Transformation of land use and land cover and its implication to the local climate in Aceh Besar District, Aceh, Indonesia

Many researchers claim that human influence on local climate change is unavoidable. Global climate change can cause catastrophic damage (disturbing human health, ecosystems, and socio-economic aspects). Characteristics of areas that affect rainfall, such as topography, slope, and land use and cover (LULC). This study aimed to specify the relationship between LULC changes and the local climate context in Aceh Besar District. LULC changes are analyzed with a transformation matrix. The method used to determine the occurrence of climate change is the Mann-Kendall Test, which looks at whether there is a trend in a data series based on the relative rankings of the data spanning 1992-2020. The Mann-Kendall test analysis results show that climate variables that change significantly on rainy days are weather temperature, humidity, and wind speeds. The statistical test results show that there has been a change in the local climate, as indicated by the variables of The Sen’s Slope Estimator test results in an increase in temperature of 0.002°C every year, and humidity increases by 0.01%. When viewed from LULC, one of the influences is changing (2000-2020) from forest, cropland, and bareland to built-up areas.


Introduction
The urbanization process has crucial implications for land use and land cover (LULC) changes, which in turn impact diverse environmental components, particularly soil and water components.A more detailed comprehension of the dynamics of LULC changes due to urbanization is needed to cope with environmental changes and achieve sustainable development.Most regions experience LULC changes to enlarge urban areas due to continuous urbanization pressures [1].
Most previous studies have proven that if the implementation practice of spatial planning is less controlled, it can cause urban heat islands, characterized by a rise in the average land surface temperature in urban areas [2][3][4].In regional and urban planning in Indonesia, socio-economic and biophysical aspects are considered when determining spatial patterns and structures.However, it still needs to be improved in assessing the effect of spatial use on the local climate [5].The determination of spatial use is sought to minimize local climate change, which causes inconvenience, especially in mitigating the 1263 (2023) 012023 IOP Publishing doi:10.1088/1755-1315/1263/1/012023 2 rising air temperature and a reduction in humidity in urban areas [1,6].LULC has an anthropogenic impact on the climate in addition to greenhouse gas emissions [7].
Moreover, LULC changes can have a crucial impact on the local climate and environment [8,9].In the use of space, it is very important to study the interconnection of natural conditions and human activities so that it can properly mitigate local climate change [10].LULC changes are approximated by local climate changes [7,11].LULC and climate change are closely related and can significantly impact each other.LULC changes can contribute to climate change by altering the amount of carbon stored in vegetation and soil, changing the reflectivity of the Earth's surface, and affecting the water cycle [12].Climate change, in turn, can affect LULC by altering temperature and precipitation patterns, leading to changes in vegetation partition and crop yields, and strengthening the density and severity of natural disasters such as wildfires and floods event [13,14].Deforestation and land conversion for agriculture or urbanization can release large amounts of carbon dioxide into the atmosphere, contributing to global warming [15].
Moreover, climate change can also cause a change in precipitation patterns, affecting water sources, crop availability, and other LULC categories [16].It can lead to LULC changes in practices, such as shifting from water-intensive crops to more drought-resistant ones.The Krueng Aceh Watershed, as part of Aceh Besar District, is an area of water and mountains where there is an increase in temperature and changes in cropping patterns [17].An increase in air temperature in the highlands also occurs [18].Engineering measures can only bring short-term results, so land management needs to be considered in light of the conditions that occur.Overall, understanding the complex relationship between LULC changes and the local climate change context is crucial for creating and expanding an effective strategy for mitigating and adapting to the climate change impact.So, this research paper aims to review the involvement of LULC changes in climate change in the Aceh Besar District.More generally, this paper is designed to assist planners in proposing strategies for mitigating local climate change in the context of land management.

Study area
The area of study was conducted within the territory boundaries that are established within the regional area of Aceh Besar District, which has a 2,969.00km 2 area (Fig. 1).Due to its proximity to the equator, Aceh Besar District is considered to have a tropical climate.LULC changes were obtained from the processing of Landsat imagery in 2000 and 2020.The average air temperature in 2020 is between 26.42°C and 28.26°C [19].

LULC changes nalysis
LULC was classified into six categories: built-up area, grassland, water body, agricultural land, forest, and bareland [19].Data from the Landsat image (2000) and satellite imagery (2020) are processed using ArcGIS 10.1 by using the Maximum Likelihood Classification method and field cross-checks [19].

Climate change analysis
The Mann-Kendal test is performed to assess whether or not there has been a change in climate data, a ranking-based non-parametric method for evaluating data over a long, monotonous period [20].Statistical tests can be performed using the Mann-Kendall Test method to assess data trends.The Mann-Kendall Test is used to see whether there is a trend in a data series based on ranking, which evaluates the data for monotonous trend results.The steps taken are as follows: (a) formulating hypotheses (b) determining significant level (α), (c) finding the Z value (criteria for normal testing).Furthermore, the Sen's Slope Estimator (SSE) was carried out to do estimation on the slope of the trend and the divergence of the constant residuals over time by using a linear model [20].

Land use and land cover changes
LULC changes from 2000-2020 in Aceh Besar District are findings from previous research (Table 1) [19].The built-up area covered in 2000 was 11,559.78ha and will be 15,038.01ha in 2020.Meanwhile, the waterbody is the LULC category with the smallest area, with an area of 3,586.05ha in 2000 and a little smaller area of 3,586.05ha in 2020.Changes in LULC will alter the pattern of ecosystem services [21].An increase in the built-up area causes a reduction in carbon storage [6] and deteriorating water quality [22].On the temperature graph, there is an increasing trend which indicates a rise in temperature at the study site.Moreover, an increase in greenhouse gases can cause this, especially the results of burning fossil fuels (CO2, CH4, and NOx) LULC changes [23], and population growth [12,24].Changes in forest area can increase greenhouse gases due to reduced carbon stocks [25].Fig. 3 shows that the rainfall graphs and irradiation duration do not show a pattern or trend.The data spread seasonally.Predictions made using the seasonal autoregressive integrated moving average (SARIMA) based on climate data indicate that there has been an increase in temperature.Test the prediction results of actual data using the Nash Sutcliffe Efficiency Pbias and Root mean square error, giving values in the good and very good categories [26].A positive Z value indicates a positive trend, so temperature and humidity have a positive trend.Rainfall, rainy days, wind speed, and duration of irradiation show a decreasing trend because they have a positive Z value.The results of the Mann-Kendall test show that the rainfall data and the duration of irradiation have no trend because they have an absolute Z value that is less than the critical value.In contrast, the data on rainy days, humidity, temperature, and wind speed have a trend because they have an absolute Z value greater than the critical value.The Sen's Slope Estimation for climate change element for rainfall (t)=97.341-0.02t.From this model, it is found that every month it will reduce 0.02 mm of rainfall.Rainy days(t)=15.186-0.007t.From this model, it is found that every month it will reduce 0.007 rainy days (in other words, in 1000 days, there will be a decrease of 7 rainy days).Temperature (t)=26.305+0.002t.This model shows that every month there is an increase in temperature of 0.002 degrees Celsius.Meanwhile, humidity (t)=79.767+0.010t.
From this model, it is found that every month it will increase the humidity by 0.010%.Climate and LULC changes will be driving factors for ecosystem service changes [27].Climate change affects ecosystem services both directly and indirectly by changing hydrological processes, evapotranspiration values, erosion and sedimentation [28], and increased CO2 concentrations [29].Climate change can be seen in the increasing trend of drought, which has an impact on agriculture and people's economies.Planting patterns that have shifted due to climate change that are occurring need to be known by the public [30].

Conclusion
Aceh Besar District has experienced LULC changes from forest to built-up land for two decades .The climate change trend test in the observation period (1992-2020) using the Mann-Kendall test showed no significant change in the climate variables rainfall and duration of irradiation.As for the rain day variable, temperature, humidity, and speed underwent significant changes.The Sen's Slope Estimator test results in an increase in temperature of 0.002 o C every time, and humidity increases by 0.01%.

Figure 2 .
Figure 2. Trends in the distribution of climate element data at research locations from 1992-2020.

Table 1 .
The area of each LULC category for the years 2000 and 2020. [19]]