents the belowground biomass carbon density of the
-th land system type (MgC/ha), and
represents the soil carbon density of the
-th land system type (MgC/ha).
,
, and
denote the
aboveground biomass carbon density, belowground biomass carbon density, and
soil carbon density, respectively, of the
-th pixel of the
-th land system type.
is the area of
the
-th pixel of the
-th land system type.
3.3 Technical Workflow
The
technical workflow of this study is shown in Figure 3. The workflow consists of
5 parts. First, land system data for Sichuan Province for 2010 and 2020 are
created. Second, parameters, including resistance, the conversion matrix,
location suitability, supply capacity, and the conversion order, are
calculated. Third, scenarios are set. This study uses GDP to reflect economic
benefits and GEP to reflect ecological benefits. By setting different annual
growth rates, the GDP and GEP for Sichuan Province in 2030 are obtained.
Fourth, land system changes in Sichuan Province from 2020 to 2030 are
predicted. Fifth, the carbon density coefficients of land system types are
calculated, and carbon storage in 2030 is predicted.

Figure
3 Workflow of the dataset development
4 Data Results and Validation
4.1 Dataset Composition
The
composition of the dataset is shown in Table 6. The dataset consists of 2
parts, namely land system data and carbon storage data. The land system data
are available for the years 2010, 2020, and 2030 in .tif format with a spatial
resolution of 1 km. The carbon storage data are available for the years 2020
and 2030, stored in .xlsx format.
Table 6 Dataset composition
Dataset
|
Item
|
Description
|
Land system data
|
Time
|
2010, 2020, 2030
|
Spatial resolution
|
1 km
|
Data format
|
.tif
|
Naming
|
Sichuan_Year(_Scenario).tif
|
Carbon storage data
|
Time
|
2020, 2030
|
Resolution
|
Sichuan Province
|
Data format
|
.xlsx
|
Naming
|
CarbonStorage&Density.xlsx
|
4.2 Data Results
4.2.1 Land System
Prediction Results
This study developed
land system maps in Sichuan Province for 2010 and 2020 and predicted land system changes from 2020 to
2030 using the CLUMondo model. The land system maps for 2010 and 2020 are shown in Figure 4,
while the land system maps for 2030 under 9 scenarios are shown in Figure
5. As observed in Figure 5, with GDP
growth, the southeastern
region of Sichuan Province will experience increased cropland density and urban
expansion due to cropland encroachment. The
higher the annual GDP growth rate, the greater the expansion of urban
agglomerations centered around Chengdu. With GEP growth, the northwestern region of Sichuan Province will experience
further increases in the density and expansion of forests and
grasslands, promoting wetland conservation and restoration in the northern part
of the province.

Figure 4 Land system maps in 2010 and 2020
4.2.2 Carbon Storage
Prediction Results
The predicted carbon storage results in
Sichuan Province under nine scenarios are detailed in the Predicting land system
and carbon storage dataset of Sichuan Province of China in 2030[8]. The results indicate that carbon
storage in 2030 under the S3 scenario shows the largest increase among all
scenarios. Compared to 2020, the carbon storage under the S3 scenario increases
by 2.89%. In terms of carbon storage components, the increase comes from
aboveground biomass carbon storage and belowground biomass carbon storage,
which increase by 13.67% and 7.37%,
respectively. From the perspective of land types, the increase in carbon storage is attributed
primarily to the expansion of high-density forests, which originates mainly
from the conversion of medium- and high-density grasslands as well as low- and
medium-density forests. In contrast, the carbon storage under the S7 scenario
in 2030 shows the largest decrease among all scenarios. Compared to 2020,
carbon storage will decrease by 3.23%. The decrease is mainly due to a decrease
in belowground biomass carbon storage and soil carbon storage, which will
decrease by 2.29% and 4.83%, respectively.

Figure 5 Land system maps for 2030 under all
scenarios
4.3 Data Validation
The
basic assumption for data validation in this study is that if the CLUMondo
model can effectively simulate historical land system changes, it can also
reliably predict future land system
changes. Based on this assumption, the study simulated land system changes in Sichuan
Province from 2010 to 2020. Then the simulated land system data in 2020 is compared
with the actual land system data in 2020.
This study uses
the Kappa coefficient and figure of merit (FoM) to evaluate the accuracy of the
land change simulations. Both the Kappa coefficient and FoM assess model
accuracy from different perspectives. The Kappa coefficient is used to evaluate
the similarity between the simulated results and the actual land system map[27],
whereas the FoM calculates the proportion of correctly simulated pixels
compared with the total number of correctly changed pixels to assess the
accuracy of the changes[28]. The calculation method for the Kappa
coefficient is shown in Equation 8. The value of the Kappa coefficient ranges
from
, with a higher value indicating better simulation accuracy.
The calculation method for FoM is shown in Equation 9. The value of FoM ranges
from
, with a higher value indicating better simulation accuracy.
(8)
(9)
where
is the overall accuracy, which represents the proportion of
correctly simulated pixels for land types;
represents the proportion of correctly simulated pixels
randomly.
refers to the number of pixels that actually changed in the
land change simulation and were correctly predicted in the simulation;
refers to the number of pixels that changed in the actual
land change process but were not predicted to change in the simulation. False
alarm refers to the number of pixels that did not change in reality but were
predicted to change in the simulation.
refers to the number of pixels that changed in reality but
were incorrectly predicted to change in the simulation.
Table 7 Validation results
|
Number of
land types
|
Kappa
coefficient (%)
|
FoM (%)
|
27
|
83.4%
|
2.1%
|
9
|
89.0%
|
4.4%
|
The Kappa coefficient and FoM results both
demonstrate the excellent performance of the land change simulation in this
study. As shown in Table 7, the Kappa coefficient
reached 83.4% for the 27 land types, and after the 27 land types were merged
into 9 categories, the Kappa coefficient was 89.0%. Although the FoM value was
relatively low for the 27 land types, it increased by 109.0% after the land
types were merged into 9 categories. Compared with similar studies, the land
change simulation accuracy in this study is relatively high. For example, in
reference[29], the FoM for 5 land types was approximately 7.0%; in reference[30],
the FoM reached approximately 50.0%, but this study considered only 2 land
types, and the FoM calculation did not account for Miss, which caused the FoM
value to be overstated.
5 Discussion and Conclusion
This
study uses the CLUMondo model to predict land system changes in Sichuan
Province from 2020 to 2030, based on a balance between ecological and economic
benefits and land-use intensity. Additionally, the carbon storage of Sichuan
Province in 2030 was estimated based on the predicted land system data.
Compared with similar studies, the land system data predicted in this study
have a higher thematic resolution, providing a more detailed depiction of
future land changes in Sichuan Province. Furthermore, through overlay analysis,
the carbon density coefficients for land system types were calculated more
accurately, leading to a more precise prediction of future carbon storage
changes in Sichuan Province.
The data
produced in this study have 2 significant implications. First, the land system
data and carbon storage estimation data predicted in this study can provide
data support for achieving coordinated ecological-economic
development in Sichuan Province in land management.
Second, the data produced can serve as data support for
multiple scientific fields. For example, predicted land system data can provide
basic data support for studies on biodiversity assessment, flood risk analysis,
water cycling, and other research areas.
Author Contributions
Gao, P. C. and Song, C. Q. contributed
to the overall design of the dataset development; Gao Y. F. collected and
processed and performed the data validation, and wrote the data paper; Wang, Y.
H., Ye, S. J. and Huang, J. R. supervised the writing of the paper.
Conflicts of Interest
The authors declare no conflicts of
interest.
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