1. Introduction
Globally, land use monitoring projects have been integral to international climate and environmental science after the start of the Land Use and Land Cover (LULC) project. Urbanization, marked by replacing natural environments with warm absorbing surfaces and houses, results in high urban temperatures relative to rural and sub urban areas [
1]. High temperatures occur in central business districts (CBD) and high density residential (HDR) areas [
2]. These kinds of temperature changes may have negative environmental and socio-economic effects on built-up areas, including enlarged consumption of heating and air conditioning thus raising energy prices and pollution-related health threats [
3,
4]. Nonetheless, due to the substitution of impermeable surfaces and buildings as cities expand their coverage and protection is diminished. The association between future temperature and LULC changes predictions needs to be understood for renewable urbanization and making plans. Surface temperatures and the effect of localized LULC need to be evaluated in order to enhance precision adaptation, prevention, rule design and execution in urban areas.
Several experiments targeted the interaction between LULC trends and LST utilizing remote sensed data without rendering possible predictions [
5]. Owing to a mixture of low warm emissivity, weak latent temperature transmission and high heat absorption capacity, this research explained that susceptible surfaces inside urban extents are distinguished by higher temperatures. Conversely, low temperatures are also characteristic of natural landscapes such as wetlands and vegetated areas [
6,
7]. Research has also looked at natural and long-term historical temperature shifts related to population development [
5]. Researchers have used vegetation and urban indices to demonstrate the measurable association between LST and LULC rather than on potential influences from weather trends [
8]. For instance [
9], describes temperature reduction with the NDVI (Normalized-difference-vegetation-Index) combined with the NDBaI (Normalized-difference-bareness-index) whereas the NDWI (Normalized-difference-wetness-index) is showing rise in temperature with the NDBI (Normalized Difference Built-up Index). The association among LST and variability of indices of LULC is strong, therefore variations in LULC indices such as FVG (Vegetation Fraction) and NDBI have the ability to predict temperature accurately. There is nevertheless a shortage of literature on the usage of LULC indices to predict the potential spatial spread of urban LULC and LST trends.
Despite their success in predicting trends of population development, only one analysis used indices of land cover to estimate projected distribution of soil surface temperature [
10]. While [
10] the NDVI has been used to estimate residual city normal ecosystems and potential LST values, Normalized difference Vegetation Index is considered to soak at large vegetation fractions, thereby giving a small temperature variation. Previous researches clearly illustrate that Normalized difference Vegetation is a weaker LST predictor than other vegetation and Non-vegetation indices that is, NDBI and ISA (Impervious Surface Areas). In addition [
10], single satellite images were used to calculate NDVI to denote the complete season; a technique that is subject to chance, given that a season may differ considerably with a land cover. Therefore, the method has to be changed such as the including seasonal estimates of indices of land cover. In another analysis, calculated LST using a linear regression method on a variety of indices resulting in the Enhanced Build-up and Bareness Index (EBBI), NDBaI, NDBI, NDWI, NDVI, Built-up-Index(BI), Soil Adjusted Vegetation Index (SAVI) and Urban Index (UI) [
11]. Thus [
10], states that if many variables are included in a linear regression model, the precision of the obtained dependent variable may be affected because of the clatter affected by the collinearity of explanatory factors. Environment predictions are as valuable as they are reliable but hints that a means to estimate LST correctly without errors due to collinearity need to be found first.
To predict changes in LULC and urban expansion, Markov Chain Models have been used [
6,
12]. For example [
9], a Markov Chain analysis for Doha, Qatar, indicated that a 20% rise in built-up areas by 2020 could be expected. Global and local model are widely used to predict temperature excluding urban trend and considering their impact [
13,
14]. These models are not very fit for understanding regional phenomena as they are at a coarse resolution and therefore need more downscaling [
15]. In addition, temperature changes induced by greenhouse gasses are emphasized by global and regional models notwithstanding temperature variations due to the impact of LULC changes. Markov Chain dependent modeling offers an ability to forecast the transition of the environment, offering insights into potential thermal surface characteristics due to vegetation changes [
10]. The research is ideal for forecasting variations in temperature at the same spatio-temporal resolution with seasonal variations in land-use land-cover patterns, hence is able to model regional processes such as urban surface dynamics. The Markov Chain model provides tremendous potential for forecasting future LST that needs to be further explored because of earlier achievements in measuring land use land cover shifts relevant effects, usability, flexibility and parsimony. This study is significant for giving direction on how thermal city environments can be projected into future based on the historical patterns of urban development. Much research from various parts of the globe suggest that urbanization contributes to changes in LST but Pakistan still lacks a literature on this issue. The country’s meteorological research have largely used large-scale climate models and in situ meteorological data, focused on precipitation and typically targets agricultural impacts [
16,
17,
18]. Remote sensing-based climate research, however, has remained scarce in the region, particularly at the scale of urban microclimates. The same time, urban development estimates based on remote sensing have concentrated mainly on quantifying recent shifts in LULC over the long term [
12].
Many of the communities are growing horizontally and vertically in core markets across the world [
19]. Pakistan and specially Faisalabad, do not have a suitable LULC management structure. Recently related urbanization to historical first patterns by means of multi-temporal and spectral Landsat datasets then did not forecast potential developments and their effects on the Faisalabad microclimate. Therefore, to the best of our understanding, predictions of potential population development rates, urban land use designs and its impact on LST based on RS (Remote Sensing) have not yet been produced in Pakistan. Therefore, it is important to predict urban development and consequences for the thermal climate of Pakistani cities with information utilizing remote sensing datasets at medium resolution. This has potential to promote local-level adaptation processes, strengthen the decision related to temperature and boost balanced city development that combines possible micro-climate effects of LULC conversions.
Environmental growth is a troubling problem in developing countries like Pakistan. Pakistan has not made a smooth urban transition due to many factors and one of them is the fact that sustainability has not been a consideration. Thus, research on urbanization, urban expansion and the expansion rate is very important for the economic development of Faisalabad and of great interest to the numerous government authorities, town planners and urban scholars around the globe. Regional policy makers and community planners can profit optimally from the work on sustainable expansion. Such research is particularly necessary in order to decide the borders of the new developments and understand urban sprawl across the Faisalabad region. Rapid urbanization has affected the agricultural land and land use patterns generating problems worldwide. Faisalabad Pakistan is not an exception.
The present research identifies seasonal landcover-indices using Landsat 5, 7 and 8 data representing correlations between seasonal (summer and winter) Land Surface Temperature (LST) and seasonal (summer and winter) Land Use Land Cover (LULC) changes in Faisalabad, Punjab, Pakistan from 1990 to 2018. The study also identified the specific indices most suited for prediction of the seasonal distribution of Land Use Land Cover and LST using the CA-Markov-Chain. A further objective was to use seasonal images of summer (May) and winter (November) in land cover indices instead of single season as used in earlier studies when modeling seasonal patterns of land cover as input in the Cellular Automata Markov model.
4. Discussion
In this research and Cellular Automata Markov Chain models were developed for prediction of seasonal land use landcover and seasonal LST in Faisalabad, Pakistan. The predictive ability of a number of indices for landcover were assessed in relation spatio-temporal temperature. Among a number of indices such as NDBI, FVG and NDVI, the UI was considered as the prior index for predicting LST distribution. Urban expansion and spatiotemporal temperature were predicted by using linear regression model. When the projected variables are not related to each other, it is appropriate to use multiple linear regression [
10,
54]. Through a diagnosis analysis, all predictors were correlated hence we found that UI provided the most robust temperature explanation. We used the UI as a reference for urbanization and its projected spread to model possible types of LST spread. The model projected temperature with an absolute average error of 1.85 °C by comparing LST computed from thermal band and linear model using UI. UI‘s success in projecting urban development based heating can be clarified by recent research that have found it to be closely associated with a number of urban expansion metrics [
55]. For example [
55], observed UI increased with building density and decreased with NDVI in Tokyo Bay.
While the association between temperature and UI has not been verified in earlier research, the strong predictive strength found in this analysis is attributed to elevated temperatures in areas with HDR and less vegetation. [
54] also reported strong urban indices in water-intensive and residential parts of Sri Lanka and Colombo. Research have also revealed that the use of water and household energy rises with the intensity of urban weather, thus the strong association between UI and LST [
3]. Given the complexity of urban LULC spread, the SVM is a high accuracy classifier tested both in 1990 and 2018. The study of Reference [
25] also shows that the SVM classifier can generate high-precision maps. The high accuracy of the map is related to the use of relevant digitized areas (rather than points) as ground data for classification, so its accuracy exceeds the standard 80% [
26].
The derived maps of seasonal LULC showed that residential areas grew while vegetation and water cover declined in the same region between 1990 and 2018, which is compatible with previous studies [
56]. The CA-Markov-Chain reliably predicts seasonal land use land cover types as showed by the strong consensus between the projected map of the year 2018 and the map prepared from the supervised rating. Based on variations in seasonal LULC between 1990 and 2018, the CA-Markov Chain predicted that unless other measures such as green spaces, cropland and water are implemented and identical trends exist, coverage of built-up area will tend to grow until 2048 at the cost of landcover. This conclusion is aligned with global projections that human growth would continue to grow at the cost of green space resulting in development of built-up areas [
6,
12]. The lowest temperature level region is predicted to decrease in this summer and winter study, whilst the region protected by warmer categories such as 36–42 °C and 26–32 °C is anticipated to increase. In addition to seasonal changes in LULC distribution, the increasing trends would see residential areas expand to the detriment of green spaces and water. The predicted temperature increases due to changes in urban development demonstrated by the land use land cover are also consistent with earlier research [
4].